Hot Events Research Articles

Modeling of network public opinion communication based on social combustion theory under sudden social hot events.

Sudden social hot events spread rapidly in the Internet era, which can easily cause group behaviors. Therefore, studying the law of public opinion communication has important theoretical and practical significance for controlling public opinion. This paper constructs the DBUS (Divorced-Burning-Unburning-Stable) model according to the social combustion theory deduced from the analogy of natural combustion phenomena. This paper comprehensively considers the influence of individual characteristics and external environment on the dissemination of online public opinion, introduces indicators such as individuals' self-awareness ability, authority to reflect individual differences, and takes the surrounding individual influence as an external environment factor. Through simulations, we find that (1) the speed of public opinion communication and the dissipation speed are related to cognitive ability, conformity and the network structure; (2) the credibility of the government and the media and the transparency of the information released are the most important factors affecting the scale of public opinion communication; In addition, the rationality and effectiveness of the model established in this paper are verified by an example.

Quantifying thermo-physiological stress exposure during extreme events: Developing a morphological case study in Istanbul

This study aimed to determine thermal comfort conditions during Extreme Heat Events (EHE), particularly focus on Very Hot Day and Heat Wave Event in Istanbul. The analysis was based on a comprehensive dataset of hourly temperature records collected from six meteorological stations over the period 1991–2021. Subsequently, Land Surface Temperature (LST) was mapped on the basis of EHE days. Finally, specific areas with different street morphologies values from the referenced LST were obtained, enabling the evaluation of heat stress for the EHE day and for the period between 2006 and 2021. The study identified August 5th, 2021 as the day of extreme heat stress in Istanbul. LST obtained for August 5th was divided into three groups: low (23.3°C), moderate (26°C), and high (29.3 - 30°C), and findings regarding heat stress were obtained through thermal indices. Physiologically Equivalent Temperature (PET) values on August 5th, 2021, were significantly higher than the 15-year average, showing a shift from moderate and slight heat stress to strong and extreme heat stress levels. PET values indicated strong heat stress, especially around noon, reaching up to 40.5°C in lower LST, and extreme heat stress level of 45.7°C in the afternoon in higher LST. Extreme thermal conditions were generally observed on the right side of streets oriented between 105° and 165° in both regions.

Agronomic adaptations to heat stress: Sowing summer crops earlier

CONTEXTSummer crops are exposed to heat and drought stresses at critical stages during and after flowering, and their intensity and frequency are likely to increase with climate change. Agronomic stress avoidance offers the opportunity to temporally separate critical crop stages from heat and drought events. However, it might require sowing cold-sensitive summer crops earlier into colder than recommended soil temperatures. There is a need to understand how cold is too cold to sow summer crops early in late winter as well as what are the yield benefits and risks. OBJECTIVEHere, we quantify the likely benefits and trade-offs of sowing sorghum, a summer cereal, earlier to adapt to the increased frequency and intensity of heat and water stresses during flowering and grain filling. METHODSTwo years of multi-environment (n=32) genotype by management trials were conducted across the main sorghum growing regions of Australia. Environments (E) consisted of the combination of years, sites, three times of sowing (early, spring, and summer), and the use of supplementary irrigation. At each E a factorial combination of four plant populations (M) and eight commercial sorghum hybrids (G) were sown with three replications. Crop growth and yield components were measured, and the APSIM model was used to simulate all trials and treatments to quantify risks and derive insights into functional relationships between simulated and measured environmental covariates, and measured crop traits. RESULTSThe tested hybrids showed small differences in cold tolerance during crop establishment. Across the tested environments, the G×M combinations produced up to 60% variation in treatment yields across environment yields, which varied between <0.5 to about 10t ha-1; this translated into a ~5.5-fold variation in water use efficiency. Significant G×E and M×E interactions were observed for grain yield components. No G×M or G×E×M interactions were observed on yield or yield components. Early sowing was associated with a reduced risk of heat stress and water use transfer from vegetative to reproductive stages. Early sowing in late winter or early spring resulted in no significant yield gain or loss when all sites and years were included in the analysis. However, early sowing yielded between 1-2 t ha-1 more when the hottest sites and years were considered separately. This resulted from both the avoidance of heat stresses and milder or no terminal drought stresses. CONCLUSIONSEarly sowing of sorghum can reduce the likelihood of heat stresses around flowering as well as the likelihood of terminal drought stresses. Advantages include reduced yield losses in the hottest years and a transfer of water use to grain filling stages, resulting in increased grain yield and improved grain quality parameters. IMPLICATIONSEarly sowing, an agronomic adaptation, offers the opportunity to quickly adapt to the increase in the frequency and intensity of extreme hot events during critical crop stages. However, for the practice to be de-risked, there is a need to increase cold and chilling tolerance in sorghum and/or identify interventions that enhance seed germination and seedling vigour when the crop is sown early into cold soils.

The effect of vertical displacements on the runaway electron avalanche in ITER mitigated disruptions

Abstract The amplitude of the runaway electron (RE) current during disruptions has to be substantially estimated in simulations before ITER may be operated at a large plasma current. Theoretically, the avalanche gain of RE population on a toroidal flux surface (TFS) is an exponential function of the change in the poloidal magnetic flux ∆ψ on that TFS. However, once a TFS is open, REs on it escape rapidly and can no longer proliferate. It is expected that the vertical motion of the plasma during a disruption could lead to the opening of TFSs as the plasma cross-section is pushed into the wall. The influence of this motion on the RE avalanche gain was rarely considered in previous studies. This study investigates the RE generation in ITER major disruptions and hot vertical displacement events mitigated by the injection of neon and hydrogen, using an axisymmetric 2D model on the JOREK code. Compared to those with a stationary plasma, our simulations show a smaller ∆ψ on a given TFS by the time it becomes open as a result of the vertical motion. The maximum potential avalanche gain is thus several orders of magnitude lower than the estimation without considering the vertical motion. In addition, the RE current produced by a typical nuclear seed (∼ 10 mA) at ITER is investigated.

Public health effectiveness of cooling centres in adverse hot weather events: a systematic review

Abstract Background The 2022 heatwave in England highlighted the need for effective public health interventions like cooling centres in temperate climates where built-in air conditioning is uncommon. Aim To determine the impacts of cooling centres on heat-related health outcomes for users in temperate climates, assessing their effectiveness and identifying barriers to usage. Methods This systematic review analysed literature sourced from MEDLINE, Embase, Web of Science, CENTRAL, and Google Scholar from January 2010 to February 2023. Criteria for inclusion focused on studies evaluating health outcomes related to cooling centre use. Screening and quality assessments were independently conducted using the Mixed Methods Appraisal Tool. Results The review included six studies: three quantitative, three qualitative. Two were evidence synthesis of prior studies. No studies conclusively measured health and wellbeing outcomes directly after cooling centre use; instead, research emphasised user demographics, barriers, and facilitators. Common barriers included accessibility, operational hours, and public perceptions, which often misalign with user needs. Successful implementations were noted in centres integrated within community facilities like libraries or community centres. One modelling study suggested a number needed to treat to avoid one heat-related death of 1 million. The relevance of this is unclear as it was in a hotter climate with greater prevalence of air conditioning than in England. Conclusions While direct health benefits in cooler climates like England are poorly documented, cooling centres play an essential role in comprehensive heat response strategies. They offer potential social benefits and provide a cost-effective alternative to urban redesign. Future studies should aim to directly measure health outcomes and refine operational strategies to maximise benefits. Key messages • Cooling centres are crucial in comprehensive heat response strategies, yet direct evidence in cooler climates like England remains limited. • Integration with existing community services may significantly enhance cooling centre utilisation and effectiveness.

Compound Hot and Dry Events in Argentina and Their Connection to El Niño‐Southern Oscillation

ABSTRACTThis work studies the simultaneous and sequential occurrence of hot and dry months in the summer season in Argentina, north of 40°S, based on three different databases: meteorological stations, a gridded observational dataset and a reanalysis product. The influence of the El Niño‐Southern Oscillation (ENSO) over the occurrence of these compound events is specially analysed using a logistic regression model. Monthly maximum temperature and precipitation data are used for the period 1979–2022 in four sub‐regions of Argentina: Northwestern Argentina (NOA), Northeastern Argentina (NEA), Cuyo (central‐western Argentina) and the Pampas (central‐eastern Argentina). Simultaneous hot and dry months and hot months preceded by dry months are the most frequent compound events. The highest frequencies are found in the centre part of the study region and NEA for simultaneous compound events, and in NOA and the Pampas region for sequential ones. In general terms, all datasets show a good representation of the spatio‐temporal variability of hot and dry months. The insights of the influence of ENSO on compound events revealed that La Niña enhances the occurrences of hot and dry months throughout the study region, with the exception of NOA, where El Niño conditions promote the occurrence of these events. Based on logistic regression models, we successfully quantify the relationship between ENSO and hot and dry months and demonstrate that ENSO plays a significant role as a driver of compound hot and dry events in the central region, Cuyo, NEA and a portion of the Pampas. This research contributes to the understanding of compound events in Argentina and how they are influenced by major drivers of climate variability providing useful information for the development of a predictive system for such events.

Enhancing public opinion monitoring for social hot events with a time series neural network-based logic map

A method for constructing a commercial map of social hotspots based on time-series neural networks is proposed. It explores map construction through three stages: atomic event graph building, fusion, and public opinion analysis. The neural network captures event dynamics and public opinion evolution. An unsupervised learning approach trains the model to explore deep event connections. A time map reflects event trends and opinion changes. A sentence-level event extraction model provides rich information. An empirical mode decomposition method analyzes IMF data to understand intrinsic patterns. Time-series neural networks classify and reconstruct event graphs, constructing a knowledge graph. Experiments show this method reduces storage costs, simplifies prediction, and exhibits robustness. It offers new insights for commercial mapping and contributes to public opinion monitoring.

Effects of Extreme Climatic Events on the Autumn Phenology in Northern China Are Related to Vegetation Types and Background Climates

The increased intensity and frequency of extreme climate events (ECEs) have significantly impacted vegetation phenology, further profoundly affecting the structure and functioning of terrestrial ecosystems. However, the mechanisms by which ECEs affect the end of the growing season (EOS), a crucial phenological phase, remain unclear. In this study, we first evaluated the temporal variations in the EOS anomalies in Northern China (NC) based on the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) from 2001 to 2018. We then used event coincidence analysis (ECA) to assess the susceptibility of EOS to four ECEs (i.e., extreme heat, extreme cold, extreme wet and extreme dry events). Finally, we examined the dependence of the response of EOS to ECEs on background climate conditions. Our results indicated a slight decrease in the proportion of areas experiencing extreme heat and dry events (1.10% and 0.66% per year, respectively) and a slight increase in the proportion of areas experiencing extreme wet events (0.77% per year) during the preseason period. Additionally, EOS exhibited a delaying trend at a rate of 0.25 days/a during the study period. The susceptibility of EOS to ECEs was closely related to local hydrothermal conditions, with higher susceptibility to extreme dry and extreme hot events in drier and warmer areas and higher susceptibility to extreme cold and extreme wet events in wetter regions. Grasslands, in contrast to forests, were more sensitive to extreme dry, hot and cold events due to their weaker resistance to water deficits and cold stress. This study sheds light on how phenology responds to ECEs across various ecosystems and hydrothermal conditions. Our results could also provide a valuable guide for ecosystem management in arid regions.

Process-Oriented Compound Long-Duration Dry and Hot Events in China: Atmospheric Conditions, Moisture, and Heat Budget Analyses

Abstract Summertime compound dry and hot events pose severe threats to agricultural production and human health, especially those with a long duration. Considering the joint evolution of such hazards in space and time, spatiotemporal compound long-duration dry and hot (SLDDH) events in China during 1961–2022 are identified with a process-oriented method. Here, we investigate the associated large-scale atmospheric circulation patterns and the physical processes causing their precipitation and temperature anomalies. In all regions of China, this persistent dry–hot compound extreme is accompanied by anomalous high pressure systems along with enhanced descending motion, increased net surface solar radiation, and decreased water vapor flux convergence. Moisture budget diagnosis shows that precipitation deficits during the SLDDH events are produced primarily by the suppressed vertical moisture advection associated with the dynamical contribution of anomalous subsidence, while the thermodynamic process due to the anomaly in atmospheric moisture content makes a small contribution. Horizontal temperature advection generally plays a negative role in sustaining SLDDH events, while it helps trigger the events in North China. In most regions, adiabatic warming due to abnormal subsidence plays a dominant role in determining the near-surface high temperatures during the long-lasting warm and dry periods, whereas diabatic heating has a cooling or small effect therein. However, in some northern areas such as North China and northern Xinjiang, hot extremes during SLDDH events arise from a combination of diabatic heating and adiabatic warming. This study thus quantifies and reveals the crucial factors leading to the severity of compound dry and hot events.

Increased exposure of rice to compound drought and hot extreme events during its growing seasons in China

Against the backdrop of global warming, compound drought and hot extreme events (CDHEEs) have intensified markedly, attracting attention from both the scientific community and society. However, a comprehensive understanding of the characteristics of the CDHEEs and their impacts on rice production during growing seasons remains limited. Thus, in this study, we use daily maximum and minimum air temperatures to derive a meteorological drought composite index for CDHEE identification. Additionally, we employ the Crop Calendar and the CROPGRIDS data to define the rice-growing seasons and regions. Detailed analyses reveal that from 1961 to 2023, the CDHEE frequency in both single-cropping rice regions (Rice1) and double-cropping rice regions (Rice2) increased at rates of 0.79 days (decade)−1 and 1.26 days (decade)−1, respectively, with a notable acceleration in the post-1990 s. The duration of the CDHEEs has lengthened, and prolonged events have become more frequent. The intensity of the CDHEEs has also enhanced, primarily driven by hot extreme events in Rice1 and the synergistic effects of droughts and hot extreme events in Rice2. Furthermore, the time span of CDHEE occurrence has expanded, starting earlier (rates of − 3.21 days (decade)−1 in Rice1 and − 4.37 days (decade)−1 in Rice2) and ending later (rates of 4.81 days (decade)−1 in Rice1 and 8.20 days (decade)−1 Rice2) during rice-growing seasons, thereby extending the exposure duration of rice. Since the 1990 s, rice exposure to the CDHEEs has also intensified, especially for the persistent CDHEEs. These findings indicate the upward trends in the frequency, intensity and duration of the CDHEEs, as well as the exposure of rice to the CDHEEs, during the rice-growing seasons in China. This research provides crucial insights into CDHEE impacts and underscores the necessity of implementing targeted adaptation and mitigation strategies to safeguard rice production amidst escalating climate challenges.

Exploration of the Upgrading Path of China's Gas Meter Industry in the Digital Economy Era

Gas supply is a fundamental public good that affects millions of households. The online hot search event in April 2024 regarding the "fast running" of gas meters in multiple cities such as Chongqing and Chengdu indicates that there is still a long way to go in improving the quality and upgrading of the gas service industry and gas meter manufacturing industry. Based on the background of the digital economy era, this paper analyzes the role of gas meter manufacturers in the multilateral market of the smart gas management platform and the role of the gas meter industry value chain, explores the basic path and countermeasures for the upgrading of the gas meter industry, with a view to providing valuable reference for the digital transformation of the traditional gas meter industry in the industrial Internet era.

Projected changes in the frequency of compound hot and dry events over Tropical Brazil in CORDEX-CORE simulations

Projected changes in the frequency of compound hot and dry events over Tropical Brazil in CORDEX-CORE simulations

The influence of sub-lethal neonicotinoid doses and ambient temperature on individual Apis mellifera scutellata flight efficiency

Honey bee (Apis mellifera) thermoregulation plays an integral part in their behaviour and physiology and has been shown to be vulnerable to the effects of neonicotinoid insecticides. Flight muscles are a crucial source of physiological heat as well as being vital for behavioural heat regulation, and are negatively affected by neonicotinoid insecticides. In this study, we evaluated the flight efficiency and capacity of Apis mellifera scutellata under the influence of both elevated ambient temperatures and sublethal neonicotinoid exposure. The various aspects of flight; success, distance, speed, and duration, were not notably affected by these factors. However, the honey bees’ ability to initiate a successful flight was significantly affected by neonicotinoid exposure. Such a reduction in honey bee flight capacity, and flight muscle function in general, especially under the increasing frequency and intensity of hot weather events, is cause for concern when considering legislation and use of these neonicotinoids in the agricultural and suburban setting.

Assessment and pre-assessment of compound hot and drought events over Yangtze River Basin

Abstract The severe compound hot and drought event (CHDE) in 2022 had serious impacts on water resources, agriculture, power supply, and ecosystems in the Yangtze River Basin (YRB). Have similar spatiotemporally overlapping compound events, like the one observed in 2022, occurred historically in the basin? How can we pre-assess the impacts of such potential events on subseasonal timescales? To address these, regional CHDEs in the YRB since 1961 were systematically identified and comprehensively assessed using a modified Intensity-Area-Duration (IAD) technique and hazard assessment method. Additionally, the subseasonal pre-assessment capability for CHDEs in the YRB using the China Meteorological Administration's third-generation climate model prediction system (CPSv3-S2S) was demonstrated. A total of 140 CHDEs occurred during 1961 to 2022, with the 21st century showing a remarkably high risk of such events. Among these, 2022 was the most intense year, with the event from July 26th to August 30th being unprecedented in severity. CPSv3-S2S effectively forecast this event’s occurrence within a 1-25 lead days, particularly in pre-assessing its extensively impacted area and high-hazard centers in the upper and middle reaches of the main river course. This pre-assessment method serves as a valuable reference in decision-making to anticipate and mitigate risks of hydropower supply shortages and heightened electricity demand during extremely high temperatures in the upstream area.

Interannual Variation of Summer Compound Hot and Drought Events in Xinjiang and Its Relationship with the North Atlantic Sea Surface Temperature

Abstract Xinjiang suffers compound hot and drought events under global warming. However, less attention has been paid to physical mechanisms of the variability of compound hot and drought events in this region. This article investigates the interannual variation of summer (June–August) compound hot and drought events in Xinjiang and its relationship with the sea surface temperature (SST) over the North Atlantic. The results show that its first empirical orthogonal function (EOF) mode features a spatially homogenous pattern. This mode is closely connected with the simultaneous meridional negative–positive–negative SST anomalies over the North Atlantic. The summer North Atlantic tripole SST anomalies can trigger a remarkable wave train extending from the North Atlantic to Eurasia, consequently inducing an anomalous high pressure system over the Iran–Pamir Plateau, which is conducive to the increase in air temperature from the surface to the upper troposphere over Xinjiang. The warmer troposphere further strengthens the western Asian subtropical meridional temperature gradient and thereby enhances the westerly wind to the north flank of the West Asian subtropical westerly jet (WASWJ). As a result, the WASWJ is displaced northward, which intensifies the sinking motion and prevents the water vapor transport to Xinjiang, leading to a decrease in precipitation in the target region. The higher temperature and less precipitation contribute to the occurrence of compound hot and drought events over Xinjiang. Numerical simulations based on the Community Atmosphere Model, version 4 (CAM4), further confirm the relationship between the North Atlantic tripole SST anomalies and compound hot and drought events in Xinjiang during summer on the interannual time scale. Significance Statement Xinjiang, located in northwest China, suffers from frequent and intense compound hot and drought events in recent decades. It is thus urgent to understand the physical mechanisms associated with its occurrence in order for disaster prevention and mitigation. In this study, we reveal that the leading mode of summer compound hot and drought events over Xinjiang, featuring a spatially homogenous pattern, is closely correlated with the simultaneous meridional negative–positive–negative SST anomalies over the North Atlantic. The North Atlantic tripole SST anomalies can lead to an anomalous high pressure system over the Iran–Pamir Plateau and a northward shift of the West Asian subtropical westerly jet through exciting a wave train propagating from the North Atlantic to Eurasia, which consequently contributes to the occurrence of compound hot and drought events over Xinjiang.

Dominant modes of interannual variability in spring compound dry and hot events over Northern Asia and the possible mechanisms

In this study, spatial and temporal variations of spring compound dry and hot events (CDHEs) over northern Asia (NA) during 1950–2020 and the related possible mechanisms are investigated on the interannual timescale. The standardized compound event indicator (SCEI) is used to represent compound dry and hot conditions over NA, which is validated by the observed summer case of CDHEs over western Russia in 2010. The first empirical orthogonal function (EOF1) mode of the SCEI over NA presents a monopole pattern, while the EOF2 mode shows an east-west dipole pattern. Possible mechanism analysis indicates that the CDHEs tend to be modulated by local high-pressure anomalies, accompanied by reduced cloud cover and more solar radiation. The high-pressure anomalies can lead to warm temperature and water vapor divergence, which synergistically contributes to the occurrence of CDHEs. Further analysis shows that the EOF1 mode is jointly affected by the Scandinavian (SCAND) pattern and the Arctic Oscillation (AO); while the EOF2 mode is influenced by the Atlantic-Eurasian (AEA) teleconnection. Moreover, the North Atlantic tripolar pattern of sea surface temperature (SST) can influence the EOF1 mode through changing the AO. And the diagonal tripolar SST pattern over the North Atlantic affects the EOF2 mode via altering the AEA pattern. The influence of the SST patterns is further confirmed by numerical experiments using the Community Atmospheric Model version CAM-5.3.

Predicting compound agricultural drought and hot events using a Cascade Modeling framework combining Bayesian Model Averaging ensemble with Vine Copula (CaMBMAViC)

Compound Agricultural Drought and Hot Events (CADHEs) cause more disastrous impacts on water-food-energy-ecology security in comparison with individual drought or hot extremes. Reliable CADHEs predictions are therefore paramount to mitigate the potential risk associated with drought and hot events and their combinations. However, there is no prediction model with multi-predictand variables for reliably predicting CADHEs by considering the compounding influence of diverse confounders. In this study, we first employed a Cascade Modeling (CaM) framework to measure the cascading effects between agricultural droughts and hot events driven by the compounding influence of different confounders. Then, a new ensemble prediction model with multi-predictand variables using a CaM framework coupling Bayesian Model Averaging ensemble with Vine Copula, namely the CaMBMAViC model, was developed to simultaneously predict agricultural droughts, hot events, and CADHEs in the warm season with 1–3-month lead times in China, in which the three most important predictors were selected as the explanatory variables. For these selected typical years (e.g., 2006, 2013, and 2019, as the droughts and hot events in these years swept over most regions of China), the proposed CaMBMAViC model has provided reliable predictions for agricultural droughts, hot events, and CADHEs with 1–3-month lead times in the warm season over most areas of China. Two performance metrics, Kling-Gupta Efficiency (KGE) and Percent Bias (PBIAS), both demonstrated that this model yielded skillful predictions for agricultural droughts (KGE > 0.9 and PBIAS = [1.79%, 1.96%]), hot events (KGE > 0.86 and PBIAS = [2.23%, 2.72%]), and CADHEs (KGE > 0.83 and PBIAS = [–0.95%, 0.36%]) for most areas in China. These findings enhance our confidence in seasonal predictions of compound climate events and help us understand their future dynamic.

The trends of non-accidental mortality burden attributed to compound hot-dry events in China and its provinces in a global warming world

BackgroundGlobal warming has provoked more co-occurrence of hot extreme and dry extreme, namely compound hot-dry events (CHDEs). However, their health impacts have seldom been investigated. This study aimed to characterize CHDEs and assess its mortality burden in China from 1990 to 2100. MethodsCHDEs were defined as a day when daily maximum temperature > its 90th percentile and Standardized Precipitation Index < its 50th percentile. A two-stage approach, including a distributed lag nonlinear model (DLNM) and a multivariate meta-analysis, was used to estimate exposure–response associations of CHDEs with mortality in 358 counties/districts during 2006–2017 in China, which was then applied to assess the national mortality burden attributable to CHDEs from 1990 to 2100. FindingsWe observed a significant increasing trend of CHDEs in China until mid-21st century, and then flatted, while the duration and intensity of CHDEs continuously increased across the 21st century. CHDEs were much riskier (ER=17.82 %, 95 %CI: 14.17 %-21.60 %) than independent hot events (ER=5.86 %,95 %CI: -0.04 %,12.45 %) or dry events (ER=0.07 %,95 %CI: -1.22 %, 1.38 %), and there was significantly additive interaction between hot events and dry events (AP=0.10,95 %CI: 0.04, 0.16). Females (ER=24.28 %, 95 %CI: 19.21 %-29.56 %), the elderly (ER=23.28 %, 95 %CI: 18.23 %-28.55 %), and people living in humid area (ER=18.98 %, 95 %CI: 15.08 %–23.02 %) had higher mortality risks than their counterparts. Mortality burden attributed to CHDEs significantly increased during historical observation and became stable since mid-21st century in China. InterpretationCHDEs would significantly increase mortality with higher risk for females, the elderly and people living in humid areas. Mortality burden has significantly increased during historical observation and will keep relatively steady since mid-21st century.

Land-atmosphere coupling amplified the record-breaking heatwave at altitudes above 5000 meters on the Tibetan Plateau in July 2022

In July 2022, regions with elevations exceeding 5 000 m on the inner Tibetan Plateau (TP) witnessed a record-breaking heatwave. But how the atmospheric circulation and soil moisture play roles in the occurrence and maintenance of the heatwave in such high elevation climate sensitive region remains unknown. Here, by using the flow analogue method, we find that negative soil moisture anomalies explain more than half of the extreme high temperature during the heatwave, while atmospheric circulation explains less than half. The high soil moisture-temperature coupling metric and the increased correlation between latent heat flux and soil moisture during heatwave revealed strong land-atmosphere feedback in the Qiangtang Plateau which has amplified the heatwave. Analyses of numerical experiments confirm that the presence of interaction between soil moisture and the atmosphere has increased the intensity of hot extreme event under the same atmospheric circulation conditions. Under the warming background, land-atmosphere coupling leads to a faster increase in extreme high temperatures compared to the global mean warming rate, and it is twice as fast as the increase in extreme high temperatures without coupling. We highlight the increased probability of extreme high temperature over the TP in the future due to soil moisture feedback and the results are hoped to inform policymakers in making decisions for climate adaptation activities.

Projected changes in extreme hot summer events in Asian monsoon regions

40% of global population, who resides in Asian monsoon region is at high risk from extreme hot summer events, which is expected to increase by 25%/30 years under RCP8.5 scenario. Using Community Earth System Model (CESM) Large-ensemble simulations we assess the relative contribution of external forcings and internal variability on hot extremes over South and East Asia. Climate change projects surface mean temperature to reach 2.0 °C and 5.0 °C by ~2050 and ~2100, respectively, making the region uninhabitable under exposed conditions. Internal variability will partly obscure anthropogenic warming over South and Southeast Asia; however, East Asia will experience a 4–6 fold rise in record breaking hot events in later periods. Nevertheless, beyond 2.35 °C warming internal variability will decrease over South Asia due to weaker albedo feedback on unforced internal variability. Our results contradict the existing hypothesis that warming will increase volatility in weather patterns everywhere, particularly the Asian monsoon regions.