1979-2010年青藏高原积雪深度时空变化遥感分析

积雪深度是表征积雪特征的重要参数,也是区域气候变化最敏感的响应因子之一。利用1979-2010年逐日中国雪深长时间序列数据集,采用GIS空间分析和地统计方法,分析了青藏高原积雪深度的时空变化规律及异常空间分布特征。结果表明：近32年来,青藏高原雪深呈显著增加趋势,增加速率为0.26 cm/10a,其中,昆仑高寒荒漠地带雪深增加最为明显,增加速率达0.73 cm/10a;20世纪80年代至90年代青藏高原雪深呈逐步增加趋势,21世纪初变化平稳;青藏高原4个季节雪深变化均呈现为上升趋势,尤以冬季增加最为明显,增加速率达0.57 cm/10a。青藏高原东南、西部和南部为雪深分布高值区;逐像元回归分析表明,高原雪深呈增加趋势的像元数占全区像元总数的67.1%,其中有91.3%为轻度和中度增加,主要分布在高原北部和西部;最大雪深变化基本维持在-0.1~0.1 cm/a（45.47%）之间,在昆仑北翼山地、柴达木山地、羌塘高寒地带南部等局部地区最大雪深有增加趋势,主要是轻度增加,面积比例为36.66%。果洛那曲高寒地带、青南高寒地带和羌塘高寒地带为青藏高原积雪深度异常变化敏感区。

Analysis of Spatial-Temporal Variations of Snow Depth over the Qinghai-Tibetan Plateau during 1979-2010

Snow depth is an important parameter to characterize snow features, and it is also one of the most sensitive factors of regional response to climate change. Based on the daily dataset of snow depth from 1979 to 2010, the spatial and temporal variations and distribution anomaly of snow depth over the Qinghai-Tibetan Plateau in China were analyzed with the use of spatial and statistics analysis function of GIS. The results showed that, during the period from 1979 to 2010, snow depth increased obviously and significantly with the rate of 0.26 cm/(10a) in the Qinghai-Tibetan Plateau, and especially the snow depth in the alpine desert zone in Kunlun Mountains increased most obviously with the rate of 0.73 cm/(10a), and it decreased most clearly with the rate of -0.34 cm/(10a) in the montane evergreen broad-leaved forest in south side of eastern Himalayas. Snow depth gradually increased from the 1980s to the 1990s, while it changed stably in the early 21th century. The results indicated that monthly average snow depth started to rise from September, reached a maximum in January, and then declined to the minimum in August. From the perspective of seasons, snow depth rose, particularly in winter with the rate of 0.57 cm/(10a), and increased most obviously in Ali, north of Kunlun Mountains and the alpine desert zone in Kunlun Mountains. Among the four seasons, spring mean snow depth contributed most significantly to the annual situation, with the correlation coefficient between them up to 0.885. As far as the spatial distribution is concerned, the deeper snow depth lied in the southeast, the western and southern areas of the Qinghai-Tibetan Plateau; the area with an annual upward trend accounted for 67.1%, of which 91.3% is the mild and moderate increase which mainly occurred in the north and west of Qinghai-Tibetan Plateau; moreover, the maximum snow depth varied between -0.1 and 0.1 cm/a, which was on the rise in the north wing of the Kunlun Mountain, the mountainous region of the Qaidam Basin, and south of Qiangtang Plateau where the snow depth mildly increased; the sensitive areas of distribution anomaly of snow depth were in the alpine shrub of Guoluo-Naqu region, south Qinghai and the Qiangtang Plateau.