Temperature Variability Research Articles

Clouds and plant ecophysiology: missing links for understanding climate change impacts

Observations and models indicate that human activity is altering cloud patterns on a global scale. Clouds impact incident visible and infrared radiation during both day and night, driving daily and seasonal variability in plant temperatures—a fundamental driver of all physiological processes. To understand the impacts of changing cloud patterns on essential plant-based processes such as carbon sequestration and food production, changes in local cloud regimes must be linked, via ecophysiology, with affected plant systems. This review provides a comprehensive treatment of cloud effects (apart from precipitation) on fundamental ecophysiological processes that serve as the basis of plant growth and reproduction. The radiative effects of major cloud types (cumulus, stratus, cirrus) are differentiated, as well as their relative impacts on plant microclimate and physiology. Cloud regimes of major climate zones (tropical, subtropical, temperate, polar) are superimposed over recent changes in cloud cover and primary productivity. The most robust trends in changing global cloud patterns include: (i) the tropical rain belt (comprised mostly of deep convective clouds) is narrowing, shifting latitudinally, and strengthening, corresponding with shorter but more intense rainy seasons, increased clouds and precipitation in some parts of the tropics, and decreases in others; (ii) tropical cyclones are increasing in intensity and migrating poleward; (iii) subtropical dry zones are expanding, resulting in fewer clouds and drier conditions at these latitudes; (iv) summer mid-latitude storm tracks are weakening and migrating poleward, and clouds in temperate regions are decreasing; and (v) clouds over the Arctic are increasing. A reduction in coastal fog and low clouds (including those associated with montane cloud forests) have also been observed, although these trends can be partially attributed to local patterns of deforestation, urbanization, and/or reductions in aerosols associated with clean air initiatives. We conclude by highlighting gaps in the cloud-ecophysiology literature in order to encourage future research in this under-studied area.

Global warming and heat extremes to enhance inflationary pressures

Climate impacts on economic productivity indicate that climate change may threaten price stability. Here we apply fixed-effects regressions to over 27,000 observations of monthly consumer price indices worldwide to quantify the impacts of climate conditions on inflation. Higher temperatures increase food and headline inflation persistently over 12 months in both higher- and lower-income countries. Effects vary across seasons and regions depending on climatic norms, with further impacts from daily temperature variability and extreme precipitation. Evaluating these results under temperature increases projected for 2035 implies upwards pressures on food and headline inflation of 0.92-3.23 and 0.32-1.18 percentage-points per-year respectively on average globally (uncertainty range across emission scenarios, climate models and empirical specifications). Pressures are largest at low latitudes and show strong seasonality at high latitudes, peaking in summer. Finally, the 2022 extreme summer heat increased food inflation in Europe by 0.43-0.93 percentage-points which warming projected for 2035 would amplify by 30-50%.

Evaluation of Fatigue in Older Drivers Using a Multimodal Medical Sensor and Driving Simulator

In recent years, the spread of wearable medical sensors has made it possible to easily measure biological signals such as pulse rate and body acceleration (BA), and from these biological signals, it is possible to evaluate the degree of biological stress and autonomic nervous activity in daily life. Accumulated fatigue due to all-day work and lack of sleep is thought to be a contributing factor to distracted driving, and technology to estimate fatigue from biological signals during driving is desired. In this study, we investigated fatigue evaluation during a driving simulator (DS) using biological information on seven older subjects. A DS experiment was performed in the morning and afternoon, and no significant differences were observed in the change over time of heart rate variability and skin temperature. On the other hand, in the afternoon DS, changes in arousal and body movements were observed based on BA calculated from the three-axis acceleration sensor and fingertip reaction time in a psychomotor vigilance test. It is suggested that by combining biological information, it may be possible to evaluate the degree of fatigue from the presence or absence of arousal and changes in body movements while driving.

Interhemispheric propagation of seasonal sea surface temperature fluctuations over the western Pacific in CMIP6

AbstractInterannual sea surface temperature (SST) variability in the western Pacific is a critical research topic in climate change, as it can significantly impact regional and global weather patterns. Previous observational studies have shown that SST in the southwestern Pacific (SWP) can effectively serve as a precursor signal for SST in the western tropical Pacific (WTP). In this study, we evaluate and compare the modelling capabilities of 32 CMIP6 models to simulate the relationship between SWP and WTP SST. The results indicate that while some CMIP6 models can simulate the spatial connection and physical processes between the SWP and WTP, there are significant intermodel differences. Specifically, the models that best simulate the cross‐equatorial propagation of SWP SST anomalies are those that accurately simulate the cross‐equatorial wind anomalies induced by SWP SST anomalies, highlighting the key role of wind‐evaporation‐SST feedback in SST propagation. Further analysis reveals that the intermodel spread in cross‐equatorial SST propagation is attributable to model biases in simulating climatological SST and wind speed. Models with warm climatological equatorial SST and strong wind speeds provide favourable conditions for the cross‐equatorial propagation of SWP‐related SST anomalies towards the north. Warm SST and strong inter‐season wind speeds near the equator facilitate the northward propagation of the SWP warm signal, leading to increased warming in the WTP.

Combined effect of warming, nutrients, and species pool size on the seasonal variability of phytoplankton composition: A modeling perspective

AbstractThe anticipated long‐term rise in temperature can have numerous effects on freshwater phytoplankton, however, there is a great deal of uncertainty about how biogeochemical processes modify community functioning under a warming climate. Previous works regarding a large shallow lake and a mesocosm study showed a positive relationship between the temporal variability of phytoplankton composition and mean temperature, which might be a sign of warming‐stimulated instability in ecosystem processes. To elucidate whether these observations are part of a more general phenomenon, we combined a numerical model describing the dependence of algal growth on temperature and nutrient concentration with a multispecies, multi‐nutrient model. We ran simulations representative of changes in phytoplankton communities with randomized initial species composition under different temperature scenarios (current annual temperature pattern increased with 1°C, 2°C, or 3°C), various levels of nitrogen and phosphorus supply and different degrees of temporal variability in those supplies. The model outputs showed that seasonal variability in composition can be enhanced by warming through the mechanistic links between nutrient availability, temperature, and species‐specific growth rates, but the rate of increase is also dependent on nutrient ratios and the size of the species pool. Moreover, temporal variability in nutrient loads also enhanced compositional variability, but the rate of increase also depended on the level of nutrient supply. The results of our study hint that the impact of climate change and eutrophication on phytoplankton dynamics can be more intricate than spatiotemporally limited field or experimental observations would suggest.

Variability and high temperature reliability of graphene field-effect transistors with thin epitaxial CaF2 insulators

Graphene is a promising material for applications as a channel in graphene field-effect transistors (GFETs) which may be used as a building block for optoelectronics, high-frequency devices and sensors. However, these devices require gate insulators which ideally should form atomically flat interfaces with graphene and at the same time contain small densities of traps to maintain high device stability. Previously used amorphous oxides, such as SiO2 and Al2O3, however, typically suffer from oxide dangling bonds at the interface, high surface roughness and numerous border oxide traps. In order to address these challenges, here we use 2 nm thick epitaxial CaF2 as a gate insulator in GFETs. By analyzing device-to-device variability for about 200 devices fabricated in two batches, we find that tens of them show similar gate transfer characteristics. Our statistical analysis of the hysteresis up to 175oC has revealed that while an ambient-sensitive counterclockwise hysteresis can be present in some devices, the dominant mechanism is thermally activated charge trapping by border defects in CaF2 which results in the conventional clockwise hysteresis. We demonstrate that both the hysteresis and bias-temperature instabilities in our GFETs with CaF2 are comparable to similar devices with SiO2 and Al2O3. In particular, we achieve a small hysteresis below 0.01 V for equivalent oxide thickness (EOT) of about 1 nm at the electric fields up to 15 MV cm−1 and sweep times in the kilosecond range. Thus, our results demonstrate that crystalline CaF2 is a promising insulator for highly-stable GFETs.

Subsurface temperature estimates from a Regional Ocean Modelling System (ROMS) reanalysis provide accurate coral heat stress indices across the Main Hawaiian Islands

As ocean temperatures continue to rise, coral bleaching events around the globe are becoming stronger and more frequent. High-resolution temperature data is therefore critical for monitoring reef conditions to identify indicators of heat stress. Satellite and in situ measurements have historically been relied upon to study the thermal tolerances of coral reefs, but these data are quite limited in their spatial and temporal coverage. Ocean circulation models could provide an alternative or complement to these limited data, but a thorough evaluation against in situ measurements has yet to be conducted in any Pacific Islands region. Here we compared subsurface temperature measurements around the nearshore Main Hawaiian Islands (MHI) from 2010 to 2017 with temperature predictions from an operational Regional Ocean Modeling System (ROMS) to evaluate the potential utility of this model as a tool for coral reef management. We found that overall, the ROMS reanalysis presents accurate subsurface temperature predictions across the nearshore MHI region and captures a significant amount of observed temperature variability. The model recreates several temperature metrics used to identify coral heat stress, including predicting the 2014 and 2015 bleaching events around Hawaiʻi during the summer and fall months of those years. The MHI ROMS simulation proves to be a useful tool for coral reef management in the absence of, or to supplement, subsurface and satellite measurements across Hawaiʻi and likely for other Pacific Island regions.

On the Estimation of the Interannual Variability of the Ocean Surface Temperature in the Area of the Peruvian Upwelling

The interannual variability of the ocean surface temperature in the area of the Peruvian upwelling for the period 1980–2022 is considered according to the satellite archive GODAS (Global Ocean Data Assimilation System) using the methods of multivariate statistical analysis. Local foci of significant trends, for average annual Sea Surface Temperature (SST) values, were identified near the Peruvian offshore. Four regions (clusters) were obtained, which describe the variability of SST in front off Peru, which could be used to pretend to develop a prognostic oceanographic model. Furthermore, coincidences of temperature fluctuations were found between the first cluster and the region N3+4

How Variable Are Cold Pools?

AbstractCold pools formed by precipitating convective clouds are an important source of mesoscale temperature variability. However, their sub‐mesoscale (100 m–10 km) structure has not been quantified, impeding validation of numerical models and understanding of their atmospheric and societal impacts. We assess temperature variability in observed and simulated cold pools using variograms calculated from dense network observations collected during a field experiment and in high‐resolution case‐study and idealized simulations. The temperature variance in cold pools is enhanced for spatial scales between ∼5 and 15 km compared to pre‐cold pool conditions, but the magnitude varies strongly with cold pool evolution and environment. Simulations capture the overall cold pool variogram shape well but underestimate the magnitude of the variability, irrespective of model resolution. Temperature variograms outside of cold pool periods are represented by the range of simulations evaluated here, suggesting that models misrepresent cold pool formation and/or dissipation processes.

Drivers of Laptev Sea interannual variability in salinity and temperature

Abstract. Eurasian rivers provide a quarter of total fresh water to the Arctic, maintaining a persistent fresh layer that covers the surface Arctic Ocean. This freshwater export controls Arctic Ocean stratification, circulation, and basin-wide sea ice concentration. The Lena River supplies the largest volume of runoff and plays a key role in this system, as runoff outflows into the Laptev Sea as a particularly shallow plume. Previous in situ and modelling studies suggest that local wind forcing is a driver of variability in Laptev sea surface salinity (SSS) but there is no consensus on the roles of Lena River discharge and sea ice cover in contributing to this variability or on the dominant driver of variability. Until recently, satellite SSS retrievals were insufficiently accurate for use in the Arctic. However, retreating sea ice cover and continuous progress in satellite product development have significantly improved SSS retrievals, giving satellite SSS data true potential in the Arctic. In this region, satellite-based SSS is found to agree well with in situ data (r>0.8) and provides notable improvements compared to the reanalysis product used in this study (r>0.7) in capturing patterns and variability observed in in situ data. This study demonstrates a novel method of identifying the dominant drivers of interannual variability in Laptev Sea dynamics within reanalysis products and testing if these relationships appear to hold in satellite-based SSS, sea surface temperature (SST) data, and in situ observations. The satellite SSS data firmly establish what is suggested by reanalysis products and what has previously been subject to debate due to the limited years and locations analysed with in situ data; the zonal wind is the dominant driver of offshore or onshore Lena River plume transport. The eastward wind confines the plume to the southern Laptev Sea and drives alongshore transport into the East Siberian Sea, and westward wind drives offshore plume transport into the northern Laptev Sea. This finding is affirmed by the strong agreement in SSS pattern under eastward and westward wind regimes in all reanalyses and satellite products used in this study, as well as with in situ data. The pattern of SST also varies with the zonal wind component and drives spatial variability in sea ice concentration.

A temperature control method of hot-bar soldering based on extended Kalman filter

PurposeThis study aims to introduce a novel technique for nonlinear sensor time constant estimation and sensor dynamic compensation in hot-bar soldering using an extended Kalman filter (EKF) to estimate the temperature of the thermocouple.Design/methodology/approachTemperature optimal control is combined with a closed-loop proportional integral differential (PID) control method based on an EKF. Different control methods for measuring the temperature of the thermode in terms of temperature control, error and antidisturbance are studied. A soldering process in a semi-industrial environment is performed. The proposed control method was applied to the soldering of flexible printed circuits and circuit boards. An infrared camera was used to measure the top-surface temperature.FindingsThe proposed method can not only estimate the soldering temperature but also eliminate the noise of the system. The performance of this methodology was exemplary, characterized by rapid convergence and negligible error margins. Compared with the conventional control, the temperature variability of the proposed control is significantly attenuated.Originality/valueAn EKF was designed to estimate the temperature of the thermocouple during hot-bar soldering. Using the EKF and PID controller, the nonlinear properties of the system could be effectively overcome and the effects of disturbances and system noise could be decreased. The proposed method significantly enhanced the temperature control performance of hot-bar soldering, effectively suppressing overshoot and shortening the adjustment time, thereby achieving precise temperature control of the controlled object.

Rainfall variability increased with warming in northern Queensland, Australia, over the past 280 years

Floods and droughts are hydrological extremes that impact ecosystems, agriculture, and human well-being. These extremes are expected to intensify in a warmer world, although many regions lack the observations needed to place current trends in the context of long-term variability. Here we present a new multi-century record of tropical rainfall based on a multi-proxy approach from northern Great Barrier Reef coral. The robust calibration with instrumental rainfall allows us to quantitatively estimate summer rainfall in northern Queensland back to 1746 CE. We find that as global climate warmed, wet-season rainfall in this region has increased by ~10% since 1750 and the standard deviation (21-yr 1-σ) of wet-season rainfall more than doubled, as rainy years became much wetter, while dry years remained dry. Reconstructed rainfall correlates with El Niño indices and the link to Pacific temperature variability has strengthened as climate warmed, consistent with expected intensification of La Niña-related rainfall.

Regime Shifts in Lake Oxygen and Temperature in the Rapidly Warming High Arctic

AbstractGlobal warming is destabilizing the cryosphere, with consequences for glaciers, permafrost, sea ice and lake ice. Polar lakes have short ice‐free seasons, and small changes in ice cover duration have the potential to provoke alterations to ecosystem structure. However, these lakes are understudied, and the consequences for mixing regimes, thermal structures and biogeochemical processes remain unclear. We measured three annual cycles of dissolved oxygen, temperature and specific conductivity in a lake at ∼83°N to investigate limnological processes and their interannual variability. There were sharp interannual contrasts in lake dynamics, with state shifts in mixing, stratification and oxygen regimes due to air temperature variability and meteorological events. We also observed unusual thermal profiles that were associated with solute gradients. These striking differences underscore the sensitivity of high Arctic lakes to interannual variations in meteorological forcing, and their susceptibility to regime shifts in response to ongoing global change.

Trends of Satellite-Derived Thermal Fronts in the Southeast and Southwest of Australia Between 1993 and 2019

Oceanic fronts play a significant role in marine ecosystems by enhancing vertical exchange, promoting the aggregation of plankton, and drawdown of organic carbon. Anthropogenic emission of carbon dioxide and other greenhouse gases in the twentieth century has driven global warming, leading to rising ocean temperatures. Specific regions warming faster than the global average—known as ‘ocean warming hotspots’—have been identified, impacting geophysical and biogeochemical dynamics of local ecosystems. Here, we aim to characterize the variability of sea surface temperature (SST) fronts in the southeast and southwest Australia hotspots. Using a histogram frontal detection method, we derived fronts from AVHRR-only and Multi-sensor 6-day SST composites on a 0.02 × 0.02 grid between January 1993 and December 2019. Our results indicate that frontal frequency and frontal density have increased in both regions in the past three decades, by around 0.2–0.3%. In addition, both regions exhibit higher frequency and density of fronts in austral winter and fewer in austral summer. Our calculations show that changes in frontal frequency/density show some relationship to El Niño-Southern Oscillation and Indian Ocean Dipole. Changes in frontal activity could strongly impact local ocean biogeochemistry and marine ecosystems. A better understanding changing fronts in hotspots will help predict and manage future changes in regional oceans to warming.

Impact of Variability on Novel Transistor Configurations in Adder Circuits at 7nm FinFET Technology

This research work focuses on implementation of the FinFET-based complementary metal-oxide-semiconductor (CMOS) Full Adder circuits for different transistor configurations using ASAP7 FinFET model. First, this work examines FinFET-based AND-OR-invert (AOI) gates using different topologies, and second, a FinFET-based CMOS Full Adder circuit at the 7[Formula: see text]nm technology node is analyzed with respect to its process, voltage and temperature (PVT) variability effect measured in terms of the normalized standard deviation of different performance metrics. The comparison is made between conventional (CFFA1) and proposed (FFA2, FFA3, FFA4, FFA5, FFA6, FFA7 and FFA8) FinFET-based CMOS full adder circuits. The aim is to determine the optimal design configuration of the FinFET full adder circuit with the minimum impact of PVT variability. On examining the power delay product (PDP) variability, it is found that variations in FFA2, FFA3, FFA4, FFA5, FFA6, FFA7 and FFA8 are significantly lower than CFFA1 by 6.30%, 4.68%, 10.30%, 65.48%, 68.05%, 65.61% and 17.20%, respectively. Among all the proposed configurations, normalized standard deviation [Formula: see text] for the PDP metric is lowest in FFA6, followed by FFA7, FFA5, FFA8, FFA4, FFA2 and FFA3. The normalized standard deviation [Formula: see text] for power dissipation, however, is lowest in FFA8. In addition, a layout comparison analysis of conventional and proposed full adder circuits reveals that FFA7 has the least area, followed by FFA8, FFA6, FFA5, FFA3, FFA4, FFA2 and CFFA1. The area of FFA2, FFA3, FFA4, FFA5 and FFA6 has decreased by 3.29%, 3.51%, 3.50%, 5.14% and 5.52%, while FFA7 and FFA8 have experienced a decrease in area by 13.87% and 14.36%, respectively, as compared to conventional CFFA1. The proposed layout of FinFET-based CMOS Full Adders can be directly transferred into the foundry’s production line for manufacturing purposes. The overall investigation led us to conclude that FFA8 is the most efficient of all due to the lowest power variation, lower delay variation and lower PDP variation, moreover it has a reduced layout area among all the discussed designs. However, there is a tradeoff in terms of penalty in nominal power, propagation delay and PDP in the proposed topologies.

Mother–offspring conflict and body temperature regulation during gestation and lactation in a wild primate

Abstract The physiological performance of a mother during reproduction represents a trade‐off between continued investment in her current offspring, and the mother's own survival and ability to invest in future offspring. Here, we used core body temperature (Tb) patterns to examine the degree to which maternal body temperatures support the infant during periods of gestation and lactation. We implanted 30 wild vervet monkeys (Chlorocebus pygerythrus) with miniature data loggers to obtain continuous measurements of core Tb during periods of typical (i.e. non‐drought periods) and limited (i.e. drought period) resource availability. We tracked maternal Tb profiles across the gestation and lactation periods, associated with 23 births, and compared those with Tb profiles of non‐reproductive females. This allowed us to examine the flexibility in maternal body temperatures and test whether limited resource availability shifts priority away from offspring investment and towards self‐maintenance. Vervet monkeys demonstrated the predicted pattern of gestational hypothermia and improved homeothermy in the gestation period during typical conditions, consistent with the maintenance of a thermal gradient to facilitate heat loss from the foetus. During periods of limited resource availability (i.e. drought), mothers were less homeothermic and more hyperthermic during the gestation period. Vervet monkeys showed no evidence of lactational hyperthermia during typical conditions. During the drought, lactating mothers demonstrated hyperthermia and increased variability in body temperature, consistent with the increased metabolic demands and water requirements for milk production required to support growing infants. Although a mother's degree of homeothermy during gestation and lactation was unrelated to her infant's chance of survival to weaning, mothers did show flexibility in the degree to which they prioritized the maintenance of a thermal environment that supports their infant's development. Together, our findings demonstrate that flexibility in a mother's investment in thermoregulation during gestation and lactation may reflect a bet‐hedging trade‐off between self‐maintenance and offspring investment. Read the free Plain Language Summary for this article on the Journal blog.

Vietnamese farmers’ perception of climate change effects on water resources and determinants of climate change

ABSTRACT This study investigates crop farmers’ perception on climate change effects on water resources and factors that influence their perceptions of it in Vietnam. A sample of 253 was randomly selected from a total population of 685 crop farmers and a structured questionnaire was created to gather data. Descriptive and inferential statistics were used. The research results showed that climate change effects on water resources varied by landform. A majority of farmers perceived that: shifts in rainfall amount and variability affect the operation of runoff water and groundwater recharge; shifts in temperature level and variability considerably influence evapotranspiration; and changes in runoff amount and runoff variability greatly influence soil water storage and groundwater. Mixed cropping systems, use of soil conservation, extension contacts, farming practices, non-agricultural activities, credit programme participation, information and communication technology (ICT) owned, and education level are the important determinants of farmers’ perceptions on climate change.

Modeling the spatial distribution of numbers of coral reef fish species and community types in the Western Indian Ocean faunal province

Predicting and mapping coral reef diversity at moderate scales can assist spatial planning and prioritizing conservation activities. We made coarse-scale (6.25 km2) predictive models for numbers of coral reef fish species and community composition starting with a spatially complete database of 70 environmental variables available for 7039 mapped reef cells in the Western Indian Ocean. An ensemble model was created from a process of variable elimination and selectivity to make the best predictions irrespective of human influences. This best model was compared to models using preselected variables commonly used to evaluate climate change and human fishing and water quality influences. Many variables (~27) contributed to the best number of species and community composition models, but local variables of biomass, depth, and retention connectivity were dominant predictors. The key human-influenced variables included fish biomass and distance to human populations, with weaker associations with sediments and nutrients. Climate-influenced variables were generally weaker and included median sea surface temperature (SST) with contributions in declining order from SST kurtosis, bimodality, excess summer heat, SST skewness, SST rate of rise, and coral cover. Community composition variability was best explained by 2 dominant community richness axes of damselfishes-angelfishes and butterflyfishes-parrotfishes. Numbers of damselfish-angelfish species were ecologically separated by depth, and damselfishes declined with increasing depth, median temperature, cumulative excess heat, rate of temperature rise, and chronic temperature stresses. Species of butterflyfish-parrotfish separated by median temperature, and butterflyfish numbers declined with increasing temperature, chronic and acute temperature variability, and the rate of temperature rise. Several fish diversity hotspots were found in the East African Coastal Current Ecoregion centered in Tanzania, followed by Mayotte, southern Kenya, and northern Mozambique. If biomass can be maintained, the broad distributions of species combined with compensatory community responses should maintain high diversity and ecological resilience to climate change and other human stressors.

Changes in glacier surface temperature across the Third Pole from 2000 to 2021

Glacier surface temperature is not only an important indicator of climate change, but is also directly related to glacier physical processes and mass balance. Glaciers over the Third Pole have shown heterogeneous but accelerated mass loss over the past two decades. However, few studies have focused on changes of glacier surface temperature in this region. In this study, we investigate this change from 2000 to 2021 using an altitudinal area-weighting method based on Landsat surface temperature products. The results show that this method can robustly derive inter-annual variability and long-term trends of subregional glacier surface temperature. Over the entire Third Pole, glacier surfaces exhibited warming at the rate of +0.17 ± 0.35 °C dec−1 (p = 0.32). The warming had a distinct seasonal pattern: warming in autumn (+0.50 ± 0.53 °C dec−1, p = 0.06) but cooling in spring (−0.22 ± 0.36 °C dec−1, p = 0.23). Correspondingly, the ablation season 0 °C isotherm altitude has risen >100 m and the glacier area with GST ≥0 °C has expanded by 10%. Moreover, the GST changes displayed large spatial heterogeneity. In the westerlies-dominated regions (e.g., Karakoram and Kun Lun), glacier surfaces showed slight warming or even cooling on average (from −0.10 to +0.06 °C dec−1), while in the monsoon-dominated regions (e.g., East Himalaya, Southeast Tibetan Plateau and Hengduan Mountains), strong warming was observed (> +0.50 °C dec−1, p < 0.05). Glacier surfaces generally showed a faster warming at north slopes than south slopes, especially in the ablation season. These results emphasize that different magnitudes of glacier surface warming are important indicators for the contrasting glacier changes over the Third Pole. The method presented here opens the way to investigate long-term surface temperature change of global mountain glaciers, which can help us further understand the mechanisms of glacier response to global climate change.

Impact of the Eurasian Zonal Circulation on the Interannual Variability of Winter Surface Air Temperature and Subseasonal Temperature Reversal in North China

AbstractThis study focuses on the interannual variability of winter mean surface air temperature (SAT) and subseasonal SAT reversal in North China, which have profound impacts on national life and economic activities. The analysis explores the temporal and spatial distribution characteristics of these variations and their relationship with the Eurasian Zonal Circulation (EZ). The findings reveal distinct interdecadal changes in North China’s winter mean SAT, along with a general subseasonal reversal of cold and warm conditions. In comparison to the North Atlantic oscillation/Arctic Oscillation, the EZ has a more significant influence on the interannual variability of winter and subseasonal reversals. Strong EZ years are associated with the weakening of the Siberian High and the Ural Blocking High, causing the East Asian Trough to move eastward, which leads to the retention of cold air from the north and increased SAT in North China. Conversely, weak EZ years exhibit opposite circulation patterns. The winter mean EZ is influenced by preceding autumn Arctic sea ice concentrations (SIC). Reduced autumn SIC results in decreased heat flux and reduced eddy energy, leading to substantial attenuation of the winter storm track across Scandinavia and Western Asia. This attenuation, mediated through the interaction between eddies and mean flow, triggers a slowdown of Eurasian zonal circulation and intensification of the Siberian High. These conditions favor a positive phase of the winter Scandinavia pattern, facilitating the transport of cold Arctic air into North China. Likewise, subseasonal reversals in SIC influence corresponding alterations in the EZ.