Dynamical downscaling simulation and projection for mean and extreme temperature and precipitation over central Asia     

Zhu  Xian  Wei  Zhigang  Dong  Wenjie  Ji  Zhenming  Wen  Xiaohang  Zheng  Zhiyuan  Yan  Dongdong  Chen  Deliang 《Climate Dynamics》2020,54(7):3279-3306

Climate Dynamics - As a typical arid and semi-arid area, central Asia (CA) has scarce water resources and fragile ecosystems that are particularly sensitive and vulnerable to climate change. In...  相似文献   

云南不同气候带极端气温变化趋势   总被引：3，自引：0，他引：3  

陈艳  段旭  董文杰  郭世昌 《气象科技》2013,41(1):126-130

利用1975-2008年云南6个气候代表站的最高气温、最低气温和平均气温资料,分析了气温序列的变化趋势,探讨了可能的形成原因.结果显示,各代表站的气温总体上呈上升趋势,但气温变化率的大小与其所处的气候带之间没有明显的规律性差异.代表高原气候的香格里拉站其气温增暖趋势最突出,代表北亚热带、中亚热带和南亚热带站点的气温与其有相似的变化趋势,主要表现为最低气温增温速率最大,平均气温次之,最高气温最小,而气温日较差(DTR:Differenceof Temperature Range)有明显减小趋势.温带和北热带代表站气温的变化则有不同的特征,温带的变化表现为最高气温显著上升,最低气温上升速率略小于平均气温的上升速率,DTR变化不显著;北热带的变化表现为平均气温增温速率最大,最低气温次之,最高气温最小,DTR变化不显著.对各站相对暖日、冷日、暖夜、冷夜和霜日的逐年统计分析表明,总体上云南的冷事件在减少,而暖事件增多.  相似文献   

最优子集回归方法在季节气候预测中的应用   总被引：7，自引：1，他引：6  

柯宗建  张培群  董文杰 《大气科学》2009,33(5):994-1002

利用DEMETER计划多个模式的模拟资料研究1959～2001年多模式集合预报的季节降水在中国区域的表现, 并结合最优子集回归(OSR)方法对中国区域的季节降水进行降尺度预报, 比较其与多模式集合预报的技巧。研究表明: 多个单模式在中国区域对季节降水的模拟性能普遍较差, 多元线性回归(MLR)集合的预报技巧不如集合平均(EM)。利用OSR方法进行降尺度预报可以极大改善中国区域季节降水的预报技巧。夏季, 降水距平相关系数(ACC)在长江以南、西藏以及内蒙古中部等地区提高很显著, ACC在中国区域的平均达到0.29, 明显高于多模式集合平均与多元线性回归集合。冬季, OSR方法可以改善多模式集合在中国北方地区较低的预报技巧。概率Brier技巧评分(BSS)也表明了OSR方法对季节降水预报的改善。需要说明的是, 虽然OSR方法在中国区域能明显提高季节降水的预报技巧, 但是其选取的预报因子与中国区域季节降水的物理机制问题仍有待于进一步的研究。  相似文献   

Assessment of surface air warming in northeast China, with emphasis on the impacts of urbanization   总被引：3，自引：1，他引：2  

Qingxiang Li  Wei Li  Peng Si  Gao Xiaorong  Wenjie Dong  Phil Jones  Jiayou Huang  Lijuan Cao 《Theoretical and Applied Climatology》2010,99(3-4):469-478

Based on homogenized land surface air temperature (SAT) data (derived from China Homogenized Historical Temperature (CHHT) 1.0), the warming trends over Northeast China are detected in this paper, and the impacts of urban heat islands (UHIs) evaluated. Results show that this region is undergoing rapid warming: the trends of annual mean minimum temperature (MMIT), mean temperature (MT), and mean maximum temperature (MMAT) are 0.40 C decade^?1, 0.32 C decade^?1, and 0.23 C decade^?1, respectively. Regional average temperature series built with these networks including and excluding “typical urban stations” are compared for the periods of 1954–2005. Although impacts of UHIs on the absolute annual and seasonal temperature are identified, UHI contributions to the long-term trends are less than 10% of the regional total warming during the period. The large warming trend during the period is due to a regime shift in around 1988, which accounted for about 51% of the regional warming.  相似文献   

Agricultural Land Use Effects on Climate over China as Simulated by a Regional Climate Model   总被引：2，自引：0，他引：2       下载免费PDF全文

ZHANG Dongfeng  GAO Xuejie  SHI Ying  GIORGI Filippo  DONG Wenjie 《Acta Meteorologica Sinica》2010,24(2):215-224

The Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model version 3 (RegCM3) is used to investigate the climate effects of land use change related to agriculture over China. The model is driven by the European Center for Medium-range Weather Forecast 40-yr Re-Analysis (ERA40)data. Two sets of experiments for 15 yr (1987-2001) are conducted, one with the potential vegetation cover and the other the agricultural land use (AG). The results show that the AG effects on temperature are weak over northern China while in southern China a significant cooling is found in both winter (December-January-February) and summer (June-July-August). The mean cooling in the sub-regions of South China (SC) in winter and the sub-regions of Southeast (SE) China in summer are found to be the greatest,up to 0.5℃ and 0.8℃, respectively. In general, the change of AG leads to a decrease of annual mean temperature by 0.5-1℃ in southern China. Slight change of precipitation in western China and a decrease of precipitation in eastern China are simulated in winter, with the maximum reduction reaching -7.5% over SE. A general decrease of precipitation over northern China and an increase over southern China are simulated in summer,in particular over SE where the increase of precipitation can be up to 7.3%. The AG effects on temperature and precipitation show strong interannual variability. Comparison of the climate effects between AG and the present-day land use (LU) is also performed. In southern China, the ratio of temperature (precipitation)changes caused by AG and LU is greater than (closer to) the ratio of the number of grid cells with changed vegetation cover due to AG and LU variations.  相似文献   

Spatio-temporal Variability Sea Level Pressure （SLP） the Mid-to-Low Reaches of Northern Hemipheric and Precipitation over of the Yangtze River   总被引：1，自引：0，他引：1  

韩雪  魏凤英  董文杰 《大气科学进展》2008,25(3):458-466

The spatio-temporal variability of Northern Hemisphere Sea Level Pressure （SLP） and precipitation over the mid-to-low reaches of the Yangtze River （PMLY） is analyzed jointly using the multi-taper/singular value decomposition method （MTM-SVD）. Statistically significant narrow frequency bands are obtained from the local fractional variance （LFV） spectrum. Significant interdecadal （i.e., 16-to-18-year periods） and interannual （i.e., 3-to-6-year periods） signals are identified. Moreover, a significant quasi-biennial signal is identified but only for PMLY data. The spatial joint evolution of patterns obtained for peaks in the LFV spectrum sheds light on relationships between SLP and PMLY： the Arctic Oscillation （AO） modulates the variability of the PMLY while the interannual variability of PMLY is in phase with the Northern Atlantic Oscillation （NAO） and the Northern Pacific Oscillation （NPO）.  相似文献   

五台山站历史气候资料的均一性分析   总被引：2，自引：0，他引：2  

高晓容  李庆祥  董文杰 《气象科技》2008,36(1):112-118

介绍了新一代天气雷达实时监测系统的结构模式和功能,通过TCP/IP通信协议的论述、天气雷达信息量和占用信道带宽的估算,证明基于宽带网络系统通信设计的可行性.同时详细分析了CINRAD/SA天气雷达实时监测信息的结构和存放特点,系统地描述天气雷达监测信息获取、传送和入库的方法,并重点介绍如何编制传输和入库软件,利用TCP/IP两种基本协议(TCP和UDP)以及ADO数据库编程技术,在现有的宽带网络基础上,对天气雷达运行状况实现远程实时监测.  相似文献   

图象分割中随机噪音的影响     

杨文杰  刘浩学  秦炼  王子美 《遥感学报》1997,1(4):267-271

该文在生成的灰度图象上加上随机噪音，用最大后验（ＭＡＰ）估计方法、模糊Ｃ－均值方法和Ｏｔｓｕ阈值方法进行了分割计算，对结果进行了对比分析，绘出了分割随噪音的标准差变化曲线，对噪音图象使用了不同的滤波方法处理之后，并进行计算。  相似文献   

中国大陆西部强震前超低频磁场时空变化特征   总被引：3，自引：1，他引：2       下载免费PDF全文

冯丽丽  冯志生  樊文杰  管贻亮  贺曼秋  李霞  何畅  廖晓峰  艾萨?伊斯马伊力  袁文秀  李莎 《地震学报》2021,43(3):359-375

对2015年至2019年期间中国大陆西部的磁通门磁力仪秒采样观测资料开展了5—100 s频段的地磁垂直强度极化分析,并运用一些数学方法对分析结果进行了处理。结果显示,极化高值在经向和纬向均无明显的形态和幅值变化,且极化高值与地磁外源场扰动无关。在此基础上筛选出18次极化高值异常事件,利用插值方法得到了极化高值异常的空间分布图,并分析了18次高值异常与中国大陆西部及周边15次强震的时空关系。分析结果表明:地磁场出现多台同步极化高值现象后的半年内,高值区可能发生M6.0以上强震;高值现象出现后,多个高值区均有可能发生强震;后续强震的震级与高值区面积呈正相关。   相似文献   

利用常熟地震台同场地形变仪记录检测对比地球自由振荡信号     

钱文杰  狄樑  刘冬冬  陆德明  丁建国 《地震地磁观测与研究》2021,42(4):110-118

利用常熟地震台同场地观测的洞体应变仪、体应变仪、水管倾斜仪、垂直摆倾斜仪记录数据,采用小波变换与功率谱密度估计方法,检测2011年3月11日日本9.0级大地震激发的地球自由振荡信号,其中检测到47个球型基频振型（₀S₃—₀S₄₉）、15个环型基频振型（₀T₅—0T₂₅）以及部分球型谐频振型,与地球初步参考模型（PREM）理论频率值基本符合,表明检测结果较好。对比结果显示：水管倾斜仪检测球型振荡振型能力最强,垂直摆倾斜仪检测环型振荡振型能力最强;体应变仪可检测到清晰的环型基频振型,且信噪比较高;倾斜仪对自由振荡信号的检测能力优于应变仪。  相似文献