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

Drought is one of the most harmful natural disasters that affects the plants yield and terrestrial ecosystems and causes significant damage. The severity of drought and duration of drought recovery (the time required for plant to return to normal conditions, after the end of drought) are vital parameters for better drought management. This article assesses and investigates the length of 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 uses. Years of 2000, 2001, and 2008 were selected as drought periods. Furthermore, using gross primary productivity (GPP), the length of drought recovery period was acquired. The results showed that the average duration of  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 indicates 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 humid climate are better than that in arid climates. In general, the drought recovery period becomes longer as one moves from a very humid climate to a dry climate.