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Validation of the Integrated Water Vapour (IWV) from Sentinel-3 Ocean and Land Colour Instrument (OLCI) was performed as a part of the “ESA/Copernicus Space Component Validation for Land Surface Temperature, Aerosol Optical Depth and Water Vapour Sentinel-3 Products” (LAW) project. High-spatial-resolution IWV observations in the near-infrared spectral region from the OLCI instruments aboard the Sentinel-3A and Sentinel-3B satellites provide continuity with observations from MERIS (Medium Resolution Imaging Spectrometer). The IWV was compared with reference observations from two networks: GNSS (Global Navigation Satellite System) precipitable water vapour from the SuomiNet network and integrated lower tropospheric columns from radio-soundings from the IGRA (Integrated Radiosonde Archive) database. Results for cloud-free matchups over land show a wet bias of 7 %–10 % for OLCI, with a high correlation against the reference observations (0.98 against SuomiNet and 0.90 against IGRA). Both OLCI-A and OLCI-B instruments show almost identical results, apart from an anomaly observed in camera 3 of the OLCI-B instrument, where observed biases are lower than in other cameras in either instrument. The wavelength drift in sensors was investigated, and biases in different cameras were found to be independent of wavelength. Effect of cloud proximity was found to have almost no effect on observed biases, indicating that cloud flagging in the OLCI IWV product is sufficiently reliable. We performed validation of random uncertainty estimates and found them to be consistent with the statistical a posteriori estimates, but somewhat higher.

We investigate Arctic polar atmospheric ozone responses to solar proton events (SPEs) using MLS (Microwave Limb Sounder) satellite measurements (2004–now) and WACCM-D (Whole Atmosphere Community Climate Model) simulations (1989–2012). Special focus is on lower-stratospheric (10–30 km) ozone depletion that has been proposed earlier based on superposed epoch analysis (SEA) of ozonesonde anomalies (up to 10 % ozone decrease at ∼ 20 km). SEA of the satellite dataset provides no solid evidence of any average SPE impact on the lower-stratospheric ozone, although at the mesospheric altitudes a statistically significant ozone depletion is present. In the individual case studies, we find only one potential case (January 2005) in which the lower-stratospheric ozone level was significantly decreased after the SPE onset (in both model simulation and MLS observation data). However, similar decreases could not be identified in other SPEs of similar or larger magnitude. Due to the input proton energy threshold of > 300 MeV, the WACCM-D model can only detect direct proton effects above 25 km, and simulation results before the Aura MLS era indicate no significant effect on the lower-stratospheric ozone. However, we find a very good overall consistency between WACCM-D simulations and MLS observations of SPE-driven ozone anomalies both on average and for the individual cases including January 2005.

The TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor (S5P) satellite was launched on 13 October 2017 to provide the atmospheric composition for atmosphere and climate research. The S5P is a Sun-synchronous polar-orbiting satellite providing global daily coverage. The TROPOMI swath is 2600 km wide, and the ground resolution for most data products is 7.2×3.5 km2 (5.6×3.5 km2 since 6 August 2019) at nadir. The Finnish Meteorological Institute (FMI) is responsible for the development of the TROPOMI UV algorithm and the processing of the TROPOMI surface ultraviolet (UV) radiation product which includes 36 UV parameters in total. Ground-based data from 25 sites located in arctic, subarctic, temperate, equatorial and Antarctic areas were used for validation of the TROPOMI overpass irradiance at 305, 310, 324 and 380 nm, overpass erythemally weighted dose rate/UV index, and erythemally weighted daily dose for the period from 1 January 2018 to 31 August 2019. The validation results showed that for most sites 60 %–80 % of TROPOMI data was within ±20 % of ground-based data for snow-free surface conditions. The median relative differences to ground-based measurements of TROPOMI snow-free surface daily doses were within ±10 % and ±5 % at two-thirds and at half of the sites, respectively. At several sites more than 90 % of cloud-free TROPOMI data was within ±20 % of ground-based measurements. Generally median relative differences between TROPOMI data and ground-based measurements were a little biased towards negative values (i.e. satellite data < ground-based measurement), but at high latitudes where non-homogeneous topography and albedo or snow conditions occurred, the negative bias was exceptionally high: from −30 % to −65 %. Positive biases of 10 %–15 % were also found for mountainous sites due to challenging topography. The TROPOMI surface UV radiation product includes quality flags to detect increased uncertainties in the data due to heterogeneous surface albedo and rough terrain, which can be used to filter the data retrieved under challenging conditions.

Understanding the atmospheric forcing from energetic particle precipitation (EPP) is important for climate simulations on decadal time scales. However, presently there are large uncertainties in energy flux measurements of electron precipitation. One approach to narrowing these uncertainties is by analyses of EPP direct atmospheric impacts and their relation to measured EPP fluxes. Here we use observations from the microwave limb sounder (MLS) and Whole Atmosphere Community Climate Model (WACCM) simulations, together with EPP fluxes from the Geostationary Operational Environmental Satellite (GOES) and Polar-orbiting Operational Environmental Satellite (POES) to determine the OH and HO2 response thresholds to solar proton events (SPEs) and radiation belt electron (RBE) precipitation. Because of their better signal-to-noise ratio and extended altitude range, we utilize MLS HO2 data from an improved offline processing instead of the standard operational product. We consider a range of altitudes in the middle atmosphere and all magnetic latitudes from pole to pole. We find that the nighttime flux limits for day-to-day EPP impact detection using OH and HO2 are 50–130 protonscm-2s-1sr-1 (E>10 MeV) and 1.0–2.5×104 electronscm-2s-1sr-1 (E = 100–300 keV). Based on the WACCM simulations, nighttime OH and HO2 are good EPP indicators in the polar regions and provide best coverage in altitude and latitude. Due to larger background concentrations, daytime detection requires larger EPP fluxes and is possible in the mesosphere only. SPE detection is easier than RBE detection because a wider range of polar latitudes is affected, i.e., the SPE impact is rather uniform poleward of 60∘, while the RBE impact is focused at 60∘. Altitude-wise, the SPE and RBE detection are possible at ≈ 35–80 and ≈ 65–75 km, respectively. We also find that the MLS OH observations indicate a clear nighttime response to SPE and RBE in the mesosphere, similar to the simulations. However, the MLS OH data are too noisy for response detection in the stratosphere below 50 km, and the HO2 measurements are overall too noisy for confident EPP detection on a day-to-day basis.

The radiation belts are regions in the near-Earth space where solar wind electrons are captured by the Earth's magnetic field. A portion of these electrons is continuously lost into the atmosphere where they cause ionization and chemical changes. Driven by the solar activity, the electron forcing leads to ozone variability in the polar stratosphere and mesosphere. Understanding the possible dynamical connections to regional climate is an ongoing research activity which supports the assessment of greenhouse-gas-driven climate change by a better definition of the solar-driven variability. In the context of the Coupled Model Intercomparison Project Phase 6 (CMIP6), energetic electron and proton precipitation is included in the solar-forcing recommendation for the first time. For the radiation belt electrons, the CMIP6 forcing is from a daily zonal-mean proxy model. This zonal-mean model ignores the well-known dependency of precipitation on magnetic local time (MLT), i.e. its diurnal variability. Here we use the Whole Atmosphere Community Climate Model with its lower-ionospheric-chemistry extension (WACCM-D) to study effects of the MLT dependency of electron forcing on the polar-ozone response. We analyse simulations applying MLT-dependent and MLT-independent forcings and contrast the resulting ozone responses in monthly-mean data as well as in monthly means at individual local times. We consider two cases: (1) the year 2003 and (2) an extreme, continuous forcing. Our results indicate that the ozone responses to the MLT-dependent and the MLT-independent forcings are very similar, and the differences found are small compared to those caused by the overall uncertainties related to the representation of electron forcing in climate simulations. We conclude that the use of daily zonal-mean electron forcing will provide an accurate ozone response in long-term climate simulations.

Atmospheric effects of solar proton events (SPEs) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, odd hydrogen and odd nitrogen are produced during SPEs, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the strongest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e., in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase in mesospheric HNO3 or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 strongest SPEs which occurred in the years 1989–2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O3, HOx (OH + HO2), Clx (Cl + ClO), HNO3, NOx (NO + NO2) and H2O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O3 and NOx and a weaker response in HOx and introduces changes in HNO3 and Clx. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.

The TROPOspheric Monitoring Instrument (TROPOMI) is the only payload of the Sentinel-5 Precursor (S5P), which is a polar-orbiting satellite mission of the European Space Agency (ESA). TROPOMI is a nadir-viewing spectrometer measuring in the ultraviolet, visible, near-infrared, and the shortwave infrared that provides near-global daily coverage. Among other things, TROPOMI measurements will be used for calculating the UV radiation reaching the Earth's surface. Thus, the TROPOMI surface UV product will contribute to the monitoring of UV radiation by providing daily information on the prevailing UV conditions over the globe. The TROPOMI UV algorithm builds on the heritage of the Ozone Monitoring Instrument (OMI) and the Satellite Application Facility for Atmospheric Composition and UV Radiation (AC SAF) algorithms. This paper provides a description of the algorithm that will be used for estimating surface UV radiation from TROPOMI observations. The TROPOMI surface UV product includes the following UV quantities: the UV irradiance at 305, 310, 324, and 380 nm; the erythemally weighted UV; and the vitamin-D weighted UV. Each of these are available as (i) daily dose or daily accumulated irradiance, (ii) overpass dose rate or irradiance, and (iii) local noon dose rate or irradiance. In addition, all quantities are available corresponding to actual cloud conditions and as clear-sky values, which otherwise correspond to the same conditions but assume a cloud-free atmosphere. This yields 36 UV parameters altogether. The TROPOMI UV algorithm has been tested using input based on OMI and the Global Ozone Monitoring Experiment-2 (GOME-2) satellite measurements. These preliminary results indicate that the algorithm is functioning according to expectations.

Spectral solar UV radiation measurements are performed in France using three spectroradiometers located at very different sites. One is installed in Villeneuve d'Ascq, in the north of France (VDA). It is an urban site in a topographically flat region. Another instrument is installed in Observatoire de Haute-Provence, located in the southern French Alps (OHP). It is a rural mountainous site. The third instrument is installed in Saint-Denis, Réunion Island (SDR). It is a coastal urban site on a small mountainous island in the southern tropics. The three instruments are affiliated with the Network for the Detection of Atmospheric Composition Change (NDACC) and carry out routine measurements to monitor the spectral solar UV radiation and enable derivation of UV index (UVI). The ground-based UVI values observed at solar noon are compared to similar quantities derived from the Ozone Monitoring Instrument (OMI, onboard the Aura satellite) and the second Global Ozone Monitoring Experiment (GOME-2, onboard the Metop-A satellite) measurements for validation of these satellite-based products. The present study concerns the period 2009–September 2012, date of the implementation of a new OMI processing tool. The new version (v1.3) introduces a correction for absorbing aerosols that were not considered in the old version (v1.2). Both versions of the OMI UVI products were available before September 2012 and are used to assess the improvement of the new processing tool. On average, estimates from satellite instruments always overestimate surface UVI at solar noon. Under cloudless conditions, the satellite-derived estimates of UVI compare satisfactorily with ground-based data: the median relative bias is less than 8 % at VDA and 4 % at SDR for both OMI v1.3 and GOME-2, and about 6 % for OMI v1.3 and 2 % for GOME-2 at OHP. The correlation between satellite-based and ground-based data is better at VDA and OHP (about 0.99) than at SDR (0.96) for both space-borne instruments. For all sky conditions, the median relative biases are much larger, with large dispersion for both instruments at all sites (VDA: about 12 %; OHP: 9 %; SDR: 11 %). Correlation between satellite-based and ground-based data is still better at VDA and OHP (about 0.95) than at SDR (about 0.73) for both satellite instruments. These results are explained considering the time of overpass of the two satellites, which is far from solar noon, preventing a good estimation of the cloud cover necessary for a good modelling of the UVI. Site topography and environment are shown to have a non-significant influence. At VDA and OHP, OMI v1.3 shows a significant improvement with respect to v1.2, which did not account for absorbing aerosols.

The total column water vapour product from the Global Ozone Monitoring Experiment-2 on board Metop-A and Metop-B satellites (GOME-2/Metop-A and GOME-2/Metop-B) produced by the Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) is compared with co-located radiosonde observations and global positioning system (GPS) retrievals. The validation is performed using recently reprocessed data by the GOME Data Processor (GDP) version 4.7. The time periods for the validation are January 2007–July 2013 (GOME-2A) and December 2012–July 2013 (GOME-2B). The radiosonde data are from the Integrated Global Radiosonde Archive (IGRA) maintained by the National Climatic Data Center (NCDC). The ground-based GPS observations from the COSMIC/SuomiNet network are used as the second independent data source. We find a good general agreement between the GOME-2 and the radiosonde/GPS data. The median relative difference of GOME-2 to the radiosonde observations is −2.7 % for GOME-2A and −0.3 % for GOME-2B. Against the GPS, the median relative differences are 4.9 % and 3.2 % for GOME-2A and B, respectively. For water vapour total columns below 10 kg m−2, large wet biases are observed, especially against the GPS retrievals. Conversely, at values above 50 kg m−2, GOME-2 generally underestimates both ground-based observations.

The three Global Ozone Monitoring Experiment-2 instruments will provide unique and long data sets for atmospheric research and applications. The complete time period will be 2007–2022, including the period of ozone depletion as well as the beginning of ozone layer recovery. Besides ozone chemistry, the GOME-2 (Global Ozone Monitoring Experiment-2) products are important e.g. for air quality studies, climate modelling, policy monitoring and hazard warnings. The heritage for GOME-2 is in the ERS/GOME and Envisat/SCIAMACHY instruments. The current Level 2 (L2) data cover a wide range of products such as ozone and minor trace gas columns (NO2, BrO, HCHO, H2O, SO2), vertical ozone profiles in high and low spatial resolution, absorbing aerosol indices, surface Lambertian-equivalent reflectivity database, clear-sky and cloud-corrected UV indices and surface UV fields with different weightings and photolysis rates. The Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) processes and disseminates data 24/7. Data quality is guaranteed by the detailed review processes for the algorithms, validation of the products as well as by a continuous quality monitoring of the products and processing. This paper provides an overview of the O3M SAF project background, current status and future plans for the utilisation of the GOME-2 data. An important focus is the provision of summaries of the GOME-2 products including product principles and validation examples together with sample images. Furthermore, this paper collects references to the detailed product algorithm and validation papers.

The surface ultraviolet (UV) radiation product, version 1.20, generated operationally in the framework of the Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) is described. The product is based on the total ozone column derived from the measurements of the second Global Ozone Monitoring Experiment (GOME-2) instrument aboard EUMETSAT's polar orbiting meteorological operational (Metop) satellites. Cloud cover is taken into account by retrieving cloud optical depth from the channel 1 reflectance of the third Advanced Very High-Resolution Radiometer (AVHRR/3) instrument aboard both Metop in the morning orbit and Polar Orbiting Environmental Satellites (POES) of the National Oceanic and Atmospheric Administration (NOAA) in the afternoon orbit. In addition, more overpasses are used at high latitudes where the swaths of consecutive orbits overlap. The input satellite data are received from EUMETSAT's Multicast Distribution System (EUMETCast). The surface UV product includes daily maximum dose rates and integrated daily doses with different biological weighting functions, integrated ultraviolet B (UVB) and ultraviolet A (UVA) radiation, solar noon UV index and daily maximum photolysis frequencies of ozone and nitrogen dioxide at the surface level. The quantities are computed in a 0.5°×0.5° regular latitude–longitude grid and stored as daily files in the hierarchical data format (HDF5) within 2 weeks from sensing. The product files are archived in the O3M SAF distributed archive and can be ordered via the EUMETSAT Data Centre.

Satellite measurements sample continuous fields of atmospheric constituents at discrete locations and times. However, insufficient or inhomogeneous sampling, if not taken into account, can result in inaccurate average estimates and even induce spurious features. We propose to characterize the spatiotemporal inhomogeneity of atmospheric measurements by a measure, which is a linear combination of the asymmetry and entropy of a sampling distribution. It is shown that this measure is related to the so-called sampling uncertainty, which occurs due to non-uniform sampling patterns. We have estimated the sampling uncertainty of zonal mean ozone profiles for six limb-viewing satellite instruments participating in the European Space Agency Ozone Climate Change Initiative project using the high-resolution ozone field simulated with the FinROSE chemistry-transport model. It is shown that the sampling uncertainty for the instruments with coarse sampling is not negligible and can be as large as a few percent. It is found that the standard deviation of the sampling uncertainty in the monthly zonal mean data allows for a simple parameterization in terms of the product of the standard deviation of natural variations and the proposed inhomogeneity measure. The sampling uncertainty estimates improve the uncertainty quantification and can be used in comprehensive data analyses. The focus of this work is the vertical ozone distributions measured by limb-viewing satellite instruments, but the developed methods can also be applied to different satellite, ground-based and in situ measurements.

In this paper, we present a HARMonized dataset of OZone profiles (HARMOZ) based on limb and occultation measurements from Envisat (GOMOS, MIPAS and SCIAMACHY), Odin (OSIRIS, SMR) and SCISAT (ACE-FTS) satellite instruments. These measurements provide high-vertical-resolution ozone profiles covering the altitude range from the upper troposphere up to the mesosphere in years 2001–2012. HARMOZ has been created in the framework of the European Space Agency Climate Change Initiative project. The harmonized dataset consists of original retrieved ozone profiles from each instrument, which are screened for invalid data by the instrument teams. While the original ozone profiles are presented in different units and on different vertical grids, the harmonized dataset is given on a common pressure grid in netCDF (network common data form)-4 format. The pressure grid corresponds to vertical sampling of ~ 1 km below 20 km and 2–3 km above 20 km. The vertical range of the ozone profiles is specific for each instrument, thus all information contained in the original data is preserved. Provided altitude and temperature profiles allow the representation of ozone profiles in number density or mixing ratio on a pressure or altitude vertical grid. Geolocation, uncertainty estimates and vertical resolution are provided for each profile. For each instrument, optional parameters, which are related to the data quality, are also included. For convenience of users, tables of biases between each pair of instruments for each month, as well as bias uncertainties, are provided. These tables characterize the data consistency and can be used in various bias and drift analyses, which are needed, for instance, for combining several datasets to obtain a long-term climate dataset. This user-friendly dataset can be interesting and useful for various analyses and applications, such as data merging, data validation, assimilation and scientific research. The dataset is available at http://www.esa-ozone-cci.org/?q=node/161 or at doi:10.5270/esa-ozone_cci-limb_occultation_profiles-2001_2012-v_1-201308.

A large zonal asymmetry of ozone has been observed over Antarctica during winter-spring, when the ozone hole develops. It is caused by a planetary wave-driven displacement of the polar vortex. The total ozone data by OMI (Ozone Monitoring Instrument) and the ozone profiles by MLS (Microwave Limb Sounder) and GOMOS (Global Ozone Monitoring by Occultation of Stars) were analysed to characterize the ozone zonal asymmetry and the wave activity during Antarctic spring. Both total ozone and profile data have shown a persistent zonal asymmetry over the last years, which is usually observed from September to mid-December. The largest amplitudes of planetary waves at 65° S (the perturbations can achieve up to 50% of zonal mean values) is observed in October. The wave activity is dominated by the quasi-stationary wave 1 component, while the wave 2 is mainly an eastward travelling wave. Wave numbers 1 and 2 generally explain more than the 90% of the ozone longitudinal variations. Both GOMOS and MLS ozone profile data show that ozone zonal asymmetry covers the whole stratosphere and extends up to the altitudes of 60–65 km. The wave amplitudes in ozone mixing ratio decay with altitude, with maxima (up to 50%) below 30 km. The characterization of the ozone zonal asymmetry has become important in the climate research. The inclusion of the polar zonal asymmetry in the climate models is essential for an accurate estimation of the future temperature trends. This information might also be important for retrieval algorithms that rely on ozone a priori information.

Sudden stratospheric warmings (SSW) are large-scale transient events, which have a profound effect on the Northern Hemisphere stratospheric circulation in winter. During the SSW events the temperature in stratosphere increases by several tens of Kelvins and zonal winds decelerate or reverse in direction. Changes in temperature and dynamics significantly affect the chemical composition of the middle atmosphere. In this paper, the response of the middle-atmosphere trace gases during several sudden stratospheric warmings in 2003–2008 is investigated using measurements from the GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite. We have analyzed spatial and temporal changes of NO2 and NO3 in the stratosphere, and of ozone in the whole middle atmosphere. To facilitate our analyses, we have used the temperature profiles data from the MLS (Microwave Limb Sounder) instrument on board the Aura satellite, as well as simulations by the FinROSE chemistry-transport model and the Sodankylä Ion and Neutral Chemistry model (SIC). NO3 observations in the polar winter stratosphere during SSWs are reported for the first time. Changes in chemical composition are found not to be restricted to the stratosphere, but to extend to mesosphere and lower thermosphere. They often exhibit a complicated structure, because the distribution of trace gases is affected by changes in both chemistry and dynamics. The tertiary ozone maximum in the mesosphere often disappears with the onset of SSW, probably because of strong mixing processes. The strong horizontal mixing with outside-vortex air is well observed also in NO2 data, especially in cases of enhanced NO2 inside the polar vortex before SSW. Almost in all of the considered events, ozone near the secondary maximum decreases with onset of SSW. In both experimental data and FinROSE modelling, ozone changes are positively correlated with temperature changes in the lower stratosphere in the dynamically controlled region below ~35 km, and they are negatively correlated with temperature in the upper stratosphere (altitudes 35–50 km), where chemical processes play a significant role. Large enhancements of stratospheric NO3, which strongly correlate with temperature enhancements, are observed for all SSWs, as expected by the current understanding of temperature-dependence of NO3 concentrations and simulations with the CTM.

No abstract available.

Large solar coronal mass ejections pose a threat in the near-Earth space. As a cause of extreme periods of space weather, they can damage satellite-based communications and create geomagnetically induced currents in power and energy grids. Further, the solar wind energetic particles can reduce the protecting layer of atmospheric ozone and pose a threat to life on Earth. The large coronal mass ejection (CME) of July 2012, although directed away from the Earth, is often highlighted as a prime example of a potentially devastating super storm. Here we show, based on proton fluxes recorded by the instruments aboard the STEREO-A satellite, that the atmospheric response to the July 2012 event would have been comparable to those of the largest solar proton events of the satellite era. Significant impact on total ozone outside polar regions would require a much larger event, similar to those recorded in historical proxy data sets. Such an extreme event would cause long-term ozone reduction all the way to the equator and increase the size, duration, and depth of the Antarctic ozone hole. The impact would be comparable to predicted drastic and sudden ozone reduction from major volcanic eruptions, regional nuclear conflicts, or long-term stratospheric geoengineering., (© 2023. Springer Nature Limited.)

Understanding atmospheric impacts of solar energetic particle precipitation (EPP) remains challenging, from quantification of the response in ozone, to implications on temperature. Both are necessary to understand links between EPP and regional climate variability. Here we use a chemistry-climate model to assess the importance of EPP on late winter/spring polar stratosphere. In transient simulations, the impact on NO y , ozone, and temperature is underestimated when using EPP forcing from the current recommendation of the Coupled Model Intercomparison Project (CMIP6). The resulting temperature response is largely masked by overall dynamical variability. An idealised experiment with EPP forcing that reproduces observed levels of NO y results in a significant reduction of ozone (up to 25%), cooling the stratosphere (up to 3 K) during late winter/spring. Our results unravel the inconsistency regarding the temperature response to EPP-driven springtime ozone decrease, and highlight the need for an improved EPP forcing in climate simulations., (© 2022. The Author(s).)