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1.
Human-induced land use changes and the resulting alterations in vegetation features are major but poorly recognized drivers of regional climatic patterns.In order to investigate the impacts of anthropogenically-induced seasonal vegetation cover changes on regional climate in China,harmonic analysis is applied to 1982-2000 National Oceanic and Atmospheric Administration(NOAA) Advanced Very High Resolution Radiometer(AVVHRR)-derived normalized difference vegetation index(NDVI) time series(ten day interval data).For two climatic divisions of South China,it is shown that the first harmonic term is in phase with air temperature,while the second and third harmonics are in phase with agricultural cultivation.The Penman-Monteith Equation and the Complementary Relationship Areal Evapotranspiration(CRAE) model suggest that monthly mean evapotranspiration is out of phase with temperature and precipitation in regions with signiffcant second or third harmonics.Finally,seasonal vegetation cover changes associated with agricultural cultivation are identiffed:for cropped areas,the temperature and precipitation time series have a single maximum value,while the monthly evapotranspiration time series has a bimodal distribution.It is hypothesized that multi-cropping causes the land surface albedo to sharply increase during harvesting,thereby altering the energy distribution ratio and contributing to observed seasonal vegetation cover changes. 相似文献
2.
A. F. Karagiannidis A. A. Bloutsos P. Maheras Ch. Sachsamanoglou 《Theoretical and Applied Climatology》2008,91(1-4):193-204
Summary This paper presents an analysis and discussion of some rainfall characteristics of the European continent. Harmonic and Spectral
Analysis are applied to monthly and annual precipitation data derived from 50 selected European meteorological stations. The
Harmonic Analysis reveals that the sum of the first and second harmonic describes satisfactorily the mean annual precipitation
regime, while the time of maximum of the first harmonic coincides with the time of the observed mean annual maximum of precipitation,
almost everywhere. Spectral Analysis reveals the existence of QBO and ENSO signals in some different areas of Europe, while
the eleven-year cycle of sunspots seem to have no effect on precipitation across the European continent. Climatic noise is
also examined. The lowest values of climatic noise are found in the British Islands and in France, whilst relatively high
values are found in the cyclogenetic region of the Gulf of Genoa. An increase in climatic noise has been identified over Mediterranean
coastal areas during the summer.
Authors’ address: A. F. Karagiannidis, A. A. Bloutsos, P. Maheras, Ch. Sachsamanoglou, Department of Meteorology and Climatology,
School of Geology, Aristotle University of Thessaloniki, 540 06 Thessaloniki, Greece. 相似文献
3.
Debris flows in the region of Ritigraben (Valais, Swiss Alps), which generally occur in the months of August and September, have been analyzed in relation to meteorological and climatic factors. The principal trigger mechanisms for such debris flows are abundant rain on the one hand, and snow-melt and runoff on the other hand, or a combination of both. Debris flows linked to rain are likely to be triggered when total rainfall amount over a three-day period exceeds four standard deviations, i.e., a significant extreme precipitation event. An analysis of climatological data for the last three decades in the region of Ritigraben has highlighted the fact that the number of extreme rainfall events capable of triggering debris flows in August and September has increased. Similar trends are observed for the 20th Century in all regions of Switzerland. The general rise in temperature in a region of permafrost may also play a role in the response of slope stability to extreme precipitation. At the foot of the Ritigraben, warming trends of both minimum and maximum temperatures have been particularly marked in the last two decades. 相似文献
4.
青海省近40年雨日、雨强气候变化特征 总被引：19，自引：2，他引：17
利用青海省1961-2002年26个代表站逐日雨量资料和青海省东部地区10个站1981～2001年降水自记资料,分析近40年来青海省雨日、雨强气候变化。结果表明：青海近年来虽然夏半年降水量和雨日在减少,但降水强度在增大。夏半年降水量的减少主要是降水日数的减少造成的;而冬半年降水量的明显增加是由于雨日增多和每个降水日平均雨量的增大造成的。近20年来10分钟、1小时最大降水的强度在明显增加。同时,20世纪90年代夜间出现强降水的几率多于80年代。 相似文献
5.
本文是作者研究近10年大气环流特征的第二部分。应用1951—1960年北半球500毫巴月平均图,用谐波分析方法计算了历年逐月55°N及35°N上波数1到4(第1到第4)波的振幅及位相角。由此分析了大气环流的季节变化。主要结果如下: 1.第1波及第3波的振幅均有明显的年变程,但趋势彼此相反。另外,第1波或第3波振幅本身在55°N及35°N年变程也相反。第2波振幅年变程不明显。 2.各波的位相角亦有明显而规则的年变程,只有55°N第2波的位相角季节变化不大。 3.从逐年波谱及位相来看,大气环流的季节变化各年虽有不同,但季节的趋势却是每年都一致的。 4.过渡季节的波谱与冬夏截然不同。因此一年可分为4个自然天气季节,但每年季节早晚、长短及特征均有一定差异。 5.北半球超长波特征与我国天气有密切关系,这可以从一些例子来说明,如1954年7月与1959年7月,1957年2月与1960年2月。 相似文献
6.
我国地闪活动和降水关系的区域差异 总被引：5，自引：2，他引：3
利用我国部分地区2005年的地闪定位资料和气象台站雨量观测资料,由南向北选取我国四个不同气候带区域(区域1～4),分析了这些区域的地闪活动与降水的相关关系。结果表明,由南向北及气候特征由潮湿趋于干旱的区域的地闪活动和降水相关性增强。闪电活动与有闪电降水(即对应闪电的降水)日变化的线性相关系数在由南向北的区域分别为0.56、0.46、0.56、0.80,旬变化的线性相关系数分别为0.73、0.86、0.89、0.92,月变化的线性相关系数分别为0.74、0.88、0.965、0.99;较干旱的区域3和区域4的地闪活动与所有降水的时间序列有较强的相关性,其线性相关系数日变化分别为0.31、0.41,旬变化分别为0.84,0.52,月变化分别为0.93、0.80;地闪与降水的空间线性关系相对复杂,但也表现出由南向北和气候趋于干旱对应关系增强的特征,区域4的闪电和降水相关性达到0.54。分析区域中较干旱地区的雷暴活动产生机制(主要受热力抬升作用)相比潮湿地区(既受热力抬升作用,又受大尺度系统相互作用)更为单一,这可能是干旱地区的闪电活动与降水有较好相关的重要原因。 相似文献
7.
利用四川地区自动气象站逐小时降水观测资料,分析了2010~2019年5~9月短时强降水事件24h累计降水量、频次和强度的时空分布特征,探讨了短时强降水事件发生的频次、极值分布及其与地形、海拔高度等的关系。结果表明:四川地区平均24h累计降雨量基本在50mm以上,盆地东北部、西南部、南部及阿坝州东部甚至超过100mm,最大值出现在广安,达175mm。四川地区短时强降水事件开始时间的日变化特征表现为“V”型结构的夜间峰值位相,事件持续时段多为傍晚至凌晨,时长可达10h以上,最长甚至可持续22h。在强降水事件极值的日变化上,极大值频次和降水量呈单峰结构,在03时达到最大,其后逐渐减小至15时达到谷值,而后再次增大;降水强度呈弱双峰结构,分别在04时和16时达到谷值,13时和18时达到峰值,其日变化呈“增-减-增-减”的特征。四川短时强降水事件与复杂地形有密切的关系,5~6月事件活跃区在四川盆地中部,7月在盆地西部的龙门山脉一带,8月在雅安、乐山附近,9月在盆地北部且频次明显减少;短时强降水事件的最大小时雨强可达80mm以上,出现在7~8月的盆地西部龙门山一带和南部地区。短时强降水事件随着海拔高度的增加,发生频次和日数逐渐减少,海拔2000m以上地区基本无强降水发生日出现( 峨眉山气象站例外)。 相似文献
8.
沙澧河上游关键区汛期强降水面雨量对洪峰的影响 总被引：1，自引：1，他引：0
根据河南省气候中心提供的1980-2000年6月1日至8月31日沙澧河流域上游关键区所选取测站逐日20时-20时降水实测资料,建立了面雨量库,并利用统计方法分析了沙澧河上游关键区面雨量气候特征以及面雨量与洪水的关系,结果表明:沙澧河上游关键区面雨量年际变化非常大,且年面雨量趋势是增加的。沙澧河流域上游关键区汛期逐月月平均面雨量以7月最多,其次是8月,6月最少,并且6月和7月月平均面雨量有增加的趋势,而8月则有减少的趋势。强降水面雨量预报对于预测洪峰有很好的指示意义。 相似文献
9.
利用中国东部160个气象观测站1951年-2012年夏季（6-8月）的月平均降水资料,运用EOF分析方法,分析中国东部夏季降水的时空分布特征及其与西太平洋副热带高压的关系。结果表明:（1)夏季,中国东部降水大值区域从华南移到江淮流域,然后到达华北和东北地区。（2) 中国东部夏季降水EOF第一模态空间分布为长江以北与黄河以南地区之间存在一个降水大值雨带, EOF第二模态显示出整个东部沿海地区的降水量以长江为界,长江以南降水偏少,长江以北降水偏多,且江南与江北的降水呈反位相。（3)在西太平洋副热带高压较强的年份,江淮流域降水偏少,华北地区降水偏多;西太平洋副热带高压较弱的年份,江淮流域降水偏多,华南地区降水偏少。 相似文献
10.
1961—2015年中国暴雨变化诊断及其与多种气候因子的关联性研究 总被引：5，自引：4，他引：5
气候变化背景下,频发的暴雨事件造成城市内涝、人员伤亡和财产损失,已经成为全社会广泛关注的焦点问题之一。为了诊断中国暴雨的时空变化及其与不同自然因子的关联性,采用1961—2015年中国659个降水站点数据,采用线性趋势、EOF分析等多种统计方法诊断了中国暴雨时空变化特征,结果表明,中国暴雨雨量、雨日和雨强在1961—2015年以胡焕庸线为界呈现出东南高-西北低的气候态空间分布格局;线性趋势分析表明1961—2015年中国暴雨雨量和雨日从东南沿海向西北内陆呈明显“增-减-增”的空间分布格局,且呈增长趋势的站点占主导,分别高达80.88%和79.81%;从西北内陆到东南沿海的年代剖面分析表明中国暴雨雨量和雨日随着年代推移在迅速增长;对低通滤波后的中国暴雨进行EOF分析表明中国暴雨雨量和雨日的增长东南沿海快,内陆地区慢。根据IPCC等已有研究中筛选出对中国地区有影响的28个气候因子,并将其与659个站点的暴雨进行相关分析,结果表明不同气候因子与不同区域暴雨呈现出错综复杂的相关性特征,其中与暴雨雨量呈现以正相关和负相关为主的气候因子分别为15和13个,全局相关因子包含AAO(Antarctic Oscillation)、Pacific Warmpool,而其它气候因子在七大分区中与暴雨的关联性各有突出,表现出明显的空间异质性。 相似文献
11.
利用2008—2016年5—9月中国气象局陆面数据同化系统(CLDAS)格点融合分析降水资料以及降水观测资料,在对CLDAS格点降水融合资料进行验证的基础上,对贺兰山区降水时空分布特征以及与地形的关系进行了分析。结果表明：贺兰山区降水呈“东多西少、南多北少”的分布特征,贺兰山主峰偏西0.1°存在一个超过240 mm的降水高值中心,日降水量极值西侧高于东侧。8月降水量和短时强降水次数最多,11:00—18:00降水次数最多,午后到前半夜短时强降水次数最多。贺兰山区降水以小雨为主,其次是中雨,中雨和小雨雨量占区域总雨量的比例高达85%。贺兰山区降水量随海拔高度的增加而增加,西坡降水随高度的增加率为5.1 mm/hm,东坡降水随高度的增加率为2.1 mm/hm,西坡明显高于东坡。中雨日数与地形高度的相关性较好,其它级别降雨日数与地形相关性不强。 相似文献
12.
13.
从小时尺度考察中国中东部极端降水的持续性和季节特征 总被引：7，自引：1，他引：6
相对于日降水量,小时尺度降水资料可以更准确地反映降水强度并描述降水过程,因而更适用于极端降水阈值确定及其特性研究.利用广义极值分布估计中国321个站最大小时降水量的分布函数,确定了5a重现期的小时降水强度阈值.阈值的空间分布呈现出明显的地域差异,西北地区阈值偏低,华北地区、长江中下游地区、华南沿海地区和四川盆地西部地区为高阈值中心.取各站5a一遇极端降水事件对其持续性特征和季节特征进行分析,发现在沿海地区、长江流域和青藏高原东坡极端降水事件的平均持续时间较长(超过12h);中国北部地区持续时间较短.在具有较大海拔落差的复杂地形区,极端降水事件较平原地区更快地发展到峰值.华南地区4月就可有极端降水事件出现,而中国北方地区要到6月底才出现极端降水;全中国大部分地区的年最晚极端降水在8-9月,但沿海地区、大陆南端和西南地区南部的少数站点在10月以后仍有极端降水发生. 相似文献
14.
Experimental Simulations of Extreme Precipitation Based on the Multi-Status Markov Chain Model 
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下载免费PDF全文 A multi-status Markov chain model is proposed to produce daily rainfall, and based on which extreme rainfall is simulated with the generalized Pareto distribution (GPD). The simulated daily rainfall shows high precision at most stations, especially in pluvial regions of East China. The analysis reveals that the multistatus Markov chain model excels the bi-status Markov chain model in simulating climatic features of extreme rainfall. Results from the selected six stations demonstrate excellent simulations in the following aspects:standard deviation of monthly precipitation,daily maximum precipitation,the monthly mean rainfall days,standard deviation of daily precipitation and mean daily precipitation, which are proved to be consistent with the observations. A comparative study involving 78 stations in East China also reveals good consistency in monthly mean rainfall days and mean daily maximum rainfall, except mean daily rainfall. Simulation results at the above 6 stations have shown satisfactory fitting capability of the extreme precipitation GPD method. Good analogy is also found between simulation and observation in threshold and return values. As
the errors of the threshold decrease, so do the di?erences between the return and real values. All the above demonstrates the applicability of the Markov chain model to extreme rainfall simulations. 相似文献
15.
J.M. Pathan 《大气科学进展》1994,11(1):111-120
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16.
Zhi-Yong Yin Yunlong Cai Xinyi Zhao Xiaoling Chen 《Theoretical and Applied Climatology》2009,97(3-4):205-218
In this study, we investigated spatial and temporal variation patterns of persistent moderate-to-heavy rainfall events in Guizhou Province of southwest China during 1951–2004. We first performed conventional frequency analysis using the annual maximum daily series at 36 weather stations fit to log-normal distribution curves. Then, we examined the frequencies of moderate-to-heavy rainfall events (>?=?20 mm/day) and persistent rainfall events (10–day running sum >?=?100 mm) during the summer season (June through August). Using principal component analysis, we identified various spatial patterns of the rainfall regime and macroscale atmospheric conditions that influence these patterns. It was found that a minor mode of variation in the 500 hPa geopotential height anomaly field over East Asia (the third principal component) had a very good relationship to the dominant regional precipitation regime (Spearman’s correlation coefficient?=?–0.623). This mode of circulation represents the N–S variation of the upper-air pressure gradients over East Asia. During its positive phase, the pressure gradient south of 40°N is reduced and accompanied by a ridge over the East China coast, while the pressure gradient north of this latitude is enhanced. Correspondingly, the study region experiences fewer persistent moderate-to-heavy rainfall events. In its negative phase, the pattern in the 500 hPa geopotential height anomaly field is reversed and the study region experiences more persistent moderate-to-heavy rainfall events. This circulation mode is related to both East Asian and Indian summer monsoons. It is also associated with the northward intrusion of the West Pacific subtropical high, the size of the circumpolar vortex over the Pacific, and the impact of the Tibetan Plateau. 相似文献
17.
This study is concerned with the spatial variability of some wet atmospheric precipitation parameters such as; pH, conductivity (EC). The study also depicts the spatial variability of some ions (cations and anions) of atmospheric precipitation in Jordan such as, Ca2+, Mg2+, Na+ and K+, HCO3−, Cl−, NO3− and SO42−. The basis of the work is to establish a relationship through the cumulative semivariogram technique between the distance ratios and the spatial dependence structure of the chemical composition of atmospheric precipitation. All semivariogram models are constructed in this study in order to understand the behavior of the spatial distribution. The spatial distributions of rainwater parameters show differences from station to station which is expressed in terms of angle, where the larger the angle the weaker the correlation. The semivariogram (SV) models are constructed to show the variation of the rainfall chemistry in Jordan. The SV models show weak correlation between mountain and leeside mountain stations, i.e. mountain and desert stations. On the other hand, good correlations are observed when transferring from south to north of the country. The larger is the found angle, the weaker is the correlation. For most of the SV model the correlation is found to be very weak between desert and mountainous locality. The Standard Regional Dependence Factor (SRDF) is used for prediction of the distribution of rain fall parameters. It shows the relative error between observed and predicted values of rainwater parameters. The overall regional relative error between the observed and estimated concentrations remains less than 15%. 相似文献
18.
STUDY ON THE MAIN CLIMATE MODES OF SHANDONG PRECIPITATION AND THEIR RELATIONS WITH THE EAST ASIAN WESTERLY JET 总被引：1，自引：0，他引：1
Summer precipitation patterns of Shandong Province are relatively independent with regard to the whole eastern China region.To study the rules and causes of precipitation variations,three main climate modes-on the annual,seasonal,and climatic intra-seasonal oscillation(CISO) scales-are extracted using a harmonic analysis method based on daily precipitation of Shandong during 1965-2009 and multi-year averaged pentad precipitation at 722 stations in China during 1971-2000.Among the three precipitation climate modes,the annual mode is closely related to the annual cycle of Earth-Atmosphere thermal system,which is characterized by the periodic dry and wet seasons.The seasonal mode reflects the monsoon effect on precipitation and the main flood season’s contribution to annual precipitation variations.As an important climatic signal,the CISO mode is more evident during summer monsoon.The gradual modulations of the CISO mode,seasonal mode,and annual mode control the annual variation of precipitation.To study the relationship between precipitation climate modes and atmospheric circulations,an East Asian Westerly Jet Index(EAWJI) is defined in this paper.It is revealed that precipitation of Shandong is closely related to EAWJI in all climate modes.A wet or dry phase of each climate mode corresponds to a specific atmospheric circulation pattern.The phase of the annual mode is reverse to that of EAWJI.During the wet phase of the seasonal mode(weak phase of EAWJI),the atmospheric circulation in and around Shandong is characterized by upper-level divergence and low-level convergence.A reversed atmospheric circulation exists for the dry phase(strong phase for EAWJI).In the summer wet phase of CISO mode(strong phase of EAWJI),Shandong is controlled by upper-level divergence and low-level convergence.Again,the dry phase is corresponding to a reversed circulation structure.The methodology employed in this research,i.e.studying the precipitation climatic variations in terms of independent components of different temporal scales,provides a new approach for annual and seasonal precipitation prediction. 相似文献
19.
黔东南暴雨气候特征及其地形影响 总被引：2，自引：2，他引：2
利用1960~2000年贵州省黔东南地区降水观测资料,统计分析黔东南地区暴雨时空分布特征,进一步揭示其活动规律及主要影响因素。结果表明:黔东南地区暴雨有显著年代际变化特征,存在准15年的周期变化,并与贵州降水和长江中下游降水呈同位相;存在两个暴雨多发中心,夜间暴雨较多。黔东南暴雨地域分布极为复杂,局地性暴雨较多,这与黔东南特殊地形有着密切关系,地形因素是影响黔东南地区暴雨的重要原因,对形成上述特征的气候学成因做了初步讨论。 相似文献
20.
Summary General harmonic analysis (FFT) and maximum entropy spectral analysis (MEM) are used in order to study annual and monthly values of air temperature, precipitation and insolation in a number of weather stations in Duero Hydrographic Basin. The corresponding spectra estimates were prepared and compared. MEM estimates show better power resolution and a better spectral definition than FFT estimates. Based on the similarity behavior of the spectra, four main climatic zones were clearly defined. Finally, physical interpretation of the main features of the most representative spectra for the four regions was attempted.With 9 Figures 相似文献