青藏高原地区积雪及其变化的不确定性:3种积雪观测资料的对比分析

为了探究青藏高原积雪不同观测资料间的差异,本文通过定义积雪覆盖率(Snow Cover Percentage,SCP)对比了NOAA-CDR卫星可见光遥感积雪资料、卫星被动微波遥感积雪资料和我国146个台站观测的积雪资料在高原地区的气候态及年际变动特征。从年平均气候态看,微波与可见光资料的SCP分布较为接近,高值区均位于念青唐古拉山与喜马拉雅山南缘之间的山区。而台站资料SCP的高值区范围则相对较小,在高原东部的巴颜喀拉山及南部的念青唐古拉山。3种资料的积雪低值区均位于高原中南部沿雅鲁藏布江一带、阿尔金山北侧以及东边界的内陆省份。从季节平均场看,不同资料的积雪分布在冬季及秋季,无论是气候态还是年际变动均较为类似。在春季时,微波和台站资料间较为一致。而在夏季,资料间差异很大,不同资料间的两两相关接近于零,甚至为负数。本文同时选取了青藏高原地区4个典型台站(索县、清水河、康定、甘孜),将卫星资料插值于台站上,对比3种资料间的异同,以及与地表气温异常间的关系。结果表明,在这4个典型站上,台站SCP在过去36 a中为线性减少的趋势,而卫星SCP主要为线性增加的趋势,且台站年平均SCP与地表气温异常的协同性最好。

Uncertainty of snow cover and its changes in the Qinghai-Tibet Plateau: a comparative analysis of three types of snow cover observation data

In order to explore the differences between different observational data of snow cover on the Qinghai-Tibet Plateau, this paper compares the climate states and interannual variations of the NOAA-CDR satellite visible light remote sensing snow cover data, satellite passive microwave remote sensing snow cover data and snow cover data observed from 146 stations in China by defining the Snow Cover Percentage (SCP). From the angle of annual average climatic state, the SCP distributions of microwave and visible light data are relatively close, and the area of high SCPs are in the mountainous area between the Nyainqentanglha Mountain and the southern edge of the Himalayas. The area of high SCPs based on the station data is relatively small and in the eastern part of the plateau and the Nyainqentanglha Mountain in the south. The areas of low SCPs of the three datasets are similar; they are along the Yarlung Zongbo River in the middle-south of the Plateau, in the northern part of Alton Mountain and in the inland provinces at the eastern edge of the plateau. From the angle of seasonal mean field, the distributions of snow cover of all the datasets are similar in winter and autumn, whether in terms of climatic state or interannual variation. In spring, the distributions are similar only between the satellite microwave and station data. In summer, the data vary greatly, and the correlation between different data is close to zero or even negative. The paper selects our typical stations in the Qinghai-Tibet Plateau (Suoxian, Qingshuihe, Kangding, Ganzi), and interpolates the satellite data on the stations to compare the similarities and differences between the three data and to investigate their consistencies with the Surface Air Temperature (SAT) anomalies. Results show that the SCPs based on the station data show linearly decreasing trends in the past 36 years while those based on the satellite data show the increasing trends. Compared to the satellite observations, the annual-mean SCPs based on the station observations have better consistencies with the SAT anomalies.