三工河流域山地—绿洲—荒漠系统降水空间变异性研究

山地—绿洲—沙漠系统（MODS）是中国内陆干旱区最基本、也最典型的地理景观格局,以天山北麓中段、准噶尔盆地南缘的三工河流域为典型区,设置降雨量监测网,获取2007-2014年5-8月份降雨量数据,利用（旋转）经验正交函数分解（REOF/EOF）、分形理论及克里金法（Kriging）等方法探讨流域尺度干旱内陆区MODS多地貌单元复合情况下降水的空间结构型及异质性特征,为深入了解MODS生态系统植被演变规律及其恢复提供借鉴。主要结论为：依据第一特征向量（对总体方差贡献82.4%）0~30 km、30~70 km及70~150 km的3个荷载区段,将研究区划分为山地区、绿洲区及沙漠区;其夏季降水场以“整体一致”型为主,表现为降水一致全流域整体增加,且增幅自山地—绿洲—荒漠依次减小。山地区半变异函数曲线符合高斯模型,绿洲区符合球状模型变程为15.3 km,荒漠区5月、6月及其它时段分别符合高斯模型、指数模型及球状模型,变程58.6 km比山地和绿洲大。随机因素引起的空间异质性占0.01%~9.57%;绿洲区降水空间变异性最大,山地次之沙漠区最小;6月份降水空间异质性最显著,8月最小;在南北方向（0°）和东南—西北方向（135°）变异性最强。

Spatial variability of precipitation for mountain-oasis-desert system in the Sangong River Basin

Mountain-Oasis-Desert System (MODS) is the typical landscape pattern in the inland arid area of Northwest China. We set the rainfall monitoring network in the Sangong River Basin, which is located in the middle part of northern Tianshan Mountains, southern margin of the Junggar Basin, to obtain the data of May-August rainfall for 2007-2014. Then empirical orthogonal function, fractal theory and geostatistics method were used to investigate characteristics of spatial distribution pattern and spatial variability of precipitation for the Mountain-Oasis-Desert System in arid inland areas. Results indicate that: (1) The first feature vector (contribution rates of the overall changes was 82.4%) has three load sections, namely, 70-150 km, 30-70 km and 0-30 km; accordingly, and the study area is divided into mountain area, oasis area and desert area. (2) The spatial distribution of summer precipitation presents a pattern of "overall uniformly type", which means that precipitation will increase over the whole basin, and the increase range is decreasing from mountain, oasis to desert. (3) The semi variation function curve of the mountainous region fits the Gauss model, the oasis area fits the Spherical model and the variation distance is 15.3 km. The desert area in May, June and other months fits the Gauss model, the exponential model and the spherical model respectively, and the variation distance is 58.6 km, which is longer than that of the mountain and oasis. (4) In research scale, owing to the random factors arising precipitation spatial heterogeneity take up 0.01%-9.57% of all, it was mainly caused by autocorrelation. (5) The spatial variability of precipitation in the oasis region was the largest, while that of the desert region was the smallest. The spatial heterogeneity of precipitation in June was the most significant, while the minimum value was observed in August. The variation was the greatest in both the north-south (0°) and the southeast-northwest directions (135°).