Evaluation of drought recovery duration in different land use and climates of Iran using remote sensing

Document Type : Research Paper

Authors

1 Department of Water Resources Engineering, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran

2 Department of Water Engineering, College of Agriculture, Islamic Azad University, Lahijan, Iran.

Abstract

Drought is one of the most harmful natural disasters that affect the function of plants and terrestrial ecosystems and causes significant damage. The severity and duration of the drought recovery period (the time it takes after the end of drought for plant performance to return to normal conditions) are vital parameters for better drought management. This article assesses and investigates the length of the drought recovery period in different land uses and climates of Iran. For this purpose, climate classification was done using the De Martonne method, and agricultural drought was monitored using the Vegetation Health Index (VHI) from 2000 to 2020 for cropland, forest, grassland, and shrubland land uses. Also, 2000, 2001, and 2008 were selected as drought periods. Furthermore, using gross primary productivity (GPP), the length of the drought recovery period was acquired. The results showed that the average duration of the drought recovery period varies from about 34 days in the forest to 81 days in the shrubland. The rapid recovery of forests after the drought is due to their deep roots. In general, the shrubland and cropland classes had a more prolonged recovery period than the other classes, and the forest class had the shortest recovery period, which shows the high resilience of the forest and the low resilience of the cropland and shrubland classes. Also, the results revealed that the average length of the recovery period varies from about 20 days in humid climates to 80 days in arid climates, which indicates that the conditions for drought recovery in wetter climates are better than in arider climates. In general, the drought recovery period becomes longer as one moves from a very humid climate to a dry climate.

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