| 青藏高原冬、春植被归一化指数变化特征及其与高原夏季降水的联系 |
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| 引用本文： | 刘雅勤,范广洲,周定文,李洪权,华 维,李学敏.青藏高原冬、春植被归一化指数变化特征及其与高原夏季降水的联系[J].气象学报,2007,65(6):959-967. |
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| 作者姓名： | 刘雅勤 范广洲 周定文 李洪权 华 维 李学敏 |
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| 作者单位： | 1. 成都信息工程学院高原大气与环境研究中心,成都,610225
2. 成都信息工程学院高原大气与环境研究中心,成都,610225;中国科学院大气物理研究所,北京,100081;中国科学院研究生院,北京,100049 |
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| 基金项目： | 国家自然科学基金;四川省青年科技基金重点项目 |
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| 摘 要： | 青藏高原气候独特,影响高原夏季降水的原因是十分复杂的和多方面的。文中利用1982—2001年的卫星遥感植被归一化指数(NDVI)资料和青藏高原55个实测台站降水资料,应用经验正交分解(EOF)、奇异值分解(SVD)等方法分析了青藏高原冬、春植被变化特征及其与高原夏季降水的联系,得到以下几点初步认识:青藏高原冬、春季植被分布基本呈现东南地区植被覆盖较好,逐渐向西北地区减少的特征。其中高原东南部地区和高原南侧边界地区NDVI值最大,而西北地区和北侧边界地区NDVI较小。EOF分析表明,20年来冬、春季高原植被的变化趋势是总体呈阶段性增加,其中尤以高原北部、西北部(昆仑山、阿尔金山和祁连山沿线)和南部的雅鲁藏布江流域植被增加明显。由SVD方法得到的高原前期NDVI与后期降水的相关性是较稳定的。青藏高原多数区域冬、春植被与夏季降水存在较好的正相关,且这种滞后相关存在明显的区域差异。高原南部和北部区域的NDVI在冬春两季都与夏季降水有明显的正相关,即冬春季植被对夏季降水的影响较显著。而冬季高原中东部玉树地区附近区域的NDVI与夏季降水也存在较明显的负相关,即冬季中东部区域的植被变化对夏季降水的影响也较显著。由此可见,高原前期NDVI的变化特征,可以作为高原降水长期预报综合考虑的一个重要参考因子。
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| 关 键 词： | 青藏高原 夏季高原降水 奇异值分解 |
| 收稿时间： | 2006/11/20 0:00:00 |
| 修稿时间： | 2006年11月20 |
VARIABILITY OF NDVI IN WINTER AND SPRING ON THE TIBETAN PLATEAU AND THEIR RELATIONSHIP WITH SUMMER PRECIPITATION |
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| Liu Yaqin,Fan Guangzhou,Zhou Dingwen,Li Hongquan,Hua Wei,Li Xuemin.VARIABILITY OF NDVI IN WINTER AND SPRING ON THE TIBETAN PLATEAU AND THEIR RELATIONSHIP WITH SUMMER PRECIPITATION[J].Acta Meteorologica Sinica,2007,65(6):959-967. |
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| Authors: | Liu Yaqin Fan Guangzhou Zhou Dingwen Li Hongquan Hua Wei Li Xuemin |
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| Abstract: | The Tibetan Plateau has a complex topography and landscape,a large variety of vegetation,and huge heterogeneity and salient geographical variability in landcover,ranging from the evergreen rainforest of the southern Himalayas to the semiarid and arid lands of the northern plateau.The Tibetan Plateau is a sensitive region in climate change,where the manifestation of global warming is particularly noticeable.The large climate variability over this region significantly affects the local land ecosystem and could consequently lead to notable vegetation changes.Based on the 20 years normalized difference vegetation index(NDVI) dataset from the Inventory Modeling and Mapping Studies(GIMMS) and precipitation station data from the National Climate Center(NCC) of China Meteorological Administration(CMA),the relationship between winter and spring NDVI and summer precipitation in the Tibetan Plateau is investigated using the singular value decomposition method.The results show that vegetation coverage is best in the eastern and southern plateau regions and deteriorates toward the west and north.On the whole,the vegetation activity evinces a gradual enhancement with an oscillatory manner during 1982-2001.The temporal variation also exhibits striking regional differences: an increasing trend is most apparent in the north, northwest,and south,whereas a decreasing trend is present along the southern plateau boundary and in the central-east region.There exist a preferable correlation between NDVI in winter and spring and summer precipitation in the Tibetan Plateau and the lag correlation also exhibits striking regional differences.The correlation of NDVI in winter and spring to summer precipitation put up strongly positive.The respond is sensitive especially in north and south region.However,in the central-east region NDVI in winter is negative correlated to the summer precipitation.The SVD analysis between the NDVI and the precipitation suggests that the vegetation change is closely related to the precipitation change.The vegetation variability should be considered as the factor of the long forecasting for the precipitation in the Tibetan Plateau. |
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| Keywords: | NDVI |
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