Previous studies have suggested that internal oceanic modes such as the Interdecadal Pacific Oscillation (IPO) and Atlantic Multidecadal Oscillation (AMO) have significant effects on the decadal temperature variability over the Tibetan Plateau (TP). However, assessments of decadal variability are very sensitive to the length of study periods. Thus, the dominant factors regulating the decadal temperature variations over the TP and the associated mechanisms have not been clearly identified. This study utilised long-term temperature observations, global reanalysis and climate model simulations to examine the decadal variations and the underlying mechanisms of surface air temperature (SAT) over the TP during boreal summer from 1901 to 2020. Results show that there exist decadal variations in summer TP SAT, with warm periods during 1929-1960 and 1999-2020 and cold periods during 1901-1928 and 1961-1998. It has also been found that the decadal changes in summer TP SAT are closely associated with the AMO. In contrast, TP SAT has a weak relationship with the IPO during 1901-2020. North Atlantic pacemaker simulations further show a zonal wave train pattern propagating from the North Atlantic to East Asia, which triggers anomalous anticyclonic circulations over the northern TP and Lake Baikal. The regional anticyclonic circulation anomalies over the TP not only weaken the subtropical westerly jet stream but also facilitate the water vapour transport into the TP and further cause local warming over the TP. Our findings elucidate the role of internal climate variability in shaping the decadal variability of summer TP SAT and also help reduce uncertainties in future projections of TP SAT changes.

Abstract The warm phase of Atlantic Multidecadal Variability (AMV) induces winter cooling in central Eurasia and widespread warming elsewhere during the instrumental period. To overcome the limitation imposed by short length of instrumental records in studying multidecadal climate variability, in this study, we examine changes in AMV teleconnections over the last millennium using the Community Earth System Model–Last Millennium Ensemble. Results show that the AMV–Eurasian temperature connection during the Medieval Climate Anomaly is similar to that during the instrumental period. In sharp contrast, during the Little Ice Age (LIA), the AMV‐induced mid‐latitude Eurasian cooling was masked, giving way to markedly strong warming across much of Eurasia. Furthermore, the anti‐correlation between AMV and mid‐latitude Eurasian winter temperature is overwhelmed by frequent strong volcanisms during the LIA, which cause temperature in‐phase changes over North Atlantic and Eurasia. Our findings emphasize the roles of natural forcings in Eurasian climate decadal predictions.

Understanding the evolution of the Asian summer monsoon (ASM) on precessional timescales is essential for reconstructing the past Asian climate, understanding environmental changes, and anticipating future climate trends. However, existing marine and terrestrial proxy records show nearly antiphase relationships in ASM rainfall: terrestrial records vary in phase with Northern Hemisphere summer insolation (NHSI), whereas marine records vary inversely with it. This discrepancy has been explained that the ASM is driven either by NHSI or by Southern Hemisphere (SH) summer insolation, leading to a longstanding debate about its fundamental forcing mechanisms. Based on a transient climate simulation spanning the past 150 kyr, this study reveals that the apparent phase contrast between marine and terrestrial rainfall records primarily reflects spatially distinct rainfall responses over land and ocean regions. Through sensitivity experiments that separately isolate Northern Hemisphere and Southern Hemisphere insolation effects, we demonstrate that the land-sea rainfall contrast in the East Asian region is predominantly driven by NHSI. Enhanced NHSI warms the mid- to high-latitudes, leading to a northward shift of the westerly jet. This shift promotes poleward moisture transport and increases moist static energy, ultimately enhancing rainfall over northern China while reducing rainfall over Japan and adjacent coastal areas. For the South Asian region, both NH and SH insolation contribute to the land-sea rainfall contrast. Land rainfall increases are mainly attributed to NHSI, whereas reduced rainfall over the Bay of Bengal is closely linked to SH insolation. When boreal summer occurs at perihelion, the NHSI increase is accompanied by SH insolation increase. The rise in SH insolation weakens the Hadley circulation and the South Asian monsoon circulation, thereby suppressing evaporation and rainfall over the Bay of Bengal. This study elucidates distinct forcing mechanisms behind the land-sea rainfall contrast in East and South Asia. The findings help reconcile inconsistencies between marine and terrestrial proxy records and deepen our understanding of ASM dynamics on precessional timescales, offering valuable insights for interpreting paleoclimate archives and projecting future monsoon behavior.

Under global warming, accelerated hydrological cycle and enhanced climate variability are expected to increase the risk of interannual dry-wet transitions (IDWTs). This study employs the Standardized Precipitation Evapotranspiration Index (SPEI) to examine historical characteristics and future changes of IDWTs over eastern Asia and North America during boreal spring and summer. Over the past six decades, springtime IDWTs are concentrated in eastern China and the southeastern United States, whereas summer transitions intensify and expand northward across eastern Asia but decrease and shift poleward over North America. Springtime IDWT frequency increases by over 50% in most regions of eastern Asia and eastern North America, whereas summer exhibits strong spatial heterogeneity, with continued but weaker increases over eastern Asia and decreases over the mid-latitudes of North America. Further analyses demonstrate that future changes in IDWT frequency are jointly influenced by dry-wet tendencies and the historical climatological dry-wet background.

This article focuses on the appointment scheduling problem with stochastic service times in a two-phase healthcare service system. In this system, the two phases' services refer to medical test and physician consulting, respectively. And two types of patients with different service process exist on a specific day. One type of patient is the new-coming patient who only needs to be served by the physician (if a test is needed, it will be booked for another day due to resource limitation). The other type of patient is the "revisiting" patient who enters the system to get complex test followed by previous suggestions of physician, and he/she will visit the physician with the test results on the same day. All patients get their services through appointments. And the current policy of managing those appointments applied in hospitals is to schedule the appointments in two phases separately. However, as this policy does not take the interaction of two phases' service into consideration, lots of conflicts emerge in the operation process. To avoid the conflict of patients from different types and improve the system's efficiency, we innovatively proposed a jointly scheduling policy, which aims to make a joint scheduling decision for all the patients in two phases. To achieve this, we first formulate this problem as a stochastic program and conduct the sample average approximation approach to reformulate it as a deterministic problem. To solve it efficiently, a hybrid VNS_LSHAPE algorithm which combines the advantage of VNS (Variable Neighborhood Search) and L shape algorithm is subtly developed based on the properties of the problem. Finally, numerical experiments show that our proposed jointly scheduling policy has an overwhelming performance on the system's total cost compared with separately scheduling policy. Both types of patients' satisfaction and the utility of physicians are improved with this policy. Note to Practitioners-In many departments of hospitals, medical test and physician diagnose are two necessary service items provided to the patients. Such a department can be regarded as a two-phase service system. Generally, two types of patients usually exist in this system simultaneously on a work day. One type refers to the new-coming patients who come for an initial consulting of the physician. And the other type refers to the patients who revisit this system to take medical test and physician's further diagnosis sequentially. Since making appointments can relieve systems' congestion, many hospitals begin to provide service through appointing. How to schedule the appointments reasonably for those two types of patients in a two-phase service system proves to be a crucial issue. In this article, a jointly scheduling policy which determines the appointment times for all the patients in two phases is proposed. To obtain a high-quality schedule in reasonable computational time according to this policy, a hybrid VNS_LSHAPE algorithm is also developed. Numerical experiments based on the cardiovascular department of Tongji Hospital in Shanghai is conducted in this article. It is proved that the proposed jointly scheduling policy can reduce the waiting for both types of patients and improve the system's efficiency at the same time.

The impacts of El Niño‐Southern Oscillation (ENSO) on regional climate may vary from decade to decade. Here, we quantify these unstable ENSO impacts on a global scale by calculating the range of possible correlation coefficients (CCs) between the Niño‐3.4 index and climate anomalies in boreal winter at each ∼1° grid point of the globe over any 31‐year running time windows during 1880–2014. In observations, the CCs between the Niño‐3.4 index and surface air temperature (SAT)/precipitation are significantly unstable at a 95% confidence level over 74.7%/73.6% of the globe, respectively, mainly over tropical Indian and Atlantic Oceans, Africa, Australia, North America, and Eurasia. Further Analyses on Community Earth System Model version 2 pacemaker simulations suggest that after the non‐ENSO‐related internal variability is largely removed, the simulated CCs are always significant over most of the tropics and North America. This suggests that internal variability is essential for driving unstable ENSO teleconnections over these regions mainly by modulating the Southern Oscillation and Pacific‐North American teleconnections. Our findings on the nonstationary impacts of ENSO have important implications for understanding and enhancing global seasonal forecast skill.

To investigate the spatio-temporal characteristics and its impact of winter extreme low temperature in North Asia, the extreme cold days index (TX10p) is used in this study. The first empirical orthogonal function (EOF) mode of extreme cold days in North Asia exhibits a consistent distribution centered on Lake Baikal, primarily showing interannual variability. It is influenced by two key factors: snow cover in the previous autumn and the Arctic Oscillation (AO) in the wintertime, modulated by the land-atmosphere. Specifically, the previous autumn snow cover can affect the strength of mid-high latitude troughs and ridges by adjusting the meridional temperature gradient and the strength of the westerly wind, thereby influencing cold waves. Meanwhile, the winter AO can modulate the southward movement of polar cold air by adjusting the strength of the polar vortex, ultimately impacting the frequency of extreme cold days in North Asia. The second EOF mode of the extreme cold days in North Asia displays a northeast-southwest dipole distribution bounded by Lake Baikal, mainly showing an interdecadal transition. Temporally, before 2000, the pattern featured more cold days in the northeast and less in the southwest, with the opposite trend in the later period. Spatially, the spatial distribution also has a corresponding interdecadal change around 2000. The northeast-southwest boundary of the dipole pattern shifted from around 50 degrees N in the early period to approximately 60 degrees N in the later period, reflecting an expansion of the southwest region. The interdecadal change characteristics of the second mode are mainly modulated by the combined effects of the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). Under the synergistic changes of the AMO and PDO phases, the sea surface temperatures of the Pacific and Atlantic can influence the strength of the polar vortex, thereby affecting the north-south gradient in the mid to high latitudes, and the strengths of westerlies and troughs and ridges, ultimately being conducive or not conducive to the southward movement of cold air. In addition, shifts in the PDO phase impact the strength and position of the Aleutian Low, which alters the East Asian trough and contributes to the north-south displacement of the EOF2 mode's spatial pattern.

We used observational data and a long-term piControl simulation from the Community Earth System Model Version 2 to investigate the influence of the Pacific Decadal Oscillation (PDO) on the winter climate over the Tibetan Plateau. The results showed that changes in the phase of the PDO have a significant effect on winter temperatures and precipitation over the southern Tibetan Plateau. Changes in the sea surface temperature (SST) during the positive PDO can weaken the Walker circulation and increase the SST in the Indian Ocean. Our analyses of the moist static energy showed that warming of the tropical troposphere over the Indian Ocean caused by the increased SST has resulted in the horizontal advection of anomalous moist enthalpy by the climatological zonal winds, which was responsible for anomalous ascending motion over the Tibetan Plateau. The additional moisture budget suggests that enhanced vertical motion contributes to the increase in winter precipitation and related total cloud cover over the Tibetan Plateau, leading to the increase of snow depth. The increased total cloud cover and snow depth, in turn, reduces net surface shortwave radiation. The surface air temperature of the Tibetan Plateau is then decreased as a result of the reduction in the net surface shortwave radiation. The PDO therefore has an important modulating role in the interdecadal variability of the winter climate over the Tibetan Plateau. We therefore need to focus on changes in the PDO in research related to the decadal prediction of the climate over the Tibetan Plateau. Under the background of global change, the climate of the Tibetan Plateau has undergone significant changes, and it has an important impact on the regional and global climate. Therefore, it is very important to find out the mechanisms of climate variabilities on the Tibetan Plateau. In this study, we aim to investigate the influences of the Pacific Decadal Oscillation (PDO) on the winter climate of the Tibetan Plateau and the related physical mechanisms by using observational data and a long-term piControl simulation from the Community Earth System Model Version 2. Results suggest that the PDO has an important modulating role in the interdecadal variability of the winter climate over the Tibetan Plateau. The positive PDO phase can increase winter precipitation and decrease the surface air temperature of the Tibetan Plateau. The related mechanisms are also investigated in this study. The positive Pacific Decadal Oscillation (PDO) can increase the precipitation and thereby decreasing the temperature in winter over the southern Tibetan Plateau The horizontal advection of anomalous moist enthalpy is responsible for anomalous ascending motion and increased precipitation The anomalous advection of zonal warm air is caused by warming of the tropical troposphere over the Indian Ocean due to the positive PDO

Reconstruction and observational studies imply a potential linkage of moisture and precipitation change in arid central Asia and monsoonal East Asia, in which the evolution of moisture and precipitation in central Asia is out of phase with that in northern China but in phase with that in southern China. In order to ascertain whether there is a robust linkage between the changes in climate in Asian arid regions and monsoon regions and to elucidate the underlying dynamic mechanisms, we analyzed the Last Millennium Reanalysis dataset and outputs from the Community Earth System Model Last Millennium Ensemble (CESM-LME). The results indicate a significant decadal linkage between precipitation changes in central Asia's arid region and the Asian monsoon region during the last millennium, which is primarily driven by the Interdecadal Pacific Oscillation (IPO). In spring, the positive IPO could enhance westerlies over the Mediterranean Sea and to its east, which could transport more water vapor and cause increased precipitation over central Asia. In summer, the positive IPO is accompanied by a weakened Asian monsoon and southward Asian subtropical westerly jet, which can lead to increased (decreased) summer precipitation over southern China (over northern China and South Asia). The IPO plays a dominant role in connecting the decadal variations in precipitation between arid central Asia and monsoonal Asia by modulating the precipitation of their respective major rainy seasons. Model results suggest that this decadal linkage stems entirely from the internal variability present in the CESM-LME control and all single-forcing simulations. Changes in external forcing factors do not alter this inherent linkage caused by the IPO. Moreover, based on analyses of the aridity index and soil moisture content, this relationship of precipitation variation also causes a similar decadal linkage of moisture changes in central Asia and monsoonal Asia. The differences in the multi-centennial-scale moisture and precipitation variations in the Asian arid region and the monsoon region between the Medieval Climate Anomaly and Little Ice Age are also likely caused by IPO-like sea surface temperature anomalies.

Historical documents provide evidence for regional droughts preceding the political turmoil and fall of Beijing in 1644 CE, when more than 20 million people died in northern China during the late Ming famine period. However, the role climate and environmental changes may have played in this pivotal event in Chinese history remains unclear. Here, we provide tree-ring evidence of persistent megadroughts from 1576-1593 CE and 1624-1643 CE in northern China, which coincided with exceptionally cold summers just before the fall of Beijing. Our analysis reveals that these regional hydroclimatic extremes are part of a series of megadroughts along the Pacific Rim, which not only impacted the ecology and society of monsoonal northern China, but likely also exacerbated external geopolitical and economic pressures. This finding is corroborated by last millennium reanalysis and numerical model simulations revealing internally driven Pacific sea surface temperature variations and the predominance of decadal scale La Niña-like conditions to be responsible for precipitation decreases over northern China, as well as extensive monsoon regions in the Americas. These teleconnection patterns provide a mechanistic explanation for reoccurring drought spells during the late Ming Dynasty and the environmental framework fostering the fall of Beijing in 1644 CE, and the subsequent demise of the Ming Dynasty.

This study assessed the capability of the historical simulations of phase 5 and 6 of the Coupled Model Intercomparison Project (CMIP5/6) in reproducing the temporal and spatial characteristics of the Interdecadal Pacific Oscillation (IPO) and its impact on global surface air temperature (SAT), surface equivalent potential temperature (Thetae_sfc) and precipitation. The IPO index time series simulated by CMIP5/6 models deviated from observations and struggled to capture the phase evolution characteristics of the IPO. Nevertheless, CMIP5/6 models successfully captured the horseshoe-shaped sea surface temperature anomaly in the Pacific. Additionally, the CMIP5/6 models were able to simulate the IPO's 10-30-year period. Notably, the simulated IPO index exhibited a statistically significant upward trend, which was absent in observations. Additionally, the IPO-related global land SAT, Thetae_sfc and precipitation simulated by CMIP5/6 models performed differently in boreal winter and boreal summer. Furthermore, the IPO-related global land SAT performed better in CMIP5/6 models during boreal winter than that in boreal summer. In CMIP6 models, it improved during both boreal winter and summer compared to CMIP5 models. In terms of the IPO-related global land Thetae_sfc, CMIP5/6 models also performed better during boreal winter than in boreal summer. However, CMIP5 models outperformed CMIP6 models during the boreal summer. In terms of the IPO-related global land precipitation, CMIP5/6 models performed better during boreal summer compared to boreal winter. Moreover, the IPO-related global land precipitation in CMIP6 models improved significantly in boreal winter, but almost the same in boreal summer, compared to CMIP5 models. Further studies showed that the enhancements in simulating IPO's spatial pattern did not correspond to improvements in the model's ability to simulate IPO's global teleconnections.

The role of land surface temperature (LST) is of the utmost importance in multiple academic disciplines, such as climatology, hydrology, ecology, and meteorology. To date, many methods have been proposed to estimate LST from satellite thermal infrared data. The single-channel (SC) algorithm can provide an accurate result in retrieving LST based on prior knowledge of known land surface emissivity (LSE). The SC algorithm is extensively employed for retrieving LST from Landsat series data due to its simplicity and its reliance on just one thermal infrared channel. The Thermal Infrared Sensor (IRS) on the Chinese ZY1-02E satellite is a pivotal instrument employed for gathering thermal infrared (TIR) data of land surfaces. The objective of this research is to evaluate the feasibility of a single-channel approach based on water vapor scaling (WVS) for deriving LST from ZY1-02E IRS data because of its wide spectrum range, i.e., 7~12 μm, which is affected strongly by both atmospheric water vapor and ozone. Three study areas, namely the Baotou, Heihe River Basin, and Yantai Sea sites, were selected as validation sites to evaluate the LST inversion accuracy. This evaluation was also conducted via cross-comparison between the retrieved LST and MODIS LST products. The results revealed that the WVS-based method exhibited an average bias of 0.63 K and an RMSE of 1.62 K compared to the in situ LSTs. The WVS-based method demonstrated reasonable accuracy through cross-validation with the MODIS LST product, with an average bias of 0.77 K and an RMSE of 2.0 K. These findings indicate that the WVS-based method is effective in estimating LST from ZY1-02E IRS data.

In this study, the effects of the Mount Pinatubo eruption on surface air temperature (SAT) over mid- to high-latitude Northern Hemisphere (NH) continents in December-January-February (DJF) 1991/92 were investigated using MPI-ESM Grand Ensemble simulations, observations and reanalysis data. The results indicated that the 1991 Mount Pinatubo eruption was not the primary cause of the SAT warming anomaly over the mid- to high-latitude NH continents in DJF 1991/92. In the observations, a positive Arctic Oscillation (AO) or North Atlantic Oscillation (NAO)-like pattern dominated the warming of Eurasia, while a Pacific North American (PNA)-like pattern dominated the warming of North America. However, the model ensemble mean (MEM) simulated SAT and sea level pressure anomalies were much weaker over high-latitude continents. Furthermore, by categorising the 100 MPI-ESM Grand Ensemble simulations into four categories, we found that the probability of warm and cold temperature anomalies occurring over Eurasia and North America was nearly equal. Only about 22% of the MPI-ESM Grand Ensemble members simulated winter warming over the mid- to high-latitude NH continents that matched observations. Our study suggested that this winter warming was mostly caused by the internal variability of the climate system, which was consistent with previous studies. A more detailed analysis indicated that, following the Mount Pinatubo eruption, the intrinsic phase shifts in the AO and PNA remained key factors driving the SAT variations in Eurasia and North America, respectively.

Abstract Over the past two decades, more frequent and intense climate events have seriously threatened the operation of water transfer projects in the Pacific Rim region. However, the role of climatic change in driving runoff variations in the water source areas of these projects is unclear. We used tree-ring data to reconstruct changes in the runoff of the Hanjiang River since 1580 CE representing an important water source area for China’s south-north water transfer project. Comparisons with hydroclimatic reconstructions for the southwestern United States and central Chile indicated that the Pacific Rim region has experienced multiple coinciding droughts related to ENSO activity. Climate simulations indicate an increased likelihood of drought occurrence in the Pacific Rim region in the coming decades. The combination of warming-induced drought stresses with dynamic El Niño (warming ENSO) patterns is a thread to urban agglomerations and agricultural regions that rely on water transfer projects along the Pacific Rim.

In the past 60 years,the global climate has undergone both rapid warming and a brief warming hiatus,while regional precipitation patterns in China have also experienced diverse and complex changes.Specifically,the factors behind the opposing trends in summer precipitation between two adjacent regions—Southwest China and the Qinghai-Tibet Plateau—are particularly intricate.After evaluating the historical runs from CMIP6 models,the authors assessed the contributions of various external forcing factors that simulated the summer precipitation trends observed over the Qinghai-Tibet Plateau and Southwest China from 1961 to 2014.The findings show that,compared to other forcing factors,greenhouse gases had a significant impact on the increase in summer precipitation over the Qinghai-Tibet Plateau,while aerosols played an important role in the decrease in summer precipitation in Southwest China.

To investigate the evolution of precipitation over Asian continent in the Holocene and the associated mechanisms, we used a set of simulations of the transient climate evolution over the past 21,000 years (TraCE-21ka), multimodel results from the Paleoclimate Modeling Intercomparison Project Phase 4 (PMIP4), and proxy records in Asia. The TraCE-21ka results showed a tripole pattern in suborbital-scale precipitation trends over the Asian continent during the Holocene, with a trend of increase over southern parts of the monsoon regions and arid Central Asia (ACA), and a trend of decline over northern parts of the monsoon regions and their areas of transition with ACA. This tripole pattern was corroborated by proxy records from multiple regions and multimodel results from the PMIP4. Further analysis based on single-forcing simulations of TraCE-21ka indicated that influences from different external forcings were different on the Asian precipitation in the main rainy seasons in the Holocene and that their combined effects shaped the tripole pattern. In summer, orbital forcing, by reducing solar radiation in mid-to-high latitudes and weakening the land-sea thermal contrast, has been the dominant factor in the long-term evolution of precipitation in the monsoon region and West Asia. In winter and spring, changes in meltwater flux played dominant roles in intensifying local water cycle and horizontal moisture advection, which drove the trend of increase in precipitation in ACA. Additionally, changes in greenhouse gas concentration and continental ice sheet forcings both also contribute to the increase in precipitation in ACA.

This study examines the interdecadal variation of cold season precipitation in arid West Asia (AWA) from 1960 to 2019 and identifies the underlying physical mechanisms. The results indicate that the precipitation in this region has exhibited significant interdecadal variation over the past 60 years, which is closely related to Interdecadal Pacific Variability (IPV). During the positive IPV phase, which was associated with a warming equatorial Middle East Pacific Ocean, an eastward-propagating Rossby wave induced a negative geopotential height anomaly over AWA, providing the dynamic conditions for precipitation. Additionally, IPV caused the westerly jet to move southward and strengthen, providing rich water vapor. Moreover, a positive geopotential height anomaly over the Indo-West Pacific, caused by cold sea surface temperature, led to the upward transport of water vapor from the Northern Indian Ocean to AWA, further enhancing the water vapor conditions. These factors together resulted in excess precipitation in AWA during the positive IPV phase, with a 17.6 mm increase compared to the negative phase, accounting for approximately 12% of the cold season precipitation. These findings were also confirmed by the piControl simulation of CESM2.

The decadal variability of extreme high temperature (EHT) in the mid and highlatitudes of continental Asia (MHLCA) and associated mechanisms were investigated. Observational analysis indicated that, after removing global warming, the first leading mode of the EHT events showed a meridional dipole pattern and had significant decadal variability. During the periods 1980–1994 and 2012–2019 (1995–2011), EHT events were more frequent and stronger (less frequent and weaker) in western-central Siberia than normal, whereas they were less frequent and weaker (more frequent and stronger) in the wide area to the south of Lake Baikal. Further Observational and CESM (Community Earth System Model) results based analysis suggested that decadal change in air–sea interaction in the North Atlantic play an important role in shaping the decadal variability of EHT events in MHLCA. On decadal timescales, meridional negative–positive–negative sea surface temperature (SST) anomalies in the North Atlantic and their coupled positive North Atlantic Oscillation can trigger stronger wave activity flux and cause a significant anticyclonic–cyclonic teleconnection wave train in the troposphere over the mid and high latitudes of the Eurasian continent. As a result, an anomalous high-pressure center is evident in western-central Siberia, and thereby reducing total cloud cover and causing stronger solar heating. Thus, EHT events become more frequent and stronger. On the contrary, for the areas south of Lake Baikal, EHT events are weakened by corresponding cyclonic circulation anomalies. Additionally, the CAM5 (Community Atmosphere Model version 5) experiments suggested more important driving role of the decadal North Atlantic tripole SST anomalies in the abovementioned processes.

Based on data observed from 1979 to 2017,the influence of Arctic sea ice in the previous spring on the first mode of interannual variation in summer drought in the middle and high latitudes of Asia(MHA)is analyzed in this paper,and the possible associated physical mechanism is discussed.The results show that when there is more sea ice near the Svalbard Islands in spring while the sea ice in the Barents-Kara Sea decreases,the drought distribution in the MHA shows a north-south dipole pattern in late summer,and drought weakens in the northern MHA region and strengthens in the southern MHA region.By analyzing the main physical process affecting these changes,the change in sea ice in spring is found to lead to the Polar-Eurasian teleconnection pattern,resulting in more precipitation,thicker snow depths,higher temperatures,and higher soil moisture in the northern MHA region in spring and less precipitation,smaller snow depths,and lower soil moisture in the southern MHA region.Such soil conditions last until summer,affect summer precipitation and temperature conditions through soil moisture-atmosphere feedbacks,and ultimately modulate changes in summer drought in the MHA.