| 西北地区东部汛期降水季节内分布特征分析 |
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| 引用本文： | 杨金虎,靳荣,刘晓云,张小明,李文举,尚军林.西北地区东部汛期降水季节内分布特征分析[J].干旱区地理,2017,40(5):942-950. |
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| 作者姓名： | 杨金虎 靳荣 刘晓云 张小明 李文举 尚军林 |
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| 作者单位： | 1.甘肃省定西市气象局, 甘肃 定西 743000;2.中国气象局兰州干旱气象研究所, 甘肃 兰州 730020;3.甘肃省酒泉市气象局, 甘肃 酒泉 735000 |
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| 基金项目： | 公益性行业（气象）科研专项GYHY201306027；国家自然基金41575149共同资助 |
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| 摘 要： | 基于西北地区东部1961-2015年54个台站汛期（5~9月）逐日降水资料，通过表征时间分配特征的参数-降水集中度和集中期，对西北地区东部5~9月逐旬降水的季节内非均匀性分布特征进行分析，结果表明：西北地区东部5~9月降水集中度和集中期的平均空间分布存在明显差异，从集中度来看，其东北部降水较集中，西南部较分散，而集中期主要在7月中旬到8月上旬，相比较甘肃陇东地区集中期较晚；从降水集中度与集中期的异常特征来看，第一模态均表现为全区一致性，第二模态均表现西北和东南反向变化特征，而集中度第三模态表现为东北和西南反向变化特征，集中期第三模态表现为东西反向变化特征；从降水集中度与集中期的变化趋势来看，近50 a来降水集中度越来越小，而降水集中期越来越早；另外从汛期降水量同同期降水集中度与集中期的关系来看，其与两者均存在正相关，其中集中度与降水的显著相关区在内蒙古西部以及陕西和宁夏北部，而集中期与降水的显著相关区在陕西和甘肃南部。另外利用前期大气环流指数对降水集中度和集中期建立的预报模型具有一定的预测能力，从而为西北东部汛期降水的季节内非均匀性分布特征的短期气候预测提供参考依据。
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| 关 键 词： | 西北东部 汛期降水 季节内 非均匀性 |
| 收稿时间： | 2017-03-08 |
Inter-seasonal distribution pattern of rainy season precipitation in the east region of northwest China |
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| YANG Jin-hu,JIN Rong,LIU Xiao-yun,ZHANG Xiao-ming,LI Wen-jun,SHANG Jun-lin.Inter-seasonal distribution pattern of rainy season precipitation in the east region of northwest China[J].Arid Land Geography,2017,40(5):942-950. |
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| Authors: | YANG Jin-hu JIN Rong LIU Xiao-yun ZHANG Xiao-ming LI Wen-jun SHANG Jun-lin |
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| Institution: | 1.Meteorological Bureau of Dingxi, Dingxi 743000, Gansu, China;2.Lanzhou Institute of Arid Meteorology of China Meteorological Administration, Lanzhou 730020, Gansu, China;3.Meteorological Bureau of Jiuquan, Jiuquan 735000, Gansu, China |
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| Abstract: | Located in the hinterland of east Asia and the edge of the Qinghai-Tibet Plateau, the east part of northwestern China is characterized by complex topography and various types of climate. It is a typical rain-fed agriculture area and also the most vulnerable areas in ecological environment. The complex climate makes the inter-annual precipitation show large inhomogeneity in the same period. During the growing seasons(from May to September, also the rainy seasons), the seasonal distribution characteristics of rainfall directly determine the grain yield. Therefore, it is of great importance to determine the seasonal distribution of precipitation during this time. Based on daily precipitation of 54 stations during rainy seasons from 1961 to 2013, this study analyzed the inter-seasonal distribution pattern of ten-day precipitation from May to September by using Precipitation Concentration Degree(PCD)and Precipitation Concentration Period(PCP). The results show that there were large spatial differences in the distribution of PCD and PCP. Compared with the northeast part including Ningxia, northern Shaanxi and western Inner Mongolia where the precipitation was relatively concentrating, the precipitation in the southwest part including eastern Qinghai, southern Gansu and Shaanxi was more scattering. The PCP was mainly in middle July and early August, while the PCP in Longdong region of Gansu was relatively late. The Empirical Orthogonal Function(EOF)analysis indicate that the first EOF mode of PCD and PCP in the whole east region was consistent. The second mode exhibited adverse variation characteristics between northwest and southeast, while the third mode of PCD exhibited adverse variation characteristics between northeast and southwest, and the third mode of PCP exhibited adverse variation characteristics between east and west. The trend analysis indicates that the PCP tended to scatter in the past 50 years, while the PCD tended to be earlier. In addition, positive correlations were found between the total precipitation and PCP as well as PCD, and areas of PCD significantly correlating to precipitation included western region of Inner Mongolia, northern Shaanxi and Ningxia, areas of PCP significantly correlating to precipitation included south of Shaanxi and Gansu. The prediction model based on previous atmospheric index is able to predict both the PCP and PCD, and can provide basis for the shortterm climate prediction of inter-seasonal precipitation distribution during rainy seasons in the east part of northwest China. |
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| Keywords: | the east part of northwest China rainfall inter-seasonal inhomogeneity |
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