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Bromine atom (Br) reactions lead to ozone depletion in the troposphere and stratosphere. Photodegradation of bromocarbons is one of the main sources of bromine atoms in the atmosphere. Here, we use high-level ab initio methods, including spin–orbit effects, to study the photodissociation of the CH2Br radical. All possible fragmentation pathways, namely CH2Br + hν → CH2 + Br, HCBr + H, and CBr + H2, have been analyzed. Potential-energy curves of the ground and several excited electronic states along the corresponding dissociating bond distance of each pathway have been calculated. Considering the actinic fluxes of solar irradiation in the troposphere and in the stratosphere in the relevant range of frequencies, it is found that the first five excited states of CH2Br can be accessed from the ground state. Analysis of the potential curves shows that the pathways producing CH2 + Br and HCBr + H can proceed through a fast direct dissociation mechanism, while the pathway leading to CBr + H2 involves much slower dissociation mechanisms like internal conversion between electronic states, predissociation, or tunneling through exit barriers. The main implications are that the two faster channels are predicted to be dominant, and the slower pathway is expected to be less relevant. The tropospheric and stratospheric solar actinic fluxes also allow for further dissociation of the HCBr and CBr fragments, generating additional Br atoms, provided that they survive possible collisions with other atmospheric reagents. Finally, we discuss the possible effect of each of the three CH2Br dissociation pathways on the depletion of atmospheric ozone. [ABSTRACT FROM AUTHOR]

• Direct and indirect climate impacts of solid waste landfills in California were quantified. • Direct impacts were positive and high whereas indirect impacts were negative and low. • Cover characteristics including material type and areal extent control climate impacts. • Global warming potential time horizon significantly influences climate impact results. • Integration of direct and indirect impacts advances landfill climate mitigation strategies. Climate impacts of landfill gas emissions were investigated for 20- and 100-year time horizons to identify the effects of atmospheric lifetimes of short- and long-lived drivers. Direct and indirect climate impacts were determined for methane and 79 trace species. The impacts were quantified using global warming potential, GWP (direct and indirect); atmospheric degradation (direct); tropospheric ozone forming potential (indirect); secondary aerosol forming potential (indirect) and stratospheric ozone depleting potential (indirect). Effects of cover characteristics, landfill operational conditions, and season on emissions were assessed. Analysis was conducted at five operating municipal solid waste landfills in California, which collectively contained 13% of the waste in place in the state. Climate impacts were determined to be primarily due to direct emissions (99.5 to 115%) with indirect emissions contributing −15 to 0.5%. Methane emissions were 35 to 99% of the total emissions and the remainder mainly greenhouse gases (hydro)chlorofluorocarbons (up to 42% of total emissions) and nitrous oxide. Cover types affected emissions, where the highest emissions were generally from intermediate covers with the largest relative landfill surface areas. Landfill-specific direct emissions varied between 683 and 103,411 and between 381 and 37,925 Mg CO 2 -eq./yr for 20- and 100-yr time horizons, respectively. Total emissions (direct + indirect) were 680 to 103,600 (20-yr) and were 374 to 38,108 (100-yr) Mg CO 2 -eq./yr. Analysis time horizon significantly affected emissions. The 20-yr direct and total emissions were consistently higher than the 100-yr emissions by up to 2.5 times. Detailed analysis of time-dependent climate effects can inform strategies to mitigate climate change impacts of landfill gas emissions. [ABSTRACT FROM AUTHOR]

A ground-based 110 GHz radiometer was designed to measure the stratospheric ozone vertical profile by observing the 110.836 GHz ozone emission spectrum and the instrument has been operational at Sookmyung Women's University (37.54° N, 126.97° E) in Seoul, Korea. In this paper, we detail the instrumental design, calibration procedures, correction methods, and the retrieved ozone vertical profile. The instrument is a heterodyne total power radiometer. It down-converts the observed 110.836 GHz ozone frequency to 0.609 GHz, with a frequency resolution of 61 kHz and a bandwidth of 800 MHz. The spectral intensity is digitized using a fast Fourier transform spectrometer. For hot-cold calibration, we use microwave absorbers at room temperature and liquid nitrogen as calibration targets. Tropospheric opacity is corrected using the continuous tipping curve calibration. The measured opacities were compared with simulated values from the Korea Local Analysis and Prediction System (KLAPS) data. Additionally, since 2016, the stratospheric ozone profiles over Seoul have been demonstrated for the vertical range of 100 hPa – 0.3 hPa (16 km–70 km) with validation performed by comparing them to the ozone profiles from the MLS on AURA satellite. [ABSTRACT FROM AUTHOR]

The Permo-Triassic mass extinction was linked to catastrophic environmental changes and large igneous province (LIP) volcanism. In addition to the widespread marine losses, the Permo–Triassic event was the most severe terrestrial ecological crisis in Earth's history and the only known mass extinction among insects, but the cause of extinction on land remains unclear. In this study, high-resolution Hg concentration records and multiple-archive S-isotope analyses of sediments from the Junggar Basin (China) provide evidence of repeated pulses of volcanic-S (acid rain) and increased Hg loading culminating in a crisis of terrestrial biota in the Junggar Basin coeval with the interval of LIP emplacement. Minor S-isotope analyses are, however, inconsistent with total ozone layer collapse. Our data suggest that LIP volcanism repeatedly stressed end-Permian terrestrial environments in the ~300 kyr preceding the marine extinction locally via S-driven acidification and deposition of Hg, and globally via pulsed addition of CO2. S-isotope and Hg geochemistry across the terrestrial Permian–Triassic mass extinction (252 Ma) provides evidence of repeated volcanic eruptions over ~300 kyr that drove acidification and poisoning of a palaeo-lacustrine ecosystem in northwest China. [ABSTRACT FROM AUTHOR]

It was recently suggested that the Sun could switch to a high‐activity regime which would lead to a rise of ultraviolet radiation with an amplitude of about four times larger than the amplitude of an average solar activity cycle and a simultaneous drop in total solar irradiance. Here, we applied the SOCOLv3‐MPIOM model with an interacting ocean to simulate the response of chemistry, dynamics, and temperature of Earth's atmosphere to such a change in solar irradiance. We studied the effect of high activity regime on the atmosphere investigating the influence of the chemical and radiative processes on the climate, and chemistry of NOx, HOx, and O3. We find a climate cooling by up to 1K and a substantial increase in stratospheric ozone (up to 14%) and total ozone (up to 8%). To understand the role of the different processes we performed simulations with two sets of forcing accounting separately for the influence on chemical processes and for direct radiation energy balance. Our calculations show that the stratospheric O3 response is almost fully driven by the chemical processes. We also found that the direct radiation processes lead to near‐surface cooling that results in the suppression of the Brewer‐Dobson circulation. This, in turn, leads to the reduction of H2O influx from the low layers of the troposphere and to less intensive transport of ozone from the tropics to the middle latitudes. The surface climate response is dominated by direct radiation influence with only a small contribution from chemical processes. Plain Language Summary: It was recently suggested that activity of the Sun could significantly rise which would lead to a rise of ultraviolet radiation and a simultaneous drop in total solar irradiance. In this study, we modeled the response of chemistry, dynamics, and temperature of Earth's atmosphere to such a change in solar irradiance. We studied the effect of high activity regime on the atmosphere investigating the influence of the chemical and radiative processes on the climate, and chemistry. We find a climate cooling by up to 1K and a substantial increase in stratospheric ozone (up to 14%) and total ozone (up to 8%). Our calculations show that the stratospheric ozone response is almost fully driven by the chemical processes. We also found that the direct radiation processes lead to near‐surface cooling that results in the suppression of the Brewer‐Dobson circulation. This, in turn, leads to the reduction of water vapor influx from the low layers of the troposphere and to less intensive transport of ozone from the tropics to the middle latitudes. The surface climate response is dominated by direct radiation influence with only a small contribution from chemical processes. Key Points: A switch of the Sun to a high activity regime would lead to a simultaneous increase of the UV irradiance and a drop of the longwave irradianceSolar UV changes control stratospheric ozone and temperature with only a small contribution from solar longwaveTropospheric climate is driven by direct changes in the surface radiation balance with no substantial contribution from the chemical processes [ABSTRACT FROM AUTHOR]

Large-scale meteorological events (e.g. cyclones), referred to as synoptic events, strongly influence weather predictability but still cannot be fully characterised in the Arctic region because of the sparse coverage of measurements. Due to the fact that atmospheric dynamics in the lower stratosphere and troposphere influence the ozone field, one approach to analyse these events further is the use of space-borne measurements of ozone vertical distributions and total columns in addition to conventional parameters such as pressure or wind speed. In this study we investigate the link between cyclones and changes in stratospheric ozone by using a combination of unique measurements during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) ship expedition, ozone profile and total column observations by satellite instruments (OMPS-LP, TROPOMI), and ERA5 reanalysis data. The final goal of the study is to assess whether the satellite ozone data can be used to obtain information about cyclones and provide herewith an additional value in the assimilation by numerical weather prediction models. Three special cases during the MOSAiC expedition were selected and classified for the analysis. They are one "normal" cyclone, where a low surface pressure coincides with a minimum in tropopause height, and two "untypical" cyclones, where this is not observed. The influence of cyclone events on ozone in the upper-troposphere lower-stratosphere (UTLS) region was investigated, using the fact that both are correlated with tropopause height changes. The negative correlation between tropopause height from ERA5 and ozone columns was investigated in the Arctic region for the 3-month period from June to August 2020. This was done using total ozone columns and sub-columns from TROPOMI, OMPS-LP, and MOSAiC ozonesonde data. The greatest influence of tropopause height changes on ozone contour levels occurs at an altitude between 10 and 20 km. Moreover, the lowering of the 250 ppb ozonopause (at about 11 km altitude) below 9 km was used to detect cyclones using OMPS-LP ozone observations. The potential of this approach was demonstrated in two case studies where the boundaries of cyclones could be determined using ozone observations. The results of this study can help improve our understanding of the relationship between cyclones, tropopause height, and ozone in the Arctic and demonstrate the usability of satellite ozone data in addition to the conventional parameters for investigating cyclones in the Arctic. [ABSTRACT FROM AUTHOR]

This article is devoted to the presentation of the MAP-IO observation program. This program, launched in early 2021, has enabled the observation of nearly 700 d of measurements over the Indian and Southern Ocean with the equipment of 17 meteorological and oceanographic scientific instruments on board the ship Marion Dufresne. Several observational techniques have been developed to respond to the difficulties of observations on board the ship, in particular for passive remote sensing data, as well as for quasi-autonomous data acquisition and transfer. The first measurements made it possible to draw up unprecedented climatological data of the Southern Ocean regarding the size distribution and optical thickness of aerosols, the concentration of trace gases and greenhouse gases, UV, and integrated water vapor. High-resolution observations of phytoplankton in surface waters have also shown a great variability in latitude in terms of abundance and community structure (diversity). The operational success of this program and these unique scientific results together establish a proof of concept and underline the need to transform this program into a permanent observatory. The multi-year rotations over the Indian Ocean will enable us to assess the trends and seasonal variability of phytoplankton, greenhouse gases, ozone, and marine aerosols in a sensitive and poorly documented climatic region. Without being exhaustive, MAP-IO should make it possible to better understand and assess the biological carbon pump, to study the variability of gases and aerosols in a region that is remote in relation to the main anthropogenic sources, and to monitor the transport of stratospheric ozone by the Brewer–Dobson circulation. The meteorological MAP-IO data set is publicly available at https://www.aeris-data.fr/catalogue-map-io/ (last access: 26 August 2024) (atmospheric data) and at 10.17882/89505 (phytoplankton data). [ABSTRACT FROM AUTHOR]

Solar proton events (SPEs) affect the Earth's atmosphere, causing additional ionization in the high-latitude mesosphere and stratosphere. Ionization rates from such solar proton events maximize in the stratosphere, but the formation of ozone-depleting nitrogen and hydrogen oxides begins at mesospheric altitudes. The destruction of mesospheric ozone is associated with protons with energies of about 10 MeV and higher and will strongly depend on the intensity of the flux of these particles. Most studies investigating the impact of SPEs on the characteristics of the middle atmosphere have been based on either simulations or reanalysis datasets, and some studies have used satellite observations to validate model results. We study the impact of SPEs on cold-season ozone loss in both the northern and southern hemispheres using Aura MLS mesospheric ozone measurements over the 2004 to 2024 period. Here, we show how strongly SPEs can deplete polar mesospheric ozone in different hemispheres and attempt to evaluate this dependence on the intensity of solar proton events. We found that moderate SPEs consisting of protons with an energy of more than 10 MeV and a flux intensity of more than 100 pfu destroy mesospheric ozone in the northern hemisphere up to 47% and in the southern hemisphere up to 33%. For both hemispheres, the peak of winter ozone loss was observed at about 76 km. In the northern hemisphere, maximum winter ozone loss was observed on the second day after a solar proton event, but in the southern hemisphere, winter ozone depletion was already detected on the first day. In the southern hemisphere, mesospheric ozone concentrations return to pre-event levels on the ninth day after a solar proton event, but in the northern hemisphere, even on the tenth day after a solar proton event, the mesospheric ozone layer may not be fully recovered. The strong SPEs with a proton flux intensity of more than 1000 pfu lead to a maximum winter ozone loss of up to 85% in the northern hemisphere, and in the southern hemisphere winter, ozone loss reaches 73%. [ABSTRACT FROM AUTHOR]

The pursuit of climate action to meet net-zero targets has triggered the call for a global energy transition from fossil fuels to clean energy sources. However, this global energy transition does not entirely recognise all countries' social, economic and technological capacities as well as emission contributions as envisaged under the Common but Differentiated Responsibilities (CBDR) principle, which underlies international climate policy. It is concerned more with the outcome of transitioning to clean energy than with justice in the transition process. Recognition justice, an element of energy justice, enables us to identify the inequalities that global energy paradigms (such as the energy transition) can create and how a justice framework can help us understand the implications of energy injustice and address the inequities across energy systems. Recognition justice acknowledges the divergent perspectives rooted in social, economic and racial differences and the varied strengths of developed and developing countries. The energy transition process ought to recognise these differences so that they are reasonably expected to benefit everyone. Implementing the energy transition in the Global South (GS) in the same way as it is being advanced in the Global North will have security, justice, economic, resource-stranding, and sustainable development implications. This issue (of injustice in the energy transition) is aggravated by two dichotomous realities: many countries in the South will be most impacted by climatic changes, yet there remains political and social opposition to climate action through the energy transition. As a solution, this paper relies on the notion of recognition justice with support from the Rawlsian justice concept to argue that a delayed transition represents justice and recognises the peculiar nature and different circumstances of the GS. It identifies that learnings from the Kigali Amendment to the Montreal Protocol on Substances that Deplete the Ozone Layer and the notion of CBDR under international climate treaties can be mainstreamed into energy transition research and policies to achieve justice for countries of the GS. The paper further finds that a delayed transition for the GS will (i) enable the region to address sustainability-related issues of hunger and multidimensional poverty, essential to realising other Sustainable Development Goals, whilst gradually implementing energy transition policies; (ii) present an attractive case against political and social opposition to energy transition in the GS; (iii) advance the goal of CBDR already recognised under international climate treaties and the bifurcated approaches established in such treaties; and, finally, (iv) ensure that developed countries contributing the most to greenhouse gas emissions take the lead now and act while the GS effectuates national contributions sustainably. [ABSTRACT FROM AUTHOR]

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The tropospheric hydroxyl (TOH) radical is a key player in regulating oxidation of various compounds in Earth's atmosphere. Despite its pivotal role, the spatiotemporal distributions of OH are poorly constrained. Past modeling studies suggest that the main drivers of OH, including NO 2 , tropospheric ozone (TO 3), and H 2 O(v), have increased TOH globally. However, these findings often offer a global average and may not include more recent changes in diverse compounds emitted on various spatiotemporal scales. Here, we aim to deepen our understanding of global TOH trends for more recent years (2005–2019) at 1×1 °. To achieve this, we use satellite observations of HCHO and NO 2 to constrain simulated TOH using a technique based on a Bayesian data fusion method, alongside a machine learning module named the Efficient CH 4 -CO-OH (ECCOH) configuration, which is integrated into NASA's Goddard Earth Observing System (GEOS) global model. This innovative module helps efficiently predict the convoluted response of TOH to its drivers and proxies in a statistical way. Aura Ozone Monitoring Instrument (OMI) NO 2 observations suggest that the simulation has high biases for biomass burning activities in Africa and eastern Europe, resulting in a regional overestimation of up to 20 % in TOH. OMI HCHO primarily impacts the oceans, where TOH linearly correlates with this proxy. Five key parameters, i.e., TO 3 , H 2 O(v), NO 2 , HCHO, and stratospheric ozone, can collectively explain 65 % of the variance in TOH trends. The overall trend of TOH influenced by NO 2 remains positive, but it varies greatly because of the differences in the signs of anthropogenic emissions. Over the oceans, TOH trends are primarily positive in the Northern Hemisphere, resulting from the upward trends in HCHO, TO 3 , and H 2 O(v). Using the present framework, we can tap the power of satellites to quickly gain a deeper understanding of simulated TOH trends and biases. [ABSTRACT FROM AUTHOR]

We calculate the climate forcing for the 2 ys after the 15 January 2022, Hunga Tonga‐Hunga Ha'apai (Hunga) eruption. We use satellite observations of stratospheric aerosols, trace gases and temperatures to compute the tropopause radiative flux changes relative to climatology. Overall, the net downward radiative flux decreased compared to climatology. The Hunga stratospheric water vapor anomaly initially increases the downward infrared radiative flux, but this forcing diminishes as the anomaly disperses. The Hunga aerosols cause a solar flux reduction that dominates the net flux change over most of the 2 yrs period. Hunga induced temperature changes produce a decrease in downward long‐wave flux. Hunga induced ozone reduction increases the short‐wave downward flux creating small sub‐tropical increase in total flux from mid‐2022 to 2023. By the end of 2023, most of the Hunga induced radiative forcing changes have disappeared. There is some disagreement in the satellite measured stratospheric aerosol optical depth (SAOD) observations which we view as a measure of the uncertainty; however, the SAOD uncertainty does not alter our conclusion that, overall, aerosols dominate the radiative flux changes. Plain Language Summary: The Hunga Tonga‐Hunga Ha'apai (Hunga) submarine volcanic eruption on 15 January 2022, produced aerosol and water vapor plumes in the stratosphere. These plumes have persisted mostly in the Southern Hemisphere throughout 2022 and into 2023. Enhanced tropospheric warming due to the added stratospheric water vapor is offset by the larger stratospheric aerosol attenuation of solar radiation. Hunga induced circulation changes that reduce stratospheric ozone and lower temperatures also play a role in the net forcing. The change in the radiative flux would result in a very slight 2022/3 cooling in Southern Hemisphere. The Hunga climate forcing has decreased to near zero by the end of 2023. Key Points: The 15 Jan. 2022, Hunga eruption increased aerosols and H2O in the southern hemisphere stratosphere and then dispersed throughout 2022/3Stratospheric water vapor, ozone, temperature, and aerosol optical depth contribute to the change in downward radiative fluxesHunga produced a global decrease in radiative of less than ∼0.25 W/m2 over the 2 yrs period [ABSTRACT FROM AUTHOR]

The Stratospheric Total Aerosol Counter (STAC) is a lightweight balloon‐borne instrument that utilizes condensational growth techniques to measure the total aerosol concentration. STAC is a miniaturized version of the legacy Wyoming condensation particle counter that operated from 1974 through 2020 in the middle latitudes and polar regions, with a few measurements in the tropics. Here we provide a description of the STAC instrument and the total aerosol measurement record, demonstrating that typical total aerosol profiles exhibit a peak in number mixing ratio, with values between 800 and 2,000 particles per mg of air (mg−1), just below the lapse rate tropopause (LRT). In the tropics and middle latitudes, mixing ratios decrease above the LRT likely due to coagulation and scavenging that results in a transfer of mass to the fewer but larger aerosol particles of the Junge layer. Exceptions to this occur in the spring time in the middle latitudes where a new particle layer between 20 and 25 km is frequently observed. In the poles, total aerosol profiles exhibit two distinct features: new particle formation in austral spring, and an increasing mixing ratio above 17 km likely due to the presence of meteoric smoke that has been concentrated within the polar vortex. High observed stratospheric particle mixing ratios, in excess of 2,000 mg−1, are observed in the polar new particle layer and at the top of polar profiles. Plain Language Summary: Particles in the stratosphere range in size from a few nanometers to many micrometers in diameter. These particles are important to the radiation balance of Earth as well as chemical processes that occur in the atmosphere. Particles with diameters greater than about 50 nm are detectable by a wide variety of scientific instruments using various techniques to measure light scattered by the particles. Particles smaller than this need to be grown to larger diameters before their concentration can be measured, and therefore these measurements must be done in situ. This paper describes the design and capabilities of an instrument, the Stratospheric Total Aerosol Counter, that makes in situ measurements from high‐altitude balloons of the total aerosol concentration. Versions of this instrument have been flown around the globe since 1974. The second portion of this paper provides an overview of the total aerosol concentration record since 1989, comprising more than 250 profiles. The key findings are that in tropical regions there is a significant source of particles from the total aerosol concentration maximum at the top of the troposphere. In polar regions, a significant source of particles is from meteorites burning up when they strike the Earth's atmosphere. Key Points: The hardware and operation of a balloon‐borne Stratospheric Total Aerosol Counter (STAC) is detailed for measurements in the lower and middle stratosphereSome of the highest total aerosol mixing ratios are found in the polar mid‐stratosphere suggesting an under appreciation of this region's importanceVolcanic injections of sulfur have minimal impact on the total aerosol concentration, but significantly increase the mass of larger aerosol [ABSTRACT FROM AUTHOR]

It remains unresolved whether the La Niña-like sea surface temperature (SST) trend pattern during the satellite era, featuring a distinct warming in the northwest/southwest Pacific but cooling in the tropical eastern Pacific, is driven by either external forcing or internal variability. Here, by conducting a comprehensive analysis of observations and a series of climate model simulations for the historical period, we show that a combination of internal variability and human activity may have shaped the observed La Niña-like SST trend pattern. As in observations, SSTs in each model ensemble member show a distinct multi-decadal swing between El Niño-like and La Niña-like trend patterns due to internal variability. The ensemble-mean trends for some models are, however, found to exhibit an enhanced zonal SST gradient along the equatorial Pacific over periods such as 1979–2010, suggesting a role of external forcing. In line with this hypothesis, single-forcing large ensemble model simulations show that human-induced stratospheric ozone depletion and/or aerosol changes have acted to enhance the zonal SST gradient via strengthening of Pacific trade winds, although the effect is model dependent. Our finding suggests that the La Niña-like SST trend is unlikely to persist under sustained global warming because both the ozone and aerosol impacts will eventually weaken. [ABSTRACT FROM AUTHOR]

It has been widely reported that isoprene emissions from the Arctic ecosystem have a strong temperature response. Here we identify sedges (Carex spp. and Eriophorum spp.) as key contributors to this high sensitivity using plant chamber experiments. We observe that sedges exhibit a markedly stronger temperature response compared to that of other isoprene emitters and predictions by the widely accepted isoprene emission model, the Model of Emissions of Gases and Aerosols from Nature (MEGAN). MEGAN is able to reproduce eddy-covariance flux observations at three high-latitude sites by integrating our findings. Furthermore, the omission of the strong temperature responses of Arctic isoprene emitters causes a 20% underestimation of isoprene emissions for the high-latitude regions of the Northern Hemisphere during 2000-2009 in the Community Land Model with the MEGAN scheme. We also find that the existing model had underestimated the long-term trend of isoprene emissions from 1960 to 2009 by 55% for the high-latitude regions. The authors identify that sedges in the Arctic have a different isoprene temperature response than other temperate plants, and this finding explains the high temperature sensitivity of isoprene emissions from Arctic terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

New particle formation in the free troposphere is a major source of cloud condensation nuclei globally. The prevailing view is that in the free troposphere, new particles are formed predominantly in convective cloud outflows. We present another mechanism using global observations. We find that during stratospheric air intrusion events, the mixing of descending ozone-rich stratospheric air with more moist free tropospheric background results in elevated hydroxyl radical (OH) concentrations. Such mixing is most prevalent near the tropopause where the sulfur dioxide (SO2) mixing ratios are high. The combination of elevated SO2 and OH levels leads to enhanced sulfuric acid concentrations, promoting particle formation. Such new particle formation occurs frequently and over large geographic regions, representing an important particle source in the midlatitude free troposphere. [ABSTRACT FROM AUTHOR]

Australian mega-wildfires in the summer of 2019-2020 injected smoke into the stratosphere, causing strong ozone depletion in the lower stratosphere. Here, we model the smoke plume and reproduce its unexpected trajectory toward the middle stratosphere at ~35-kilometer altitude. We show that a smoke-charged vortex (SCV) induced and maintained by absorbing aerosols played a key role in lofting pollutants from the lower stratosphere and nearly doubled the southern hemispheric aerosol burden in the middle stratosphere. The SCV caused a redistribution of stratospheric aerosols, which boosted heterogeneous chemistry in the middle stratosphere and enhanced ozone production, compensating for up to 70% of the ozone depletion in the lower stratosphere. As global warming continues, we expect a growing frequency and importance of SCVs in promoting the impacts of wildfires on stratospheric aerosols and chemistry. [ABSTRACT FROM AUTHOR]

The hyperspectral SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument, launched by Envisat in March 2002, measures atmospheric scattered radiance within the ultraviolet (UV) to near infrared range and has three geometric observation modes: nadir, occultation, and limb. This study describes a retrieval scheme to obtain middle and upper stratospheric ozone profiles from SCIAMACHY limb-scattered solar radiance. Owing to the low ozone concentration at high altitudes and rapid changes in ozone absorption cross-sections in the Hartley – Huggins band, a fundamental objective of this study was to establish a simple and effective retrieval scheme to derive reliable ozone profiles at high altitudes from UV spectral bands. In this study, short UV wavelengths of 302, 312, and 322 nm and a long wavelength of 331 nm were used for wavelength pairing to simplify the retrieval algorithm. Moreover, we employed the weighted multiplicative algebraic reconstruction technique (WMART), which is straightforward to understand, and easy to implement, combined with a radiative transfer model (i.e. SCIATRAN), and produced stable results. The retrieval error estimates for the upper stratosphere were provided, and the total retrieval error of the ozone profile was usually < 18% in the altitude range of 30–53 km. The results were compared with the SCIAMACHY v3.5 product and validated against profiles derived from Optical Spectrometer and InfraRed Imaging System (OSIRIS) v7.1, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) v4.0 for 30–53 km altitude. The retrieved ozone profiles agreed with data from SCIAMACHY v3.5 within − 10%–5%, except at an altitude of 45 km, where the bias became larger (approximately −15%). The comparison of retrieved profiles with OSIRIS v7.1 showed differences within ± 10% for 30–53 km altitude. The errors were mostly less than − 5% below 43 km compared with ACE-FTS v4.0, but there was a large negative deviation in the upper stratosphere. [ABSTRACT FROM AUTHOR]

The Sentinel-5 Precursor (S5P) satellite operated by the European Space Agency has carried the TROPOspheric Monitoring Instrument (TROPOMI) on a Sun-synchronous low-Earth orbit since 13 October 2017. The S5P mission has acquired more than 5 years of TROPOMI nadir ozone profile data retrieved from the level 0 to 1B processor version 2.0 and the level 1B to 2 optimal-estimation-based processor version 2.4.0. The latter is described in detail in this work, followed by the geophysical validation of the resulting ozone profiles for the period May 2018 to April 2023. Comparison of TROPOMI ozone profile data to co-located ozonesonde and lidar measurements used as references concludes to a median agreement better than 5 % to 10 % in the troposphere. The bias goes up to - 15 % in the upper stratosphere (35–45 km) where it can exhibit vertical oscillations. The comparisons show a dispersion of about 30 % in the troposphere and 10 % to 20 % in the upper troposphere to lower stratosphere and in the middle stratosphere, which is close to mission requirements. Chi-square tests of the observed differences confirm on average the validity of the ex ante (prognostic) satellite and ground-based data uncertainty estimates in the middle stratosphere above about 20 km. Around the tropopause and below, the mean chi-square value increases up to about four, meaning that the ex ante TROPOMI uncertainty is underestimated. The information content of the ozone profile retrieval is characterised by about five to six vertical subcolumns of independent information and a vertical sensitivity (i.e. the fraction of the information that originates from the measurement) nearly equal to unity at altitudes from about 20 to 50 km, decreasing rapidly at altitudes above and below. The barycentre of the retrieved information is usually close to the nominal retrieval altitude in the 20–50 km altitude range, with positive and negative offsets of up to 10 km below and above this range, respectively. The effective vertical resolution of the profile retrieval usually ranges within 10–15 km, with a minimum close to 7 km in the middle stratosphere. Increased sensitivities and higher effective vertical resolutions are observed at higher solar zenith angles (above about 60°), as can be expected, and correlate with higher retrieved ozone concentrations. The vertical sensitivity of the TROPOMI tropospheric ozone retrieval is found to depend on the solar zenith angle, which translates into a seasonal and meridian dependence of the bias with respect to reference measurements. A similar although smaller effect can be seen for the viewing zenith angle. Additionally, the bias is negatively correlated with the surface albedo for the lowest three ozone subcolumns (0–18 km), despite the albedo's apparently slightly positive correlation with the retrieval degrees of freedom in the signal. For the 5 years of TROPOMI ozone profile data that are available now, an overall positive drift is detected for the same three subcolumns, while a negative drift is observed above (24–32 km), resulting in a negligible vertically integrated drift. [ABSTRACT FROM AUTHOR]

This paper describes the addition of a stratospheric prognostic aerosol (SPA) capability – developed with the goal of accurately simulating sulfate aerosol formation and evolution in the stratosphere – in the Department of Energy (DOE) Energy Exascale Earth System Model, version 2 (E3SMv2). The implementation includes changes to the four-mode Modal Aerosol Module microphysics in the stratosphere to allow for larger particle growth and more accurate stratospheric aerosol lifetime following the Pinatubo eruption. E3SMv2-SPA reasonably reproduces stratospheric aerosol lifetime, burden, aerosol optical depth, and top-of-atmosphere flux when compared to remote sensing observations. E3SMv2-SPA also has close agreement with the interactive chemistry–climate model CESM2-WACCM (Community Earth System Model version 2–Whole Atmosphere Community Climate Model) – which has a more complete chemical treatment – and the observationally constrained, prescribed volcanic aerosol treatment in E3SMv2. Global stratospheric aerosol size distributions identify the nucleation and growth of sulfate aerosol from volcanically injected SO 2 from both major and minor volcanic eruptions from 1991 to 1993. The modeled aerosol effective radius is consistently lower than satellite and in situ measurements (max differences of ∼ 30 %). Comparisons with in situ size distribution samples indicate that this simulated underestimation in both E3SMv2-SPA and CESM2-WACCM is due to overly small accumulation and coarse-mode aerosols 6–18 months post-eruption, with E3SMv2-SPA simulating ∼ 50 % of the coarse-mode geometric mean diameters of observations 11 months post-eruption. Effective radii from the models and observations are used to calculate offline scattering and absorption efficiencies to explore the implications of smaller simulated aerosol size for the Pinatubo climate impacts. Scattering efficiencies at wavelengths of peak solar irradiance (∼ 0.5 µ m) are 10 %–80 % higher for daily samples in models relative to observations through 1993, suggesting higher diffuse radiation at the surface and a larger cooling effect in the models due to the smaller simulated aerosol; absorption efficiencies at the peak wavelengths of outgoing terrestrial radiation (∼ 10 µ m) are 15 %–40 % lower for daily samples in models relative to observations, suggesting an underestimation in stratospheric heating in the models due to the smaller simulated aerosol. These potential biases are based on aerosol size alone and do not take into account differences in the aerosol number. The overall agreement of E3SMv2-SPA with observations and its similar performance to the well-validated CESM2-WACCM makes E3SMv2-SPA a viable alternative to simulating climate impacts from stratospheric sulfate aerosols. [ABSTRACT FROM AUTHOR]

Ground-level ozone (O3) pollution has emerged as a significant concern impacting air quality in urban agglomerations, primarily driven by meteorological conditions and social-economic factors. However, previous studies have neglected to comprehensively reveal the spatial distribution and driving mechanism of O3 pollution. Based on the O3 monitoring data of 41 cities in the Yangtze River Delta (YRD) from 2014 to 2021, a comprehensive analysis framework of spatial analysis-spatial econometric regression was constructed to reveal the driving mechanism of O3 pollution. The results revealed the following: (1) O3 concentrations in the YRD exhibited a general increasing and then decreasing trend, indicating an improvement in pollution levels. The areas with higher O3 concentration are mainly the cities concentrated in central and southern Jiangsu, Shanghai, and northern Zhejiang. (2) The change of O3 concentration and distribution is the result of various factors. The effect of urbanization on O3 concentrations followed an inverted U-shaped curve, which implies that achieving higher quality urbanization is essential for effectively controlling urban O3 pollution. Traffic conditions and energy consumption have significant direct positive influences on O3 concentrations and spatial spillover effects. The indirect pollution contribution, considering economic weight, accounted for about 35%. Thus, addressing overall regional energy consumption and implementing traffic source regulations are crucial paths for O3 pollution control in the YRD. (3) Meteorological conditions play a certain role in regulating the O3 concentration. Higher wind speed will promote the diffusion of O3 and increase the O3 concentration in the surrounding city. These findings provide valuable insights for designing effective policies to improve air quality and mitigate ozone pollution in urban agglomeration area. [ABSTRACT FROM AUTHOR]

Anthropogenic perturbations from fossil fuel burning, nuclear bomb testing, and chlorofluorocarbon (CFC) use have created useful transient tracers of ocean circulation. The atmospheric 14C/C ratio (∆14C) peaked in the early 1960s and has decreased now to pre‐industrial levels, while atmospheric CFC‐11 and CFC‐12 concentrations peaked in the early 1990s and early 2000s, respectively, and have now decreased by 10%–20%. We present the first analysis of a decade of new observations (2007 to 2018–2019) and give a comprehensive overview of the changes in ocean ∆14C and CFC concentration since the WOCE surveys in the 1990s. Surface ocean ∆14C decreased at a nearly constant rate from the 1990–2010s (20‰/decade). In most of the surface ocean ∆14C is higher than in atmospheric CO2 while in the interior ocean, only a few places are found to have increases in ∆14C, indicating that globally, oceanic bomb 14C uptake has stopped and reversed. Decreases in surface ocean CFC‐11 started between the 1990 and 2000s, and CFC‐12 between the 2000–2010s. Strong coherence in model biases of decadal changes in all tracers in the Southern Ocean suggest ventilation of Antarctic Intermediate Water was enhanced from the 1990 to the 2000s, whereas ventilation of Subantarctic Mode Water was enhanced from the 2000 to the 2010s. The decrease in surface tracers globally between the 2000 and 2010s is consistently stronger in observations than in models, indicating a reduction in vertical transport and mixing due to stratification. Plain Language Summary: The ocean contains many dissolved gases that can be measured by sampling ocean water from ships. Some of these dissolved gases are changing over time because their atmospheric concentrations are changing. By measuring these changes in the ocean, we can learn about ocean transport and mixing, which is an important factor regulating climate change. We describe ocean measurements from the past three decades of radiocarbon in dissolved inorganic carbon, that was affected by nuclear bomb testing, and of chlorofluorocarbon gases, CFCs, that were banned in the 1990s due to their destructive effects on the ozone layer. The measurements show how their oceanic distributions have changed, as a result of their atmospheric histories and the patterns of ocean uptake and transport. By comparing the measurements with ocean models, we can identify biases in the models that affect how well future climate change can be predicted. In the most recent decade, the presence of all three tracers is shown to be decreasing in the upper ocean, a reversal of the preceding decades. Also in the most recent decade, the decrease in surface tracers is stronger in the observations than the models, suggesting a change to upper ocean mixing and stratification. Key Points: Recent trends in upper ocean Δ14C, pCFC‐11, and pCFC‐12 are negative, reflecting their decreasing atmospheric trendsIncreases in ∆14C are only observed in a few places over 2000–2010s, showing oceanic bomb 14C uptake has stopped and reversedModel‐data Δ14C and chlorofluorocarbon differences could be consistent with decadal ventilation changes and large‐scale stratification or model errors [ABSTRACT FROM AUTHOR]

The search is on for safer alternatives to fumigants like methyl bromide and phosphine, which harm the ozone layer and pose other risks. Ethyl formate is a promising candidate due to its potential antimicrobial and insecticidal action in stored products like date fruits. The susceptibility of date fruits to microbial spoilage is significantly influenced by factors such as moisture content, storage practices, and environmental conditions. In the present study, the in vitro antimicrobial effect of ethyl formate against three microbial species, namely Aspergillus niger F4, Mucor circinelloides YMM22, and Pseudomonas aeruginosa B1 was tested under laboratory conditions. In addition, two common date fruit varieties, semi-dry El-Wady I and the dry Frehi, were fumigated with ethyl formate alone in a laboratory-scale prototype and with a mixture of ethyl formate and CO2 at a semi-industrial scale prototype. Both varieties had an initial moisture content of around 13.40 and 12.48% for El-Wady I and Frehi, respectively. The fumigation was conducted using the optimal concentration of 70 mg/L air for 24 h incubation period. Fumigation with ethyl formate alone or in combination with CO2 significantly reduced the number of viable bacteria and fungi (CFU/g), but the potential for a combined effect with CO2 was not investigated. The percentages of reduction in the fungal count were 78.18 and 90.76% for Frehi and El-Wady I varieties, respectively in a semi-industrial scale prototype. Moreover, the percentages of reduction in the bacterial count were 53.31 and 65.20%, respectively for Frehi and El-Wady I varieties. Ethyl formate showed promise as a natural alternative to control microbial contamination of stored date fruits. Further research suggests that increasing fumigation duration or concentration could provide comprehensive control of microbial pathogens at all stages of development. [ABSTRACT FROM AUTHOR]

Dichlorodifluoromethane (CFC‐12) is an ozone‐depleting substance and potent greenhouse gas, which was required to be phased out after 2010 under the Montreal Protocol. CFC‐12 emissions need to be quantitatively traced. However, estimates of CFC‐12 emissions in China based on atmospheric inversions are unavailable after 2010. Here, using atmospheric observations at nine sites across China and inversion techniques, we quantify CFC‐12 emissions in China during 2011–2020 (on average 11.0 ± 0.6 Gg yr−1). The emissions derived from observations are 8.5 times larger than the previously reported inventories. Apart from emissions from eastern China revealed in previous studies, this study reveals that 71% of national total emissions were from other parts of China. Moreover, this study reconciled the global CFC‐12 emissions during 2011–2020: 28% were traced to China by this study, 9% of emissions were traced in previous studies, while 63% remain untraced, indicating the need for more regional emission inversion studies. Plain Language Summary: Chlorofluorocarbons (CFCs), well known as Freon, are damaging to the stratospheric ozone layer and are potent greenhouse gases. Dichlorodifluoromethane (CFC‐12; CCl2F2) is one of the major CFCs. The production and consumption of CFC‐12 are controlled under the regulations of the Montreal Protocol and have been phased out globally since 2010. As the largest developing country and once a major producer and consumer of CFC‐12, CFC‐12 emissions in China are of great interest. In this study, we quantified emissions of CFC‐12 in China during 2011–2020 based on atmospheric observations in a network of nine sites across China. We find that the emissions derived from atmospheric inversion are 8.5 times larger than the previous emission inventories estimated using production and consumption information, suggesting unaccounted‐for emissions occurring in China. Apart from emissions from eastern China revealed in previous studies, this study reveals that 71% of national total emissions were from other parts of China. The Chinese emissions of CFC‐12 accounted for 28% of global totals from 2011 to 2020. However, there is a big gap between the total CFC‐12 emission from China, western Europe, Australia, the United States, India, and global totals, suggesting that more regional atmospheric inversion estimates are encouraged. Key Points: China's Dichlorodifluoromethane (CFC‐12) emissions during 2011–2020 were quantified using atmospheric observations at nine sites across China and inverse modelingA quantitative depiction of spatial CFC‐12 emissions across China was provided by this study28% of global CFC‐12 emissions for 2011–2020 occurred in China, according to this study [ABSTRACT FROM AUTHOR]

Background Aims Methods Results Conclusion With growing interest in hair health, researchers are exploring aspects beyond the surface qualities of hair, such as its porous inner structure. While previous studies have focused on the effects of treatments such as perming and hair dying on hair porosity, less emphasis has been paid to the effects of harmful environmental factors such as ultraviolet (UV) rays and particulate matter on the porous nature of hair.The aim of this study was to bridge this gap by investigating how UV rays and particulate matter affect hair porosity in different ways. Our study could help elucidate how these external factors influence hair health and shed light on previously unknown aspects of hair porosity.Hair tresses were bleached, cut into 1 cm‐long sections, and stained with methylene blue. The sections were then irradiated with UV light or exposed to particulate matter.Bleached hair absorbed more methylene blue than normal hair. UV radiation‐induced hair porosity occurred at 3 h after irradiation and increased with time. Particulate matter alone did not affect the porosity of the damaged hair; however, in combination with UV irradiation, it substantially increased hair porosity.Environmental challenges such as a depleted ozone layer and increasing pollution may increase hair porosity, which can be prevented by maintaining healthy hair. [ABSTRACT FROM AUTHOR]

The depletion of the ozone layer over the last four decades has increased Earth's exposure to ultraviolet (UV) radiation, posing significant health risks. Indium‐Gallium‐Zinc‐Oxide (IGZO) phototransistors have emerged as promising UV detection candidates, boasting a wide bandgap (>3 eV), low off‐current, high on‐current, and stability. However, previous efforts to enhance the photoresponse of IGZO phototransistors focused on visible light absorption layers, neglecting UV detection. Here, zinc oxide (ZnO) nanoparticles (NPs) as an absorption layer in IGZO TFTs for UV phototransistors are introduced. IGZO/ZnO TFTs exhibit robust photoresponsivity for UV light below 360 nm, showcasing rejection ratios (Ruv / Rvis) of 20 258, 62 261, 193 649, and 401 582 for wavelengths of 360, 340, 320, and 300 nm, respectively. The combination of IGZO's wide bandgap with ZnO NPs proves effective for detecting UV light below 360 nm, even at low incident light intensities (15 µW cm−2). Enhanced photoresponse characteristics are confirmed via ultraviolet photoelectron spectroscopy. This research highlights the potential of IGZO materials for UV phototransistors and introduces a novel perspective on the utilization of an additional absorption layer traditionally employed for the conventional extension into the visible light range. [ABSTRACT FROM AUTHOR]

Large constellations of small satellites will significantly increase the number of objects orbiting the Earth. Satellites burn up at the end of service life during reentry, generating aluminum oxides as the main byproduct. These are known catalysts for chlorine activation that depletes ozone in the stratosphere. We present the first atomic‐scale molecular dynamics simulation study to resolve the oxidation process of the satellite's aluminum structure during mesospheric reentry, and investigate the ozone depletion potential from aluminum oxides. We find that the demise of a typical 250‐kg satellite can generate around 30 kg of aluminum oxide nanoparticles, which may endure for decades in the atmosphere. Aluminum oxide compounds generated by the entire population of satellites reentering the atmosphere in 2022 are estimated at around 17 metric tons. Reentry scenarios involving mega‐constellations point to over 360 metric tons of aluminum oxide compounds per year, which can lead to significant ozone depletion. Plain Language Summary: With ongoing plans for many constellations of small satellites, the number of objects orbiting the Earth is expected to continue increasing in the foreseeable future. At the end of service life, satellites are disposed into the atmosphere, burning up during the process and generating aluminum oxides, which are known to accelerate ozone depletion. The environmental impacts from the reentry of satellites are currently poorly understood. This paper investigates the oxidation process of the satellite's aluminum content during atmospheric reentry utilizing atomic‐scale molecular dynamics simulations. We find that the population of reentering satellites in 2022 caused a 29.5% increase of aluminum in the atmosphere above the natural level, resulting in around 17 metric tons of aluminum oxides injected into the mesosphere. The byproducts generated by the reentry of satellites in a future scenario where mega‐constellations come to fruition can reach over 360 metric tons per year. As aluminum oxide nanoparticles may remain in the atmosphere for decades, they can cause significant ozone depletion. Key Points: We present the first atomic‐scale molecular dynamics simulation of high‐temperature aluminum ablation during reentry from low‐Earth orbitThe amount of aluminum oxide nanoparticles generated is quantified and the accumulation in the atmosphere is estimatedThe long‐term accumulation of aluminum oxides from reentering satellites can cause significant ozone depletion [ABSTRACT FROM AUTHOR]

Perchlorate in the environment originates from both natural and anthropogenic sources. A previous study of a 300‐year Greenland ice core perchlorate record found that anthropogenic impact on environmental perchlorate became significant starting around 1980, while natural formation is the only significant source of environmental perchlorate prior to that. The study also found increased perchlorate deposition in the Arctic following certain volcanic eruptions and suggested that at least some volcanic eruptions could enhance natural perchlorate production. Here we compare the perchlorate record with the volcanic record from sulfate in the same Greenland ice core and find that only stratospheric eruptions—large eruptions injecting volcanic substances directly into the stratosphere—enhance perchlorate production. No contribution to naturally formed perchlorate is detected from non‐stratospheric eruptions. The high‐resolution ice core perchlorate data are used to quantify contributions from volcanic eruptions, non‐volcanic natural processes, as well as from human activities during different periods. For the location in the Arctic in the perchlorate Pre‐Anthropogenic Era (1701–1979), the magnitude (0.26 μg m−2 yr−1 on average) of perchlorate produced during sporadic stratospheric eruptions is comparable to that (0.23 μg m−2 yr−1) produced by non‐volcanic natural processes. In the Anthropogenic Era (1980–2006), the magnitude of both the volcanic and non‐volcanic natural perchlorate production is similar to the enhancement (0.29 μg m−2 yr−1) by human activities. Plain Language Summary: Perchlorate is widespread in the environment. In remote regions such as the Arctic, environmental perchlorate primarily comes from natural formation in the atmosphere from common‐place chemicals containing chlorine. Previously, we studied a 300‐year chronological perchlorate record from a Greenland ice core and found that, prior to 1980, perchlorate production was not affected by human activities. We also found that certain volcanic eruptions may increase the amount of perchlorate produced in the atmosphere and deposited in Greenland snow. In this study, we use the ice‐core perchlorate and sulfate data to determine that only very large eruptions can cause additional perchlorate to be formed in the atmosphere. On average, large volcanic eruptions contribute about 50% of perchlorate from all natural sources at this location in the Arctic. Since 1980, human activities have contributed approximately the same amount of perchlorate to the environment as that from all natural sources. Key Points: Atmospheric perchlorate formation is enhanced by only stratospheric volcanic eruptions, not by non‐stratospheric eruptionsVolcanic perchlorate in the Arctic is on average approximately 50% of all naturally produced perchlorate prior to 1980Contribution from anthropogenic activities since 1980 is approximately equal to that from natural perchlorate sources [ABSTRACT FROM AUTHOR]

A cloud‐resolved storm and chemistry simulation of a severe convective system in Oklahoma constrained by anvil aircraft observations of NOx was used to estimate the mean production of NOx per flash in this storm. An upward ice flux scheme was used to parameterize flash rates in the model. Model lightning was also constrained by observed lightning flash types and the altitude distribution of flash channel segments. The best estimate of mean NOx production by lightning in this storm was 80–110 mol per flash, which is smaller than many other literature estimates. This result is likely due to the storm having been a high flash rate event in which flash extents were relatively small. Over the evolution of this storm a moderate negative correlation was found between the total flash rate and flash extent and energy per flash. A longer‐term simulation at 36‐km horizontal resolution with parameterized convection was used to simulate the downwind transport and chemistry of the anvil outflow from the same storm. Convective transport of low‐ozone air from the boundary layer decreased ozone in the anvil outflow by up to 20–40 ppbv compared with the initial conditions, which contained stratospheric influence. Photochemical ozone production in the lightning‐NOx enhanced convective plume proceeded at a rate of 10–11 ppbv per day in the 9–11 km outflow layer over the 24‐hr period of downwind transport to the Southern Appalachians. Photochemical production plays a large role in the restoration of upper tropospheric ozone following deep convection. Plain Language Summary: Nitrogen oxides are important precursors for tropospheric ozone, an important greenhouse gas. The global amount of nitrogen oxides produced by lightning remains highly uncertain, primarily because of uncertainty in the amount produced per flash. In this paper we use an approach that involves cloud‐resolved modeling with chemistry, constrained by observed flash rates and aircraft measurements of nitrogen oxides, to make an estimate of the mean production per flash for an observed severe storm over Oklahoma. We estimate that the mean production rate was 80–110 mol per flash for this high flash rate storm, which is at the lower end of the range reported in the literature. We use a regional model to follow the outflow of the Oklahoma storm downwind to estimate the amount of ozone produced in the upper tropospheric outflow plume by the lightning‐generated nitrogen oxides. Our estimate is in the range found in previous studies, and we note that the ozone production by photochemistry is an important process in restoring upper tropospheric ozone following storms that lofted low values of ozone from the layer of air near the surface. Key Points: Mean lightning NOx production was 80–110 mol flash−1 for a high flash rate storm, based on a model constrained by flash and NOx observationsNet O3 production in the upper outflow of a high flash rate storm was at a rate of 10–11 ppbv day−1 during 24 hr of downwind transportProduction of O3 due to lightning NOx contributed to the recovery of upper tropospheric O3 following reductions due to convective transport [ABSTRACT FROM AUTHOR]

Polar stratospheric clouds (PSCs) form in polar regions, typically between 15 and 25 km above mean sea level, when the local temperature is sufficiently low. PSCs play an important role in the ozone chemistry and the dehydration and denitrification of the stratosphere. Lidars with a depolarization channel may be used to detect and classify different classes of PSCs. The main PSC classes are water ice, nitric acid trihydrate (NAT), and supercooled ternary solutions (STSs), the latter being liquid droplets consisting of water, nitric acid, and sulfuric acid. PSCs have been observed at the lidar observatory at Concordia Station from 2014 onward. The harsh environmental conditions at Concordia during winter render successful lidar operation difficult. To facilitate the operation of the observatory, several measures have been put in place to achieve an almost complete remote control of the system. PSC occurrence is strongly correlated with local temperatures and is affected by dynamics, as the PSC coverage during the observation season shows. PSC observations in 2021 are shown as an example of the capability and functionality of the lidar observatory. A comparison of the observations with the satellite-borne CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) lidar has been made to demonstrate the quality of the data and their representativeness for the Antarctic Plateau. [ABSTRACT FROM AUTHOR]

Over the past decade, surface ozone has emerged as a significant air pollutant in China, especially in the North China Plain (NCP). For effective ozone management in the NCP, it is crucial to accurately estimate the surface ozone levels and identify the primary influencing factors for ozone pollution in this region. This study utilized ozone precursors such as volatile organic compounds (VOCs) and nitrogen oxides (NOX), meteorological data, land cover, normalized difference vegetation index (NDVI), terrain, and population data to build an extreme gradient boosting (XGBoost)-based ozone estimation model in the NCP during 2019 to 2021. Four ozone estimation models were developed using different NO2 and formaldehyde (HCHO) datasets from the Sentinel-5 TROPOMI observations and Copernicus Atmosphere Monitoring Service (CAMS) reanalysis data. Site-based validation results of these four models showed high accuracy with R2 values above 0.86. Among these four models, two models with higher accuracy and higher spatial coverage ratio were selected, and their results were averaged to produce the final ozone estimation products. The results indicated that VOCs and NOX were the two main pollutants causing ozone pollution in the NCP, and their relative contributions accounted for more than 23.34% and 10.23%, respectively, while HCHO also played a significant role, contributing over 5.64%. Additionally, meteorological factors also had a notable impact, contributing 28.63% to ozone pollution, with each individual factor contributing more than 2.38%. The spatial distribution of ozone pollution identified the Hebei–Shandong–Henan junction as a pollution hotspot, with the peak occurring in summer, particularly in June. Therefore, for this hotspot region in the NCP, promoting the reduction in VOCs and NOx can play an important role in the mitigation of O3 pollution and the improvement in air quality in this region. [ABSTRACT FROM AUTHOR]

Previous research has shown that stratospheric aerosol causes only a small temperature change per unit forcing because they produce stronger cooling in the tropical Indian Ocean and the western Pacific Ocean than in the global mean. The enhanced temperature change in this so-called "warm-pool" region activates strongly negative local and remote feedbacks, which dampen the global mean temperature response. This paper addresses the question of why stratospheric aerosol forcing affects warm-pool temperatures more strongly than CO 2 forcing, using idealized MPI-ESM simulations. We show that the aerosol's enhanced effective forcing at the top of the atmosphere (TOA) over the warm pool contributes to the warm-pool-intensified temperature change but is not sufficient to explain the effect. Instead, the pattern of surface effective forcing, which is substantially different from the effective forcing at the TOA, is more closely linked to the temperature pattern. Independent of surface temperature changes, the aerosol heats the tropical stratosphere, accelerating the Brewer–Dobson circulation. The intensified Brewer–Dobson circulation exports additional energy from the tropics to the extratropics, which leads to a particularly strong negative forcing at the tropical surface. These results show how forced circulation changes can affect the climate response by altering the surface forcing pattern. Furthermore, they indicate that the established approach of diagnosing effective forcing at the TOA is useful for global means, but a surface perspective on the forcing must be adopted to understand the evolution of temperature patterns. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) significantly influence air quality, atmospheric chemistry, and human health. An observational study was performed at the urban site of Hangzhou, China, to analyze VOC characteristics, sources, chemical reactivities, and their impact on ozone (O3) and secondary organic aerosol (SOA) formation throughout the year 2021. During the observation period, alkanes (40.13%) emerging as the predominant VOC species. Seasonal variation in VOCs followed the order of winter (26.49 ppb) > spring (23.63 ppb) > summer (23.62 ppb) > autumn (20.47 ppb). The results of positive matrix factorization (PMF) revealed that solvent usage, combustion, and vehicle exhaust were the dominant VOC sources. Regional transport from nearby provinces also significantly contributed to VOC levels. These contributions varied seasonally, with southeastern air masses prevailing in both spring and autumn, eastern air masses impacting summer, and northwestern air masses affecting winter. The campaign-averaged value of total hydroxyl (OH) radicals was 19.08 s-1. NO2 accounted for the most significant contribution to the overall OH reactivity (39.11%), followed by VOCs (28.72%). Notable seasonal fluctuations in OH reactivity followed the order of winter (24.20 s-1) > spring (19.22 s-1) > autumn (18.07 s-1) > summer (14.86 s-1). The average ozone formation potential (OFP) for the measured VOCs was calculated as 75.54 ppb, with alkenes being the dominant contributor. The highest value was observed in spring (83.05 ppb), the lowest value was in autumn (60.43 ppb). The SOA formation potential, mainly contributed by the aromatics, was averaged as 2.92 µgm-3. Additionally, the top four SOA-contributing species across four seasons were toluene, benzene, m-xylene, and ethylbenzene. VOC-PM2.5 sensitivity analysis showed that VOCs exhibited higher sensitivity to PM2.5 on clean level (PM2.5 < 35 µgm-3) than on level with heavy pollution. Alkenes, oxygenated volatile organic compounds (OVOCs) and aromatics played significant roles in the transformations of O3 and SOA in Hangzhou. Therefore, controlling the concentrations of these species is crucial for reducing complex atmospheric pollution in the region. Overall, this study compiles scientific evidence on pollution sources in Hangzhou, providing the government with valuable information. [ABSTRACT FROM AUTHOR]

Agricultural nitrous oxide (N2O) emission reduction strategies are required given the potency of N2O as a greenhouse gas. However, the growing influence of N2O on stratospheric ozone (O3) with declining stratospheric chlorine means the wider atmospheric impact of N2O reductions requires investigation. We calculate a N2O emission reduction of 1.35 TgN2O yr-1 (~5% of 2020 emissions) using spatially separate deployment of nitrification inhibitors ($70–113 tCO2e−1) and crushed basalt (no-cost co-benefit) which also sequesters CO2. In Earth System model simulations for 2025–2075 under high (SSP3-7.0) and low (SSP1-2.6) surface warming scenarios, this N2O mitigation reduces NOx-driven O3 destruction, driving regional stratospheric O3 increases but with minimal impact on total O3 column recovery. By 2075, the radiative forcing of the combined N2O and CO2 reductions equates to a beneficial 9–11 ppm CO2 removal. Our results support targeted agricultural N2O emission reductions for helping nations reach net-zero without hindering O3 recovery. [ABSTRACT FROM AUTHOR]

This paper presents the observational, remote sensing, and model simulation used to analyze southern Brazil Antarctic ozone hole influence (SBAOHI) events that occurred between 2005 and 2014. To analyze it, we use total ozone column (TOC) data provided by a Brewer spectrophotometer (BS) and the OMI (Ozone Monitoring Instrument). In addition to the AURA/MLS (Microwave Limb Sounder) instrument, satellite ozone profiles were utilized with DYBAL (Dynamical Barrier Localization) code in the MIMOSA (Modélisation Isentrope du Transport Mésoéchelle de l'Ozone Stratosphérique par Advection) model Potential Vorticity (PV) fields. TOC has 7.0 ± 2.9 DU reductions average in 62 events. October has more events (30.7%). Polar tongue events are 19.3% in total, being more frequently observed in October (50% of cases), with medium intensity (58.2%), and in the stratosphere medium levels (55.0%). Already, polar filament events (80.7%) are more frequent in September (32.0%), with medium intensity (42.0%), and stratosphere medium levels (40.7%). [ABSTRACT FROM AUTHOR]

We present a union of three measurement systems on the basis of the Siberian lidar station and mobile ozone lidar. The lidars are designed for studying the ozonosphere using the method of differential absorption and scattering, as well as for studying aerosol fields using elastic single scattering. The systems are constructed on the basis of Nd:YAG lasers (SOLAR) and an Nd:YAG laser (LOTIS TII), a XeCl laser (Lambda Physik) and receiving telescopes assembled using the Kassegrain system with a diameter 0.35 m and the Newtonian 0.5 m system. Lidars operate in photon-counting mode and record lidar signals with a spatial resolution from 1.5 m to 160 m at sensing wavelengths of 299/341 nm in the altitude range of ~0.1–12 km and ~5–20, and at 308/353 nm in the altitude range of ~15–45 km. The union of these three measurement systems was used to carry out field experiments of atmospheric lidar sensing in Tomsk and to present the results of retrieving the vertical profile of the ozone concentration. In this study, coverage of the entire ozonosphere by the lidars was carried out for the first time in Russia. [ABSTRACT FROM AUTHOR]

For new satellite instruments, specifications of the stability required for climate variables are provided in order to be useful for certain applications – for instance, deriving long-term trends. The stability is usually stated in units of percent per decade (% per decade) and is often associated with or termed instrument drift. A stability requirement of 3 % per decade or better has been recently stated for tropospheric and stratospheric ozone. However, the way this number is derived is not clear. In this study, we use Monte Carlo simulations to investigate how a stability requirement translates into uncertainties in long-term trends depending on the lifetime of individual observing systems, which are merged into time series, and the period of available observations. Depending on the need to observe a certain trend over a given period, e.g., typically + 1 % per decade for total ozone and + 2 % per decade for stratospheric ozone over 30 years, stability for observation systems can be properly specified and justified in order to achieve statistical significance in the observed long-term trend. Assuming a typical mean lifetime of 7 years for an individual observing system and a stability of 3 % per decade results in a 2 % per decade trend uncertainty over a period of 30 years, which is barely sufficient for stratospheric ozone but too high for total ozone. Having two or three observing systems simultaneously reduces the uncertainty by 30 % and 42 %, respectively. Such redundancies may be more efficient than developing satellite instruments with higher long-term stability to reduce long-term trend uncertainties. The method presented here is applicable to any variable of interest for which long-term changes are to be detected. [ABSTRACT FROM AUTHOR]

This article discusses the issue of indoor ozone in research laboratories, particularly during the COVID-19 pandemic. While outdoor ozone has both beneficial and detrimental effects, indoor ozone is often overlooked and can pose health risks. The article explores ozone formation, its use in research, health effects, incidents of ozone poisoning, and guidelines for safety in laboratories. It emphasizes the need for proper handling and monitoring of ozone in indoor laboratory spaces to ensure the safety of workers. The article also highlights the age and gender-specific susceptibility to ozone exposure and provides recommendations for improving safety in laboratories. [Extracted from the article]

The loss of the soil fumigant methyl bromide (MeBr) and adoption of soil fumigant alternatives has been challenging for farmers, particularly for those crops in which pathogens previously controlled by MeBr have emerged as significant problems, but it has resulted in some unanticipated benefits for the scientific community and the environment. Applauded as one of the most effective environmental agreements to date, the universally accepted Montreal Protocol on Ozone Depleting Substances has had a significant impact on the environment, reducing the release of halogenated compounds from anthropogenic sources enough to mitigate global warming by an estimated 1.1°C by 2021. The funding associated with various MeBr transition programs has increased collaboration across scientific disciplines, commodity groups, industry, and regulatory agencies. Chemical alternatives and improved application strategies, including the development of gas-retentive agricultural films, coupled with sound efficacy data and grower ingenuity have resulted in the sustained production of many of the impacted crops; although there has been some loss of acreage and value, particularly for Florida fumigated crops, for some. value has continued to increase, allowing production to continue. The loss of a single, broad-spectrum tool for pest control has led to a deeper understanding of the specific pest complexes impacting these at-risk crops, as well as the development of new, biologically based management tools for their control while increasing our understanding of the role of the soil microbiome in pest control and crop production. [ABSTRACT FROM AUTHOR]

The protection of Earth's stratospheric ozone (O3) is an ongoing process under the auspices of the universally ratified Montreal Protocol and its Amendments and adjustments. A critical part of this process is the assessment of the environmental issues related to changes in O3. The United Nations Environment Programme's Environmental Effects Assessment Panel provides annual scientific evaluations of some of the key issues arising in the recent collective knowledge base. This current update includes a comprehensive assessment of the incidence rates of skin cancer, cataract and other skin and eye diseases observed worldwide; the effects of UV radiation on tropospheric oxidants, and air and water quality; trends in breakdown products of fluorinated chemicals and recent information of their toxicity; and recent technological innovations of building materials for greater resistance to UV radiation. These issues span a wide range of topics, including both harmful and beneficial effects of exposure to UV radiation, and complex interactions with climate change. While the Montreal Protocol has succeeded in preventing large reductions in stratospheric O3, future changes may occur due to a number of natural and anthropogenic factors. Thus, frequent assessments of potential environmental impacts are essential to ensure that policies remain based on the best available scientific knowledge. [ABSTRACT FROM AUTHOR]

The results of numerical experiments with a chemistry–climate model of the lower and middle atmosphere are presented to study the sensitivity of the polar stratosphere of the Northern and Southern Hemispheres to sea surface temperature (SST) variability, both as a result of interannual variability associated with the Southern Oscillation, and because of long-term increases in SST under global warming. An analysis of the results of model experiments showed that for both scenarios of SST changes, the response of the polar stratosphere for the Northern and Southern Hemispheres is very different. In the Arctic, during the El Niño phase, conditions are created for the polar vortex to become less stable, and in the Antarctic, on the contrary, for it to become more stable, which is expressed in a weakening of the zonal wind in the winter in the Arctic and its increase in the Antarctic, followed by a spring decrease in temperature and concentration of ozone in the Antarctic and their increase in the Arctic. Global warming creates a tendency for the polar vortex to weaken in winter in the Arctic and strengthen it in the Antarctic. As a result, in the Antarctic, the concentration of ozone in the polar stratosphere decreases both in winter (June–August) and, especially, in spring (September–November). Global warming may hinder ozone recovery which is expected as a result of the reduced emissions of ozone-depleting substances. The model results demonstrate the dominant influence of Brewer–Dobson circulation variability on temperature and ozone in the polar stratosphere compared with changes in wave activity, both with changes in SST in the Southern Oscillation and with increases in SST due to global warming. [ABSTRACT FROM AUTHOR]

Jupiter's South Polar Region (SPR) was observed by James Webb Space Telescope/Mid‐Infrared Instrument in December 2022. We used the Medium Resolution Spectrometer mode to provide new information about Jupiter's South Polar stratosphere. The southern auroral region was visible and influenced the atmosphere in several ways: (a) In the interior of the southern auroral oval, we retrieved peak temperatures at two distinct pressure levels near 0.01 and 1 mbar, with warmer temperatures with respect to non‐auroral regions of 12 ± 2 K and 37 ± 4 K respectively. A cold polar vortex is centered at 65°S at 10 mbar. (b) We found that the homopause is elevated to 590−118+25 ${590}_{-118}^{+25}$ km above the 1‐bar pressure level inside the auroral oval compared to 460−50+60 ${460}_{-50}^{+60}$ km at neighboring latitudes and with an upper altitude of 350 km in regions not affected by auroral precipitation. (c) The retrieved abundance of C2H2 shows an increase within the auroral oval, and it exhibits high abundances throughout the polar region. The retrieved abundance of C2H6 increases toward the pole, without being localized in the auroral oval, in contrast with previous analysis (Sinclair et al., 2018, https://doi.org/10.1016/j.icarus.2017.09.016). We determined that the warming at 0.01 mbar and the elevated homopause might be caused by the flux of charged particles depositing their energy in the SPR. The 1‐mbar hotspot may arise from adiabatic heating resulting from auroral‐driven downwelling. The cold region at 10 mbar may be caused by radiative cooling by stratospheric aerosols. The differences in spatial distribution seem to indicate that the hydrocarbons analyzed are affected differently by auroral precipitation. Plain Language Summary: James Webb Space Telescope/Mid‐Infrared instrument observed Jupiter's south polar region in December 2022. The instrument acquired spectroscopic data in the mid‐infrared part of the spectrum, which is sensitive to the temperature of the atmosphere and the chemical abundances. These observations revealed that within the auroral oval there are two regions of high temperatures located at two different altitudes. These are presumably caused by two different phenomena: direct heating from the incoming charged particles in the aurora at a height of 0.01 mbar and adiabatic heating in downdrafts at lower levels. A decrease in temperature was also observed as we approached the South Pole, probably caused by a cold polar vortex associated with stratospheric hazes. We found that the altitude of the homopause (the limit between the well‐mixed part of the atmosphere and the part where molecules are separated according their specific weight) is altered by the auroras, being up to 100 km higher in the auroral region. The atmospheric abundances of acetylene and ethane showed an enrichment of acetylene within the auroral oval, and of ethane at the pole, which may indicate that these molecules are not affected in the same way by the energy input of the aurora. Key Points: The homopause is spatially variable within the polar region and highest within the auroral ovalThe atmosphere inside the Southern Auroral Oval at 1 and 0.01 mbar shows a warming compared with non‐auroral regionsThe C2H2 abundance is enhanced inside the Southern Auroral Oval at 0.1 and 7 mbar, and C2H6 shows an increase polewards [ABSTRACT FROM AUTHOR]

The aim of this study of sun protection factor boosting effect sunscreen compositions with herbal extract and combination with octocrylene. The standardized herbal extracts procured and studied their sun protection Factors. Camellia Sinensis (Green tea) leaf Extract, Eclipta prostrata (bhringraj) leaf extract are selected for the development of the herbal sunscreen composition along with octocrylene as synthetic sunscreen. The developed sunscreen composition contains defined concentration of herbal extracts and octocrylene were evaluated for their different physicochemical properties and stability. Sun protection factor boosting effect of herbal extracts is studied combination with octocrylene. Invitro SPF studied for herbal extract individually and combination with octocrylene. The results of Invitro SPF study revealed the presence of green tea extract and, Eclipta prostrata (bhringraj) leaf extract shows excellent sun protection factor (SPF) boosting value of sunscreen composition containing 5% concentration of herbal extract and octocrylene. The sunscreen formulation containing 5% herbal extracts are stable for 12 weeks in an oven (45 °C). The findings of this in-vitro SPF study revealed a sun protection boosting capacity of green tea extract and bhringraj extract confirmed. The over exposure of human skin to Ultra-Violet Radiation (UVR) can trigger photodamage, UV burn, pigmentation, erythema, and enhance the chance of dermal carcinoma. UVR causes DNA damage, which leads to dermal cancer. Daily sunscreens protect the skin from the adverse effects of sun rays, especially UVB (290-320 nm) and UVA (320-400 nm). The ozone layer filters UVC (200-290 nm) radiation when it enters into atmosphere of the earth. UVB causes sunburn, photo damage and cause mutagenic changes in nucleic acids. UVA increases ROS (Reactive Oxygen Species) accumulation. ROS is responsible for cell repair which leads to carcinogenesis, and the cause of photodamage. Herbal extracts contain polyphenols, and flavonoids act as a natural sunscreen that will filter Ultra-Violet (UVB) light and contain antioxidant characteristics to modulate the photo-oxidative damage that results from UV-induced Reactive Oxygen Species production. The UVR protection of most herbal extracts are required to attain the higher UV protection in the sun care products. The approaches for preparing sun care products with higher Sun Protection Factor (SPF) possible through Oil in water formulation with herbal extract combinations of octocrylene. The developed sunscreen composition containing different concentration of herbal extracts were evaluated for their other physicochemical properties and stability. Invitro SPF was studied for Camellia Sinensis (Green tea) Leaf Extract and Eclipta prostrata (bhringraj) leaf extract individually and in combination with octocrylene. The results of the Invitro SPF study revealed the Camellia Sinensis (Green tea) Leaf Extract with octocrylene shows better Sun protection factor than Eclipta prostrata (bhringraj) leaf extract with octocrylene. The Sun Protection Factor (SPF) enhancement value of sunscreen compositions was compared to both sunscreen macroemulsion and nanoemulsion. [ABSTRACT FROM AUTHOR]

Stratospheric ozone is an important constituent of the atmosphere. Significant changes in its concentrations have great consequences for the environment in general and for ecosystems in particular. Here, we analyse ground-based, ozonesonde and satellite ozone measurements to examine the ozone depletion and the spatiotemporal trends in ozone in the tropics during the past 5 decades (1980–2020). The amount of column ozone in the tropics is relatively small (250–270 DU) compared to high and mid-latitudes (Northern Hemisphere (NH) 275–425 DU; Southern Hemisphere (SH) 275–350 DU). In addition, the tropical total ozone trend is very small (± 0–0.2 DU yr -1), as estimated for the period 1998–2022. No observational evidence is found regarding the indications or signatures of severe stratospheric ozone depletion in the tropics in contrast to a recent claim. Finally, current understanding and observational evidence do not provide any support for the possibility of an ozone hole occurring outside Antarctica today with respect to the present-day stratospheric halogen levels. [ABSTRACT FROM AUTHOR]

There are obstacles in better understanding the climate impacts associated with new materials that could be used for Stratospheric Aerosol Injections (SAI), like the lack of an integrated framework that combines climate modeling across scales, laboratory studies and small‐scale field experiments. Vattioni et al. (2023, https://doi.org/10.1029/2023gl105889) explored one aspect of using alternative, non‐sulfate materials for SAI. They investigated how uncertain the response of stratospheric ozone would be to alumina injections for SAI. In their study, they quantify chlorine activation rates in the presence of alumina, and then cascade these uncertainties into estimates of ozone depletion, concluding that alumina might have less detrimental impacts on stratospheric chemistry than sulfate, but with large uncertainties. Their results provide a useful basis upon which future research endeavors combining indoor and outdoor experiments and modeling may be structured to produce robust assessments of SAI impacts, benefits and uncertainties, together with clarifying what kind of research needs to be prioritized. Plain Language Summary: We could use tiny particles injected into the higher atmosphere to reflect a small portion of incoming sunlight and thereby cool the planet. But doing so comes with risks and uncertainties: for instance, one might wonder how do we select which kind of particles to use. Sulfate is present in nature, for instance during the aftermath of volcanic eruptions followed by an observable surface cooling. However, we know that mimicking that effect would come with some drawbacks, for example, it heats the upper layer of the atmosphere and affects ozone. Alumina, supposedly, would impact atmospheric chemistry less than sulfate and so might be considered "preferable," but not being naturally present in the atmosphere, there are lots of things we don't know. For example, Vattioni et al. (2023, https://doi.org/10.1029/2023gl105889) demonstrate that even potential implications for atmospheric chemistry are highly uncertain when looking at alumina particles as a candidate for Stratospheric Aerosol Injections (SAI). Therefore, their study is a good opportunity to think more broadly about intended SAI‐associated climate impacts and unwanted side effects, and how to better coordinate research activities in this space. Key Points: Vattioni et al. (2023, https://doi.org/10.1029/2023gl105889) demonstrated large uncertainties in the projected impacts of alumina particles in the stratosphereWe use the results to discuss more broadly how to better think about the climate impacts and side effects of Stratospheric Aerosol InjectionWe propose the idea of a "living assessment" of Stratospheric Aerosol Injections that can constantly integrate useful experimental results with modeling work [ABSTRACT FROM AUTHOR]

The stratosphere has previously been shown to be a significant source of subseasonal tropospheric predictability. The ability of ensemble prediction systems to appropriately exploit this depends on their ability to reproduce the statistical properties of the real atmosphere. In this study, we investigate predictability properties of the coupled stratosphere‐troposphere system in the sub‐seasonal to seasonal prediction project hindcasts by fitting a simple, minimal model. We diagnose the signal and noise components of each system in the stratosphere and troposphere and their coupling. We find that while the correlation skill scores are similar in most systems, the signal to noise properties can be substantially different. In the stratosphere, some systems are significantly overconfident, with a quantifiable impact on the tropospheric confidence. We link the method and details of the design of a prediction system to these predictive properties. Plain Language Summary: Subseasonal weather prediction systems make use of ensemble forecasting approaches, in which each forecast is made up of a number of complimentary predictions (ensemble members), that produce more skillful predictions by averaging and allows forecasters to anticipate the uncertainty in any particular forecast. There is a "battle" between the useful signal, hidden in the initial conditions of a simulation run, against the noise that chaotically builds up over the run from inaccuracies in the representation of the initial conditions. We use a simple statistical model with a minimal number of parameters to investigate how well the prediction systems capture both the signal and noise properties of the real atmosphere. We find that while the skill in the troposphere and stratosphere are in line with expectations from the real‐world, the ratio between the signal and the noise is too large, particularly in the stratosphere. We find this has an impact on the troposphere below, increasing the signal‐to‐noise ratio there too—artificially inflating it—giving it an overconfidence which is not wholly statistically or physically justified. We link the method and details of the design of a prediction system to these predictive properties. Key Points: Fitting a detailed statistical model to subseasonal prediction systems reveals some have significant overconfidence in the stratosphereLarge diversity in stratospheric error growth properties between different systemsSystems that are overconfident in the stratosphere have an overconfidence bias in the troposphere [ABSTRACT FROM AUTHOR]

A correction notice has been issued for a research paper on electricity-generation technologies in West Texas. The correction addresses a minor mistake in the modeling of Battery Energy Storage Systems (BESS). The correction does not change the overall conclusions of the research, but it slightly alters the ranking of impacts associated with wind and solar generation facilities when BESS is added. The corrected figures and tables have been provided, along with additional information from another study on power generation systems. The paper includes tables comparing the environmental impact of solar PV + BESS generation, including data on various impact pathways. The authors express gratitude to those who provided feedback and support for the project. [Extracted from the article]

Stratospheric ozone, and its response to anthropogenic forcings, provides an important pathway for the coupling between atmospheric composition and climate. In addition to stratospheric ozone's radiative impacts, recent studies have shown that changes in the ozone layer due to 4xCO2 have a considerable impact on the Northern Hemisphere (NH) tropospheric circulation, inducing an equatorward shift of the North Atlantic jet during boreal winter. Using simulations produced with the NASA Goddard Institute for Space Studies (GISS) high-top climate model (E2.2), we show that this equatorward shift of the Atlantic jet can induce a more rapid weakening of the Atlantic meridional overturning circulation (AMOC). The weaker AMOC, in turn, results in an eastward acceleration and poleward shift of the Atlantic and Pacific jets, respectively, on longer time scales. As such, coupled feedbacks from both stratospheric ozone and the AMOC result in a two-time-scale response of the NH midlatitude jet to abrupt 4xCO2 forcing: a "fast" response (5–20 years) during which it shifts equatorward and a "total" response (∼100–150 years) during which the jet accelerates and shifts poleward. The latter is driven by a weakening of the AMOC that develops in response to weaker surface zonal winds that result in reduced heat fluxes out of the subpolar gyre and reduced North Atlantic Deep Water formation. Our results suggest that stratospheric ozone changes in the lower stratosphere can have a surprisingly powerful effect on the AMOC, independent of other aspects of climate change. [ABSTRACT FROM AUTHOR]