TRMM多卫星资料在黑河上游降水时空特征研究中的应用

论文利用数字高程模型(DEM),使用多元回归模型对黑河上游2000-2009年TRMM多卫星降水资料的月数据进行了降尺度研究,并用地面气象台站观测数据对降尺度的结果进行了检验,检验结果表明这种降尺度的方法能够在不降低(甚至提高)数据质量的情况下,得到空间精度更高的降水资料。在此基础上,基于降尺度后的月降水数据,对黑河上游2000-2009年降水10 a平均值年总量空间变化,以及年内降水分配、年内降水的空间差异进行了分析。结果表明:①降尺度之后的数据比原始数据能更加表现降水变化的细节和趋势;②坡向对降水的影响表明,在东西方向,东坡的降水要高于西坡,最高可以达到10%,而南北坡的降水差异变化较小;③黑河上游2000-2009年的年平均降水为344 mm,整个上游大多数地区的降水主要分布在250~400 mm之间;④在海拔3 800 m以下,降水随高程的增加而增加,而在3 800 m以上,降水总体平均略有减少,但是降水的最大值出现在这一带;⑤黑河上游的降水具有东南-西北的递减趋势,但递减趋势在不同的月份存在差异;⑥降水量的年内分配极不均匀,冬春季稀少,主要降水集中在6-9月。

A Study of the Spatio-Temporal Distribution of Precipitation in Upper Reaches of Heihe River of China Using TRMM Data

The precipitation in mountains is the main source of surface water and the beginning of water cycle in an inland river basin, where the shortage of water resource is a restricting factor for ecological balance and socio-economic development. However, terrain complexity and scarcity of meteorological stations in mountains make the precise estimation of spatio-temporal precipitation distribution in mountainous regions a difficult problem in the field of hydrology and ecology. Fortunately, the multi-satellite precipitation analysis (TMPA) product from the Tropical Rainfall Measuring Mission (TRMM) and statistical downscaling models can provide an effective solution for this issue.
Heihe River is the second largest inland river in arid-semiarid regions of China, where the water resource of Heihe River Basin is important for sustainable development of natural environment and social economics in arid and semi-arid regions. This paper firstly used Digital Elevation Model and multivariate regression model to make an attempt for statistical downscaling of the TRMM 3B42 products obtained from 2000 to 2009. The downscaled results were tested using observed data. Secondly, the high-resolution downscaled data was used to analyze the spatio-temporal variation of precipitation at upper reaches (mountainous regions) of Heihe River from 2000 and 2009. Results show that: 1) Compared with the original TRMM data, the downscaled data with high resolution could capture more details about variation and trends of precipitation; 2) the effect of slope aspect on precipitation indicates that precipitation in east aspect is more than west aspect with the largest value reaching 10% in east-west direction, while there is no significant difference in south-north direction; 3) during the last decade, the mean annual precipitation was 344 mm/a in the upper reaches of Heihe River, and ranged from 250-400 mm/a in most regions; 4) the precipitation has the positive relationship with elevation below 3800 m, even the mean precipitation has a slight decrease, the largest precipitation zone exists in the zones with elevation greater than 3800 m; 5) the precipitation in the upper reaches of Heihe River followed a gradual decreasing trend from southeast to northwest, however, with different decreased amounts in different months; and 6) the precipitation took place mainly from June to September and was relatively scarce in winter and spring.