摘要:为有效利用太行山区降水资源，实现科学的水资源管理和生态建设，本研究利用1998—2017年CMORPH CRT卫星降水产品数据探究山区降水的时空格局和变化趋势，并通过18个地面雨量站的数据验证山区多年来降水趋势变化。结果表明：在年尺度上，1998—2017年太行山区年均降水量和各季节降水量无明显变化趋势，太行山区南坡和东坡降水量高于北坡和西坡；在月尺度上，7月是全年降水的主要贡献时段，占全年总降水量的7.2%~32.4%，其次是8月和6月。太行山区南部和西北部降水呈现下降趋势，年均降水量减少2~6 mm；山区西部和北部降水呈现增长趋势，年均增加量大于8 mm；7月是山区降水趋势差异最大的月份，趋势变化范围在-8.6~8 mm·a-1。根据地面实测数据验证降水变化趋势，在年尺度上，两者数据计算得到的降水趋势呈现极显著相关（P < 0.01）；在季节尺度上，冬季（干季）和夏季（湿季）降水趋势变化与地面实测数据的降水趋势具有极显著相关性（R=0.902，P < 0.001；R=0.550，P=0.018），但在春季和秋季相关性不显著。根据1998—2017年降水趋势的空间分布栅格图，提取每一栅格的像元值，再将提取所得的降水趋势（PT）划分为6个区间（PT≤-5 mm·a-1、-5 mm·a-1 < PT≤0 mm·a-1、0 mm·a-1 < PT≤5 mm·a-1、5 mm·a-1 < PT≤10 mm·a-1、10 mm·a-1 < PT≤15 mm·a-1和PT>15 mm·a-1），在不同的趋势区间探索20年来的降水趋势变化特征，研究发现在降水趋势>5 mm·a-1的区间，降水量从1998年到2017年呈现显著增加的趋势。基于高分辨率卫星数据阐明太行山区降水时空格局和变化趋势，能够为该区域水资源合理利用和生态恢复提供建议和支持。
关键词:CMORPH CRT产品/
太行山区/
降水时空格局/
降水趋势
Abstract:In order to effectively use precipitation over the Taihang Mountains, and to perform water resource management and ecological construction scientifically, we used satellite precipitation data to explore the spatio-temporal precipitation pattern and precipitation trend over the Taihang Mountains from 1998 to 2017. In general, the complex terrain and sparse meteorological stations lead to limited precipitation measurement in mountainous areas especially in high-altitude regions. Satellite-based precipitation measurement is an effective supplement for measuring precipitation information in such regions. The CMOPRH CRT product is recognized worldwide. A previous study had proved the applicability of CMORPH CRT over the Taihang Mountains owing to the lower root mean square error and relative bias in this region, which indicated that this product had applicability over the Taihang Mountains. Therefore, in this study, we adopted the method of time series analysis and trend analysis to explore the spatial and temporal patterns of precipitation and precipitation trend over the Taihang Mountains based on the data obtained using the CMORPH CRT product from 1998 to 2017. Meanwhile, the ground observations of 18 rain gauges were used to validate the precipitation trend measured using the CMOPRH CRT product over the Taihang Mountains with "Pixel to Point" extraction method via ArcGIS. The results showed that there was no significant variation trend in the annual and seasonal precipitation from 1998 to 2017 over the Taihang Mountains. Higher precipitation occurred in the southern and eastern regions of the Taihang Mountains than in the northern and western regions. On a monthly scale, the precipitation in July accounted for the highest rate of annual precipitation, 7.2%-32.4% of the total annual precipitation, followed by August and June. There was a decrease trend in the south and northwest regions of the Taihang Mountains, and decreased by 2-6 mm·a-1 on an average. The increasing precipitation trend appeared in the western and northern regions of the Taihang Mountains, and the annual precipitation increased by more than 8 mm. The greatest difference in precipitation trend was found in July on a spatial scale with a variation range of -8.6 to 8 mm·a-1. We used actual data obtained using rain gauges to validate the precipitation trend measured using CMORPH CRT. Two sets of data showed a strong significant correlation at the annual scale. On the seasonal scale, the precipitation trend in winter (dry season) and summer (wet season) had a strong significant correlation with the precipitation trend measured using rain gauges, but the precipitation trend in spring and autumn did not show a significant correlation with the precipitation measured using rain gauges. We extracted the pixel values according to the spatial pattern of precipitation trend from 1998 to 2017 over the Taihang Mountains, and further divided them into six different precipitation trend (PT) ranges (PT ≤ -5 mm·a-1, -5 mm·a-1 < PT ≤ 0 mm·a-1, 0 mm·a-1 < PT ≤ 5 mm·a-1, 5 mm·a-1 < PT ≤ 10 mm·a-1, 10 mm·a-1 < PT ≤ 15 mm·a-1, and PT ≥ 15 mm·a-1) depending on the actual precipitation trend over study areas. There was a significant increase in precipitation from 1998 to 2017 in the PT > 5 mm·a-1 area.
Key words:CMORPH CRT product/
Taihang Mountains/
Spatial-temporal pattern of precipitation/
Precipitation trend
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