利用CAM5.1模拟中国东部大规模城市化对东亚地区夏季大气环流及降水分布的影响   总被引：2，自引：1，他引：1  

邹松佐  郭品文  沙天阳  马红云 《气象科学》2012,32(5):473-481

利用CAM5.1大气环流模式研究中国东部大规模城市化对东亚夏季大气环流及降水分布的影响。通过在模式中修改中国东部地区(22～42°N,110～125°E)城市比重的方法,探讨东亚地区夏季大气环流与降水等气象要素在一般城市化及极端城市化两种情景下的响应。结果表明:(1)CAM5.1模式能够很好地模拟出东亚地区夏季大气环流形势及降水分布。(2)城市比重增大后,晴空时地面吸收的净辐射增多,近地层气温升高,低层增温中心上空的大气由于受热产生上升运动,35°N以南的气流向增温区辐合,东亚夏季风出现增强的趋势,大量暖湿水汽往北输送,导致降水在中国北方地区增多而南方减少。(3)城市化的发展程度越高,它所产生的气候效应对各气象要素的影响就表现得越明显。  相似文献   

秋季热带中太平洋SST异常型与冬季中国降水和气温的关系   总被引：3，自引：1，他引：2  

王苏瑶  李忠贤  王大钧  刘长征 《气象科学》2012,32(6):653-658

用NOAA延长重构的月平均海表温度以及NCEP/NCAR提供的比湿、风场、温度场资料和中国160站的月平均气温、降水资料,利用相关分析及合成分析的方法,研究了秋季热带中太平洋SST异常型的变化特征及其与冬季中国降水和气温的关系。结果表明:(1)秋季热带中太平洋SST异常型具有准10 a周期。(2)当秋季热带中太平洋SST为正异常时,12月份东亚大槽加深,贝加尔湖及其西侧的高压脊加强,有利于来自高纬度的冷空气向中国北方及东部地区输送,850 hPa水汽在江苏及安徽北部、山东南部、河南中部等地存在辐合,使得上述地区降水偏多,反之亦然。(3)当秋季热带中太平洋发生SST正异常时,12月份吉林、辽宁、内蒙古东部及河北气温升高,反之亦然。  相似文献   

1960-2009年咸宁市气候变化特征分析   总被引：1，自引：0，他引：1       下载免费PDF全文

刘梦祁士华  袁林喜 《气象与环境学报》2012,28(1):71-76

利用1960-2009年咸宁市3个地面气象站气象资料,统计分析近50 a来该区域气温、降水等主要气候要素的年变化、四季变化及年代际变化的趋势特征。结果表明：近50 a研究区气温有上升趋势,气候倾向率为0.23℃/10a,年平均气温在20世纪90年代末发生突变。春秋季平均气温分别在2002年和1999年发生突变,夏季平均气温在2006年发生突变,冬季平均气温早在1990年发生突变。春季与秋季平均气温的变化比较一致,冬季平均气温对全球变暖响应最敏感,春秋与秋季对气候变暖的响应是比较敏感,而夏季对气候变暖的响应最为迟缓。近50 a年降水量呈波动但无明显增降的趋势,其中春夏两季变化趋势较为一致并有下降的趋势,且春夏降水量的变化主导着年降水量的变化;而冬季降水量有上升的趋势。通过对气温与降水变化趋势的比较,发现冬季对气候变化的响应最显著、其余季节无明显相关性。  相似文献   

三峡库区降水—径流关系及径流量预报模型研究     

邬昀  陈海山  倪东鸿 《气象与减灾研究》2010,33(1):46-52

利用2000—2007年长江上游各分流域面雨量实测资料、雷达遥测面雨量资料以及各水文站的历史资料,对流域降水量、洪水传播时间、径流数据以及基流值进行了针对性处理;通过单日产流Pa+P—R(降水量加前期影响雨量—径流)分析和场次洪水总量Crr—P(a径流系数—前期影响雨量)分析,结合各分流域拟合效果及检验,研究了三峡库区降水—径流关系,证明采用雷达遥测的降水数据作为降水量输入来预报各分流域未来时段内产流量是最佳选择,由此建立了三峡库区径流量的预报模型。  相似文献   

Influence of meteorological variability upon aerosol mass size distribution     

J.F. Nicols  E. Yubero  C. Pastor  J. Crespo  A. Carratal 《Atmospheric Research》2009,94(2):330-337

Aerosol mass size distribution has been measured by using an optical particle counter. The measurements were done in an urban background location in the western Mediterranean during winter 2006. The study has been focused in determining the mass size distribution under special meteorological conditions like moderate rain, considerable winds and high atmospheric stability. The results obtained showed a mass predominance of accumulation mode during rain and high stability periods although for different reasons. In the case of rain, it is due to greater atmospheric cleansing effectiveness that rain has upon coarse mode particles. However, during stagnant periods, the meteorological situation favored coagulation processes among nucleation mode particles giving like result a mass increase in the accumulation mode. Finally, strong winds favor the resuspension of the largest particles and the dispersion of particles with sizes inferior to 7.5 μm. Similar results have been reproduced using principal component analysis (PCA). In this way, three components were identified. The first (PC1) represents particles in the accumulation mode. The second component (PC2) is constituted by coarse particles to 7.5 μm, and the third (PC3) corresponds to coarser particles. The contribution of each group to the overall average concentration was determined: 27.2% corresponds to particles with sizes belonging within the first component, 35.4% to PC2 and 37.3% to PC3. Important percentage variability for each component under meteorological episodes has been obtained. Results obtained showed an important increase of PC1 during Rainy Days (53.8%) and High Pollution Days (40.2%). Contrary to this on Windy Days this component decreases to 7.4%. However, during this kind of day PC3 increases to 64.6%.  相似文献   

Sub-daily scale validation of satellite-based high-resolution rainfall products     

Dawit A. Zeweldi  Mekonnen Gebremichael   《Atmospheric Research》2009,92(4):427-433

Recent research efforts have been geared towards developing high-resolution rainfall products from satellites for hydrological applications. A necessary step in assessing the potential and utility of these products is to quantify the uncertainty associated with them at validation scales appropriate for hydrological applications. The main objective of this paper is to evaluate the accuracy of the widely-known PERSIANN-CCS high-resolution (hourly, 0.04° × 0.04°) satellite rainfall products against high-quality NEXRAD radar rainfall observations in the Little Washita watershed. Our results reveal that (1) PERSIANN-CCS shows high skills in reproducing the patterns of inter-annual rainfall variability on a monthly basis; (2) both at the hourly and storm scales, the performance statistics of PERSIANN-CCS exhibit large spread, suggesting that the quality of PERSIANN-CCS product is almost unique for each hour and storm; and (3) significant improvement in performance statistics is obtained as PERSIANN-CCS products are averaged to longer sub-daily time scales. The implications of our results are: (1) PERSIANN-CCS could be used with high confidence for inter-annual rainfall variability studies; (2) PERSIANN-CCS products need to be accompanied by corresponding hourly error estimates in order to provide meaningful error estimates for hydrological applications; and (3) research is needed to characterize the tradeoff between the quality of rainfall input and the space-time resolution of hydrological modeling, as a function of watershed size and hydrologic model complexity level.  相似文献   

Evaluation of statistical downscaling in short range precipitation forecasting   总被引：1，自引：0，他引：1  

A. Fernndez-Ferrero  J. Senz  G. Ibarra-Berastegi  J. Fernndez 《Atmospheric Research》2009,94(3):448-461

The objective of this study is to compare several statistical downscaling methods for the development of an operational short-term forecast of precipitation in the area of Bilbao (Spain). The ability of statistical downscaling methods nested inside numerical simulations run by both coarse and regional model simulations is tested with several selections of predictors and domain sizes. The selection of predictors is performed both in terms of sound physical mechanisms and also by means of “blind” criteria, such as “give the statistical downscaling methods all the information they can process”.Results show that the use of statistical downscaling methods improves the ability of the mesoscale and coarse resolution models to provide quantitative precipitation forecasts. The selection of predictors in terms of sound physical principles does not necessarily improve the ability of the statistical downscaling method to select the most relevant inputs to feed the precipitation forecasting model, due to the fact that the numerical models do not always fulfil conservation laws or because precipitation events do not reflect simple phenomenological laws. Coarse resolution models are able to provide information usable in combination with a statistical downscaling method to achieve a quantitative precipitation forecast skill comparable to that obtained by other systems currently in use.  相似文献   

基于月动力延伸预报最优信息的中国降水降尺度预测模型   总被引：7，自引：0，他引：7  

顾伟宗  陈丽娟  张培群  李维京  李想  刘绿柳 《气象学报》2009,67(2):280-287

利用国家气候中心月动力延伸预报结果、NCEP/NCAR再分析资料和中国160个站观测资料,通过计算两次相关的方法,获取最优预报信息作为建立降尺度预测模型的预测因子,提取的最优预测因子同时满足既是观测环流要素场影响降水的关键区域,又是模式要素场预报的高技巧区域两个条件.结合挑选出的最优预测因子,利用最优子集回归建立月平均降水的降尺度预测模型.文中设计了消除预测因子和预测量的线性趋势值后建立预测模型(方案1)和直接利用原始资料建立预测模型(方案2)两种方案.经过独立样本检验,发现这两种方案建立的预测模型都能够提高月尺度降水预测,方案1对月尺度降水预测的距平相关系数平均可达0.35.利用该方案对超前时间分别为0、5、10 d的月动力延伸预报产品进行月降水的降尺度预测表明,模式初值信息不仅影响月动力延伸预报结果,也影响降尺度应用效果,利用超前时间为0和5 d的月动力延伸预报结果进行降水降尺度预测可在业务中参考.此外,降尺度预测模型中选取的预测因子不仪在统计上是显著的,同时也具有清楚的物理意义.  相似文献   

全球变暖背景下亚非典型干旱区降水变化及其与水汽输送的关系研究   总被引：2，自引：0，他引：2  

徐栋  李若麟  王澄海 《气候与环境研究》2016,21(6):737-748

分析比较了中蒙(35°N~50°N,75°E~105°E)、中亚(28°N~50°N,50°E~67°E)和北非(15°N~32°N,17°W~32°E)三个典型干旱区水汽输送特征的异同,及其1961~2010年间的降水时空变化,分析了水汽来源和输送变化及其可能原因。结果显示,由于受不同的气候系统影响,中蒙、北非和中亚干旱区的降水在年内变化上有着显著不同。中蒙和北非干旱区降水呈现夏季风降水的特征;而中亚干旱区降水则为更多受到冬季风的影响。1961~2010年,随着全球气温上升,中蒙干旱区冬季纬向水汽输送增加而经向输送减少,总水汽输送增加;中亚干旱区冬季纬向输送减少而经向增加,总水汽输送减少;北非干旱区冬季纬向输送增加而经向输送减少,总水汽输送增加。夏季中蒙和北非干旱区经向、纬向输送均减小,中亚干旱区夏季纬向输送减少而经向减少,总输送增加。相应的,中蒙干旱区年、冬季和夏季降水分别以4.2、1.3和1.0 mm/10 a的趋势增加;而中亚干旱区冬季(1.2 mm/10 a)和夏季(0.1 mm/10 a)降水增加,年降水则呈减少趋势(-0.8 mm/10 a);北非干旱区年降水和夏季降水分别以0.5 mm/10 a和0.1 mm/10 a的速率增加。冬季中蒙干旱区主要水汽来源是水汽经向输送,而中亚干旱区水汽主要为纬向输送,经纬向水汽均为净输出是北非干旱区降水极少的主要原因,平均总水汽输送量约为-9.48×104 kg/s。冬季低纬度和高纬度环流通过定常波影响干旱区冬季降水。中蒙和中亚干旱区冬季降水主要受西太平洋到印度洋由南向北的波列影响,北非干旱区冬季降水主要和北大西洋上空由北到南的波列相联系。各干旱区的降水对海温变化有着不同的响应:中蒙干旱区冬季降水与冬季太平洋西海岸和印度洋海温呈显著正相关,夏季与海温相关不显著;中亚干旱区与地中海和阿拉伯海温相关,且与阿拉伯海温为正相关。  相似文献   

初春青藏高原地表温度变化对长江中下游降水的影响   总被引：2，自引：1，他引：1       下载免费PDF全文

何冬燕  邓学良  赵勇 《高原气象》2010,29(3):579-586

基于NCEP/NCAR再分析资料及全国160个测站降水资料,分析了2～3月青藏高原地表温度升温幅度与6月长江中下游地区降水的关系。结果表明:青藏高原2～3月地表温度升温幅度的主空间分布型为边缘升温大、中心升温小,低海拔大、高海拔小。这种升温形势与长江中下游南部降水呈明显的负相关关系:在升温幅度大的年份,长江中下游南部降水较常年偏少;而升温幅度小的年份,长江中下游南部降水明显增加。进一步分析表明,升温弱年大气环流的形势和各种天气系统的配置为长江中下游南部降水提供了更有利的水汽、动力及热力条件,其中100 hPa南亚高压强度整体偏强并向东西方向伸展,500 hPa极涡增强偏东、贝加尔湖及鄂霍次克海之间大脊增强及西太平洋副热带高压西伸是降水增加的主要原因。  相似文献