利用1961-2012年海河流域35个气象台站的逐日降水资料,采用连续复小波（Morlet）、正交函数分解法（EOF）、线性回归分析法、滑动t检验及空间差值法等,研究不同等级降水的时空变化特征及其影响。研究结果表明：（1）海河流域年降水量存在5a、15a、25a左右的周期变化;降水变化场表现出全区一致多雨或少雨、南-北向降水分布相反、东南-西北向降水分布相反的空间分布特征;（2）海河流域夏季对年降水量、年降水日数和年平均降水强度的贡献最大,各时间尺度降水日数均以小雨为主,各级别降水强度也均呈夏、秋、春、冬季依次递减。其中,年暴雨量和暴雨强度、夏季暴雨量和暴雨日数均呈明显减小趋势,夏季大雨量和大雨日数也有明显减少趋势;（3）永定河系对全流域降水量和降水强度的贡献最小,各子流域降水日数也均以小雨为主。其中,永定、子牙、大清河系的暴雨量和永定、大清、北三河系的暴雨强度均呈明显减少趋势,北三河系的大雨量和大雨日数减少趋势明显,子牙河系的中雨量、中雨日数和中雨强度均呈明显减少趋势;（4）海河流域降水的时空变化会引起地表径流减少和地下水位下降,导致海河流域水资源短缺现象恶化。

Based on daily measured precipitation data for 35 stations in the Haihe River Basin from 1961 to 2012,we used Morlet,EOF,Linear regression analysis,T-tests and spatial interpolation methods to analyze spatial-temporal variation in precipitation of different categories and impacts in the Haihe River Basin. We found that the time period of annual precipitation in the Haihe River Basin is about 5a,15a and 25a. We identified spatial distribution characteristics of wetter or drier,north to south direction-distribution instead,northwest to southeast-distribution instead. Precipitation,precipitation days and average precipitation intensity in summer made the biggest contribution to the Haihe River Basin,and precipitation days were given priority to light rain in five kinds of time scales. The obvious decreasing trend was annual rainstorm intensity,summer rainstorm intensity and heavy rain days in summer. The precipitation and average precipitation intensity in the Yongding River system made the smallest contribution to the whole Haihe River Basin,and precipitation days were given priority to light rain in seven sub basins. The obvious decreasing trend was rainstorm intensity of Yongding,Daqing,Beisan River system,and for heavy rain days the Beisan River system. Spatial-temporal variation in precipitation causes natural river runoff reduction and ground water levels to fall,further leading to increases in the area and number of ground water funnels and deteriorating water shortages in the Haihe River Basin.

雅鲁藏布江流域是全球气候变化的敏感区,该流域降水变化对青藏高原的水系统、生态系统和山地灾害系统的演变具有重要影响。本文通过流域水文分析,将雅鲁藏布江流域的三大水资源区细分为9个分区。基于雅鲁藏布江流域1979—2018年降水数据,综合分析了雅鲁藏布江流域及9个分区的年、干湿季、月降水量以及日、小时尺度极端降水的时空变化特征,探讨了降水和典型大尺度大气环流因子的相关性。结果表明：① 1979—2018年间,在流域尺度上,各时间尺度降水整体上均呈上升趋势。其中,年降水量上升趋势最大,为2.5 mm·a^-1;年、干湿季降水量以及典型小时尺度极端降水（Rx3hour、Rx12hour）均在95%信度水平下显著上升。在水资源分区尺度上,各分区不同时间尺度降水的变化趋势呈现更明显的非一致性,所有分区除小时尺度极端降水均呈上升趋势外,其余时间尺度降水的趋势变化方向各异。② 雅鲁藏布江流域降水存在明显的空间分异性,且降水空间分异性会随着降水指标时间尺度的缩短而增强。各时间尺度降水整体上均呈现出自东部向西部逐渐减少的趋势,流域东南部（分区Ⅲ-2）始终是高值中心,流域中西部（分区Ⅰ-2、Ⅱ-1）存在区域性高值中心。③ 北半球副热带高压和北半球极涡对雅鲁藏布江流域降水变化具有显著影响。研究结果有助于掌握当地降水的多尺度变化特征,可为雅鲁藏布江流域和青藏高原地区的水循环研究、水资源开发利用和山洪灾害防治等提供科学基础。

The Yarlung Zangbo river basin (YZRB) is sensitive to global climate change. The precipitation changes in the YZRB have a great impact on the evolutions of water system, ecosystem and mountain disaster system on the Qinghai-Tibet Plateau. In this study, we divided three water resources regions of the YZRB into nine subregions through hydrological analysis. Based on precipitation data within the YZRB from 1979 to 2018, we examined the spatio-temporal variations of precipitation at annual, wet and dry seasons, monthly scales, daily and hourly extreme precipitation in the study area and its nine subregions. We further discussed the correlation between precipitation and typical large-scale atmospheric circulation factors. The results showed that: (1) From 1979 to 2018, at the whole basin scale, precipitation at each time scale showed an overall upward trend. Among them, annual precipitation showed the largest increasing trend of 2.5 mm·a^-1. Annual precipitation, dry and wet precipitation, and typical hourly scale extreme precipitation (Rx3hour and Rx12hour) increased significantly at the 95% confidence level. At the regional scale, the variation trend of precipitation at different time scales in each subregion showed more obvious inconsistencies. Except for the increasing trend of hourly scale extreme precipitation, the trends of precipitation in all the subregions were different. (2) There was an obvious spatial heterogeneity of precipitation in the YZRB, and the spatial heterogeneity of precipitation did increase with the shortening of the precipitation time scale. The precipitation at each time scale showed a gradual decreasing trend from the east to the west. The southeastern part of the YZRB (i.e. subregion Ⅲ-2) had been the center of high value, and the central and western parts (i.e. subregions Ⅰ-2 and Ⅱ-1) had a regional high value center. (3) The Northern Hemisphere Subtropical High (NHSH) and the Northern Hemisphere Polar Vortex (NHPV) had significant effects on precipitation changes. The results can help us to understand the characteristics of local precipitation at multiple scales, and provide a scientific basis for water cycle research, water resources development and utilization, and prevention of flash flood disasters in the YZRB and the Qinghai-Tibet Plateau.

基于太湖流域1960—2017年逐日降水数据，运用Mann-Kendall非参数检验法、R/S分析等方法，分析太湖流域不同等级降水的时空变化特征，并探讨了不同等级降水对年降水的影响。结果表明：1）近60年来，流域小雨发生率最高，为73.55%；年总降水量中，中雨量所占比例最大，为32.05%。小雨发生率呈显著减少趋势，暴雨贡献率呈显著增加趋势。2）太湖流域大雨、暴雨的降水量和降水日数都呈显著增加，小雨日数显著减少，小雨强度、年总降水强度显著增强。3）不同等级降水变化趋势的空间分布存在明显差异。小雨日数与年总降水日数，以及小雨强度与年总降水强度的变化趋势空间格局相一致。中雨日数、大雨日数、暴雨日数变化趋势的空间分布与其对应的降水量变化趋势的空间格局相似。4）R/S分析结果显示，小雨、暴雨、年总降水相关指标（小雨量除外）都表现出较强的持续性，未来变化趋势与过去相一致。5）近60年来，太湖流域年总降水量、降水日数、年总降水强度的变化，分别受中雨量、小雨日数、暴雨量的影响较大。在旱年流域年降水量偏少受大雨量减少的影响较大，而涝年年降水量偏多受暴雨增加的影响较大。

论文以青藏高原大通河流域为例,分别采用基于日、月降雨集中度指标（CI和CIM）,表征大通河流域的降水结构特征,并分析其演变特征;采用交叉小波分析探究太阳黑子和大气环流异常指数太平洋10 a涛动（PDO）、厄尔尼诺/南方涛动（ENSO）、北极涛动（AO）与流域降水结构变化的联系。结果表明：1）流域南部的年均CI值高于北部,中部的年均CIM值高于流域其他部分;2）流域年CI值上升趋势明显,而其年CIM值具有明显下降趋势,且两者的一致性被破坏;3）太阳黑子对于流域降水结构影响最为显著,AO和ENSO的影响次之,PDO的影响最弱。研究成果有助于揭示大通河流域降水结构的驱动机理,为其模拟与预测奠定坚实的基础。

In this paper, Datong River Basin in the Qinghai-Tibet Plateau is taken as an example. The characteristics of rainfall structure in Datong River Basin are characterized by daily and monthly rainfall concentration indices (<em>CI</em> and <em>CIM</em>), and the evolution characteristics of these indices are analyzed. Cross-wavelet analysis is used to investigate the relationship between sunspot, atmospheric circulation anomaly index (PDO, ENSO, Arctic Oscillation) and changes in rainfall structure. The results show that: 1) The annual <em>CI</em> is higher in the south of the basin than in the north, while the annual average <em>CIM</em> is higher in the central part of the basin than in other parts of the basin. 2) The <em>CI</em> value has a slight increasing trend, and the annual <em>CIM</em> value decreased significantly. 3) Sunspot has the most significant effect on the precipitation structure, followed by AO and ENSO, and PDO has the weakest effect.

全球变暖背景下的极端天气气候事件显著增加。本研究基于PreWhitening Mann-Kendall(PWMK)、极点对称模态分解法和广义可加模型,利用鄱阳湖流域1959—2019年16个国家级气象站点的逐日降水数据,从极端降水的强度、频率和持续性3个维度系统检测和分析流域极端降水的时空分布和非平稳性特征。结果表明: 研究期间,鄱阳湖流域极端降水强度和频率呈显著增加趋势,持续性呈下降趋势,极端降水整体表现出强度大、频率高、持续时间短的特点;极端降水存在明显的汛期和非汛期时间分异规律,汛期极端降水集中在流域北部和中部,而非汛期多集中于中部,子流域中信江流域降水量增加趋势最显著,达到2.10 mm·a^-1;汛期极端降水的持续时间越长,强度和范围越小,非汛期极端降水则相反;鄱阳湖流域的极端降水强度和频率以平稳性特征为主,持续性表现出非平稳性特征。随着鄱阳湖流域极端降水量的不断增加,其可能引发的灾害风险将进一步增大。

Extreme weather/climate events increased significantly because of global warming. Based on daily records from 16 meteorological stations in the Poyang Lake Basin (PLB) from 1959 to 2019, we comprehensively investigated the temporal-spatial and non-stationarity characteristics of extreme precipitation from three dimensions (intensity, frequency and duration) using PreWhite-ning Mann-Kendall (PWMK), extreme-point symmetric mode decomposition method (ESMD) and the generalized additive models for location, scale and shape (GAMLSS). The results showed that the intensity and frequency of extreme precipitation increased significantly in the PLB, while the duration of extreme precipitation decreased from 1959 to 2019. The extreme precipitation had features of high intensity, high frequency, and short duration in the PLB. There was a clear distinction between flood season and non-flood season for extreme precipitation. Extreme precipitation was concentrated in the northern and central PLB during the flood season and in the central PLB during the non-flood season. The increasing trend of extreme precipitation amount was 2.10 mm·a^-1 in the Xinjiang basin, which had the largest increment over the PLB. In the flood season, the extreme precipitation had longer duration but weaker intensity and smaller range, contrasting with the status during the non-flood season. The intensity and frequency of extreme precipitation showed stationarity characteristics in the PLB. However, the duration of extreme precipitation showed non-stationarity characteristics. With the continuous increase of extreme precipitation amount, the risk of related disasters would increase.

Linear regression, the decomposition of Empirical Orthogonal Function (EOF), Mann-Kendall Test and Pettitt Test are used to analyze the spatial-temporal distribution characteristics of precipitation in the Weihe River Basin in 49 years based on the data from 1965 to 2013 at 22 meteorological stations in the Weihe River Basin and nearby. The results showed: 1) From the view of temporal variation, the changes of annual and seasonal precipitation were not significant at the level of 0.05 but the precipitation in spring which showed an obvious decreasing trend (-6.23 mm/10 a). Meantime, there was no obvious abrupt change of annual and seasonal precipitations but the spring of 1991 on basis of mutation test. 2) Precipitation in the Weihe River Basin was unevenly distributed, decreasing spatially from southeast to northwest, and the decreasing trend in the upstream was more obvious than that in the midstream. 3) The EOF decomposition indicated that the spatial distribution of annual and seasonal precipitation in the Weihe River Basin are overall coherent, and there was an opposite phase in the direction of southeast-northwest.

在流域尺度上研究水文循环过程中的水汽含量和降水量,为流域综合治理和水资源开发利用提供依据。基于ASTER GDEM V2地形数据、ERA-Interim逐月再分析资料及降水资料,研究金沙江流域石鼓断面上游上空水汽含量和降水量的时空分布特征,并讨论两者的相关性。研究表明:研究区上空水汽含量由南向北、由东向西呈递减趋势,西南部呈斜倒“U”型,东南部呈正“U”型;多年平均降水量自西北向东南逐渐增加;年平均水汽含量和降水量呈现上升趋势,四季水汽含量和降水量从大到小均依次为“夏、秋、春、冬”,多年平均月水汽含量和降水量为单峰型分布;年平均水汽含量同降水量之间为弱相关关系,各季节相关性差异显著,逐月相关性更具有指导意义。

The water vapor content and precipitation in hydrological cycle process are studied on basin scale to provide a basis for the comprehensive management of river basin and the development and utilization of air water resources. Based on topographic data ASTER GDEM V2,ERA-Interim monthly reanalysis data and precipitation data,we studied the temporal and spatial characteristics of water vapor content and precipitation over the upper reaches of Shigu Section in the Jinsha River basin,and discussed the correlation between the two. Our research reveals that the water vapor content over the study area displays a decreasing trend from south to north and from east to west,an oblique “U” shape trend in the southwest,and a positive “U” shape in tthe southeast. The average precipitation over the years has gradually increased from northwest to southeast. The annual average water vapor content and precipitation are on the rise. The water vapor content and precipitation in summer are the largest,followed by those in autumn,spring and winter in sequence. The average monthly water vapor content and precipitation for many years distribute in a unimodal type. Moreover,the annual average water vapor content is weakly correlated with precipitation,and the correlation differs significantly among four seasons. The monthly correlation is more instructive.

本文研究了长江上游金沙江流域及邻近地区空中水资源的气候特征，主要结论如下：①金沙江流域大气可降水量具有明显的季节变化特征，冬季最低，夏季最高。流域主要位于高原东侧大气可降水量最大经向梯度带上，受到了高原大地形的显著影响；②冬、春季节金沙江流域水汽主要来源于中纬度偏西风水汽输送，高原南侧经过孟加拉湾北部的南支偏西风水汽的贡献尤其重要；夏季该流域上空水汽主要来源于孟加拉湾和南海、西太平洋地区；秋季则主要来源于南海、西太平洋地区；③20世纪60年代至今，金沙江流域的主要水汽源地、水汽输送通道上空大气可降水量总体呈增加趋势，尤其是20世纪90年代以来，上述区域上空增湿更是明显；1958年-2002年金沙江流域大部分地区夏季水汽输送总体呈增强趋势，主要由纬向输送增强所致；④近年来金沙江流域整体大气降水、径流量地增加以及极端天气气候事件的频繁发生都与空中水资源的变化密切相关。

The Yangtze River rises in the Tanggula Mountains and the Qinghai-Tibet Plateau insouthwestern China. The reach from Yushu in Qinghai Province to Yibin in Sichuan Province iscalled the Jinsha River, lying on the eastern edge of the Plateau and influenced by a variety ofmonsoon, e.g., tropic monsoon, subtropical monsoon, and Qinghai-Tibetan Plateau Monsoon. Thisleads to a complex and particular climate. In the meanwhile, this region plays a prominent role indetermining water resources of China. Water vapor resources, as the ultimate source of supply forthe surface water and groundwater, are the key component of water resources. Moreover, mostmajor impacts of climate variability and climate change on water resources over some criticalregions still remain uncertain. Based on monthly precipitation and runoff in the Jinsha RiverReaches, and monthly reanalysis data provided by the European Center for Medium-RangeWeather Forecasts (ECMWF), climate characteristics of the water vapor resources over the JinshaRiver Reaches and its surroundings were comprehensively examined. Results indicated that theprecipitable water of the Jinsha River reaches attains the minimum in winter and the maximum insummer, with an evident seasonal variation. The Jinsha River reaches lies on the maximummeridional grads of the precipitable water around the Plateau, significantly affected by the Plateau.In winter and spring, the moisture over this region comes mainly from the middle-latitude westerlywater transports, among which, the south branch water vapor transports south to plateau are ofparticular importance. In summer, the moisture originates mainly from the Bay of Bengal, theSouth China Sea, and the west Pacific Ocean. In autumn, the water vapor is from the South ChinaSea and the West Pacific Ocean. Since the 1960s, through the main water vapor source and watervapor transport channels of the Jinsha River reaches, the atmospheric precipitable water had anincreased trend in general, in particular showing an evident increasing trend since the 1990s. From1958 to 2002, the water transport of most Jinsha River reaches were enhanced in summer largelycaused by the enhanced zonal transport. Variations in precipitation and runoff, and frequentextreme weather and climate events over the Jinsha River reaches since the 1990s appeared to beclosely related to changes in the water vapor resources. Soil erosion in the Jinsha River of YunnanProvince is significant. Much attention should therefore be paid to ecological construction in thecontext of increased heavy rainfall events in the future.