气候变化背景下陆地极端降水和温度变化区域差异

利用月平均地表气候要素数据集(CRU TS 3.22)和百分位的方法定义极端事件,分析了19012012年气候变化背景下极端降水和温度变化的趋势特征以及在气温相对冷暖时段极端事件发生频率的区域差异,重点关注20世纪70年代中后期至90年代末的加速变暖时段和1998 2012年变暖减缓时段。结果表明,在全球平均气温显著上升的112年中,全球极端强降水事件和极端高温事件均表现出增多的趋势,极端低温事件呈现减少的趋势。夏季极端强降水事件发生频率在加速变暖时段的分布与1956 1976年相近,高值区位于北美中高纬、南美洲和欧亚大陆低纬地区,在变暖减缓时段北美中高纬地区变为低值区,而欧亚大陆中纬度地区频率增大。冬季极端强降水事件发生频率大值区在变暖减缓时段位于南美洲北部、欧亚大陆和大洋洲西部地区,北美洲和非洲南部为明显的低值区。全球极端高温事件发生频率在气温偏暖时段明显增大,欧亚大陆中东部地区在加速变暖时段是冬季极端高温事件发生频率大值区。极端低温事件发生频率的变化与极端高温事件相反,但欧亚大陆中纬度地区在相对较暖的1931 1955年是冬季极端低温事件发生频率高值区,大于最冷的1901 1930年和相对较冷的1956 1976年。与加速变暖时段相比,变暖减缓时段大洋洲西北部夏季与冬季的极端低温事件和欧亚大陆中高纬冬季极端低温事件明显增多。     

华南后汛期极端降水特征及变化趋势

利用中国国家气象信息中心提供的华南89个代表站1969-2008年逐日降水资料,对华南后汛期（7-月）极端降水时空演变特征进行研究。结果表明：多年平均总降水量、强降水量、降水频率、强降水频率以及暴雨频率与强降水量阈值空间分布一致,广东和广西的南部及福建西南部为大值区;强降水量、降水频率及暴雨频率很大程度影响着华南后汛期总降水量的空间分布。强降水量、强降水频率、暴雨频率对后汛期总降水量的时间变化有很好的指示意义。华南后汛期极端降水在1992--1993年发生一次明显的年代际转折,1993年以来各指标的均值（除降水频率外）和方差均显著增加,华南发生极端旱涝的情况增多。另外,转折前后两个时段的总降水量、降水频率均呈减小趋势,但减小显著的区域有一定差异。     

FGOALS-g2模式模拟和预估的全球季风区极端降水及其变化

利用LASG/IAP（中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室）全球耦合模式FGOALS-g2,评估了其对全球季风区极端气候指标的模拟能力,并讨论了RCP8.5排放情景下21世纪季风区极端气候指标的变化特征。总体而言,模式对季风区总降水和极端气候指标1997～2014年气候态和年际变率的空间分布均具有一定的模拟能力。偏差主要表现在模式低估了亚洲季风强降水中心,低估了中雨（10～20 mm d-1）和大雨（20～50 mm d-1）的频率而高估了暴雨（>50 mm d-1）频率。在RCP8.5排放情景下,由于可降水量的增加,模式预估的全球季风区极端降水、降水总量和降水强度将持续增加。到2076～2095年,极端降水和降水强度在北美季风区增加最显著（约22%和17%）,降水总量在澳大利亚增加最显著（约37%）。然而,FGOALS-g2对全球季风区平均的日降水量低于1 mm的连续最大天数（CDD）的预估变化不显著,这是由于预估的CDD在陆地季风区将增加,而在海洋季风区将减少。对各子季风区的分析显示,CDD在南美季风区变长最显著,达到30%,在澳洲季风区变短最显著,达到40%,这与两季风区日降水量低于1 mm的降水事件发生频率变化不同有关。     

近四十年我国东部盛夏日降水特性变化分析

基于中国地区740台站的日降水资料,细致分析了近40年我国东部盛夏即7、8月份降水长期趋势和年代际变化特征。按小雨、中雨、大雨以及暴雨降水强度分类,探讨了不同强度降水在我国东部降水变化中的贡献。结果表明,中国东部地区盛夏降水变化主要受暴雨强度降水变化的影响,占总降水变化60%以上。近40年来,盛夏长江流域降水量、 降水频率、极端降水频率以及暴雨降水强度均呈增大趋势,在华北地区则呈减小趋势,除降水频率在长江流域的变化趋势绝对值比华北地区小外,另三个指标在长江流域的趋势变化值大约是后者的2倍。降水强度在中国东部表现出一致的增大趋势,但华北地区增大趋势不显著。华北地区降水的减少主要是小雨强度降水频率减小的结果,强降水的频率和强度在该地区也呈微弱的减小趋势,其中小雨强度降水频率减小趋势大值中心值达到-3%/10a,比中雨以上强度降水频率变化趋势值大一个量级;长江流域降水的增多,是各强度降水频率和强度增大共同作用的结果。长江流域和华北地区在区域平均降水频率、降水强度、极端降水频率、最大降水量的时间序列上,彼此均为负相关关系,其中降水频率和极端降水频率序列在两区域的相关系数通过99%的信度检验。Mann-Kendall检验表明,除华北地区降水强度外,其他降水指标均存在显著的年代际跃变。与1970年代末的气候跃变相对应,华北地区降水频率较之长江流域的跃变明显;但长江流域极端降水在1970年代末的跃变较之华北地区更显著,其降水强度、极端降水频率以及最大降水量均于1970年代末期前后发生显著年代际跃变。     

中国1961—2016年夏季持续和非持续性极端降水的变化特征

基于国家气象信息中心提供的1961—2016年2400多站逐日降水观测资料,根据百分位法确定极端降水,对中国夏季持续（持续2 d及以上）和非持续性（持续1 d）极端降水事件的变化特征进行了研究。结果表明：在气候变暖背景下,以江淮流域为代表,中国大部分地区极端降水量趋于增多,但华北、西南及西部部分地区趋于减少;除内蒙古中部、四川等地以外,中国大部极端降水对总降水的贡献呈增多趋势。进一步对华北、江淮、华南、西南4个代表区域进行分析,发现华北、西南地区的持续和非持续性极端降水量都呈减少趋势,持续性极端降水量的减少更突出,极端降水更多以非持续性形式出现;江淮、华南一带,两类极端降水量都呈增多趋势,持续性极端降水量的增加更明显,极端降水更多以持续性形式出现。     

7个IPCC AR4模式对中国地区极端降水指数模拟能力的评估及其未来情景预估

利用中国区域550个站点1961～2000年日降水量资料, 考察参与政府间气候变化委员会(IPCC)第四次评估报告的7个新一代全球模式及多模式集合对现代气候情景下(20C3M)5个极端降水指数的模拟能力, 同时进行中国区域未来不同排放情形下极端降水事件变化的预估, 结果表明: 最新全球模式能较好地模拟出极端降水指数气候场的空间分布及其中国区域的线性趋势, 且模式集合模拟能力优于大部分单个模式, 但在青藏高原东侧、 高原南部存在虚假的极端降水高值区, 模拟的东部季风区的极端降水强度系统性偏低, 区域平均序列年际变率的模拟能力也较低。中国地区21世纪与降水有关的事件都有趋于极端化的趋势, 极端降水强度可能增强, 干旱也将加重, 且变化幅度与排放强度成正比。     

近50年西北干旱区极端降水的时空变化特征

利用西北干旱区1961-2010年76个测站的逐日降水量,采用线性趋势,Mann-Kendall（M-K）突变检验等现代统计诊断方法,研究我国西北干旱区极端降水的时空变化特征。结果表明:（1）过去50年北疆地区和天山山区极端降水量总体上呈增加趋势,河西-阿拉善地区变化不明显;（2）除南疆地区外,北疆、天山山区、河西-阿拉善地区极端降水量分别于1982年、1990年、1987年发生显著的上升突变;（3）极端降水量空间分布的区域差异性显著,在研究区西部表现为以天山山区大值为中心,呈现北高南低的特点;研究区的东部主要是自东南向西北递减的特点;（4）极端降水频率与极端降水量的空间分布基本一致。     

中国近40年极端气温和降水的分布特征及年代际差异

利用全国119（154）站1961-2000年逐日平均气温（降水）资料，采用世界气象组织（WMO）最近公布的极端气候指数，分析了中国近40a来极端气温和降水的分布及变化特征。结果表明：40a气温极端冷指数整体呈下降趋势，极端暖指数整体呈上升趋势，表现为气温变暖，与全球变暖一致，北方地区极端气温指数变化最大；比较了1961-1975年和1976-2000年2个子时段各极端气温指数的变化趋势，第一时段表现为气温变冷趋势，第二时段为气温变暖趋势。全国年降水量、中等雨日指数（R75％）、强降水日指数（R95％）和强降水比率指数（R95％tot）的整体线性变化为上升趋势，前2个指数地理差异明显，后2个指数地理差异不明显。在上述2个时段中，第二时段较第一时段的年雨日数减少，但强降水日数和平均降水强度增大，且极端降水正线性变化趋势范围比第一时段也增大。     

近50a西北干旱区极端降水的时空变化特征

利用西北干旱区1961—2010年76个测站的逐日降水量,采用线性趋势,MannKendall(M-K)突变检验等现代统计诊断方法,研究我国西北干旱区极端降水的时空变化特征。结果表明:(1)过去50 a北疆地区和天山山区极端降水量总体上呈增加趋势,河西—阿拉善地区变化不明显;(2)除南疆地区外,北疆、天山山区、河西—阿拉善地区极端降水量分别于1982年、1990年、1987年发生显著的上升突变;(3)极端降水量空间分布的区域差异性显著,在研究区西部表现为以天山山区大值为中心,呈现北高南低的特点;研究区的东部主要是自东南向西北递减的特点;(4)极端降水频率与极端降水量的空间分布基本一致。     

大理苍山不同海拔高度湿季降水日变化特征分析

基于大理国家气候观象台苍山-洱海梯度观测系统2011—2020年湿季小时降水资料,分析山顶、山腰和坝区3个站的降水日变化特征。结果显示:降水量日变化,坝区站呈现单峰型,山腰站和山顶站则是双峰型;降水频次日变化,坝区站和山顶站为单峰型,山腰站日变化比较平缓;各时次的降水量、降水频次基本随海拔高度的增加而增多;降水强度日变化,山顶站为双峰型,坝区站和山腰站波动较大,午后为小值区,夜间为大值区,3个站在14:00—17:00的降水强度相差不大,而其他时段山腰站和坝区站的降水强度比山顶站大。夜间降水量在持续时间2～16 h是大值区,随海拔的增加降水量大值区持续时间较长;白天降水量在持续时间小于6 h是大值区,随海拔的增加,大值出现的时间向后移。降水频次在持续时间小于6 h,3个站在白天、夜间分别有一个大值区,而持续时间7～18 h的只有山顶站夜间有大值区;坝区站和山顶站夜间降水频次大于白天降水频次,山腰站白天、夜间降水频次相差不大。长历时(中历时、短历时)的累计降水量、降水频次随海拔高度的增加而增大(减小);3个站长历时降水量(长历时降水频次)对总降水量(总降水频次)的贡献最大,贡献最小的是短...     

GIS-based high-resolution spatial interpolation of precipitation in mountain–plain areas of Upper Pakistan for regional climate change impact studies

In this study, the baseline period (1960–1990) precipitation simulation of regional climate model PRECIS is evaluated and downscaled on a monthly basis for northwestern Himalayan mountains and upper Indus plains of Pakistan. Different interpolation models in GIS environment are used to generate fine scale (250?×?250 m²) precipitation surfaces from PRECIS precipitation data. Results show that the multivariate extension model of ordinary kriging that uses elevation as secondary data is the best model especially for monsoon months. Model results are further compared with observations from 25 meteorological stations in the study area. Modeled data show overall good correlation with observations confirming the ability of PRECIS to capture major precipitation features in the region. Results for low and erratic precipitation months, September and October, are however showing poor correlation with observations. During monsoon months (June, July, August) precipitation pattern is different from the rest of the months. It increases from south to north, but during monsoon maximum precipitation is in the southern regions of the Himalayas, and extreme northern areas receive very less precipitation. Modeled precipitation toward the end of the twenty-first century under A2 and B2 scenarios show overall decrease during winter and increase in spring and monsoon in the study area. Spatially, both scenarios show similar pattern but with varying magnitude. In monsoon, the Himalayan southern regions will have more precipitation, whereas northern areas and southern plains will face decrease in precipitation. Western and south western areas will suffer from less precipitation throughout the year except peak monsoon months. T test results also show that changes in monthly precipitation over the study area are significant except for July, August, and December. Result of this study provide reliable basis for further climate change impact studies on various resources.     

中国夏季风影响过渡区与其他地区蒸发皿蒸发量趋势相反的原因

夏季风影响过渡区是天气和气候的敏感区,随着全球和区域的变暖,该区域特殊的气候环境响应引起人们重点关注。以南昌、定西、乌鲁木齐作为夏季风影响区、夏季风影响过渡区以及非夏季风影响区的代表站,通过对比中国夏季风影响过渡区和其他地区50年来温度、日照时数、相对湿度、降水量、低云量、风速的变化趋势,以及分析各气象因子单独变化对蒸发皿蒸发量的影响,发现在夏季风影响过渡区各个气象因子的变化均使蒸发皿蒸发量增加,而在其他地区,只有温度变化会使蒸发皿蒸发量增加,其他各因子的变化均会造成蒸发皿蒸发量的下降。贡献度更直观的反映各气象因子对不同地区蒸发皿蒸发的作用。结果表明温度变化对夏季风影响过渡区蒸发皿蒸发变率的贡献最大,贡献度为48.93%。风速变化对夏季风影响区蒸发皿蒸发变率的贡献最大,贡献度为51.54%。降水变化对非夏季风影响区蒸发皿蒸发变率的贡献最大,贡献度为58.57%。此外,低云量的变化对夏季风影响过渡区、夏季风影响区和非夏季风影响区的贡献均达到20%以上。因此,不同地区影响蒸发皿蒸发的最主要的因子是不同的,但低云量对任何地区蒸发皿蒸发的影响都非常重要。     

最优气候值方法在中国的应用

该文用最优气候值方法研究了 1 951～ 1 998年中国 1 60个站点季、月的气温和降水 .结果表明 ,在中国最优气候值方法对气温具有相当的可用性 ,尤其是对冬季气温有很好的预报效果 ;对于降水 ,只对个别时间段的个别地区有一定的可用性 .对季的预报好于对月的预报 .无论是预报值与观测值的相关系数还是最优气候值的平均年份数在每一固定时期内都呈现出有规则的连续性空间分布 ,但是空间分布随时间变化而变化     

Potential increase of flood hazards in Korea due to global warming from a high-resolution regional climate simulation

Because of the importance of the changes in the hydrologic cycle, accurate assessment of precipitation characteristics is essential to understand the impact of climate change due to global warming. This study investigates the changes in extreme precipitation with sub-daily and daily temporal scales. For a fine-scale climate change projection focusing on the Korean peninsula (20 km), we performed the dynamical downscaling of the global climate scenario covering the period 1971?C2100 (130-year) simulated by the Max-Planck-Institute global climate model, ECHAM5, using the latest version of the International Centre for Theoretical Physics (ICTP) regional climate model, RegCM3. While annual mean precipitation exhibits a pronounced interannual and interdecadal variability, with the increasing or decreasing trend repeated during a certain period, extreme precipitation with sub-daily and daily temporal scales estimated from the generalized extreme value distribution shows consistently increasing pattern. The return period of extreme precipitation is significantly reduced despite the decreased annual mean precipitation at the end of 21^st century. The decreased relatively weak precipitation is responsible for the decreased total precipitation, so that the decreased total precipitation does not necessarily mean less heavy precipitation. Climate change projection based on the ECHAM5-RegCM3 model chain clearly shows the effect of global warming in increasing the intensity and frequency of extreme precipitation, even without significantly increased total precipitation, which implies an increased risk for flood hazards.     

京津冀城市群气候变化及影响适应研究综述

本文对2000年以来京津冀城市群气候变化及影响适应的研究成果进行了综述。研究表明：20世纪60年代以来,京津冀城市群年平均气温和极端高温指数显著升高,年降水量波动减少,到21世纪10年代,极端强降水指数降低。京津冀气候变化是全球变暖和城市化共同作用的结果,城市化加速了京津冀变暖趋势,增加了极端高温和极端强降水的频率和强度,气候风险高。未来京津冀城市群协同发展,面临高温热浪、强降水、水资源短缺和海平面上升等风险将更严峻,气候变化适应是京津冀城市群可持续发展面临的紧迫问题,适应策略等方面研究已取得了明显进展,但适用性和针对性还存在不足。本文提出了未来研究展望：深入研究城市化对气候变化的反馈,发展全球气候变化和城市化共同作用下的气候风险精细化预估技术,系统研究气候变化对城市的影响和不同行业的脆弱性,加强温室气体监测评估技术研究,加强适应气候变化的策略、路径和技术研究。     

Regional changes in extreme monsoon rainfall deficit and excess in India

With increasing concerns about climate change, the need to understand the nature and variability of monsoon climatic conditions and to evaluate possible future changes becomes increasingly important. This paper deals with the changes in frequency and magnitudes of extreme monsoon rainfall deficiency and excess in India from 1871 to 2005. Five regions across India comprising variable climates were selected for the study. Apart from changes in individual regions, changing tendencies in extreme monsoon rainfall deficit and excess were also determined for the Indian region as a whole. The trends and their significance were assessed using non-parametric Mann–Kendall technique. The results show that intra-region variability for extreme monsoon seasonal precipitation is large and mostly exhibited a negative tendency leading to increasing frequency and magnitude of monsoon rainfall deficit and decreasing frequency and magnitude of monsoon rainfall excess.     

藏东南色季拉山气温和降水垂直梯度变化

色季拉山气温和降水垂直梯度变化规律的研究能更好的了解色季拉山动植物分布随高度变化的生理生态特点,也为未来此区域流域水文模拟提供可靠的数据支持。根据色季拉山11个气象站2013-2018年逐日的平均气温和降水量(4-10月)数据,分析了色季拉山及其西坡和东坡的气温和降水量与海拔的关系。结果表明:(1)色季拉山、西坡和东坡2013-2018年各年气温递减率年际变化幅度小,平均气温递减率分别为0.60,0.71和0.55℃·(100m)-1;(2)季节上,色季拉山气温递减率表现为冬春季高值,夏秋低值的特点,并且在色季拉山受印度季风影响强烈的6-9月季风期是相对的一个低值,这与青藏高原其他受印度季风区域的研究的结果一致;(3)坡向的对比发现,相同时段的气温递减率均表现为西坡的气温递减率均高于东坡的,这可能与西坡降水量比东坡少有关;(4)西坡2013-2018年平均年降水总量与海拔的相关性不显著,而东坡两者相关性显著,降水梯度为10.5 mm·(100m)-1;(5)除西坡非季风期降水量随海拔升高而增加外,西坡季风期、东坡季风期和东坡非季风期的降水量随海拔变化复杂,在色季拉山的中海拔区域均存在相对的少雨区,西坡在3035~3698 m,东坡在3326~3390 m,而在色季拉山的高海拔区域,降水量随海拔升高降水量增加。     

An overview of dry-wet climate variability among monsoon-westerly regions and the monsoon northernmost marginal active zone in China

Climate in mainland China can be divided into the monsoon region in the southeast and the westerly region in the northwest as well as the intercross zone, i.e., the monsoon northernmost marginal active zone that is oriented from Southwest China to the upper Yellow River, North China, and Northeast China. In the three regions, dry-wet climate changes are directly linked to the interaction of the southerly monsoon flow on the east side of the Tibetan Plateau and the westerly flow on the north side of the Plateau from the inter-annual to inter-decadal timescales. Some basic features of climate variability in the three regions for the last half century and the historical hundreds of years are reviewed in this paper. In the last half century, an increasing trend of summer precipitation associated with the enhancing westerly flow is found in the westerly region from Xinjiang to northern parts of North China and Northeast China. On the other hand, an increasing trend of summer precipitation along the Yangtze River and a decreasing trend of summer precipitation along the monsoon northernmost marginal active zone are associated with the weakening monsoon flow in East Asia. Historical documents are widely distributed in the monsoon region for hundreds of years and natural climate proxies are constructed in the non-monsoon region, while two types of climate proxies can be commonly found over the monsoon northernmost marginal active zone. In the monsoon region, dry-wet variation centers are altered among North China, the lower Yangtze River, and South China from one century to another. Dry or wet anomalies are firstly observed along the monsoon northernmost marginal active zone and shifted southward or southeastward to the Yangtze River valley and South China in about a 70-year timescale. Severe drought events are experienced along the monsoon northernmost marginal active zone during the last 5 centuries. Inter-decadal dry-wet variations are depicted by natural proxies for the last 4--5 centuries in several areas over the non-monsoon region. Some questions, such as the impact of global warming on dry-wet regime changes in China, complex interactions between the monsoon and westerly flows in Northeast China, and the integrated multi-proxy analysis throughout all of China, are proposed.     

1951-2006年包头气温极端事件变化分析

利用包头气象站1951-2006年逐日平均气温资料,建立了高温和低温极端气候事件的阈值,检测了56年来包头逐日气温的极端事件出现频率,分析了极端事件的年、季、月变率。统计了逐日平均气温的各级别出现频数。结果显示：该地区56年里气温显著升高,平均每10年升高0．42℃;在56年时间尺度上平均气温有明显的由冷变暖的突变特征,突变点为1987年;气候变暖后,高温事件明显增多,低温事件明显减少。     

Multi-decadal scenario simulation over Korea using a one-way double-nested regional climate model system. Part 2: future climate projection (2021–2050)

An analysis of simulated future surface climate change over the southern half of Korean Peninsula using a RegCM3-based high-resolution one-way double-nested system is presented. Changes in mean climate as well as the frequency and intensity of extreme climate events are discussed for the 30-year-period of 2021–2050 with respect to the reference period of 1971–2000 based on the IPCC SRES B2 emission scenario. Warming in the range of 1–4°C is found throughout the analysis region and in all seasons. The warming is maximum in the higher latitudes of the South Korean Peninsula and in the cold season. A large reduction in snow depth is projected in response to the increase of winter minimum temperature induced by the greenhouse warming. The change in precipitation shows a distinct seasonal variation and a substantial regional variability. In particular, we find a large increase of wintertime precipitation over Korea, especially in the upslope side of major mountain systems. Summer precipitation increases over the northern part of South Korea and decreases over the southern regions, indicating regional diversity. The precipitation change also shows marked intraseasonal variations throughout the monsoon season. The temperature change shows a positive trend throughout 2021–2050 while the precipitation change is characterized by pronounced interdecadal variations. The PDF of the daily temperature is shifted towards higher values and is somewhat narrower in the scenario run than the reference one. The number of frost days decreases markedly and the number of hot days increases. The regional distribution of heavy precipitation (over 80 mm/day) changes considerably, indicating changes in flood vulnerable regions. The climate change signal shows pronounced fine scale signal over Korea, indicating the need of high-resolution climate simulations