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There is an ongoing debate on the relationship between accelerated warming in the Arctic and extreme weather patterns in mid-latitudes. As extreme weather events have dramatic socioeconomic costs, it is important to investigate the possibility of the increased risk of such events in mid-latitudes. We investigated changes in the frequency of extreme weather events in Eastern Europe and Western to Central Asia (30–60 ∘ N, 20–75 ∘ E) in the post-Arctic amplification (2002–2022) compared to the pre-Arctic amplification (1979–1999) period. We analyzed the daily detrended near-surface temperature and precipitation of the ERA5 data. There is no robust evidence for the contribution of Arctic amplification to changes in extreme precipitation in Eastern Europe and Western to Central Asia. Most regions of the study area have experienced a decrease in annual precipitation in the post-Arctic amplification period. We also identified an increase in consecutive dry days in most parts of Central Asia by approximately 16 days per year, which could be attributed to a warmer climate because dry areas generally become drier in a warmer climate. Greater warming of the Earth in the more recent period has been associated with a significant increase in both warm days and nights and a significant decrease in cold days and nights over Eastern Europe and Western to Central Asia. Depending on the season, we identified both intensification and weakening of the upper tropospheric jet stream in the post-Arctic amplification period. The jet stream is intensified from the eastern Black Sea toward northern Kazakhstan and southeastern Russia in spring. In contrast, it has significantly weakened in the northern Mediterranean Sea and western Kazakhstan in summer and the Caspian Sea and Caucasus in autumn. Our results have important implications for a better understanding of the potential impact of rapid Arctic warming on extreme weather events in mid-latitudes. [ABSTRACT FROM AUTHOR]

The investigation of the height variations of the westerly in the mid-latitudes of the Northern Hemisphere is crucial for monitoring changes in the intricate atmospheric system. This study examined the hypothesis of changes in the thickness of the westerly domain by analyzing the height of the 500 hPa pressure level. To this end, monthly data from the European Centre for Medium-Range Weather Forecasts (ECMWF) spanning from 1959 to 2021 was utilized to investigate three components: geopotential height (GH), zonal, and meridional wind components. The dataset underwent statistical tests, including trend analysis using Least Squares Error linear regression (LSE-LR) and shift (jump) analysis using the Standard Normal Homogeneity Test (SNHT). The results revealed a significant increasing trend in the height of the troposphere and the westerlies in the mid-latitudes of the Northern Hemisphere, accompanied by significant fluctuations, indicating an increase in the height of the 500 hPa pressure level and a decrease in the thickness of the westerly domain. The extent of these trends was observed to be greater in cold months, particularly in January and February, while the changes were minimal in November. Notably, the spatial distribution of upward jumps, indicative of change, was highest in January, July, and August in the eastern and southeastern regions of Asia. Furthermore, the convergence section of the westerlies trough exhibited a substantial number of jumps, particularly in March, spanning Central America and southern parts of North America. Regarding decadal coincidence onset, the highest number of jumps occurred in February, encompassing the western Pacific Ocean, western Atlantic Ocean, Eastern Europe, and western Asia. The end of these jumps coincided in February, and the spatial proximity of the end times was closer compared to the onset times in February, March, April, July, and August. [ABSTRACT FROM AUTHOR]

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Potassium (K), calcium (Ca), and magnesium (Mg) are essential elements with important physiological functions in plants. Previous studies showed that leaf K, Ca, and Mg concentrations generally increase with increasing latitudes. However, recent meta-analyses suggested the possibility of a unimodal pattern in the concentrations of these elements along latitudinal gradients. The authenticity of this unimodal latitudinal pattern, however, requires validation through large-scale field experimental data, and exploration of the underlying mechanisms if the pattern is confirmed. Here, we collected leaves of common species of woody plants from 19 montane forests in the north-south transect of eastern China, including 322 species from 160 genera, 67 families; and then determined leaf K, Ca, and Mg concentrations to explore their latitudinal patterns and driving mechanisms. Our results support unimodal latitudinal patterns for all three elements in woody plants across eastern China, with peak values at latitude 36.5 ​± ​1.0° N. The shift of plant-functional-type compositions from evergreen broadleaves to deciduous broadleaves and to conifers along this latitudinal span was the key factor contributing to these patterns. Climatic factors, mainly temperature, and to a lesser extent solar radiation and precipitation, were the main environmental drivers. These factors, by altering the composition of plant communities and regulating plant physiological activities, influence the latitudinal patterns of plant nutrient concentrations. Our findings also suggest that high leaf K, Ca, and Mg concentrations may represent an adaptive strategy for plants to withstand water stress, which might be used to predict plant nutrient responses to climate changes at large scales, and broaden the understanding of biogeochemical cycling of K, Ca, and Mg.

• Including low-cost variometers can improve sparse geomagnetic field interpolation • Interpretable equivalent current basis functions are presented for mid-latitudes • The adapted interpolation scheme can be used directly by utilities for GIC modelling Space weather and its impact on infrastructure presents a clear risk in the modern era, as evidenced by the adverse effects of geomagnetically induced currents (GICs) in power networks. To model GICs, ground-based geomagnetic field (B-field) measurements are critical and need to be available in the region of interest. A challenge globally lies in the sparse distribution of magnetometer arrays, which are seldom located near critical power network nodes. Interpolation of the geomagnetic field (B-field) is often needed, with the spherical elementary current system (SECS) approach developed for high-latitude regions favoured. We adapt this interpolation scheme to include low-cost variometers to interpolate dB / dt directly and increase interpolation accuracy. A further adaptation to the scheme is to physically represent the mid-latitude context where most power networks and pipelines lie. The driving current systems in these regions differ from their high-latitude counterparts. Using a physics-consistent mid-latitude version of SECS, we show why previous implementations in Southern Africa are incorrect but still result in useful interpolation. The scope of these adaptations not only has direct application to research in general, but also to utilities, where effective low-cost instrumentation can be used to improve GIC modelling accuracy. [ABSTRACT FROM AUTHOR]

Abstract This study, for the first time, reports the geomagnetically conjugate structure of a plasma bubble extending to the mid-latitudes and the asymmetrical structure of the decay of the plasma bubble during a geomagnetic storm. We investigated the temporal and spatial variations of plasma bubbles in the Asian sector during a geomagnetic storm on March 1, 2013, using Global Navigation Satellite System-total electron content data with high spatiotemporal resolutions. The first important point of our data analysis results is that the plasma bubble extended from the equator to the mid-latitudes with geomagnetic conjugacy along the magnetic field lines. The total electron content data showed that the plasma bubbles appeared in the equatorial regions near 150° E after sunset during the main phase of the geomagnetic storm. From ionosonde data over both Japan and Australia, they suggest that a large eastward electric field existed in the Asian sector. Finally, the plasma bubbles extended up to the mid-latitudes (~ 43° geomagnetic latitude) in both hemispheres, maintaining geomagnetic conjugacy. The second point is that the mid-latitude plasma bubble disappeared 1–2 h earlier in the northern hemisphere than in the southern hemisphere at close to midnight. In the northern hemisphere, the ionospheric virtual height decreased near midnight, followed by a rapid decrease in the total electron content and a rapid increase in the ionospheric virtual height. These results imply that the mid-latitude plasma bubble disappeared as the background plasma density decreased after midnight due to the recombination resulting from the descent of the F layer. Therefore, we can conclude that mid-latitude plasma bubbles can be asymmetric between the northern and southern hemispheres because of the rapid decay of plasma bubbles in one of the hemispheres. Graphical Abstract

This study, for the first time, reports the geomagnetically conjugate structure of a plasma bubble extending to the mid-latitudes and the asymmetrical structure of the decay of the plasma bubble during a geomagnetic storm. We investigated the temporal and spatial variations of plasma bubbles in the Asian sector during a geomagnetic storm on March 1, 2013, using Global Navigation Satellite System-total electron content data with high spatiotemporal resolutions. The first important point of our data analysis results is that the plasma bubble extended from the equator to the mid-latitudes with geomagnetic conjugacy along the magnetic field lines. The total electron content data showed that the plasma bubbles appeared in the equatorial regions near 150° E after sunset during the main phase of the geomagnetic storm. From ionosonde data over both Japan and Australia, they suggest that a large eastward electric field existed in the Asian sector. Finally, the plasma bubbles extended up to the mid-latitudes (~ 43° geomagnetic latitude) in both hemispheres, maintaining geomagnetic conjugacy. The second point is that the mid-latitude plasma bubble disappeared 1–2 h earlier in the northern hemisphere than in the southern hemisphere at close to midnight. In the northern hemisphere, the ionospheric virtual height decreased near midnight, followed by a rapid decrease in the total electron content and a rapid increase in the ionospheric virtual height. These results imply that the mid-latitude plasma bubble disappeared as the background plasma density decreased after midnight due to the recombination resulting from the descent of the F layer. Therefore, we can conclude that mid-latitude plasma bubbles can be asymmetric between the northern and southern hemispheres because of the rapid decay of plasma bubbles in one of the hemispheres. [ABSTRACT FROM AUTHOR]

Mesoscale convective systems (MCSs) are the main source of precipitation in the tropics and parts of the mid‐latitudes and are responsible for high‐impact weather worldwide. Studies showed that deficiencies in simulating mid‐latitude MCSs in state‐of‐the‐art climate models can be alleviated by kilometer‐scale models. However, whether these models can also improve tropical MCSs and whether we can find model settings that perform well in both regions is understudied. We take advantage of high‐quality MCS observations collected over the Atmospheric Radiation Measurement (ARM) facilities in the US Southern Great Plains (SGP) and the Amazon basin near Manaus (MAO) to evaluate a perturbed physics ensemble of simulated MCSs with 4 km horizontal grid spacing. A new model evaluation method is developed that enables to distinguish biases stemming from spatiotemporal displacements of MCSs from biases in their reflectivity and cloud shield. Amazon MCSs are similarly well simulated across these evaluation metrics than SGP MCSs despite the challenges anticipated from weaker large‐scale forcing in the tropics. Generally, SGP MCSs are more sensitive to the choice of model microphysics, while Amazon cases are more sensitive to the planetary boundary layer (PBL) scheme. Although our tested model physics combinations had strengths and weaknesses, combinations that performed well for SGP simulations result in worse results in the Amazon basin and vice versa. However, we identified model settings that perform well at both locations, which include the Thompson and Morrison microphysics coupled with the Yonsei University (YSU) PBL scheme and the Thompson scheme coupled with the Mellor‐Yamada‐Janjic PBL scheme. Key Points: Simulated US and Amazonian mesoscale convective systems (MCSs) are evaluated accounting for spatiotemporal and rotational errorsCentral US MCSs are found more sensitive to microphysics while planetary boundary layer physics are more influential in BrazilOptimal mid‐latitude and tropical MCS model settings are identified [ABSTRACT FROM AUTHOR]

This study applies new satellite datasets and methodologies to build on previous research exploring the physical relationship between lightning and precipitation in mid‐/high latitudes. Specifically, 3 years of Geostationary Lightning Mapper and Global Precipitation Measurement Mission core satellite coincident observations are examined to investigate relationships between lightning flash rate and microwave characteristics of convective precipitation features (cPFs) over the Americas and surrounding oceans between ±50° latitude. Mid‐/high latitude cPFs with lightning are characterized by colder temperatures of maximum 30 dBz echo top height and a smaller range of microwave brightness temperatures when compared to the tropics. Brightness temperature characteristics of electrically active cPFs are highly correlated to radar‐diagnosed ice mass and largely insensitive to synoptic‐scale proxies for convective strength and organization. Low flash density cPFs tend to be more sensitive to synoptic‐scale instability and shear than high flash density cPFs. Regional differences in the environmental forcing and characteristics of electrically active cPFs are shown. For example, the elevated terrain surrounding the Amazon River Basin is characterized by stronger vertical updrafts indicated by higher values of normalized CAPE while the La Plata River Basin is characterized by both stronger updrafts and higher values of radar‐diagnosed ice water mass. Plain Language Summary: New satellite‐based lightning observations collected over Earth's mid‐/high latitudes provide opportunities to observe and better understand relationships between lightning and precipitation properties over a larger domain than that of the historically sampled global tropics. Considered at hemispheric scales, newly combined continuously observed lightning data and low‐Earth orbiting precipitation "snapshots" suggest lightning and precipitation relationships derived from tropical observations also hold for the mid‐/high latitudes. Regional nuances are found in the electrical and microwave characteristics of deep convection—mid‐/high latitude convection is characterized by colder 30‐dBz echo top heights (indicating stronger updrafts) and a smaller range of microwave brightness temperatures when compared to the tropics. Large‐scale environments where electrically active convection is observed are also examined. Physical processes tied to deep convection (e.g., lofting of ice or updraft strength) can explain some trends in the satellite‐observed precipitation and lightning data. Regional differences in the percentage of electrically active convection characterized by stronger inferred updrafts and higher derived values of ice are discussed. Key Points: Global precipitation measurement combined with geostationary lightning mapper observations facilitates new investigations of convective precipitation in the mid‐/high latitudesConvective life cycle stage can be inferred by examining flash rate in terms of radar and passive microwave propertiesDifferent synoptic environmental influences on observed precipitation/lightning properties are explained by impacts on physical processes [ABSTRACT FROM AUTHOR]

Using meteor radar measurements at Mohe (MH, 53.5°N, 122.3°E) and the reanalysis data from 2011 to 2020, the characteristics of intraseasonal oscillations (ISOs) in the mesosphere and lower thermosphere (MLT) region over MH are investigated for the first time. The radar observation shows a prominent ISO with periods of 40–60 days in the zonal wind during the 2015/2016 winter. The observed ISO is the strongest in the oscillation period of 30–60 days during nearly a decade of observation. The ISO amplitude reaches a maximum of 16 m/s at 90 km. The vertical structure indicates that intraseasonal variabilities in the lower mesosphere contribute to the ISO in the MLT region. By bandpassing the zonal wind obtained from the reanalysis data along 122.5°E at 52 km in the Northern Hemisphere with cutoff periods of 40 and 60 days, we show that ISOs in the tropical and mid‐latitude mesosphere are related to each other. Our results also indicate that the tropical mesospheric ISO and the tropospheric Madden‐Julian Oscillations (MJO) are highly correlated. Our analysis suggests that the MJO in the equatorial troposphere may contribute to the enhancement of the ISO in the MLT region over MH. Additionally, a very strong El Niño during the 2015/2016 winter was accompanied by the positive Indian Ocean Dipole, which confines the active MJO in phases 2‒4 for a long time. This may be the reason that in the oscillation period of 30–60 days, the ISO observed at MH is the strongest during almost a decade of observation. Key Points: A strong intraseasonal oscillation (ISO) with a period of 40–60 days is first observed in the mesosphere and lower thermosphere at MoheThe ISO observed at Mohe is likely associated with the equatorial Madden‐Julian Oscillations in the troposphereStrong El Niño and the positive Indian Ocean Dipole indices may contribute to the enhancement of the ISO at MH [ABSTRACT FROM AUTHOR]

Abstract Mesoscale convective systems (MCSs) are the main source of precipitation in the tropics and parts of the mid‐latitudes and are responsible for high‐impact weather worldwide. Studies showed that deficiencies in simulating mid‐latitude MCSs in state‐of‐the‐art climate models can be alleviated by kilometer‐scale models. However, whether these models can also improve tropical MCSs and whether we can find model settings that perform well in both regions is understudied. We take advantage of high‐quality MCS observations collected over the Atmospheric Radiation Measurement (ARM) facilities in the US Southern Great Plains (SGP) and the Amazon basin near Manaus (MAO) to evaluate a perturbed physics ensemble of simulated MCSs with 4 km horizontal grid spacing. A new model evaluation method is developed that enables to distinguish biases stemming from spatiotemporal displacements of MCSs from biases in their reflectivity and cloud shield. Amazon MCSs are similarly well simulated across these evaluation metrics than SGP MCSs despite the challenges anticipated from weaker large‐scale forcing in the tropics. Generally, SGP MCSs are more sensitive to the choice of model microphysics, while Amazon cases are more sensitive to the planetary boundary layer (PBL) scheme. Although our tested model physics combinations had strengths and weaknesses, combinations that performed well for SGP simulations result in worse results in the Amazon basin and vice versa. However, we identified model settings that perform well at both locations, which include the Thompson and Morrison microphysics coupled with the Yonsei University (YSU) PBL scheme and the Thompson scheme coupled with the Mellor‐Yamada‐Janjic PBL scheme.

• Diurnal, monthly and seasonal variations of high resolution foF2, HmF2 and TEC are presented. • Ionosphere in summer displays high fluctuations compared to winter over İstanbul. • Four types of foF2 daily variations indicate different dynamics over Istanbul. Observations of the ionosphere over Istanbul, Turkey have been made using an ionosonde installed at the Istanbul Technical University (ITU) Maslak campus. In this paper, we present average diurnal, monthly, seasonal, and noon-midnight statistics of key F2 layer parameters observed over a one-year period. Those parameters are the F2 layer critical frequency (f o F2), its peak height (h m F2), and the estimated total electron content (TEC). The data show that the overall average behavior at Istanbul is consistent with the findings of other studies of the mid-latitude ionosphere. Also presented are the results of a close look at the diurnal variations of F2 layer. Categorizing these variations provides suggestions about the possible causes or drivers that affect the Eurasian ionosphere. [ABSTRACT FROM AUTHOR]

Recently, much attention has been devoted to better understand the internal modes of variability of the climate system. This is particularly important in mid-latitude regions like the North-Atlantic, which is characterized by a large natural variability and is intrinsically difficult to predict. A suitable framework for studying the modes of variability of the atmospheric circulation is to look for recurrent patterns, commonly referred to as Weather Regimes. Each regime is characterized by a specific large-scale atmospheric circulation pattern, thus influencing regional weather and extremes over Europe. The focus of the present paper is the study of the Euro-Atlantic wintertime Weather Regimes in the climate models participating to the PRIMAVERA project. We analyse here the set of coupled historical simulations (hist-1950), which have been performed both at standard and increased resolution, following the HighresMIP protocol. The models' performance in reproducing the observed Weather Regimes is assessed in terms of different metrics, focussing on systematic biases and on the impact of resolution. We also analyse the connection of the Weather Regimes with the Jet Stream latitude and blocking frequency over the North-Atlantic sector. We find that—for most models—the regime patterns are better represented in the higher resolution version, for all regimes but the NAO-. On the other side, no clear impact of resolution is seen on the regime frequency of occurrence and persistence. Also, for most models, the regimes tend to be more tightly clustered in the increased resolution simulations, more closely resembling the observed ones. However, the horizontal resolution is not the only factor determining the model performance, and we find some evidence that biases in the SSTs and mean geopotential field might also play a role. [ABSTRACT FROM AUTHOR]

Knowledge of the dynamic evolution of vegetation and its forcing mechanisms in the mid-latitude zone is critical to understanding how climate change modulates ecosystems. However, the forcing mechanism of changes in the relative abundance of C3/C4 plants in terrestrial vegetation is unclear due to the lack of comprehensive data sets from the vast study area. Here, the organic carbon isotope (δ13C org) data of mid-latitude modern plants (n = 2833) and topsoil (n = 2017) are compiled, and the linear relationship with the corresponding mean annual temperature (MAT) and precipitation (MAP) is established. Our results demonstrate a close relationship between MAT and the δ13C org values of C3/C4 mixed plants in the soil, implying that temperature is the primary climatic factor determining the relative abundance of C3/C4 plants at mid-latitudes. The results of quantitative reconstruction of paleo-temperature in the Xiaolongwan Lake in Northeast Asia are consistent with the published reconstruction records based on pollen and phytolith, which confirms the reliability of our δ13C org -MAT conversion function. Using the transformation function established in this study, we quantitatively reconstruct the paleo-temperature variation of the Harbin loess in Songnen Plain since the Holocene. The reconstructed MAT shows a continuous increase in the C4 plants abundance with increasing temperature since the mid-Holocene, which is consistent with changes in summer solar insolation at 65° N, oxygen isotopes of cave stalagmite, and phytolith records in the Songnen Plain. Compilation of 715 absolute ages, δ13C org data, regional and global climate records, and human activity intensity records from five dune fields at high risk of desertification from the edge of the East Asian monsoon shows the importance of climate and human activity to the expansion of C4 plants and solidification of dunes. • Temperature controls C4 vegetation expansion in mid-latitudes. • Conversion function between δ13C org -temperature under mixed C3/C4 plants established. • Paleoclimate of Xiaolongwan Lake and Harbin loess was quantitatively reconstructed. • The desert vegetation was controlled by climate and human activities in Holocene. [ABSTRACT FROM AUTHOR]

In this paper, we build upon previous literature in directly addressing the temporal relationship between the stratospheric and tropospheric polar vortex (PV), sea level pressure (SLP), and resultant cold air outbreaks (CAO). An atmospheric and teleconnection analysis was conducted on 49 predefined CAOs across the eastern United States from 1948 to 2016. Clusters of SLP, 100 and 10‐mb geopotential height anomalies were mapped utilizing self‐organizing maps (SOMs) to understand the surface, tropospheric PV, and stratospheric PV patterns preceding CAOs. The Arctic Oscillation (AO), North Atlantic Oscillation (NAO), and Pacific–North American (PNA) teleconnections were used as variables to explain the magnitude and location of mid‐latitude Arctic air displacement. Persistently negative SLP anomalies across the Arctic and North Atlantic were evident 1–2 weeks prior to the CAOs throughout the winter. The tropospheric and stratospheric PV were found to be persistently weak/weakening prior to mid‐winter CAOs and predominantly strong and off‐centred prior to early and late season CAOs. Negative phases of the AO and NAO were favoured prior to CAOs, while the PNA was found to be less applicable. This method of CAO and synoptic pattern characterization benefits from a continuous pattern representation and provides insight as to how specific teleconnections and atmospheric patterns lead to CAOs in the eastern United States. This study has shown that persistently negative SLP anomalies across the Arctic and North Atlantic were evident 1–2 weeks prior to cold air outbreaks (CAOs) in the eastern United States throughout the winter. The tropospheric and stratospheric polar vortex (PV) were found to be persistently weak/weakening prior to mid‐winter CAOs and predominantly strong and off‐centred prior to early and late season CAOs. [ABSTRACT FROM AUTHOR]

Understanding past climate variability is important for obtaining better predictions of future changes. Documentary records are high temporal resolution proxies that can be used to reconstruct aspects of the climate, such as precipitation. Vicuña Mackenna developed a compilation of historical climatic events between the 16th and 19th centuries using chronicles from Spanish colonizers and town council records. The objective of this work was to classify dry and wet periods beginning in the 16th century using records from Vicuña Mackenna by generating a precipitation index based on events in the documentary evidence (e.g., epidemics, "pro pluvia" rogations, and infrastructural damage) into a simple annual precipitation index on an ordinal scale. The index used a three‐term classification scale, with 0 representing normal years, 1 representing wet years, and −1 representing dry years. The documentary records were not substantial enough to identify wet/dry periods during the 16th and 17th centuries. However, it was possible to identify dry and wet years described by conquerors and settlers that first arrived in the study area. During the 18th century, two long periods of drought were identified: 1705 to 1718 and 1770 to 1797. During these droughts, people organized rogations to the Virgen and different saints in desperation due to the lack of water. Finally, during the 19th century, technological improvements in measuring precipitation made it possible to identify intermittent dry and wet periods with higher resolution and precision, and these events could be related to the El Niño–Southern Oscillation (ENSO). The objective of this work was to classify dry and wet periods since the 16th century using Vicuña Mackenna's records by generating a precipitation index based on the transformation of documentary evidence into a simple annual precipitation index. The classification scale used was 0 for normal years, 1 for wet years, and −1 for dry years. During the 18th century it identified two long periods of droughts that are not fully recorded in literature. [ABSTRACT FROM AUTHOR]

We describe a midlatitude ionospheric measurement experiment conducted 19–27 January 2014 at White Sands Missile Range, New Mexico, United States. This experiment was one of a series of experiments conducted under the IARPA high‐frequency Geo program. The objective was to develop a data set to be used by data assimilation studies focused on modeling of the bottomside of ionosphere and high‐frequency signal propagation. We outline the specific objectives of the experiment and the experimental configuration and describe the transmit sites and antenna array that allowed us to estimate angles‐of‐arrival for both O‐ and X‐mode signals. We provide a detailed example from 22 January 2014. This period shows the variations characteristic of medium‐scale traveling ionospheric disturbances. We use the data from this period to estimate the resolution of our angle‐of‐arrival measurements to be about 0.1°. Key Points: We conducted an HF propagation experiment to be used with data assimilation studies as part of the IARPA HFGeo programMeasurements utilized an antenna array to obtain angles‐of‐arrival for both O and X modesMedium‐scale traveling ionospheric disturbances were seen in measurements over most of the experiment [ABSTRACT FROM AUTHOR]

We show that ensemble forecasts of extreme European windstorms can be improved up to a lead time of 36–48 hr by sub‐selecting ensemble members based on their performance at very short lead times (up to 12 hr). This applies to both the ensemble mean position of the cyclone centre and the ensemble windstorm footprint over the continent. A number of ensemble forecasts, including those from the ECMWF Ensemble Prediction System, are initialised every 12 hr and disseminated several hours after initialisation; therefore our approach has the potential to provide improved forecasts in an operational context. The analysis is performed on GEFS reforecast data. Mean error of the full ensemble mean forecasts of European windstorms (blue) and mean error of a sub‐ensemble created by performance selection at t = 12 hr (orange). The numbers in parentheses indicate the number of underlying cases. [ABSTRACT FROM AUTHOR]

Atmospheric fronts are fundamental features of the weather variability in the mid‐latitudes and are frequently associated with high‐impact weather events such as hail, wind gusts or precipitation. A method to link precipitation with synoptic‐scale fronts on sub‐daily timescales is developed based on ERA‐Interim data (1979–2016). A case study, a climatology and a trend analysis are presented and discussed. Spatially, an optimal attribution radius is identified based on a random sampling technique. The method is demonstrated using a past weather event that occurred over western Europe. Annual and seasonal cycles are presented and confirm, in agreement with previous studies, that frontal precipitation accounts for a large fraction of all precipitation (up to 80%) in the mid‐latitudes, especially during autumn and winter. Finally, a negative trend in frontal precipitation is identified, mostly affecting the Gulf Stream region. Cold fronts drive most of the observed trends in this region and the trend pattern suggests a polewards displacement of the zone of enhanced precipitation. A method is presented to relate, in time and space, precipitation to mid‐latitudes synoptic‐scale fronts using 6‐hourly ERA‐Interim data, distinguishing warm and cold fronts (a). The method is validated using a case study occurred over the North Atlantic and European sector (b). Annual and seasonal climatological means for precipitation assigned to fronts are analysed (c). A trend analysis for the period 1979–2016 suggests a statistically significant decrease of precipitation south of the Gulf Stream SST zone, mostly driven by cold fronts. [ABSTRACT FROM AUTHOR]

Located in the mid‐latitudes and exhibiting the greatest topographic relief in the eastern United States, the southern Appalachian Mountains (SAM) contain some of the most diverse climatological environments in the United States. This diversity is most pronounced in the winter season when temperature and snowfall can vary drastically across the region. In this study, we identify long‐term trends and variation of temperature and snowfall in the SAM of the southeastern United States during climatological winter (DJF) from 1910 to 2017. Along with recognizing statistically significant climatic trends, we also identify the influence of several teleconnection patterns, namely the El Niño‐Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), and Pacific Decadal Oscillation (PDO) that further scientific understanding of how this region has remained a climatic anomaly. Results of this study indicate the SAM have experienced a statistically significant long‐term cooling trend since the early 20th century, with recent decades suggesting a reversal towards a warming pattern. Snowfall exhibited high interannual variability, with the 1960s and 1970s producing anomalously high amounts of snowfall. Several atmospheric forcing couplings are identified that align with anomalous conditions in the region. Most notably, negative temperature anomalies and higher snowfall amounts were frequently found during El Niño and negative NAO seasons, with the opposite being true during La Niña and positive NAO winters. The influence of these teleconnection patterns was spatially dependent, with lower elevations and eastern‐facing slopes being highly dependent on the phase of ENSO for snowfall, whereas higher elevations and western‐facing slopes were more reliant on the NAO. The identification of pattern couplings is critical to improving understanding of the anomalous climate of the SAM, enhancing seasonal forecasting, and predicting future climate change in the region. In this study, we identify long‐term trends of temperature and snowfall in the southern Appalachian Mountains—a globally anomalous region—during climatological winter (DJF) from 1910 to 2017. Several atmospheric forcing couplings are identified that align with anomalous conditions in the region. Notably, negative temperature anomalies and higher snowfall amounts are frequently found during El Niño and negative North Atlantic Oscillation seasons. The identification of these couplings is critical to improving understanding of regional anomalies and predicting future climate change. [ABSTRACT FROM AUTHOR]

In December 2021 three Global Navigation Satellite System (GNSS) ionospheric scintillation and Total Electron Content (TEC) monitors were installed in Puerto Rico (∼24.5° N dip latitude). The installation is part of an effort to better understand the occurrence of ionospheric irregularities and scintillation at mid-latitudes. Puerto Rico (PR) is commonly referred to as being located at mid-latitudes or at the boundary between low and mid-latitudes. Previous reports already presented observations of ionospheric irregularities and scintillation detected from PR. These observations, however, were limited in number. Additionally, the reports related the observed scintillation and irregularities events with different types of mid-latitude ionospheric disturbances. Here we present results from the analyses of the first three months of observations, December 21st, 2021 to March 20th, 2022. The analyses focus on the occurrence rate, severity and origin of scintillation detected on the signals tracked by the PR monitors during geomagnetically quiet times. We show that, out of the 43 geomagnetically quiet nights, 34 (∼80%) showed the occurrence of L-band scintillation. The results also indicate the recurrent existence of severe scintillation (S 4 ∼ 1.0) accompanied by large TEC depletions. The temporal evolution of the observed scintillation showed that scintillation-causing plasma irregularities first occurred near the magnetic equator and propagated towards PR (reaching up to ∼22o dip latitude). Simultaneous space-based observations of the ionospheric F-region peak electron densities made by the GOLD mission confirmed that the quiet-time scintillation observed by the monitors in PR was associated with equatorial plasma bubbles. GOLD observations also show enhanced background F-region densities at the location of the Ionospheric Pierce Points of the affected GNSS signals, indicating conditions that favor the occurrence of intense scintillation. • GNSS-based monitors were deployed in Puerto Rico - PR (∼24.5° N dip latitude) and detected L-band scintillation on ∼80% of geomagnetically quiet nights. • Cases of very intense amplitude scintillation (S4 ∼ 1.0) were commonly observed and were accompanied by large TEC depletions. • The latitudinal extent of EPBs and of the northern crest of the EIA create conditions for the strong quiet-time scintillations observed by GNSS receivers in PR. [ABSTRACT FROM AUTHOR]

Cloud fraction (CF) is known as the dominant modulator of Earth’s radiative fluxes. Ground-based CF observations are useful to characterize the cloudiness of a specific site and are valuable for comparison with satellite observations and numerical models. We present for the first time CF statistics (relative to liquid clouds only) for Bern, Switzerland, derived from the observations of a ground-based microwave radiometer. CF is derived with a new method involving the analysis of the integrated liquid water distribution measured by the radiometer. The 10-year analyzed period (2004–2013) allowed us to compute a CF climatology for Bern, showing a maximum CF of 60.9% in winter and a minimum CF of 42.0% in summer. The CF monthly anomalies are identified with respect to the climatological mean values, and they are confirmed through MeteoSwiss yearly climatological bulletins. The CF monthly mean variations are similar to the observations taken at another Swiss location, Payerne, suggesting a large-scale correlation between different sites on the Swiss Plateau. A CF diurnal cycle is also computed, and large intraseasonal variations are found. The overall mean CF diurnal cycle, however, shows a typical sinusoidal cycle, with higher values in the morning and lower values in the afternoon.

Ten years of tornadoes (TR) and waterspouts (WS) in Italy are analysed in terms of geographical, seasonal, monthly, diurnal, and rating distribution. Starting from the European severe weather database, a comprehensive data set is developed for the period 2007–2016, which includes 707 WS and 371 TR. The category of WS includes many weak events but also some intense vortices, able to produce significant damages as they make landfall. WS develop mainly near the Italian coasts exposed to westerly flows (Tyrrhenian and Apulia region Ionian coast); 25% of them makes landfall and becomes TR. The majority of WS develops in autumn (43%), followed by summer (33%). The average density is 0.9 events per 100 km of coastline per year, although there is a strong subregional variation, with peaks of around 5 in some spots along the Tyrrhenian coast. TR originate from WS in about half of cases; the average density of TR is 1.23 events per 104 km2 per year, which is comparable with other Mediterranean regions. The occurrence of TR is more frequent in summer, followed by autumn; however, limiting the analysis to TR originated inland, the number of events is maximum in summer and late spring. The latter result suggests a distinction of “continental” cases, mainly affecting northern Italy in late spring and summer, and “maritime” cases, which affect mainly the peninsular regions in late summer and autumn. The highest density of TR was reported along the coasts of Lazio and Tuscany, in the Venetian plain, in the southern part of Apulia: in these regions, the density of events is comparable with that of the U.S. states with the highest TR rates. In contrast, the probability of significant TR in any Italian region is much smaller than that of the U.S. states with the highest risk. [ABSTRACT FROM AUTHOR]

Crocodylians are ectothermic animals, and their past distribution has been greatly influenced by changing climate since their Cretaceous origin. The Pliocene-Pleistocene witnessed a contraction of the crocodylian latitudinal ranges due to rapid cooling with superimposed pronounced orbital-scale climate oscillations. However, a chronologically-continuous record of the geographically marginal populations of crocodylians is yet to be provided for this time interval, and crocodylian response to such climatic changes is poorly known. This study describes a partial crocodylian skeleton from the Middle Pleistocene of Osaka, Japan, diagnosed as Toyotamaphimeia cf. machikanensis , on the basis of character comparisons, including ontogenetic skull shape change, and consideration of the reconstruction error in the holotype of T. machikanensis . Pliocene-Pleistocene record of fossil crocodylians in the Kinki, Tokai, and Kanto districts of Japan extends from ~3.5 Ma to ~0.3 Ma. The paleotemperature estimates for the crocodylian-bearing horizons indicate that late Early–Middle Pleistocene crocodylians in the Kinki district of Japan were living near their lower thermal limit. During the glacial periods, they might have moved to the southern extremity of Japan or locally became extinct from Japan, while re-expanding their range after the end of glacial periods. [ABSTRACT FROM AUTHOR]

ABSTRACT: Periods of extreme cold impact the mid‐latitudes every winter. Depending on the magnitude and duration of the occurrence, extremely cold periods may be deemed cold air outbreaks (CAOs). A systematic CAO index and ranking system was developed from 20 surface weather stations from 1948 through 2016, based on a set of criteria concerning magnitude, duration, and spatial extent. Standard deviations in temperature were used to identify extreme temperatures relative to the station. A total of 49 CAOs occurred during the 67‐year period, with the majority occurring during mid‐winter. The number of CAOs proved to be largely dependent on the stations latitude and maritime influence. The duration, magnitude, and spatial extent were dependent on the time of the winter season in which the CAO occurred. Furthermore, two prominent clusters of an increased number of CAOs occurred during the 67‐year period, suggesting multi‐decadal circulations may be a factor in CAOs. [ABSTRACT FROM AUTHOR]

To clarify the properties of lake ice at mid-latitudes subject to moderate air temperature, heavy snow and abundant solar radiation even in winter, we conducted field observations at Lake Abashiri in Japan for three winters and developed a one-dimensional (1-D) thermo-dynamical ice growth model. Using this model with meteorological data-sets, we examined the role of snow in the ice thickening process, as well as the Lake Abashiri ice phenology (including the interannual trend) for the past 55 years to compare with high latitude lakes. The ice was composed of two distinct layers: a snow ice (SI) layer and a congelation ice layer. The SI layer occupied a much greater fraction of total ice thickness than that at high latitude lakes. In-situ observations served to demonstrate the validity of the model. Freeze-up and break-up dates supplied by satellite imagery enabled further model validation prior to the availability of field data (2000/01–2015/16). Based on both observations and numerical experiments, it was found that one important role of snow is to moderate the variability of ice thickness caused by changes in meteorological conditions. Furthermore, ice thickness is more sensitive to snow depth than air temperature. When applied to an extended 55-year period (1961/62–2015/16) for which local meteorological observations are available, the mean dates of freeze-up and break-up, ice cover duration and ice thickness in February were estimated to be 12 December (no significant trend), 17 April (−1.7 d/decade), 127 d (−2.4 d/decade) and 43 cm (−1.4 cm/decade). For this long-term period, while snow still played an important role in ice growth, the surface air temperature warming trend was found to be a strong factor influencing ice growth, as reported for the high latitude lakes.

The evolution of the near-surface phytoplankton bloom towards a Deep Chlorophyll Maximum (DCM) in mid-latitudes and subpolar regions of the global ocean is a well-known biological feature. However, our knowledge about the exact mechanism that determines the end of the bloom and its irreversible evolution towards a DCM is still limited. In this work, combining satellite and in-situ oceanographic data together with reanalysis data, we investigate why and when this transition between the near-surface phytoplankton bloom and the development of a DCM occurs. For this aim, we investigate the links between changes in air-sea heat exchanges, the near-surface signature of phytoplankton bloom, and the water column vertical structure by calculating the mixed layer depth (MLD) and depth of the DCM on hydrographic and chlorophyll profiles. We find that the occurrence of the last convective mixing event (heat loss by the ocean surface) at the end of the spring which is able to reach the base of the MLD and inject new nutrients into the mixed layer marks the end of the near-surface bloom and its transition towards a DCM. Identified in this way, the spring bloom duration and the start of the transition towards a DCM can be systematically and objectively determined, providing sensitive indexes of climate and ecosystem variability.

The Iberian Margin is a sensitive area to track high and low latitude processes, and is a key location to understand major past climatic and oceanographic changes. Here we present new biomarker data from IODP Site U1385 (“Shackleton site”) (1017–336 ka) that, when combined with existing data from Cores MD01-2443/4 (last 335 ka), allows us to assess the evolution of sea surface temperature (SST) and meltwater influx over the last 1 Ma at the Iberian Margin. Interglacial periods throughout the last 1 Ma show SST close to 20 °C, even during the so-called “luke-warm” interglacials that are marked by relatively low atmospheric CO 2 concentrations. During glacial periods, extremely cold stadial events are recognized at the Iberian Margin, and are very likely related to meltwater discharges from the European and British-Irish ice sheets into the NE Atlantic, which were transported southwards by the Portugal Current. We subdivided the record into four intervals on the basis of the timing and the magnitude of these extremely cold stadials: 1) from 1017 to ∼900 ka, only minor sporadic freshwater input occurred during deglaciations; 2) from 900 to 675 ka extreme cold events occur as terminal stadial events at the beginning of the deglaciations, which results in abrupt deglacial SST shifts; 3) from 675 to 450 ka only a few, very short-lived events are recorded and seldom is there freshwater input at the Iberian Margin; 4) during the last 450 ka the extreme cold events occurred under full glacial conditions, with particularly severe events during MIS 6 and 8. We propose these mid –glacial events are associated with a strong discharges of European ice sheet (EIS). The fact that these extreme cold events do not coincide with deglaciations questions the role of European ice sheet discharges in triggering deglaciations. [ABSTRACT FROM AUTHOR]

The spatiotemporal variability of surface air pressure and surface air temperature in the Northern Hemisphere troposphere in 1990-2014 is described. In 2005 the low-frequency component (LFC) of average air temperature in January averaged over the latitude zone of 32.5°-67.5° N has stopped its increase that lasted for 35 years (from 1970). The LFC of air temperature in July has continued growing since 1975 (for 39 years). The anomalies of air pressure and air temperature for thirty-year periods and the dynamics of LFC of air temperature and air pressure in the atmospheric centers of action are analyzed. [ABSTRACT FROM AUTHOR]

Atmospheric modes of variability relevant for extreme temperature and precipitation events are evaluated in models currently being used for extreme event attribution. A 100 member initial condition ensemble of the global circulation model HadAM3P is compared with both the multi-model ensemble from the Coupled Model Inter-comparison Project, Phase 5 (CMIP5) and the CMIP5 atmosphere-only counterparts (AMIP5). The use of HadAM3P allows for huge ensembles to be computed relatively fast, thereby providing unique insights into the dynamics of extremes. The analysis focuses on mid Northern Latitudes (primarily Europe) during winter, and is compared with ERA-Interim reanalysis. The tri-modal Atlantic eddy-driven jet distribution is remarkably well captured in HadAM3P, but not so in the CMIP5 or AMIP5 multi-model mean, although individual models fare better. The well known underestimation of blocking in the Atlantic region is apparent in CMIP5 and AMIP5, and also, to a lesser extent, in HadAM3P. Pacific blocking features are well produced in all modeling initiatives. Blocking duration is biased towards models reproducing too many short-lived events in all three modelling systems. Associated storm tracks are too zonal over the Atlantic in the CMIP5 and AMIP5 ensembles, but better simulated in HadAM3P with the exception of being too weak over Western Europe. In all cases, the CMIP5 and AMIP5 performances were almost identical, suggesting that the biases in atmospheric modes considered here are not strongly coupled to SSTs, and perhaps other model characteristics such as resolution are more important. For event attribution studies, it is recommended that rather than taking statistics over the entire CMIP5 or AMIP5 available models, only models capable of producing the relevant dynamical phenomena be employed. [ABSTRACT FROM AUTHOR]

Wind plays a significant role in the flight altitudes selected by nocturnally migrating birds. At mid-latitudes in the Northern Hemisphere, atmospheric conditions are dictated by the polar-front jet stream, whose amplitude increases in the autumn. One consequence for migratory birds is that the region’s prevailing westerly winds become progressively stronger at higher migration altitudes. We expect this seasonality in wind speed to result in migrants occupying progressively lower flight altitudes, which we test using density estimates of nocturnal migrants at 100 m altitudinal intervals from 12 weather surveillance radar stations located in the northeastern USA. Contrary to our expectations, median migration altitudes deviated little across the season, and the variance was lower during the middle of the season and higher during the beginning and especially the end of the season. Early-season migrants included small- to intermediate-sized long-distance migrants in the orders Charadriiformes and Passeriformes, and late-season migrants included large-bodied and intermediate-distance migrants in the order Anseriformes. Therefore, seasonality in the composition of migratory species, and related variation in migration strategies and behaviours, resulted in a convex–concave bounded distribution of migration altitudes. Our results provide a basis for assessing the implications for migratory bird populations of changes in mid-latitude atmospheric conditions probably occurring under global climate change.

At the mid/late Miocene boundary, a northward shift occurred in the Subtropical Front neighbouring the New Zealand continental landmass. The terrestrial palaeoenvironment of New Zealand concurrently underwent a period of cooling. The Dunedin Volcanic Group in southern New Zealand spans the mid/late Miocene boundary and the sedimentary deposits from Kaikorai Valley and Double Hill within this group contain diverse and well-preserved floral assemblages. We used terrestrial palaeoclimate proxies CLAMP (Climate Leaf Analysis Multivariate Program) and BA (Bioclimatic Analysis) to determine the paleoenvironment at southern mid-latitudes during the mid/late Miocene transition. Our results indicate that the mid/late Miocene climate of the Dunedin Volcano was warm-temperate to subtropical (mean annual temperature [MAT]: ~ 17–19 °C) at Double Hill, similar to modern coastal Queensland, and cool- to warm-temperate (MAT: ~ 12–14 °C) at Kaikorai Valley, similar to modern northern New Zealand. Winter temperatures at Kaikorai Valley were distinctly cooler (~ 6–8 °C). Differing aspect (i.e. north vs south facing) may have played a part in determining solar radiation, particularly in an area of high relief, such as the Dunedin Volcano. Because Kaikorai Valley was situated facing south and Double Hill facing north, the two sites would have received differing radiative fluxes, particularly in winter, thereby possibly influencing the local environment, biota, and potentially also the palaeoclimate signal produced by floral proxies. This study provides evidence for the temperature decline in terrestrial palaeoenvironments at mid-latitudes caused by the northward movement of the Subtropical Front and strengthening of the Antarctic Circumpolar Current during the mid/late Miocene. [ABSTRACT FROM AUTHOR]

Cloud fraction (CF) is known as the dominant modulator of Earth's radiative fluxes. Ground-based CF observations are useful to characterize the cloudiness of a specific site and are valuable for comparison with satellite observations and numerical models. We present for the first time CF statistics (relative to liquid clouds only) for Bern, Switzerland, derived from the observations of a ground-based microwave radiometer. CF is derived with a new method involving the analysis of the integrated liquid water distribution measured by the radiometer. The 10-year analyzed period (2004-2013) allowed us to compute a CF climatology for Bern, showing a maximum CF of 60.9% in winter and a minimum CF of 42.0% in summer. The CF monthly anomalies are identified with respect to the climatological mean values, and they are confirmed through MeteoSwiss yearly climatological bulletins. The CF monthly mean variations are similar to the observations taken at another Swiss location, Payerne, suggesting a large-scale correlation between different sites on the Swiss Plateau. A CF diurnal cycle is also computed, and large intraseasonal variations are found. The overall mean CF diurnal cycle, however, shows a typical sinusoidal cycle, with higher values in the morning and lower values in the afternoon. [ABSTRACT FROM AUTHOR]

The Manuherikia Group in southern New Zealand represents terrestrial sediments associated with a large paleolake, Lake Manuherikia, formed during a period of basin subsidence in the early Miocene, ca. 18.7-15.1 Ma. Micro- and macrofloral assemblages collected throughout the Manuherikia Group were studied to derive terrestrial climate proxies, relying on leaf physiognomy (CLAMP) and taxonomic affinity (bioclimatic analysis). The assemblages were also analyzed for the component loading of the relative abundances of different leaf morphotypes and the results were interpreted in light of stratigraphic and lateral ecological variation. Independent paleoclimate proxies from a variety of depositional environments consistently indicate warm-temperate to marginally subtropical mean annual temperatures (16.5-20 °C) and high annual precipitation (1,500-2,500 mm) during the Burdigalian-Langhian of mid-latitude New Zealand. Leaf physiognomy reveals an amplified seasonal contrast in both precipitation and temperature, possibly caused by seasonal shifts in the position of the subtropical high-pressure cells and westerly wind belts, causing overcast wet winters and dry summers. Regional and local vegetation variation was most likely caused by fluctuations in lake levels, which in turn may have been affected by enhanced seasonality from short-term climate oscillations. [ABSTRACT FROM AUTHOR]

Copyright of Atmosphere -- Ocean (Taylor & Francis Ltd) is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atmosphere -- Ocean (Taylor & Francis Ltd) is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: The diurnal variation of the mid-latitude upper thermosphere zonal winds during equinoxes has been studied using data recently generated from CHAMP measurements from 2002 to 2004 using an iterative algorithm. The wind data was separated into two geomagnetic activity levels, representing high geomagnetic activity level (Ap>8) and low geomagnetic activity level (Ap⩽8). The data were further separated into two solar flux levels; with F10.7>140 for high and F10.7⩽140 for low. Geomagnetic activity is a correlator just as significant as solar activity. The response of mid-latitude thermospheric zonal winds to increases in geomagnetic disturbances and solar flux is evident. With increase in geomagnetic activity, midday to midnight winds are generally less eastward and generally more westward after the about midnight transitions. The results show that east west transitions generally occurred about midnight hours for all the situations analyzed. The west to east transition occurs from 1400–1500MLT. Enhanced westward averaged zonal wind speeds going above 150ms−1 are observed in the north hemisphere mid-latitude about sunrise hours (∼0700–1100MLT). Nighttime winds in the north hemisphere are in good agreement with previous single station ground observations over Millstone Hill. Improved ground observations and multi satellite observations from space will greatly improve temporal coverage of the Earth’s thermosphere. [Copyright &y& Elsevier]

The externally imposed vertical drift in the F-region is an extremely important driver of ionospheric dynamics but is very difficult to measure or map. Ionospheric servo algorithms have used h m F 2 as F-region observable to infer the vertical drift. However, an even more plentiful observable is the total electron content (TEC) whose coverage over northern mid-latitudes has both spatial and temporal availability that matches those of the probable mechanisms responsible for vertical drift dynamics. This ionospheric, first principle physics, model study shows that TEC is a viable servo parameter at mid-latitudes in the noon sector. The servo relationship is shown to be quite linear over at least 1 h for vertical drifts between ±100 m/s. Simulations over a full range of seasons and the solar cycle confirm the near linear relationship between TEC and vertical drift with changing linear rate coefficients. These simulation results are dependent upon the vertical drift adopted to generate a baseline ionosphere from which the servo simulations evolve. Thus this type of TEC servo would generate relative vertical drifts. These, in turn, would create latitude-longitude maps of the vertical drift dynamics. • TEC is found to be an excellent candidate for an ionospheric servo algorithm. • TEC changes are linearly related to ionospheric vertical drift. • TEC is available on scales commensurate with the vertical drift drivers at mid-latitudes. • Such a servo algorithm would map mid-latitude vertical drift dynamics. [ABSTRACT FROM AUTHOR]