| 卫星遥感藏北积雪分布及影响因子分析 |
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| 引用本文： | 张佳华, 吴杨, 姚凤梅. 卫星遥感藏北积雪分布及影响因子分析[J]. 地球物理学报, 2008, 51(4): 1013-1021, |
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| 作者姓名： | 张佳华 吴杨 姚凤梅 |
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| 作者单位： | 1中国气象科学研究院遥感与气候信息开放实验室, 北京 100081; 2 浙江省气象信息中心, 杭州 310017; 3中国科学院研究生院地球科学学院, 北京 100049 |
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| 基金项目： | 科技部科研项目，国家自然科学基金，中国气象局气候变化专项基金，中国气象局高原气象基金 |
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| 摘 要： | 利用1993~2004年SSM/I被动微波辐射仪反演的雪深资料，1996~2004年NOAA/AVHRR可见光和红外反演的积雪覆盖面积资料，1966~2003年藏北地区6个地面台站的积雪观测资料来检验卫星资料的可用性，并研究近年来藏北积雪的时空分布和影响因素.结果表明，SSM/I, NOAA/AVHRR和实际观测的积雪资料具一致性.从积雪时间变化看：季节尺度上，藏北地区秋冬季积雪迅速增加，但春季(3~5月)融雪速度不快，呈现正反馈特征；年际尺度上，藏北地区20世纪60年代末期起积雪开始减少，80年代积雪增加，90年代起到2003年积雪总体上减少，呈现出减少—增加—减少趋势.采用小波分析发现积雪振荡周期存在着一个准2~3年，准9年和13年的周期，从20世纪70年代初到90年代中期还有一个5年的周期.积雪空间上看，藏北地区积雪主要集中在东部地区，该区每个冬春年积雪覆盖旬数超过15旬，显著高于西部少雪区，大部分积雪集中在4900~5600 m的高度左右；藏北高原积雪变动的显著区位于藏北中东部的安多和聂荣地区.利用藏北地区1966~2003年的地面温度和降水资料建立回归方程模拟年累积雪日，结果表明模拟值与实测值之间的相关系数达0.74.积雪时空分布受温度、降水等因子影响明显.1998~2003年藏北积雪的减少与全球变暖有关，但降水的减少可能是导致近年来藏北积雪减少的更主要因素.
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| 关 键 词： | 积雪 SSM/I资料 卫星遥感 影响因子 藏北地区 |
| 收稿时间： | 2007-11-29 |
| 修稿时间： | 2008-03-13 |
Study on the snow distribution and influencing factors in Northern Tibet based on remote sensing information |
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| ZHANG Jia-Hua, WU Yang, YAO Feng-Mei. Study on the snow distribution and influencing factors in Northern Tibet based on remote sensing information[J]. Chinese Journal of Geophysics (in Chinese), 2008, 51(4): 1013-1021, |
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| Authors: | ZHANG Jia-Hua WU Yang YAO Feng-Mei |
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| Affiliation: | 1 Lab. for Remote Sensing and Climate Information Sciences, Chinese Academy of Meteorological Science, Beijing 100081, China; 2 Zhejiang Meteorological Information Center, Hangzhou 310017,China; 3 College of Earth Sciences, the Graduate University of the Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | Based on two kinds of remote sensing data (snow depth of Special Sensor Microwave/ Imager SSM/I from 1993 to 2004, snow cover of NOAA/AVHRR from 1996 to 2004) and snow depth and snow cover days of six stations over northern Tibet from 1966 to 2003, we studied snow cover distribution in temporal and spatial scales, and analyzed the influencing factors of snow in Northern Tibet region. The result showed that the remote sensing snow data (retrieval from SSM/I, NOAA/AVHRR) was in general agreement with the weather stations data. In temporal scale, for the seasonal cycle, during 1966 to 2003, the snow cover extent increased rapidly in autumn and winter seasons in Northern Tibet. However, in spring (March-April-May), snow cover extent did not show a continual decrease，whereas indicated a positive feedback. For the interannual cycle, from the end of 1960s the snow cover of Northern Tibet region reduced, but in 1980s, the snow cover increased as a whole, and from 1990s it decreased again. Thus, the snow cover variation showed a reducing-increasing-reducing dynamic process in the study area. The result of a wavelet analysis on temporal distributions of annual cumulative snow cover indicated that there were mainly oscillation periods of quasi-2~3 yr, quasi-9 yr, quasi-13 yr, and from the beginning of 1970s to the middle of 1990s, there was an oscillation period about quasi-5 yr. In spatial scale, the east part of Northern Tibet region was the main snow cover area, where the snow cover days exceeded 15 ten-days in each winter-spring, and were obviously distinguished from the western part of Northern Tibet region. The majority of snow cover pixels exist in altitude of 4900~5600 m. The greatest variance of snow cover was found in middle and eastern part of the Northern Tibet Plateau, i.e. Andu and Nierong regions. We selected two important factors influencing snow-cover (i.e., temperature, precipitation) and calculated multiple linear regressions. The result showed that the correlation coefficient between simulated annual cumulative snow days and observation data was 0.74. It revealed that temperature and precipitation are the main factors influencing the snow cover in Northern Tibet region. Global warming might be one reason causing snow cover declining in recent years in Northern Tibet region. However, the effect of precipitation seems larger than that of temperature. |
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| Keywords: | Snow cover SSM/I data Remote sensing Influencing factors Northern Tibet |
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