青海省2006年冬季及年气候

1冬季气候概况2006年冬季(2006年12月~2007年2月)青海省气候特点是:气温偏高,降水略多但时空分布不均,日照正常。主要的天气气候事件是海晏、大柴旦、德令哈、河南、久治、甘德、达日、都兰、玛多发生冬季轻~中雪灾,1月上旬青海省北部地区的低温天气,2月东部农业区的异常高温天     

内蒙古地区气温异常变化特征及可能影响分析

基于内蒙古地区52个站点1961-2005年的逐月气温资料,利用趋势变化、累积距平统计、气温异常指标等方法,分析了内蒙古东冲、西部气温平均状态和异常波动特征。结果表明：1．内蒙古地区气温增暖特征显著,其增暖幅度高于全国平均水平．并且不同区域响应程度不同,内蒙古中西部地区大于东部地区。尤其在1986年发生气温突变以后,增温速率加快。2．目前年平均气温处于高气候平均态和高气候变率时期,致使20世纪90年代之后,异常暖年和极端暖年事件呈增加趋势。3．高温日数逐年增加和寒冷日数逐年的急剧减少,以及异常冷年出现在90年代之前和异常暖年发生在90年代之后等特征,进一步说明内蒙古地区气候变暖的事实。4．内蒙古地区极端气温事件出现频率较高．并在近20年主要以异常暖和极端暖事件为主。     

1991～1995年El Ni?o事件的特征及其对中国天气气候异常的影响

利用多种资料分析了１９９１～１９９５年异常ＥｌＮｉｎｏ事件的特征及东亚环流变异和中国异常天气气候的特征。根据所采用的划分ＥｌＮｉｎｏ事件的标准和指数,９０年代初的５年里共发生了３次ＥｌＮｉｎｏ事件,即１９９１年６月～１９９２年９月、１９９３年４～１２月、１９９４年６月～１９９５年２月（简称１９９１～１９９５年３次ＥｌＮｉｎｏ事件）。这３次事件都是中部型,间隔时间短（以年尺度为主）是它们的一个显著特点。研究表明１９９１～１９９５年３次ＥｌＮｉｎｏ事件对中国天气气候的影响有许多不同的方面。其中１９９１年（ＥｌＮｉｎｏ当年）夏季和１９９２年（ＥｌＮｉｎｏ次年）夏季降水异常分布与１９５１～１９９０年间１０次ＥｌＮｉｎｏ事件的平均结果相似,但１９９３、１９９４年夏季降水与平均结果相反。这说明ＥＮＳＯ事件不是唯一决定中国夏季天气气候的强信号,还有别的气候因子影响中国夏季的天气气候异常。在东亚,夏季风的活动可能是另一个关键气候信号。通过对１９９１年和１９９４年夏季东亚大尺度环流变化和南海地区经纬向风时间演变的分析发现,两者虽都处于ＥｌＮｉｎｏ爆发的当年,但相反的环流形势造成了这两年夏季相反的降水形势。这一方面表明ＥｌＮｉ     

青海省2005年冬季及年气候

1冬季气候概况2005年冬季(2005年12-2006年2月,下同),青海省气候特点是:气温偏高,是有气象资料以来最暖的冬季,也是连续出现的第9个暖冬;降水除东部农业区、海北东部、柴达木盆地中西部偏多外,其余地区偏少,全省平均降水量较1971-2000年气候平均值偏少18.2%;日照时数,除青南高原大部偏多以外,其余地区偏少,冬季平均日照时数较1971- 2000年气候平均值偏少了4%。主要的天气气候事件是玉树称多等地、都兰、门源的雪灾,2005年12月省内北部地区持续低温、干燥等天气气候,2006年1、2月本省的异常高温天气,2006年1月3-5日出现大范围寒潮强降温天气等。1.1气温     

青海省2007年春季气候

1基本气候概况2007年春季(3~5月)青海省气候特点是:全省气温偏高,大部分地区降水、日照时数接近常年。主要的天气气候事件是柴达木盆地东部和青南部分地区出现的雪灾、4月~5月上旬全省中南部出现的干旱。1.1气温全省气温偏高明显。东部农业区春季平均气温在5.8~11.0℃之间,比常     

贵州2003年的异常气候事件介绍

通过对贵州2003年全年的气候事件进行分析,得出2003年的气候异常主要表现在温度和降水两方面,其中温度异常主要表现在暖冬、夏季高温和全年温度持续偏高等方面;降水异常主要表现在降水的分布不均和夏秋季的持续偏少上。2003年依然存在低温冷害事件,突出表现为冬季的降雪和春季的“倒春寒”事件;2003年春季西部的春旱严重,全省大部地区出现夏秋连旱。     

青海省2007年夏季气候

2007年夏季（6—8月）青海省气候特点是：全省气温偏高，大部分地区降水偏多，日照时数偏少。主要的天气气候事件是6月上旬东部农业区部分地区出现的干旱，8月下旬全省首次出现入夏以来大范围的高温天气，洪涝、冰雹、雷击等气象灾害以及强降水引发的山体滑坡、泥石流等次生灾害。     

四川省2001年气候事件回顾

2001年,四川省盆地区发生了多起异常气候事件.冬春的异常高温干旱,夏季伏旱的异常偏早偏强,秋季连阴雨早而强,盆地西北部秋季大涝等,均为历史同期所少见.本文将对四川省2001年气候事件做一回顾.     

新、旧气候态差异及对中国地区气候和极端事件评估业务的影响

利用1961—2020年中国区域2089个地面观测站资料,分析了1991—2020年和1981—2010年新、旧气候态下,平均气温、最高气温、最低气温和降水量等变量的空间变化特征,探讨对气候距平值、极端事件等评估结果的影响。结果表明：新气候态下,全国三类气温年和季节平均均一致升高,年降水增加,空间上气温偏高（低）、降水偏多（少）的特征将弱（强）化;华北东部、华东中部和北部以及青海西南部的年平均风速和日照时数距平增加;极端高温年减少,低温年增多,其中平均气温和最低气温受到的影响较最高气温更大;夏季南北方两条雨带极端强降水年的发生概率降低,冬季东北中部和南部、华北、华东北部、西北东部极端弱降水年概率显著增加;全国超过一半的站点极端日高温、低温和强降水事件的历史频次发生改变;新气候态还减弱了极端日高温事件的增速,加快了极端日低温事件的降速。     

鄂尔多斯地区2007年冬季异常气候影响的思考

通过对鄂尔多斯地区2007年冬季异常气候及产生的灾害性天气事件进行了调查,结合IPCC公布的最新数据及专家研究成果,提出了鄂尔多斯地区应对异常气候造成的灾害性天气事件的一些措施。     

美国宣布退出《巴黎协定》后全球气候减缓、资金和治理差距分析

2017年6月1日,美国总统特朗普正式宣布退出《巴黎协定》,有关美国退协原因、后续影响和应对策略的研究成为国际社会关注的焦点。本文基于自主构建的美国政策评估模型,综合定性定量分析,系统评估了美国宣布退出《巴黎协定》可能造成的全球气候变化减缓、资金和治理"三大赤字",并据此提出中国的应对策略和建议。研究表明,考虑美国退协对后续政策的影响,美国2030年的排放将有可能达57.9（56.0~59.8）亿t CO₂-eq,仅相当于在2005年的水平上下降12.1%（9.1%~15.0%）,相对自主贡献目标情景将上升16.4（12.5~20.1）亿t CO₂-eq,额外增加8.8%~13.4%的全球减排赤字。美国拒绝继续履行资金支持义务还将使得本不充裕的气候资金机制更加雪上加霜,绿色气候基金（GCF）的筹资缺口将增加20亿美元,而长期气候资金（LTF）的缺口每年将增加50亿美元左右。这就要求欧盟和日本对GCF的捐助至少上升40%,同时欧盟及其成员国的长期资金支持至少上浮25.2%才能填补上述资金赤字。美国是全球气候博弈的重要一方,且美国退协的影响已蔓延至全球治理的主要议事平台,期望中欧、基础四国+等模式短期内迅速填补美国退出后全球气候治理的治理赤字是不现实的,政治推动乏力的情况可能会在今后一段时期内始终存在。虽然国际社会对中国领导全球气候治理充满期待,但中国应有清醒认识,全面评估"接盘"美国领导力的成本、效益和可行性,并秉持"国家利益"优先的原则,谋定而后动。同时,中国应聚焦国内工作,凝聚应对气候变化的战略共识,做好长期战略谋划,并积极推动国际社会从合作中寻找出路应对"三大赤字"难题。     

2002年全球重大气候事件概述

全球气候仍为异常暖年。赤道中、东太平洋形成新的ENSO暖事件。冬季前期连续大雪严寒席卷了欧洲大部地区，美国南部也受到罕见大雪袭击。南亚东部、中南半岛湄公河三角洲雨季降水频繁，引发严重洪涝灾害。8月，欧洲异常暴雨引发世纪大洪水，多国受灾严重。印度尼西亚、澳大利亚、美国西部、非洲大部降水持续偏少，发生严重干旱。太平洋、大西洋的热带风暴给沿岸国家带来不同程度的灾害。     

The potential effects of climate change on summer season dairy cattle milk production and reproduction

The potential direct effects of possible global warming on summer season dairy production and reproduction were evaluated for the United States and Europe. Algorithms used for milk production and conception rate were previously developed and validated. Three widely known global circulation models (GISS, GFDL, and UKMO) were used to represent possible scenarios of future climate. Milk production and conception rate declines were highest under the UKMO model scenario and lowest under the GISS model scenario. Predicted declines for the GCM scenarios are generally higher than either 1 year in 10 probability-based declines or declines based on the abnormally hot summer of 1980 in the United States. The greatest declines (about 10% for the GISS and GFDL scenarios, and about 20% for the UKMO scenario) in the United States are predicted to occur in the Southeast and the Southwest. Substantial declines (up to 35%) in conception rates were also predicted in many locations, particularly the eastern and southern United States. These areas correspond to areas of high dairy cattle concentration. They already have relatively large summer season milk production declines resulting from normally hot conditions. Thus, the actual impacts of increased production declines may be greater in other areas, which are not accustomed to large summer season declines and therefore may require more extensive mitigation measures.Published as Paper No. 9698 Journal Series, Nebraska Agricultural Research Division. The work reported here was conducted under Nebraska Agricultural Research Division Project 27–007.     

1997年全球重大气候事件概述

近年来,全球气候持续偏暖,１９９７年又成为一个多世纪以来最暖的一年。年内赤道中、东太平洋发生了一次本世纪最强的厄尔尼诺事件,全球气候受到重大影响,特别是热带地区出现了大范围的气候异常,高温干旱、暴雨洪水事件此起彼伏,连续不断,造成严重灾害。欧洲、北美前冬和春季严寒多雪;欧洲夏季暴雨频繁,中欧发生了百年不遇的特大洪水;中国北部和朝鲜出现罕见的持续高温干旱天气;美国和加拿大边境地区发生了一百多年来最严     

Simulating the impact of the large-scale circulation on the 2-m temperature and precipitation climatology

The impact of the simulated large-scale atmospheric circulation on the regional climate is examined using the Weather Research and Forecasting (WRF) model as a regional climate model. The purpose is to understand the potential need for interior grid nudging for dynamical downscaling of global climate model (GCM) output for air quality applications under a changing climate. In this study we downscale the NCEP-Department of Energy Atmospheric Model Intercomparison Project (AMIP-II) Reanalysis using three continuous 20-year WRF simulations: one simulation without interior grid nudging and two using different interior grid nudging methods. The biases in 2-m temperature and precipitation for the simulation without interior grid nudging are unreasonably large with respect to the North American Regional Reanalysis (NARR) over the eastern half of the contiguous United States (CONUS) during the summer when air quality concerns are most relevant. This study examines how these differences arise from errors in predicting the large-scale atmospheric circulation. It is demonstrated that the Bermuda high, which strongly influences the regional climate for much of the eastern half of the CONUS during the summer, is poorly simulated without interior grid nudging. In particular, two summers when the Bermuda high was west (1993) and east (2003) of its climatological position are chosen to illustrate problems in the large-scale atmospheric circulation anomalies. For both summers, WRF without interior grid nudging fails to simulate the placement of the upper-level anticyclonic (1993) and cyclonic (2003) circulation anomalies. The displacement of the large-scale circulation impacts the lower atmosphere moisture transport and precipitable water, affecting the convective environment and precipitation. Using interior grid nudging improves the large-scale circulation aloft and moisture transport/precipitable water anomalies, thereby improving the simulated 2-m temperature and precipitation. The results demonstrate that constraining the RCM to the large-scale features in the driving fields improves the overall accuracy of the simulated regional climate, and suggest that in the absence of such a constraint, the RCM will likely misrepresent important large-scale shifts in the atmospheric circulation under a future climate.     

《巴黎协定》与特朗普政府的履约前景

《巴黎协定》生效标志着全球气候治理进程从达约阶段转向履约阶段。但是,履约阶段并不意味着全球气候风险得到控制,反而面临新的挑战。本文从《巴黎协定》入手,分析了《巴黎协定》自身存在的不足,重点考察了美国的履约意愿,分析了特朗普政府退出《巴黎协定》及其影响,探讨了未来美国的气候立场。研究发现,《巴黎协定》在减排力度、气候资金及遵约条款三方面存在先天不足,导致《巴黎协定》有效性仍取决于缔约方的履约意愿和履约能力。当前美国国内政局演变导致美国联邦政府气候政策出现倒退,有可能对《巴黎协定》缔约方的履约意愿和履约能力产生不良影响。但是,这种不良影响仅仅是短暂的。美国在国际格局中的地位变化以及美国业已成形的低碳转型,共同决定了特朗普气候政策并不会从根本上动摇《巴黎协定》。长期来看,美国对全球领导力的诉求、国内应对气候变化的内在动力以及来自外部的道义压力这三大因素势将促使美国在未来重新回归《巴黎协定》。     

Historical and future changes in maximum and minimum temperature records over Europe

Recent studies examining changes in temperature record frequency over the continental United States have reported that the number of Tmax records has been increasing over the past 50 years and occurring at twice the frequency of Tmin records. In a stationary climate, the number of records should decrease with time as 1/n, where n is the number of years of record-keeping. Here we seek to understand how European temperature records have changed during the late 20th century and how they are expected to change as greenhouse gases increase during the 21st century, using a new ensemble method to filter out the effect of the starting year in the calculation of the records. We find that until 1980, the ratio of Tmax to Tmin records remains close to one, indicating that the climate was relatively stationary. After 1980, there is a distinct positive trend where the observed ratio averages around four during the early part of the 21st century, indicative of a warming trend. We note considerable spatial variability in the observations. Further, the ratio of Tmax to Tmin records set by the year 2100 as simulated by five RCM simulations reaches values of up to several hundred by the end of the 21st century. However, the changes in record frequency vary spatially over Europe. The models project the highest numbers of Tmax records over the Mediterranean during summer, and Scandinavia during the spring and fall. Tmin records decrease most substantially over eastern Europe and western Russia, and the Mediterranean. Our analysis confirms the value of the use of maximum and minimum temperature records in regional climate change studies.     

美国全球变化研究现状

美国的全球变化研究主要由美国全球变化研究计划（ＵＳＧＣＲＰ）支持,重点资助季节—年际尺度气候变率,十年—百年尺度的气候变化,臭氧、ＵＶ辐射以及大气化学的变化,土地利用以及陆地、海洋生态系统的变化等４个领域。当前,水汽与云仍是全球变化研究中不确定性较大的一个方面,因而受到关注。关于气候变化的信号检测以及成因分析也是一个研究热点。气候模拟研究是全球变化研究的一个主要方法。卫星资料在全球变化研究中的应用取得了大量成果。近期美国在全球变化研究领域的重点是气候模拟,短期气候预测,十年—百年尺度的气候变化,臭氧、ＵＶ辐射以及大气化学的变化,地表以及陆地、海洋生态系统变化,对全球变化的区域尺度估计,卫星资料的应用,气候变化影响的国家级评估等８个方面。     

Influence of modern land cover on the climate of the United States

I have used a high-resolution nested climate modeling system to test the sensitivity of regional and local climate to the modern non-urban land cover distribution of the continental United States. The dominant climate response is cooling of surface air temperatures, particularly during the warm-season. Areas of statistically significant cooling include areas of the Great Plains where crop/mixed farming has replaced short grass, areas of the Midwest and southern Texas where crop/mixed farming has replaced interrupted forest, and areas of the western United States containing irrigated crops. This statistically significant warm-season cooling is driven by changes in both surface moisture balance and surface albedo, with changes in surface moisture balance dominating in the Great Plains and western United States, changes in surface albedo dominating in the Midwest, and both effects contributing to warm-season cooling over southern Texas. The simulated changes in surface moisture and energy fluxes also influence the warm-season atmospheric dynamics, creating greater moisture availability in the lower atmosphere and enhanced uplift aloft, consistent with the enhanced warm-season precipitation seen in the simulation with modern land cover. The local and regional climate response is of a similar magnitude to that projected for future greenhouse gas concentrations, suggesting that the climatic effects of land cover change should be carefully considered when crafting policies for regulating land use and for managing anthropogenic forcing of the climate system.     

Variation of the North Atlantic subtropical high western ridge and its implication to Southeastern US summer precipitation

Variations of the North Atlantic subtropical high (NASH) western ridge and their implication to the Southeastern United States (SE US) summer precipitation were analyzed for the years 1948–2007. The results show that the movement of the NASH western ridge regulates both moisture transport and vertical motion over the SE US, especially in the last three decades, during which the ridge moved westward towards the American continent. When the NASH western ridge is located southwest (SW) of its mean climate position, excessive summer precipitation is observed due to an enhanced moisture transport. In contrast, when the western ridge is located in the northwest (NW), a precipitation deficit prevails as downward motion dominates the region. Composite analysis indicates that SW ridging results mainly from the NASH center’s intensification; whereas NW ridging is likely caused by stationary wave propagation from the eastern Pacific/US western coast. In recent decades, both the SW and NW ridge positions have been observed to increase in frequency. Our results suggest that the increase in the SW ridging consistently follows the NASH’s intensification associated with anthropogenic forcing as projected by coupled climate models. However, the increased frequency of NW ridging tends to follow the positive Pacific decadal oscillation (PDO) index. Thus, the enhanced variability in the SE US summer precipitation in recent decades might be a combined result of anthropogenic forcing and internal variability of the climate system. Results suggest that, as anthropogenic forcing continues to increase, the SE US will experience more frequent wet summers and an increase in the frequency of dry summers during positive PDO phases.