论文部分内容阅读
利用1998-2013年热带测雨卫星TRMM 3B42V7降水数据产品和18个气象站点观测数据对怒江上游进行了降雨时空分布特征的对比分析,研究了TRMM 3B42V7数据产品在该区域的精度.结果显示:研究区内TRMM 3B42V7数据和站点数据相关性月尺度最强(R＞0.9),年尺度次之(R＞0.5),日尺度较差(R＜0.5);流域面雨量两组数据在月尺度上有极强的相关性(R≈0.98),时间序列拟合较好,但在降水量大的月份TRMM 3B42V7数据较站点观测数据略偏大;不同时间尺度下两组数据的空间分布特征总体具有较好的一致性,局部分布特征有差异;流域西北和东南局部区域TRMM降水分别有低估和高估趋势,其他大部区域相当.利用TRMM 3B42V7数据对流域降水进行季节占比分析,结果显示,流域降水季节分配不均匀,夏季(6-8月)降水占全年降水总量的比例较大,高达42％～72％;其他春(3 5月)、秋(9-11月)、冬(12月至次年2月)三季节降水整体较少,总占比为28％ ～ 58％.“,”The Nujiang river is a typical area of lacking data with complicated terrain and climate characteristics.TRMM (Tropical Rainfall Measuring Mission) precipitation data can effectively describe the spatial distribution characteristics of regional precipitation,and it has great reference value to the area of lacking information.We use TRMM 3B42V7 data and 18 weather stations data to explore the spatial and temporal distribution characteristics of precipitation and analyze the accuracy of TRMM 3B42V7 data in the upper reaches of Nujiang river.The correlation coefficient method and spatial analysis method are used to solve the problem.By analyzing the correlation coefficient,it shows that the best correlation coefficient between TRMM 3B42V7 data and the site observation data occurs at monthly scale (R＞0.9),second is yearly scale (R＞0.5),the worst is daily scale (R＜0.5).The two sets of data have strong correlation under monthly scale when it comes to areal precipitation (R ≈ 0.98).Time series also fit well though TRMM 3B42V7 data is slightly larger than the site observation data in the month of abundant precipitation.Spatial-temporal comparative analysis indicates that precipitation spatial distribution has good consistency of these two group data at different time scales though the local distribution characteristics are different.There is an underestimation tendency of TRMM 3B42V7 data in the northwest of the basin,and overestimation tendency in the southeast.Precipitation in most other area has little difference between TRMM 3B42V7 data and the site observation data.TRMM 3B42V7 data is also used to analyze the seasonal proportion of precipitation in the basin and it is found that seasonal patterns of precipitation in study area vary greatly.Precipitation in summer (from June to August) account for a large proportion of total annual precipitation.The ratio of precipitation in summer is 42％ ～72％,while the total ratios of spring (from March to May),autumn (from September to November) and winter (from December to February) to annual precipitation are 28％ ～58％.