荒漠草原不同植被盖度区面积对降水的响应
收稿日期: 2013-12-13
修回日期: 2014-02-20
网络出版日期: 2015-03-20
基金资助
国家自然科学基金项目(41271193)
Responses of Vegetation Area with Different Coverages to Precipitation Fluctuations in Desert Steppe
Received date: 2013-12-13
Revised date: 2014-02-20
Online published: 2015-03-20
降水波动是气候变化的主要指标之一,其在半干旱荒漠草原区植被变化中起着主要的驱动作用。在考虑到年降水量与生长期降水量的前提下,本文通过地面植被盖度反射光谱模型构建和基于3S技术的区域植被盖度分布格局反演,分析了荒漠草原不同植被盖度分布面积对降水的响应。结果表明:在荒漠草原区,不同植被盖度的区域面积和年降水量、生长期降水量呈波动变化。年降水量和生长期降水量与不同植被盖度区域面积可以拟合成线性、幂函数、指数和对数函数曲线关系。植被盖度小于10%的区域面积随着降水量的增加而下降,植被盖度大于10%区域面积随着降水量的增加而增加,盖度10%是低盖度与高盖度间相互转化阈值。当植被盖度为<2%、2%~6%、10%~15%、15%~20%、20%~25%时,拟合的曲线关系能较好地表达不同植被盖度区域面积随降水量变化的趋势(p< 0.01)。荒漠草原不同植被盖度区域面积的波动变化主要与多根葱、阿尔泰狗娃花、松叶猪尾菜和小画眉草等草本植物生长响应降水变化密切相关。
刘良旭 , 常学礼 , 王玮 , 岳喜元 , 高羽翼 . 荒漠草原不同植被盖度区面积对降水的响应[J]. 中国沙漠, 2015 , 35(2) : 499 -507 . DOI: 10.7522/j.issn.1000-694X.2014.00029
Precipitation fluctuation is one of the main indicators of climate change, which plays a significant role in driving various vegetation processes in the semi-arid desert steppe. Due to change trends of annual precipitation and growth period precipitation, we analyzed the responses of different vegetation coverage area changing process to precipitation fluctuations by building ground reflectance spectrum model and predicting regional vegetation coverage distribution pattern based on "3S" technology. The results showed that vegetation coverage areas were fluctuated with the annual and growth period precipitation. The relations between vegetation coverage areas and annual and growth period precipitation were fitted through four kinds of functions which were linear, power, exponential and logarithm function. Vegetation coverage area around 10% could be considered to be the thresholds of whether vegetation coverage distribution areas were increase or decrease in semi-arid desert steppe. And it would be decrease when vegetation coverage was less than 10% with rainfall increase and other was versa. The functions simulated the trends between different vegetation coverage areas and precipitation fluctuations were better fitted when the vegetation coverage area were at the level of <2%,2%-6%,10%-15%,15%-20% and20%-25% (p<0.01). The fluctuation was related to the massive growth of different desert perennial grasses, such as Allium polyrhizum, Heteropappus altaicus, Salsola laricifolia, and Eragrostis minor Host during yearly (or seasonal) ample precipitation.
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