The East Asian trough(EAT)profoundly influences the East Asian spring climate.In this study,the relationship of the EATs among the three spring months is investigated.Correlation analysis shows that the variation in M...The East Asian trough(EAT)profoundly influences the East Asian spring climate.In this study,the relationship of the EATs among the three spring months is investigated.Correlation analysis shows that the variation in March EAT is closely related to that of April EAT.Extended empirical orthogonal function(EEOF)analysis also confirms the co-variation of the March and April EATs.The positive/negative EEOF1 features the persistent strengthened/weakened EAT from March to April.Further investigation indicates that the variations in EEOF1 are related to a dipole sea surface temperature(SST)pattern over the North Atlantic and the SST anomaly over the tropical Indian Ocean.The dipole SST pattern over the North Atlantic,with one center east of Newfoundland Island and another east of Bermuda,could trigger a Rossby wave train to influence the EAT in March−April.The SST anomaly over the tropical Indian Ocean can change the Walker circulation and influence the atmospheric circulation over the tropical western Pacific,subsequently impacting the southern part of the EAT in March−April.Besides the SST factors,the Northeast Asian snow cover could change the regional thermal conditions and lead to persistent EAT anomalies from March to April.These three impact factors are generally independent of each other,jointly explaining large variations in the EAT EEOF1.Moreover,the signals of the three factors could be traced back to February,consequently providing a potential prediction source for the EAT variation in March and April.展开更多
The relationship between variations in the East Asian trough(EAT)intensity and spring extreme precipitation over Southwest China(SWC)during 1961-2020 is investigated.The results indicate that there is an interdecadal ...The relationship between variations in the East Asian trough(EAT)intensity and spring extreme precipitation over Southwest China(SWC)during 1961-2020 is investigated.The results indicate that there is an interdecadal increase in the relationship between the EAT and spring extreme precipitation over eastern SWC around the late1980 s.During the latter period,the weak(strong)EAT corresponds to a strong and large-scale anomalous anticyclone(cyclone)over the East Asia-Northwest Pacific region.The EAT-related anomalous southerlies(northerlies)dominate eastern SWC,leading to significant upward(downward)motion and moisture convergence(divergence)over the region,providing favorable(unfavorable)dynamic and moisture conditions for extreme precipitation over eastern SWC.In contrast,during the former period,the EAT-related circulation anomalies are weak and cover a relatively smaller region,which cannot significantly affect the moisture and dynamic conditions over eastern SWC;therefore,the response in extreme precipitation over eastern SWC to EAT is weak over the period.The interdecadal change in the relationship between eastern SWC spring extreme precipitation and the EAT could be related to the interdecadal change in the EAT variability.The large(small)variability of the EAT is associated with significant(insignificant)changes in spring extreme precipitation over eastern SWC during the latter(former)period.展开更多
This paper documents a decadal strengthened co-variability of the Antarctic Oscillation （AAO） and ENSO in austral spring after the mid-1990s. During the period 1979-93, the ENSO （AAO） spatial signatures are restri...This paper documents a decadal strengthened co-variability of the Antarctic Oscillation （AAO） and ENSO in austral spring after the mid-1990s. During the period 1979-93, the ENSO （AAO） spatial signatures are restricted to the tropicsmidlatitudes （Antarctic-midlatitudes） of the Southern Hemisphere （SH）, with a weak connection between the two oscillations. Comparatively, after the mid-1990s, the E1 Nifio-related atmospheric anomalies project on a negative AAO pattern with a barotropic structure in the mid-high latitudes of the SH. The expansion of E1 Nifio-related air temperature anomalies have a heightened impact on the meridional thermal structure of the SH, contributing to a weakened circumpolar westerly and strengthened subtropical jet. Meanwhile, the ENSO-related southern three-cell circulations expand poleward and then strongly couple the Antarctic and the tropics. Numerical simulation results suggest that the intensified connection between ENSO and SST in the South Pacific since the mid-1990s is responsible for the strengthened AAO-ENSO relationship.展开更多
China has been frequently affected by severe snowstorms in recent years that have particularly large economic and human impacts.It is thus of great importance to increase our understanding of the underlying mechanisms...China has been frequently affected by severe snowstorms in recent years that have particularly large economic and human impacts.It is thus of great importance to increase our understanding of the underlying mechanisms of and future changes in snowfall occurrences over China.In this study,the effects of anthropogenic influences on snowfall and the associated future changes are explored using new simulations from CMIP6(phase 6 of the Coupled Model Intercomparison Project)models.Observational evidence reveals a decrease in the annual total snowfall days and an increase in intense snowfall days over the snowfall-dominated regions in China during recent decades.Fingerprints of anthropogenic influences on these changes are detectable,especially the impacts of increased greenhouse gas emissions.During the winter seasons,low temperatures still cover the regions of northern China,and the associated precipitation days show an increase due to anthropogenic warming,which substantially benefits the occurrence of snowfall over these regions,particularly for intense snowfall events.This is also true in the future,despite rapid warming being projected.By the end of this century,approximately 23%of grids centered over northern China are projected to still experience an increase in daily intense snowfall events in winters.Additionally,the length of the snowfall season is projected to narrow by nearly 41 days compared to the current climate.Thus,in the future,regions of China,especially northern China,are likely to experience more intense snowfall days over a more concentrated period of time during the winter seasons.展开更多
In order to examine the response of the tropical Pacific Walker circulation（PWC） to strong tropical volcanic eruptions（SVEs）, we analyzed a three-member long-term simulation performed with Had CM3, and carried out...In order to examine the response of the tropical Pacific Walker circulation（PWC） to strong tropical volcanic eruptions（SVEs）, we analyzed a three-member long-term simulation performed with Had CM3, and carried out four additional CAM4 experiments. We found that the PWC shows a significant interannual weakening after SVEs. The cooling effect from SVEs is able to cool the entire tropics. However, cooling over the Maritime Continent is stronger than that over the central-eastern tropical Pacific. Thus, non-uniform zonal temperature anomalies can be seen following SVEs. As a result, the sea level pressure gradient between the tropical Pacific and the Maritime Continent is reduced, which weakens trade winds over the tropical Pacific. Therefore, the PWC is weakened during this period. At the same time, due to the cooling subtropical and midlatitude Pacific, the Intertropical Convergence Zone（ITCZ） and South Pacific convergence zone（SPCZ） are weakened and shift to the equator. These changes also contribute to the weakened PWC. Meanwhile, through the positive Bjerknes feedback, weakened trade winds cause El Nino-like SST anomalies over the tropical Pacific, which in turn further influence the PWC. Therefore, the PWC significantly weakens after SVEs. The CAM4 experiments further confirm the influences from surface cooling over the Maritime Continent and subtropical/midlatitude Pacific on the PWC. Moreover, they indicate that the stronger cooling over the Maritime Continent plays a dominant role in weakening the PWC after SVEs. In the observations,a weakened PWC and a related El Nino-like SST pattern can be found following SVEs.展开更多
The possible mechanism behind the variability in the dipole pattern of boreal winter precipitation over East Asia is analyzed in this study. The results show that the SST anomalies（SSTAs） over the South Pacific Ocea...The possible mechanism behind the variability in the dipole pattern of boreal winter precipitation over East Asia is analyzed in this study. The results show that the SST anomalies（SSTAs） over the South Pacific Ocean（SPO） in boreal autumn are closely related to the variability in the dipole pattern of boreal winter precipitation over East Asia. The physical link between the boreal autumn SPO SSTAs and the boreal winter East Asian precipitation dipole pattern is shown to mainly be the seasonal persistence of the SPO SSTAs themselves. The seasonal persistence of the SPO SSTAs can memorize and transport the signal of the boreal autumn SSTAs to the following winter, and then stimulates a meridional teleconnection pattern from the SH to the NH, resulting in a meridional dipole pattern of atmospheric circulation over East Asia in boreal winter. As a major influencing factor, this dipole pattern of the atmospheric circulation can finally lead to the anomalous precipitation dipole pattern over East Asia in boreal winter. These observed physical processes are further confirmed in this study through numerical simulation. The evidence from this study, showing the impact of the SPO SSTAs in boreal autumn,not only deepens our understanding of the variability in East Asian boreal winter precipitation, but also provides a potentially useful predictor for precipitation in the region.展开更多
Multi-model ensemble prediction is an effective approach for improving the prediction skill short-term climate prediction and evaluating related uncertainties. Based on a combination of localized operation outputs of ...Multi-model ensemble prediction is an effective approach for improving the prediction skill short-term climate prediction and evaluating related uncertainties. Based on a combination of localized operation outputs of Chinese climate models and imported forecast data of some international operational models, the National Climate Center of the China Meteorological Administration has established the China multi-model ensemble prediction system version 1.0 (CMMEv1.0) for monthly-seasonal prediction of primary climate variability modes and climate elements. We verified the real-time forecasts of CMMEv1.0 for the 2018 flood season (June-August) starting from March 2018 and evaluated the 1991-2016 hindcasts of CMMEv1.0. The results show that CMMEv1.0 has a significantly high prediction skill for global sea surface temperature (SST) anomalies, especially for the El Nino-Southern Oscillation (ENSO) in the tropical central-eastern Pacific. Additionally, its prediction skill for the North Atlantic SST triple (NAST) mode is high, but is relatively low for the Indian Ocean Dipole (IOD) mode. Moreover, CMMEv1.0 has high skills in predicting the western Pacific subtropical high (WPSH) and East Asian summer monsoon (EASM) in the June-July-August (JJA) season. The JJA air temperature in the CMMEv1.0 is predicted with a fairly high skill in most regions of China, while the JJA precipitation exhibits some skills only in northwestern and eastern China. For real-time forecasts in March-August 2018, CMMEv1.0 has accurately predicted the ENSO phase transition from cold to neutral in the tropical central-eastern Pacific and captures evolutions of the NAST and IOD indices in general. The system has also captured the main features of the summer WPSH and EASM indices in 2018, except that the predicted EASM is slightly weaker than the observed. Furthermore, CMMEv1.0 has also successfully predicted warmer air temperatures in northern China and captured the primary rainbelt over northern China, except that it predicted much more precipitation in the middle and lower reaches of the Yangtze River than observation.展开更多
Climate extreme events and their changes can generally exert severe impacts on society and ecosystems and cause large economic losses each year. Robust projections of their future changes are thus urgently important f...Climate extreme events and their changes can generally exert severe impacts on society and ecosystems and cause large economic losses each year. Robust projections of their future changes are thus urgently important for policymaking to provide reliable information with respect to climate mitigation and adaptation.展开更多
In July 2013, the Jianghuai–Jiangnan region of China experienced a persistent extreme high temperature,and the surface air temperature(SAT) over many areas of the region set a new record, which had a profound impact ...In July 2013, the Jianghuai–Jiangnan region of China experienced a persistent extreme high temperature,and the surface air temperature(SAT) over many areas of the region set a new record, which had a profound impact on people's lives. This study explored the possible mechanism for this extreme climate phenomenon. The results show that the sea surface temperature(SST) over the midNorth Atlantic in July 2013 was the warmest observed over the past 160 years. The strong anomaly of the SST connects to the East Asian upper level westerly and western Pacific subtropical high(WPSH) via the teleconnection wave train and further contributes to the SAT variability over the Jianghuai–Jiangnan region; this connection could be one possible mechanism for the formation of the recordbreaking extreme hot event(EHE) over the Jianghuai–Jiangnan region in July 2013. In addition, for the EHE over the Jianghuai–Jiangnan region, the role of the WPSH was generally emphasised. This study found that the variability of the upper level westerly over the Jianghuai–Jiangnan region is also an important climate factor impacting the SAT of the region. In particular, the record-breaking weakness of the upper level westerly corresponded to the record-breaking SAT over the Jianghuai–Jiangnan region in July 2013. These results indicate that the role of the upper level westerly should be emphasised in addition to the WPSH, according to both the variability in the summer air temperature and the EHE over the Jianghuai–Jiangnan region.展开更多
The rapid expansion of lake area in the Tibetan Plateau(TP)has attracted a considerable amount of concern in recent decades.Limited evidence has suggested that climate warming and the cryosphere change are the most pr...The rapid expansion of lake area in the Tibetan Plateau(TP)has attracted a considerable amount of concern in recent decades.Limited evidence has suggested that climate warming and the cryosphere change are the most prominent contributors to lake expansion.The widespread changes in lake area result from a combination of increased precipitation,melting glaciers,permafrost degradation,and changes in other components of terrestrial water.However,debate remains as to whether melting glaciers or increased precipitation have a greater impact on lake expansion.Varied topography and limited datasets hinder the ability to perform extensive research,and there is currently no definitive conclusion on the issue.展开更多
The research and applications of fiber materials are directly related to the daily life of social populace and the development of relevant revolutionary manufacturing industry.However,the conventional fibers and fiber...The research and applications of fiber materials are directly related to the daily life of social populace and the development of relevant revolutionary manufacturing industry.However,the conventional fibers and fiber products can no longer meet the requirements of automation and intellectualization in modern society,as well as people’s consumption needs in pursuit of smart,avant-grade,fashion and distinctiveness.The advanced fiber-shaped electronics with most desired designability and integration features have been explored and developed intensively during the last few years.The advanced fiber-based products such as wearable electronics and smart clothing can be employed as the second skin to enhance information exchange between humans and the external environment.In this review,the significant progress on flexible fiber-shaped multifunctional devices,including fiber-based energy harvesting devices,energy storage devices,chromatic devices,and actuators are discussed.Particularly,the fabrication procedures and application characteristics of multifunctional fiber devices such as fiber-shaped solar cells,lithium-ion batteries,actuators and electrochromic fibers are introduced in detail.Finally,we provide our perspectives on the challenges and future development of functional fiber-shaped devices.展开更多
Elevation-dependent warming(EDW),whereby warming rates are stratified by elevation,may increase the threat to the life-supporting solid water reservoir on the Tibetan Plateau.Previous studies have debated whether EDW ...Elevation-dependent warming(EDW),whereby warming rates are stratified by elevation,may increase the threat to the life-supporting solid water reservoir on the Tibetan Plateau.Previous studies have debated whether EDW exists and how it is driven.Using temperatures at 133 weather stations on the Tibetan Plateau during 17 different periods generated using a 30-year sliding window over 1973-2018,this study finds that the existence of EDW varies as the period moves forward,and critically it has become more severe over time.During the early part of the record with weaker regional warming,there were limited changes in snow depth and no EDW,but as time advances and regional warming intensifies,snow depth declines significantly at higher elevations,causing development of EDW.We conclude that enhanced regional warming has caused decreases in snow depth,largely controlling the pattern of EDW on the Tibetan Plateau.This may explain contrasting conclusions on EDW from previous studies which have used data for different periods,and our findings support enhanced EDW and more severe depletion of the Tibetan Plateau solid water reserves in a warmer future.展开更多
There is overwhelming evidence that anthropogenic activity has exerted a great influence on climate extremes,especially on heat events at continental to global scales[1].Recently,increasing evidence has also identifie...There is overwhelming evidence that anthropogenic activity has exerted a great influence on climate extremes,especially on heat events at continental to global scales[1].Recently,increasing evidence has also identified the anthropogenic influence on climate extremes over China[2-4].展开更多
In permafrost areas, the timing of thermal surface settlement hazard onset is of great importance for the construction and maintenance of engineering facilities.Future permafrost thaw and the associated thermal settle...In permafrost areas, the timing of thermal surface settlement hazard onset is of great importance for the construction and maintenance of engineering facilities.Future permafrost thaw and the associated thermal settlement hazard onset timing in the Qinghai-Tibet engineering corridor(QTEC) were analyzed using high-resolution soil temperature data from the Community Land Model version4 in combination with multiple model and scenario soil temperature data from the fifth phase of the Coupled Model Intercomparison Project(CMIP5). Compared to the standard frozen ground map for the Tibetan Plateau and ERAInterim data, a multimodel ensemble reproduces the extent of permafrost and soil temperature change in the QTEC at a 1 m depth from 1986–2005. Soil temperature and active layer thickness increase markedly during 2006–2099 using CMIP5 scenarios. By 2099, the ensemble mean soil temperature at 15 m depth will increase between 1.0 and 3.6 ℃ in the QTEC. Using crushed-rock revetments can delay the onset of thermal settlement hazard for colder permafrost areas by approximately 17 years in the worst case scenario of RCP8.5. Nearly one-third of the area of the QTEC exhibits settlement hazard as early as 2050, and half of this one-third of the area is traversed by the QinghaiTibet highway/railway, a situation that requires more planning and remedial attention. Simulated onsets of thermal settlement hazard correspond well to the observed soil temperature at 15 m depth for seven grid areas in the QETC, which to some extent indicates that these timingestimates are reasonable. This study suggests that climate model-based timing estimation of thermal settlement hazard onset is a valuable method, and that the results are worthy of consideration in engineering design and evaluation.展开更多
Inoperable liver tumors are often treated by thermal ablation that destroys the tumor in situ and spares the adjacent hepatic tissue.Thermal–physical treatment has many advantages,but treatment by freezing or heating...Inoperable liver tumors are often treated by thermal ablation that destroys the tumor in situ and spares the adjacent hepatic tissue.Thermal–physical treatment has many advantages,but treatment by freezing or heating alone has some limitations.By taking the advantages and disadvantages of cryosurgery and thermotherapy into consideration,a new thermal technique that combines cryosurgery and radio frequency ablation has been proposed,thereby overcoming the disadvantages of each treatment strategy and improving therapeutic outcomes.This new approach remains to be systematically studied in the liver;therefore,this study was performed to estimate survival after alternated cooling and heating ablation therapy in a VX2 rabbit liver tumor model.Sixteen days after VX2 carcinoma implantation into the rabbit liver,tumors were treated with alternated cooling and heating ablation therapy.Rabbits were monitored for 6 months after treatment and assessed with ultrasound(US)and computed tomography at 1,7,14,and 30 days posttreatment.Untreated tumor-bearing animals served as the control group.Our results show that alternate freezing and heating ablation therapy resulted in a good recovery of VX2 rabbits.Compared with the control group,treated rabbits lived significantly longer(P\0.05),with 70%of treated animals surviving to 196 days posttreatment without metastasis or recurrence,while none of the controls did so.There was no local recurrence in the treatment group.All rabbits in the control group developed metastasis,while metastasis was only observed in 30% of treated rabbits.These results suggest that alternate cooling and heating ablation therapy can prolong the survival time of rabbits with VX2 liver tumors and is an effective method for tumor therapy.Furthermore,we also showed in this model that contrast enhanced US is a valid follow-up approach to assess treatment effectiveness.展开更多
This study investigates the influences of strong tropical volcanic eruptions(SVEs) on daily temperature and precipitation extreme events using long-term simulations from the Hadley Centre Coupled Model version 3(HadCM...This study investigates the influences of strong tropical volcanic eruptions(SVEs) on daily temperature and precipitation extreme events using long-term simulations from the Hadley Centre Coupled Model version 3(HadCM3) and the Community Earth System Model version 1.1(CESM1). The results indicate that the occurrences of daily hot extremes and daily heavy precipitation extremes decrease over most parts of the world in the peak forcing years of SVEs. Due to the volcanic cooling effect, the average probability of daily hot extremes decreases by approximately 50% across the globe. The decrease in intensity is stronger for midlatitude land regions and tropical South America.In contrast, daily cold extremes occur more frequently over most parts of continental regions. Globally, a cold extreme event expected once every 3 years under non-volcanic conditions can be expected every 1.5 years on average in the peak forcing years. Overall, the SVE-induced cooling effect plays a dominant role in regulating daily cold and hot extremes. Over high-latitude Eurasian regions, in contrast to other continental regions, the probability and intensity of daily cold extremes decrease due to an SVE-strengthened polar vortex and the associated temperature advection anomalies. With regard to daily heavy precipitation extremes, the probability and intensity both decrease over most monsoon areas. Further analysis suggests that the reduced probability and intensity of daily heavy precipitation extremes are mainly due to the SVE-induced global decrease in the water-holding capacity.展开更多
基金the National Natural Science Foundation of China(Grant Nos.41825010 and 42005024).
文摘The East Asian trough(EAT)profoundly influences the East Asian spring climate.In this study,the relationship of the EATs among the three spring months is investigated.Correlation analysis shows that the variation in March EAT is closely related to that of April EAT.Extended empirical orthogonal function(EEOF)analysis also confirms the co-variation of the March and April EATs.The positive/negative EEOF1 features the persistent strengthened/weakened EAT from March to April.Further investigation indicates that the variations in EEOF1 are related to a dipole sea surface temperature(SST)pattern over the North Atlantic and the SST anomaly over the tropical Indian Ocean.The dipole SST pattern over the North Atlantic,with one center east of Newfoundland Island and another east of Bermuda,could trigger a Rossby wave train to influence the EAT in March−April.The SST anomaly over the tropical Indian Ocean can change the Walker circulation and influence the atmospheric circulation over the tropical western Pacific,subsequently impacting the southern part of the EAT in March−April.Besides the SST factors,the Northeast Asian snow cover could change the regional thermal conditions and lead to persistent EAT anomalies from March to April.These three impact factors are generally independent of each other,jointly explaining large variations in the EAT EEOF1.Moreover,the signals of the three factors could be traced back to February,consequently providing a potential prediction source for the EAT variation in March and April.
基金supported by the National Natural Science Foundation of China[grant number 42275025]the Youth Innovation Promotion Association of the Chinese Academy of Sciences[grant number 2023084].
基金jointly supported by the National Natural Science Foundation of China[grant number 41825010]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA23090102]。
文摘The relationship between variations in the East Asian trough(EAT)intensity and spring extreme precipitation over Southwest China(SWC)during 1961-2020 is investigated.The results indicate that there is an interdecadal increase in the relationship between the EAT and spring extreme precipitation over eastern SWC around the late1980 s.During the latter period,the weak(strong)EAT corresponds to a strong and large-scale anomalous anticyclone(cyclone)over the East Asia-Northwest Pacific region.The EAT-related anomalous southerlies(northerlies)dominate eastern SWC,leading to significant upward(downward)motion and moisture convergence(divergence)over the region,providing favorable(unfavorable)dynamic and moisture conditions for extreme precipitation over eastern SWC.In contrast,during the former period,the EAT-related circulation anomalies are weak and cover a relatively smaller region,which cannot significantly affect the moisture and dynamic conditions over eastern SWC;therefore,the response in extreme precipitation over eastern SWC to EAT is weak over the period.The interdecadal change in the relationship between eastern SWC spring extreme precipitation and the EAT could be related to the interdecadal change in the EAT variability.The large(small)variability of the EAT is associated with significant(insignificant)changes in spring extreme precipitation over eastern SWC during the latter(former)period.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.41421004 and 41210007)the Special Fund for Public Welfare Industry(Meteorology)(Grant No.GYHY201306026)
文摘This paper documents a decadal strengthened co-variability of the Antarctic Oscillation （AAO） and ENSO in austral spring after the mid-1990s. During the period 1979-93, the ENSO （AAO） spatial signatures are restricted to the tropicsmidlatitudes （Antarctic-midlatitudes） of the Southern Hemisphere （SH）, with a weak connection between the two oscillations. Comparatively, after the mid-1990s, the E1 Nifio-related atmospheric anomalies project on a negative AAO pattern with a barotropic structure in the mid-high latitudes of the SH. The expansion of E1 Nifio-related air temperature anomalies have a heightened impact on the meridional thermal structure of the SH, contributing to a weakened circumpolar westerly and strengthened subtropical jet. Meanwhile, the ENSO-related southern three-cell circulations expand poleward and then strongly couple the Antarctic and the tropics. Numerical simulation results suggest that the intensified connection between ENSO and SST in the South Pacific since the mid-1990s is responsible for the strengthened AAO-ENSO relationship.
基金jointly supported by the National Natural Science Foundation of China[grant numbers 41991284,41922034,42088101]the Strategic Priority Research Program of theChinese Academy of Sciences[grant numbers XDA23090102 and XDA19070201]。
文摘China has been frequently affected by severe snowstorms in recent years that have particularly large economic and human impacts.It is thus of great importance to increase our understanding of the underlying mechanisms of and future changes in snowfall occurrences over China.In this study,the effects of anthropogenic influences on snowfall and the associated future changes are explored using new simulations from CMIP6(phase 6 of the Coupled Model Intercomparison Project)models.Observational evidence reveals a decrease in the annual total snowfall days and an increase in intense snowfall days over the snowfall-dominated regions in China during recent decades.Fingerprints of anthropogenic influences on these changes are detectable,especially the impacts of increased greenhouse gas emissions.During the winter seasons,low temperatures still cover the regions of northern China,and the associated precipitation days show an increase due to anthropogenic warming,which substantially benefits the occurrence of snowfall over these regions,particularly for intense snowfall events.This is also true in the future,despite rapid warming being projected.By the end of this century,approximately 23%of grids centered over northern China are projected to still experience an increase in daily intense snowfall events in winters.Additionally,the length of the snowfall season is projected to narrow by nearly 41 days compared to the current climate.Thus,in the future,regions of China,especially northern China,are likely to experience more intense snowfall days over a more concentrated period of time during the winter seasons.
基金supported by the National Key R&D Program of China(Grant No.2016YFA0600701)the National Natural Science Foundation of China(Grant Nos.41661144005,41575086 and 41320104007)the CAS–PKU Joint Research Program
文摘In order to examine the response of the tropical Pacific Walker circulation（PWC） to strong tropical volcanic eruptions（SVEs）, we analyzed a three-member long-term simulation performed with Had CM3, and carried out four additional CAM4 experiments. We found that the PWC shows a significant interannual weakening after SVEs. The cooling effect from SVEs is able to cool the entire tropics. However, cooling over the Maritime Continent is stronger than that over the central-eastern tropical Pacific. Thus, non-uniform zonal temperature anomalies can be seen following SVEs. As a result, the sea level pressure gradient between the tropical Pacific and the Maritime Continent is reduced, which weakens trade winds over the tropical Pacific. Therefore, the PWC is weakened during this period. At the same time, due to the cooling subtropical and midlatitude Pacific, the Intertropical Convergence Zone（ITCZ） and South Pacific convergence zone（SPCZ） are weakened and shift to the equator. These changes also contribute to the weakened PWC. Meanwhile, through the positive Bjerknes feedback, weakened trade winds cause El Nino-like SST anomalies over the tropical Pacific, which in turn further influence the PWC. Therefore, the PWC significantly weakens after SVEs. The CAM4 experiments further confirm the influences from surface cooling over the Maritime Continent and subtropical/midlatitude Pacific on the PWC. Moreover, they indicate that the stronger cooling over the Maritime Continent plays a dominant role in weakening the PWC after SVEs. In the observations,a weakened PWC and a related El Nino-like SST pattern can be found following SVEs.
基金jointly supported by the Special Fund for Public Welfare Industry (meteorology) (Grant No. GYHY201306026)the National Natural Science Foundation of China (Grant Nos. 41421004 and 41522503)
文摘The possible mechanism behind the variability in the dipole pattern of boreal winter precipitation over East Asia is analyzed in this study. The results show that the SST anomalies（SSTAs） over the South Pacific Ocean（SPO） in boreal autumn are closely related to the variability in the dipole pattern of boreal winter precipitation over East Asia. The physical link between the boreal autumn SPO SSTAs and the boreal winter East Asian precipitation dipole pattern is shown to mainly be the seasonal persistence of the SPO SSTAs themselves. The seasonal persistence of the SPO SSTAs can memorize and transport the signal of the boreal autumn SSTAs to the following winter, and then stimulates a meridional teleconnection pattern from the SH to the NH, resulting in a meridional dipole pattern of atmospheric circulation over East Asia in boreal winter. As a major influencing factor, this dipole pattern of the atmospheric circulation can finally lead to the anomalous precipitation dipole pattern over East Asia in boreal winter. These observed physical processes are further confirmed in this study through numerical simulation. The evidence from this study, showing the impact of the SPO SSTAs in boreal autumn,not only deepens our understanding of the variability in East Asian boreal winter precipitation, but also provides a potentially useful predictor for precipitation in the region.
基金Supported by the National Key Research and Development Program of China(2017YFC1502306,2017YFC1502302,and 2018YFC-1506004)China Meteorological Administration Special Project for Developing Key Techniques for Operational Meteorological Forecast(YBGJXM201805)
文摘Multi-model ensemble prediction is an effective approach for improving the prediction skill short-term climate prediction and evaluating related uncertainties. Based on a combination of localized operation outputs of Chinese climate models and imported forecast data of some international operational models, the National Climate Center of the China Meteorological Administration has established the China multi-model ensemble prediction system version 1.0 (CMMEv1.0) for monthly-seasonal prediction of primary climate variability modes and climate elements. We verified the real-time forecasts of CMMEv1.0 for the 2018 flood season (June-August) starting from March 2018 and evaluated the 1991-2016 hindcasts of CMMEv1.0. The results show that CMMEv1.0 has a significantly high prediction skill for global sea surface temperature (SST) anomalies, especially for the El Nino-Southern Oscillation (ENSO) in the tropical central-eastern Pacific. Additionally, its prediction skill for the North Atlantic SST triple (NAST) mode is high, but is relatively low for the Indian Ocean Dipole (IOD) mode. Moreover, CMMEv1.0 has high skills in predicting the western Pacific subtropical high (WPSH) and East Asian summer monsoon (EASM) in the June-July-August (JJA) season. The JJA air temperature in the CMMEv1.0 is predicted with a fairly high skill in most regions of China, while the JJA precipitation exhibits some skills only in northwestern and eastern China. For real-time forecasts in March-August 2018, CMMEv1.0 has accurately predicted the ENSO phase transition from cold to neutral in the tropical central-eastern Pacific and captures evolutions of the NAST and IOD indices in general. The system has also captured the main features of the summer WPSH and EASM indices in 2018, except that the predicted EASM is slightly weaker than the observed. Furthermore, CMMEv1.0 has also successfully predicted warmer air temperatures in northern China and captured the primary rainbelt over northern China, except that it predicted much more precipitation in the middle and lower reaches of the Yangtze River than observation.
基金This work was jointly supported by the National Natural Science Foundation of China(41991284 and 41922034)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23090102)the National Key Research and Development Program of China(2016YFA0602401).
文摘Climate extreme events and their changes can generally exert severe impacts on society and ecosystems and cause large economic losses each year. Robust projections of their future changes are thus urgently important for policymaking to provide reliable information with respect to climate mitigation and adaptation.
基金supported by the National Basic Research Program of China (2012CB955401)the Strategic Priority Research Program-Climate Change: Carbon Budget and Relevant Issues of the Chinese Academy of Sciences (XDA05090306)+1 种基金the CAS-CSIRO Cooperative Research Program (GJHZ1223)the Jiangsu Collaborative Innovation Center for Climate Change
文摘In July 2013, the Jianghuai–Jiangnan region of China experienced a persistent extreme high temperature,and the surface air temperature(SAT) over many areas of the region set a new record, which had a profound impact on people's lives. This study explored the possible mechanism for this extreme climate phenomenon. The results show that the sea surface temperature(SST) over the midNorth Atlantic in July 2013 was the warmest observed over the past 160 years. The strong anomaly of the SST connects to the East Asian upper level westerly and western Pacific subtropical high(WPSH) via the teleconnection wave train and further contributes to the SAT variability over the Jianghuai–Jiangnan region; this connection could be one possible mechanism for the formation of the recordbreaking extreme hot event(EHE) over the Jianghuai–Jiangnan region in July 2013. In addition, for the EHE over the Jianghuai–Jiangnan region, the role of the WPSH was generally emphasised. This study found that the variability of the upper level westerly over the Jianghuai–Jiangnan region is also an important climate factor impacting the SAT of the region. In particular, the record-breaking weakness of the upper level westerly corresponded to the record-breaking SAT over the Jianghuai–Jiangnan region in July 2013. These results indicate that the role of the upper level westerly should be emphasised in addition to the WPSH, according to both the variability in the summer air temperature and the EHE over the Jianghuai–Jiangnan region.
基金supported by the National Natural Science Foundation of China(41421004,41825010)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA19070201)+1 种基金the Open Program of Joint Laboratory of Climate and Environment Change,Chengdu University of Information Technology(JLCEC201801)the CAS-PKU(Chinese Academy of Science-Peking University)Joint Research Program
文摘The rapid expansion of lake area in the Tibetan Plateau(TP)has attracted a considerable amount of concern in recent decades.Limited evidence has suggested that climate warming and the cryosphere change are the most prominent contributors to lake expansion.The widespread changes in lake area result from a combination of increased precipitation,melting glaciers,permafrost degradation,and changes in other components of terrestrial water.However,debate remains as to whether melting glaciers or increased precipitation have a greater impact on lake expansion.Varied topography and limited datasets hinder the ability to perform extensive research,and there is currently no definitive conclusion on the issue.
基金the Science and Technology Commission of Shanghai Municipality[16JC1400700]the Program of Introducing Talents of Discipline to Universities[No.111-2-04]+2 种基金the Innovative Research Team in University[IRT_16R13].C.H.thanks the Natural Science Foundation of China[No.51603037]DHU Distinguished Young Professor Program[LZB2019002]Young Elite Scientists Sponsorship Program by CAST[2017QNRC001].
文摘The research and applications of fiber materials are directly related to the daily life of social populace and the development of relevant revolutionary manufacturing industry.However,the conventional fibers and fiber products can no longer meet the requirements of automation and intellectualization in modern society,as well as people’s consumption needs in pursuit of smart,avant-grade,fashion and distinctiveness.The advanced fiber-shaped electronics with most desired designability and integration features have been explored and developed intensively during the last few years.The advanced fiber-based products such as wearable electronics and smart clothing can be employed as the second skin to enhance information exchange between humans and the external environment.In this review,the significant progress on flexible fiber-shaped multifunctional devices,including fiber-based energy harvesting devices,energy storage devices,chromatic devices,and actuators are discussed.Particularly,the fabrication procedures and application characteristics of multifunctional fiber devices such as fiber-shaped solar cells,lithium-ion batteries,actuators and electrochromic fibers are introduced in detail.Finally,we provide our perspectives on the challenges and future development of functional fiber-shaped devices.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0102)the National Natural Science Foundation of China(41991281 and 41775076)Youth Innovation Promotion Association of Chinese Academy of Sciences(2018103)。
文摘Elevation-dependent warming(EDW),whereby warming rates are stratified by elevation,may increase the threat to the life-supporting solid water reservoir on the Tibetan Plateau.Previous studies have debated whether EDW exists and how it is driven.Using temperatures at 133 weather stations on the Tibetan Plateau during 17 different periods generated using a 30-year sliding window over 1973-2018,this study finds that the existence of EDW varies as the period moves forward,and critically it has become more severe over time.During the early part of the record with weaker regional warming,there were limited changes in snow depth and no EDW,but as time advances and regional warming intensifies,snow depth declines significantly at higher elevations,causing development of EDW.We conclude that enhanced regional warming has caused decreases in snow depth,largely controlling the pattern of EDW on the Tibetan Plateau.This may explain contrasting conclusions on EDW from previous studies which have used data for different periods,and our findings support enhanced EDW and more severe depletion of the Tibetan Plateau solid water reserves in a warmer future.
基金jointly supported by the National Natural Science Foundation of China(41922034,41991284,and42075021)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23090102)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0102)。
文摘There is overwhelming evidence that anthropogenic activity has exerted a great influence on climate extremes,especially on heat events at continental to global scales[1].Recently,increasing evidence has also identified the anthropogenic influence on climate extremes over China[2-4].
基金supported by the National Basic Research Program of China (2012CB955401)the National Natural Science Foundation of China under Grants (41130103, 41421004, and 41405087)
文摘In permafrost areas, the timing of thermal surface settlement hazard onset is of great importance for the construction and maintenance of engineering facilities.Future permafrost thaw and the associated thermal settlement hazard onset timing in the Qinghai-Tibet engineering corridor(QTEC) were analyzed using high-resolution soil temperature data from the Community Land Model version4 in combination with multiple model and scenario soil temperature data from the fifth phase of the Coupled Model Intercomparison Project(CMIP5). Compared to the standard frozen ground map for the Tibetan Plateau and ERAInterim data, a multimodel ensemble reproduces the extent of permafrost and soil temperature change in the QTEC at a 1 m depth from 1986–2005. Soil temperature and active layer thickness increase markedly during 2006–2099 using CMIP5 scenarios. By 2099, the ensemble mean soil temperature at 15 m depth will increase between 1.0 and 3.6 ℃ in the QTEC. Using crushed-rock revetments can delay the onset of thermal settlement hazard for colder permafrost areas by approximately 17 years in the worst case scenario of RCP8.5. Nearly one-third of the area of the QTEC exhibits settlement hazard as early as 2050, and half of this one-third of the area is traversed by the QinghaiTibet highway/railway, a situation that requires more planning and remedial attention. Simulated onsets of thermal settlement hazard correspond well to the observed soil temperature at 15 m depth for seven grid areas in the QETC, which to some extent indicates that these timingestimates are reasonable. This study suggests that climate model-based timing estimation of thermal settlement hazard onset is a valuable method, and that the results are worthy of consideration in engineering design and evaluation.
文摘Inoperable liver tumors are often treated by thermal ablation that destroys the tumor in situ and spares the adjacent hepatic tissue.Thermal–physical treatment has many advantages,but treatment by freezing or heating alone has some limitations.By taking the advantages and disadvantages of cryosurgery and thermotherapy into consideration,a new thermal technique that combines cryosurgery and radio frequency ablation has been proposed,thereby overcoming the disadvantages of each treatment strategy and improving therapeutic outcomes.This new approach remains to be systematically studied in the liver;therefore,this study was performed to estimate survival after alternated cooling and heating ablation therapy in a VX2 rabbit liver tumor model.Sixteen days after VX2 carcinoma implantation into the rabbit liver,tumors were treated with alternated cooling and heating ablation therapy.Rabbits were monitored for 6 months after treatment and assessed with ultrasound(US)and computed tomography at 1,7,14,and 30 days posttreatment.Untreated tumor-bearing animals served as the control group.Our results show that alternate freezing and heating ablation therapy resulted in a good recovery of VX2 rabbits.Compared with the control group,treated rabbits lived significantly longer(P\0.05),with 70%of treated animals surviving to 196 days posttreatment without metastasis or recurrence,while none of the controls did so.There was no local recurrence in the treatment group.All rabbits in the control group developed metastasis,while metastasis was only observed in 30% of treated rabbits.These results suggest that alternate cooling and heating ablation therapy can prolong the survival time of rabbits with VX2 liver tumors and is an effective method for tumor therapy.Furthermore,we also showed in this model that contrast enhanced US is a valid follow-up approach to assess treatment effectiveness.
基金Supported by the National Key Research and Development Program of China(2016YFA0600701)National Natural Science Foundation of China(41822502 and 41661144005)Joint Programming Initiative Climate—Belmont Forum Project InterDec。
文摘This study investigates the influences of strong tropical volcanic eruptions(SVEs) on daily temperature and precipitation extreme events using long-term simulations from the Hadley Centre Coupled Model version 3(HadCM3) and the Community Earth System Model version 1.1(CESM1). The results indicate that the occurrences of daily hot extremes and daily heavy precipitation extremes decrease over most parts of the world in the peak forcing years of SVEs. Due to the volcanic cooling effect, the average probability of daily hot extremes decreases by approximately 50% across the globe. The decrease in intensity is stronger for midlatitude land regions and tropical South America.In contrast, daily cold extremes occur more frequently over most parts of continental regions. Globally, a cold extreme event expected once every 3 years under non-volcanic conditions can be expected every 1.5 years on average in the peak forcing years. Overall, the SVE-induced cooling effect plays a dominant role in regulating daily cold and hot extremes. Over high-latitude Eurasian regions, in contrast to other continental regions, the probability and intensity of daily cold extremes decrease due to an SVE-strengthened polar vortex and the associated temperature advection anomalies. With regard to daily heavy precipitation extremes, the probability and intensity both decrease over most monsoon areas. Further analysis suggests that the reduced probability and intensity of daily heavy precipitation extremes are mainly due to the SVE-induced global decrease in the water-holding capacity.
