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1.
Based on daily observation data in the Three Gorges Region (TGR) of the Yangtze River Basin and global reanalysis data, the authors analyzed the climate characteristics and associated temporal variations in the main meteorological factors in 2021, as well as the year's climatic events and meteorological disasters. The 2021 average temperature was 0.2°C above the 1991–2020 average and the 13th-warmest year since 1961. Seasonally, winter and autumn were both warmer than usual. The annual mean precipitation was 12.8% above normal, and most regions experienced abundant rainfall throughout the year. The seasonal variation in precipitation was significant and the TGR had a wetter-than-normal spring and summer. The number of rainstorm days was higher than normal; the wind speed was above normal; and the relative humidity was higher than normal. In terms of rain acidity, 2021 was tied with 2020 as the lowest since 1999. From mid-September to early October 2021, the TGR experienced exceptional high-temperature weather, which was driven by abnormal activity of mid- and high-latitude atmospheric circulation over the Eurasian continent and the western Pacific subtropical high (WPSH). In addition, a strong blocking high over the Ural Mountains accompanied by intense mid-latitude westerly winds prevented cyclonic disturbances from extending to the subtropical region. As a result, under the combined effect of the weaker-than-normal cold-air activities and the anomalous WPSH, the TGR experienced extreme high-temperature weather during early autumn 2021.摘要本文分析了2021年长江三峡地区气候特征及主要天气气候事件. 2021年, 三峡地区年平均气温较常年偏高0.2°C, 降水量偏多12.8%, 年暴雨日数偏多, 年平均风速偏大, 年平均相对湿度偏高. 2021年与2020年同为有记录以来酸雨强度最弱年. 汛期区域强降水频发; 春季多低温阴雨; 秋冬寒潮过程降温幅度大影响广. 9月中旬至10月初, 三峡地区遭遇罕见“秋老虎”, 分析表明该时段内异常高温与中高纬度大气环流及西太平洋副热带高压活动异常等因子密切相关.  相似文献   

2.
This report is a summary of China's climate, as well as major weather and climate events, during 2021. In 2021, the mean temperature in China was 10.5°C, which was 1.0°C above normal (1981–2010 average) and broke the highest record since 1951. The annual rainfall in China was 672.1 mm, which was 6.7% above normal. Also, the annual rainfall in northern China was 40.2% above normal, which ranked second highest since 1961. The rainstorm intensity in the rainy season was strong and featured significant extremes, and disasters caused by rainstorms and flooding were more serious than the average in the past decade. In particular, the extremely strong rainstorm in Henan during July and autumn caused flooding in the middle and lower reaches of the Yellow River with severe consequences. Heatwaves occurred more frequently than normal, and their durations in southern China were longer than normal in summer and autumn. Phased drought was obvious, and caused serious impacts in South China. The number of generated and landfalling typhoons was lower than normal; however, Typhoon In-fa broke the record for the longest overland duration, held since 1949, and affected a wide area. Severe convective weather and extreme windy weather occurred frequently, causing serious impacts. The number of cold waves was more than normal, which caused wide-ranging extremely low temperatures in many places. Sandstorms appeared earlier than normal in 2021, and the number of strong dust storm processes was more than normal.摘要2021年, 中国气候暖湿特征明显, 全国平均气温10.5℃, 较常年偏高1.0℃, 创下了1951年以来最高纪录; 全国平均降水量672.1毫米, 比常年偏多6.7%, 其中北方地区平均降水量较常年偏多40.2%, 为1961年以来第二多. 汛期暴雨过程强度大, 极端性显著, 河南特大暴雨灾害影响重, 黄河中下游流域秋汛明显; 高温过程多, 夏秋南方高温持续时间长; 区域性, 阶段性气象干旱明显, 华南干旱影响较重; 台风生成和登陆均偏少, “烟花”陆地滞留时间长, 影响范围广; 强对流天气强发, 极端大风频发, 局地致灾重; 寒潮过程多, 强度大, 极端低温频现; 沙尘天气出现早, 强沙尘暴过程多.  相似文献   

3.
The Arctic stratospheric polar vortex was exceptional strong, cold and persistent in the winter and spring of 2019–2020. Based on reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research and ozone observations from the Ozone Monitoring Instrument, the authors investigated the dynamical variation of the stratospheric polar vortex during winter 2019–2020 and its influence on surface weather and ozone depletion. This strong stratospheric polar vortex was affected by the less active upward propagation of planetary waves. The seasonal transition of the stratosphere during the stratospheric final warming event in spring 2020 occurred late due to the persistence of the polar vortex. A positive Northern Annular Mode index propagated from the stratosphere to the surface, where it was consistent with the Arctic Oscillation and North Atlantic Oscillation indices. As a result, the surface temperature in Eurasia and North America was generally warmer than the climatology. In some places of Eurasia, the surface temperature was about 10 K warmer during the period from January to February 2020. The most serious Arctic ozone depletion since 2004 has been observed since February 2020. The mean total column ozone within 60°–90°N from March to 15 April was about 80 DU less than the climatology.摘要2019-2020冬季北极平流层极涡异常并且持续的偏强,偏冷.利用NCEP再数据和OMI臭氧数据, 本文分析了此次强极涡事件中平流层极涡的动力场演变及其对地面暖冬天气和臭氧低值的影响.此次强极涡的形成是由于上传行星波不活跃.持续的强极涡使得2020年春季的最后增温出现时间偏晚.平流层正NAM指数向下传播到地面, 与地面AO指数和NAO指数相一致, 欧亚大陆和北美地面气温均比气候态偏暖, 在欧亚大陆的一些地区, 2020年1月和2月的气温甚至偏高了10K.2020年2月以来北极臭氧出现了2004年以来的最低值, 2020年3-4月60°–90°N的平均臭氧柱总量比气候态偏低了80DU.  相似文献   

4.
In November 2020, the eastern Arctic experienced an extensive extreme warm anomaly (i.e., the second strongest case since 1979), which was followed by extreme cold conditions over East Asia in early winter. The observed Arctic warm anomaly in November 2020 was able to extend upwards to the upper troposphere, characterized as a deep Arctic warm anomaly. In autumn 2020, substantial Arctic sea-ice loss that exceeded the record held since 1979, accompanied by increased upward turbulent heat flux, was able to strongly warm the Arctic. Furthermore, there was abundant northward moisture transport into the Arctic from the North Atlantic, which was the strongest in the past four decades. This extreme moisture intrusion was able to enhance the downward longwave radiation and strongly contribute to the warm conditions in the Arctic. Further analysis indicated that the remote moisture intrusion into the Arctic was promoted by the large-scale atmospheric circulation patterns, such as the wave train propagating from the midlatitude North Atlantic to the Arctic. This process may have been linked to the warmer sea surface temperature in the midlatitude North Atlantic.摘要2020年11月北极东部显著偏暖, 表面气温暖异常为1979年以来第二强, 且北极表层偏暖可以延伸至对流层上层. 本文进一步研究了此次北极极端偏暖的可能原因. 2020年秋季北极海冰大幅减少, 11月从北大西洋向北极的水汽输送显著增加, 且二者的变化幅度均超过了1979年以来的最高纪录, 进而导致北极出现极端暖异常. 此外, 从中纬度向北极的Rossby波传播有利于向极水汽输送增加, 且此过程可能与北大西洋中纬度海温异常有关.  相似文献   

5.
The ocean's thermal inertia is a major contributor to irreversible ocean changes exceeding time scales that matter to human society. This fact is a challenge to societies as they prepare for the consequences of climate change, especially with respect to the ocean. Here the authors review the requirements for human actions from the ocean's perspective. In the near term (～2030), goals such as the United Nations Sustainable Development Goals (SDGs) will be critical. Over longer times (～2050–2060 and beyond), global carbon neutrality targets may be met as countries continue to work toward reducing emissions. Both adaptation and mitigation plans need to be fully implemented in the interim, and the Global Ocean Observation System should be sustained so that changes can be continuously monitored. In the longer-term (after ～2060), slow emerging changes such as deep ocean warming and sea level rise are committed to continue even in the scenario where net zero emissions are reached. Thus, climate actions have to extend to time scales of hundreds of years. At these time scales, preparation for “high impact, low probability” risks — such as an abrupt showdown of Atlantic Meridional Overturning Circulation, ecosystem change, or irreversible ice sheet loss — should be fully integrated into long-term planning.摘要在全球变化背景下, 海洋的很多变化在人类社会发展的时间尺度上 (百年至千年) 具有不可逆转性, 海洋巨大的热惯性是造成该不可逆性的主要原因. 这个特征为人类和生态系统应对海洋变化提出一系列挑战. 本文从海洋变化的角度总结了人类应对气候变化的要求, 提出需要进行多时间尺度的规划和统筹. 在近期 (到2030年) , 实现联合国可持续发展目标至关重要. 在中期 (2050–2060年前后) , 全球需要逐步减排并实现碳中和目标. 同时, 适应和减缓气候变化的行动和措施必须同步施行; 全球海洋观测系统需要得以维持并完善以持续监测海洋变化. 在远期 (在2060年之后) , 即使全球达到净零排放, 包括深海变暖和海平面上升在内的海洋变化都将持续, 因此应对全球变化的行动需持续数百年之久. 在该时间尺度, 应对“低概率, 高影响”气候风险 (即发生的可能性较低, 但一旦发生影响极大的事件带来的风险, 例如: 大西洋经圈反转环流突然减弱, 海洋生态系统跨过临界点, 无可挽回的冰盖质量损失等) 的准备应充分纳入长期规划.  相似文献   

6.
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.摘要本文分析了亚洲中高纬度地区 (MHA) 年际尺度夏季干旱的主模态时空变化特征, 以及影响第一模态的主要影响因子和可能的物理过程. 结果显示该区域夏季干旱第一模态主要呈现一个南北偶极性的分布. 而影响MHA夏季干旱的主要影响因子为前春北极海冰. 当春季斯瓦尔巴群岛附近海冰偏多, 而巴伦支海-喀拉海海冰减少时, 通过冰-气相互作用, 使得MHA北部春季降水增加, 雪深加厚, 土壤湿度偏高, 而南部则相反. 然后这样的土壤湿度条件从春季持续到夏季, 通过土壤湿度-大气反馈影响夏季MHA降水和温度变化, 最终对夏季干旱主模态产生影响.  相似文献   

7.
Using model simulated data, the distribution characteristics, genesis, and impacts on precipitation of available potential energy (APE) are analyzed for a heavy rainfall event that took place over the eastern Tibetan Plateau during 10–11 July 2018. Results show that APE was mainly distributed below 4 km and within 8–14 km. The APE distribution in the upper level had a better correspondence with precipitation. Northwestern cold advection and evaporation of falling raindrops were primary factors leading to positive anomalies of APE in the lower level, while positive anomalies of APE in the upper level were caused by a combination of thermal disturbances driven by latent heat and potential temperature perturbations resulting from the orography of the Tibetan Plateau. Budget analysis of APE indicated that APE fluxes and conversion between APE and kinetic energy (KE) were the main source and sink terms. Meridional fluxes of APE and conversion of KE to APE fed the dissipation of APE in the lower level. Vertical motion enhanced by conversion of APE to KE in the upper level was the major factor that promoted precipitation evolution. A positive feedback between APE and vertical motion in the upper level generated a powerful correlation between them. Conversion of KE to APE lasted longer in the lower level, which weakened vertical motion; whereas, northwestern cold advection brought an enhanced trend to the APE, resulting in a weak correlation between APE and vertical motion.摘要针对2018年7月10-11日青藏高原东部一次暴雨过程, 利用模式模拟资料分析了有效位能分布特征,成因及其对降水发展演变的影响.结果表明, 有效位能主要分布在对流层低层4km以下和高层8-14km, 高层有效位能和降水有更好的对应性西北冷平流和降水粒子下落的蒸发作用是低层有效位能高值中心的主要成因, 而降水过程释放潜热带来的热力扰动叠加高原大地形造成的位温扰动是导致高层有效位能高值的主要原因.有效位能收支分析表明, 有效位能的通量输送项以及与动能间的转换项是主要源汇项.低层有效位能的经向通量输送和动能向有效位能的转化补给了有效位能的耗散;高层有效位能向垂直动能转化增强垂直运动是促进降水发展演变的主要因素.高层有效位能与垂直运动之间的正反馈过程使得两者相关性较强;低层较长时间内均存在垂直动能向有效位能的转化, 削弱了垂直运动, 而西北冷平流使得低层有效位能有增强的趋势, 因此二者相关性较弱.  相似文献   

8.
The frequent and rapid onset of flash drought poses a serious threat to agriculture and ecosystems. Detecting human influences on flash droughts and estimating their future risks under climate change have attracted great attention. Focusing on a record-breaking flash drought event in the southeastern coastal region of China in summer 2020, the authors found that the suppression of convective precipitation and high temperature caused by the persistent high geopotential height anomalies and land–atmosphere dry coupling were important reasons for the rapid onset and strong intensity of the flash drought. Event attribution analysis with the latest CMIP6 data showed that anthropogenic climate change has not only increased the likelihood of an onset speed and intensity like those of the 2020 flash drought event, by about 93% ± 20% and 18% ± 15%, respectively, but also increased the chance of their simultaneous occurrence, by about 86% ± 38%, according to their joint probability distribution. Under a business-as-usual future scenario (SSP2-4.5), the likelihood of such an onset speed, intensity, and their simultaneous occurrence will further increase, by 85% ± 33%, 49% ± 8%, and 81% ± 48%, respectively, as compared with current climate conditions. This study highlights the importance of anthropogenic climate change for accelerating and intensifying flash drought in the southeastern coastal region of China.摘要快速爆发的骤旱对农业生产, 生态环境等造成严重威胁, 亟须量化当前及未来气候变化对骤旱爆发过程的影响. 2020年夏季, 在持续高压异常和陆气干耦合的控制下, 我国东南沿海地区出现高温少雨天气并引发极端骤旱事件. 基于第六次国际耦合模式比较计划 (CMIP6) 数据开展归因分析, 本文发现相比天然情景, 温室气体排放等人为因子导致的气候变化不仅使类似2020年骤旱爆发速度和强度的发生概率分别增加93%和18%, 还使其联合概率增加86%. 在目前排放水平下, 此类骤旱爆发速度和强度发生概率及其联合概率在21世纪末将提高85%, 49%, 和81%, 极大增加了干旱适应的挑战.  相似文献   

9.
降水日变化受大气热力,动力过程以及复杂地形影响,演变特征复杂且区域差异显著.本文采用中国气象局发布的中国地面与CMORPH融合逐小时降水产品(2008-2019年),分析了新疆省暖季降水日变化特征.研究结果表明:(1)新疆大部分地区降水主峰值发生在清晨;(2)持续时间超过三小时的降水事件是新疆地区主要降水事件,贡献了南...  相似文献   

10.
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 late 1980s. 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.摘要本文研究表明东亚大槽强度与中国西南地区东部春季极端降水的关系在20世纪80年代末后显著增强, 这可能与东亚大槽自身变率的年代际变化有关. 在80年代末之后, 东亚大槽的变率显著增强, 其对应的大气环流异常也偏强, 范围偏大, 可以显著影响西南地区东部的水汽和动力条件, 从而引起该地区春季极端降水的显著变化. 而在80年代末之前, 东亚大槽的变率偏弱, 其对应的大气环流异常也偏弱, 范围偏小, 因此不能对西南地区东部春季极端降水的变化产生显著影响.  相似文献   

11.
2019 was one of the hottest years in recent decades, with widespread heatwaves over many parts of the world, including Africa. However, as a developing and vulnerable region, the understanding of recent heatwave events in Africa is limited. Here, the authors incorporated different climate datasets, satellite observations, and population estimates to investigate patterns and hotspots of major heatwave events over Africa in 2019. Overall, 2019 was one of the years that experienced the strongest heatwaves in terms of intensity and duration since 1981 in Africa. Heatwave hotspots were clearly identified across western-coastal, northeastern, southern, and equatorial Africa, where major cities and human populations are located. The proportion of urban agglomerations (population) exposed to extreme (99th percentile) heatwaves in the Northern Hemisphere and Southern Hemisphere rose from 4% (5 million people) and 15% (17 million people), respectively, in the baseline period of 1981–2010 to 36% (43 million people) and 57% (53 million people), respectively, in 2019. Heatwave patterns and hotspots in 2019 were related to anomalous seasonal change in atmospheric circulation and above-normal sea surface temperature. Without adaptation to minimize susceptibility to the effects of heatwave events, the risks they pose in populated areas may increase rapidly in Africa.摘要2019 年是近几十年来最热的年份之一, 包括非洲在内的全球许多地区都受到大范围的热浪侵袭. 然而, 非洲作为脆弱的发展中地区, 我们对其近年热浪事件的了解非常有限. 本研究中, 我们结合了不同的气候数据集, 卫星观测资料和人口数据, 研究了 2019 年非洲地区主要热浪事件发生的时空特征和热点分布区. 总体而言, 2019 年是非洲地区自 1981 年以来热浪强度最强, 持续时间最久的年份之一. 在主要城市和人口所在的非洲西海岸, 东北部, 南部和赤道地区是热浪发生的热点区. 位于赤道以北的非洲地区, 暴露于极端 (第 99 个百分位) 热浪的城市人口比例从 1981–2010 年基准期的 4% (500 万人) 上升至2019 年的 36% (4300 万人). 位于赤道以南地区, 暴露于极端热浪的城市人口则从基准期的15% (1700 万人) 上升至57% (5300 万人). 2019 年的热浪时空特征和热点分布与大气环流的季节变化异常和海温的暖异常有关. 如果不及时采取适应措施以尽量减少人口对热浪事件影响的敏感性, 热浪对非洲人口稠密地区构成的风险可能会迅速增加.  相似文献   

12.
Sugarcane provides around 80% of the world's sugar production and is also one of the most efficient bioenergy crops. China is the third largest sugarcane-producing country in the world, and skillful simulation of the sugarcane yield in China is thus vital for global production and the trade of sugar and ethanol. Global Gridded Crop Models (GGCMs) are commonly used to predict global and regional crop yield as well as to assess the impacts of climate, environment, and agronomic management changes and feedbacks of crop growth. So far, two GGCMs (CLM5-crop and LPJmL) have been able to model sugarcane, but their performance in China remains unknown. In this study, the authors comprehensively evaluated the sugarcane yield simulations of these two models for the period 1980–2009 using the crop yield statistics collected from the National Bureau of Statistics of China. Results showed that these two models substantially underestimate the multi-year average sugarcane yield, with simulated yields less than one quarter of observations. In addition, CLM5-crop successfully simulates the spatial pattern, while LPJmL does not. In terms of temporal variability, the two models can reproduce the significant upward trend for the national average and in most provinces, but underestimate the magnitude. They also fail to simulate the pattern of interannual variability. The two models underestimate the sugarcane yield partly because they incorrectly set the sugarcane yield coming from the grain as other grain crops, which is inconsistent with the fact that the stem is harvested.摘要中国是全球第三大甘蔗生产国, 中国甘蔗产量模拟可服务于全球食糖和乙醇的生产和贸易. 全球格点作物模式CLM5-crop和LPJmL已实现对甘蔗的模拟, 但它们在中国的模拟能力未知. 本文评估结果表明: 两个模式均严重低估了甘蔗产量, 模拟均不足观测的1/4. CLM5-crop能有技巧地模拟产量的空间分布特征, 而LPJmL不能. 两个模式均不能合理模拟产量的年际变化, 且低估了产量的上升趋势. 模式低估甘蔗产量的部分原因是模式假设收割的是甘蔗的穗而非茎.  相似文献   

13.
Extreme precipitation events cause severe environmental and societal damage worldwide. Southwest China (SWC) is sensitive to such effects because of its overpopulation, underdevelopment, and fragile ecosystems. Using daily observations from 108 rain-gauge stations, the authors investigated the frequency of extreme precipitation events and their contribution to total precipitation in SWC since the late 1970s. Results indicate that total precipitation is decreasing insignificantly, but rainfall-events frequency is decreasing significantly, whereas the region is experiencing more frequent and intense extreme precipitation events. Note that although fewer stations are statistically significant, about 60% of the rain-gauge stations show an increasing trend in the frequency and intensity of extreme precipitation. Furthermore, there is an increasing trend in the contribution of total extreme precipitation to total precipitation, with extreme precipitation becoming dominant in the increasingly arid SWC region. The results carry important implications for policymakers, who should place greater emphasis on extreme precipitation and associated floods and landslides when drafting water-resource management policies.摘要本文分析了中国西南20世纪70年代末以来极端降水事件的频率, 强度及其对总降水的贡献. 结果表明, 该地区约60%的降水站点极端降水的频率和强度正在增加, 而大多数站点总降水频率明显减少. 同时极端降水总量对总降水量的贡献有显著增加的趋势, 极端降水在日益干旱的中国西南地区变得更具主导性. 研究结果提醒应更加重视极端降水及其可能引发的次生灾害, 如洪水, 山体滑坡等.  相似文献   

14.
2019年,长江三峡地区年平均气温17.5℃,较常年偏高0.3℃;冬季偏冷,春,夏,秋三季气温均偏高;年高温日数偏多.2019年三峡地区年降水量1035.1毫米,较常年偏少13％;四季降水均偏少;年暴雨日数偏少.2019年,长江三峡地区年平均风速较常年偏大;年平均相对湿度接近常年;酸雨强度弱,为1999年以来的最弱年,...  相似文献   

15.
The response of the warming magnitude over the Tibetan Plateau (TP; elevation ≥ 3000 m) to global climate change is not spatially uniform. Rather, it enhances with elevation, referred to as elevation-dependent warming (EDW). The degree of EDW over the TP is season-dependent, with the largest amplitude of 0.21°C km−1 observed during boreal winter. Several factors have been proposed in previous studies as possible drivers of TP EDW, but the relative importance of these factors has been less studied. To quantitatively identify the major drivers of TP EDW in winter over recent decades (1979–2018), the authors applied the radiative kernels diagnostic method with several datasets. The results robustly suggest that, the surface albedo feedback associated with changes in snow cover plays the leading role in TP EDW. Observations show that the snow cover has reduced significantly over regions with high elevation during the winters of the past four decades, leading to reductions in outgoing shortwave radiation and thus EDW.摘要青藏高原 (海拔≥ 3000 m 地区) 对全球气候变化的变暖响应是空间不均匀的, 其增温幅度会随着海拔升高而增大, 被称为海拔依赖性增温. 青藏高原海拔依赖性增温具有季节依赖性, 在冬季最为显著, 达0.21°C km−1. 在以往的研究中, 众多因素被认为是青藏高原海拔依赖性增温的可能驱动因素, 但关于这些因素相对重要性的研究较少. 基于多个数据集, 本文应用辐射核 (radiative kernel) 技术方法定量诊断了近几十年 (1979–2018年) 冬季不同物理过程对青藏高原海拔依赖性增温的贡献. 结果表明, 与积雪变化相关的地表反照率反馈在其中起主导作用. 观测数据分析显示, 在过去40年的冬季,高海拔地区的积雪覆盖率显著减少, 导致地表反射的短波辐射减少, 从而促进了海拔依赖性增温.  相似文献   

16.
Coordinated numerical ensemble experiments with six different state-of-the-art atmosphere models were used to evaluate and quantify the impact of global SST (from reanalysis data) on the early winter Arctic warming during 1982–2014. Two sets of experiments were designed: in the first set (EXP1), OISSTv2 daily sea-ice concentration and SST variations were used as the lower boundary forcing, while in the second set (EXP2) the SST data were replaced by the daily SST climatology. In the results, the multi-model ensemble mean of EXP1 showed a near-surface (~850 hPa) warming trend of 0.4 °C/10 yr, which was 80% of the warming trend in the reanalysis. The simulated warming trend was robust across the six models, with a magnitude of 0.36–0.50 °C/10 yr. The global SST could explain most of the simulated warming trend in EXP1 in the mid and low troposphere over the Arctic, and accounted for 58% of the simulated near-surface warming. The results also suggest that the upper-tropospheric warming (~200 hPa) over the Arctic in the reanalysis is likely not a forced signal; rather, it is caused by natural climate variability. The source regions that can potentially impact the early winter Arctic warming are explored and the limitations of the study are discussed.摘要本文使用六个不同的最新大气模式进行了协调数值集合实验, 评估和量化了全球海表面温度 (SST) 对1982–2014年冬季早期北极变暖的影响.本研究设计了两组实验:在第一组 (EXP1) 中, 将OISSTv2逐日变化的海冰密集度和SST数据作为下边界强迫场;在第二组 (EXP2) 中, 将逐日变化的SST数据替换为逐日气候态.结果表明: (1) EXP1的多模式集合总体平均值显示0.4 °C/10年的近地表 (约850 hPa) 升温趋势, 为再分析数据结果中升温趋势的80%. (2) 在这六个模式中, 模拟的变暖趋势均很强, 幅度为0.36–0.50 °C/10年. (3) 全球海表温度可以解释北极对流层中低层EXP1的大部分模拟的变暖趋势, 占再分析数据结果的58%. (4) 再分析数据结果中, 北极上空的对流层上层变暖 (约200 hPa) 不是由强迫信号而可能是由自然气候变率引起的.本文还探索了影响北极初冬变暖的可能源区, 并讨论了该研究的局限性.  相似文献   

17.
Changes in the water cycle on the Tibetan Plateau (TP) have a significant impact on local agricultural production and livelihoods and its downstream regions. Against the background of widely reported warming and wetting, the hydrological cycle has accelerated and the likelihood of extreme weather events and natural disasters occurring (i.e., snowstorms, floods, landslides, mudslides, and ice avalanches) has also intensified, especially in the high-elevation mountainous regions. Thus, an accurate estimation of the intensity and variation of each component of the water cycle is an urgent scientific question for the assessment of plateau environmental changes. Following the transformation and movement of water between the atmosphere, biosphere and hydrosphere, the authors highlight the urgent need to strengthen the three-dimensional comprehensive observation system (including the eddy covariance system; planetary boundary layer tower; profile measurements of temperature, humidity, and wind by microwave radiometers, wind profiler, and radiosonde system; and cloud and precipitation radars) in the TP region and propose a practical implementation plan. The construction of such a three-dimensional observation system is expected to promote the study of environmental changes and natural hazards prevention.摘要青藏高原的水循环变化对于高原及其下游区域人类的生产生活具有举足轻重的影响. 在高原暖湿化的背景下, 其水文循环加快, 极端天气和自然灾害事件概率增大, 比如, 雪灾, 洪水, 滑坡, 泥石流, 冰崩在山区频发. 因此, 如何准确的估算青藏高原水循环各分量的大小及变化幅度是评估高原环境变化影响亟需解决的科学问题. 根据水在各圈层间转换过程, 我们提出了建立第三极地区 (尤其是复杂山区) 的三维立体多圈层地气相互作用综合观测系统(包括涡动相关系统, 行星边界层塔, 微波辐射计, 风廓线仪和无线电探空系统观测的风温湿廓线及云雨雷达等)的紧迫性和具体方案, 进而为研究青藏高原环境变化和山区灾害预测服务.  相似文献   

18.
使用1961—2020年的观测数据和2021—2080年的模式预估数据,首先分析了云南初夏干燥度指数（aridity index,AI）的演变特征和影响因子相对贡献,然后采用国际耦合模式比较计划第六阶段（CMIP6）中的20个全球模式,对SSP1-2.6、SSP2-4.5以及SSP5-8.5情景下云南初夏未来干湿变化进行了预估研究。结果表明：(1) 1961—2020年云南初夏气候整体湿润,但为变干燥的趋势,有明显的年代际变化特征,1960s、1970s以及2000s气候相对湿润,其余年代相对干燥,2000s（2010s）为1961年以来最湿润（干燥）的10年。(2) 2021—2080年在3种排放情景下,云南初夏气候较1995—2014年均为变干燥的趋势,SSP1-2.6、SSP2-4.5以及SSP5-8.5情景下,AI分别减少13.9%、17.9%以及24.9%,西南部将可能是湿润度降幅最大值中心。(3) 1961—2020年,降水对云南初夏气候干湿变化的贡献大于潜在蒸散量;而2021—2080年,潜在蒸散量对气候变干燥的贡献大于降水量,且随排放情景的增高和时间推移,其贡献将逐渐增大。  相似文献   

19.
Land–atmosphere interaction, as one of the key processes affecting the atmosphere and climate over East Asia, has drawn increasing attention during the past few decades. However, the current level of understanding regarding the mechanisms through which land surface processes impact the East Asian climate needs to be improved. Based on existing studies, six key regions where land surface processes affect the East Asian climate are proposed in this study, which can provide a valuable reference for future research into land–atmosphere interaction in East Asia.摘要陆气相互作用是影响东亚大气环流和气候的一个关键过程, 受到了越来越多的关注. 然而, 关于陆面过程影响东亚气候的相关机理的理解还有待提升. 在已有研究基础上, 提出了陆面过程影响东亚气候研究值得关注的青藏高原, 欧亚中高纬地区, 中国东部季风区, 中南半岛, 中亚中纬度区域, 西亚等6个关键区, 期待为加强陆面过程与东亚气候研究提供一定参考.  相似文献   

20.
基于ETCCDI指数2017年中国极端温度和降水特征分析   总被引：1，自引：0，他引：1  
利用中国1961—2017年2419站均一化逐日气候数据,计算了气候变化检测和指数联合专家组定义的26个极端气候指数,分析2017年中国极端温度和降水特征。结果表明：2017年中国区域平均的所有极端高温指数均高于1961—1990年30年平均,所有极端低温指数均低于1961—1990年30年平均。中国区域平均的多个极端温度指数达到或者接近历史极值,其中年最小日最高气温(TXn)和年最小日最低气温(TNn)均达到历史最高值,冷夜(TN10p)、冷昼(TX10p)和持续冷日日数(CSDI)达到历史最低值。年最大日最高气温(TXx)、年最大日最低气温(TNx)、暖夜(TN90p)、霜冻(FD)、冰冻(ID)、热夜(TR)、生长期长度(GSL)排在1961年以来的第2或第3位,其余极端温度指数全部排在了1961年以来前10位。2017年中国区域平均的10个极端降水指数中,有7个指数值处于1961—2017年1个标准差范围内,指示2017年的极端降水接近正常年。  相似文献   

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