Monitoring vegetative drought dynamics in the Brazilian semiarid region
Monitoring vegetative drought dynamics in the Brazilian semiarid region
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DOI：
10.1016/j.agrformet.2015.09.010
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发表时间：
2015-12-15
影响因子：
6.2
通讯作者：
Carvalho, M. A.
中科院分区：
文献类型：
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作者：
Cunha, A. P. M.;Alvala, R. C.;Carvalho, M. A.
干旱是一种复杂的自然现象，可导致供水减少，从而对农业和社会经济活动产生重大影响，造成社会危机和政治问题。不同的干旱指标用于识别干旱。这项工作探讨了使用Terra-MODIS归一化植被指数（NDVI）和地表温度（LST）产品的近实时干旱监测方法的适用性。这种方法被称为植被供水指数（VSWI），它综合了地表反射率和热特性。结果表明，在2012年至2013年的一次重大干旱事件中，大约85%的巴西半干旱地区受到影响。利用一个简单的水分平衡模型计算出的土壤水分亏缺天数和日降水量进行验证。对VSWI与降水和土壤水分亏缺的相关性分析表明，VSWI与降水和土壤含水量密切相关，尤其是在干旱条件下，VSWI可以作为一种合适的近实时干旱监测方法。考虑到VSWI指数，对2012-2014年干旱的评估突出了植被对干旱条件反应的两个主要特征，即，植被的恢复和记忆效应。(C)2015爱思唯尔B. V.保留所有权利。
Drought is a complex natural phenomenon that can lead to reduced water supplies and can consequently have substantial effects on agriculture and socioeconomic activities that cause social crises and political problems. Different drought indicators are used for identifying droughts. This work explored the applicability of a near-real time drought monitoring methodology using Terra-MODIS Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST) products. This approach is called the Vegetation Supply Water Index (VSWI), which integrates land surface reflectance and thermal properties. The results indicate that during a major drought event from 2012 to 2013, approximately 85% of the Brazilian semiarid region was affected. The number of days of soil moisture deficit, which was derived from a simple water balance model and the daily interpolated precipitation, were used to verify the results. A correlation analysis of VSWI, precipitation and soil moisture deficit shows that VSWI is closely related to rainfall and soil water content, especially under dry conditions, and indicates that the use of VSWI can be a suitable near-real time drought monitoring approach. The evaluation of the 2012-2014 drought considering the VSWI index highlighted two major characteristics of vegetation response to drought conditions, i.e., the recovery and memory effects of vegetation. (C) 2015 Elsevier B.V. All rights reserved.