Testing of Drought Exceedance Probability Index (DEPI) for Turkey using PERSIANN data for 2000-2021 period

Drought is a climatic event that threatens the environment and human life with an ambiguity of location and time. Recently, droughts can be analyzed for different periods with the help of different mathematical methods and developing technology. This study aims to perform a drought analysis in 126 designated study points of Turkey. The analyzed data includes monthly total precipitation values between March 2000 and February 2021, obtained from PERSIANN system (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks). Monthly precipitation totals of these designated points were used as input parameters in the Drought Exceedance Probability Index (DEPI) which is a new drought analysis method. The analysis was conducted separately for the whole of Turkey from January to December. Moreover, the findings were compared with the Standardized Precipitation Index (SPI), a globally accepted and commonly used drought index, to measure the drought detection performance of DEPI. SPI was calculated for periods of 6, 12 and 24 months. Pearson correlation coefficients between drought values of SPI-6, SPI-12 and SPI-24 and DEPI results were calculated. The second part of the study includes possible trend of drought determined by the Mann-Kendall trend analysis method. Both DEPI and SPI results and trend analysis results were mapped and visualized with the help of ArcGIS package program. The highest correlation is between DEPI and SPI-12 with 0.75, while the lowest correlation is between DEPI and SPI-24 with a value of 0.62. SPI monthly drought maps indicated the wettest months were January and February, while the driest months were March and July. Besides the DEPI monthly drought maps, the wettest months were October and November, while the driest months were May and June. The Mann-Kendall trend maps showed a significant increase in drought for summer.

Drought analysis and management for Tamil Nadu: Science-stakeholder-policy linkage

The complex and multi-dimensional nature of droughts in Tamil Nadu state and its impact on agricultural sector and farming community requires a thorough analysis for developing short and long– term adaptation and mitigation measures with institutional arrangement and policy support. In the present investigation, drought analysis was made for Tamil Nadu state using 148 years (1871 – 2018) monthly rainfall data obtained at district scale from India Meteorological Department (IMD) and Tamil Nadu Agricultural University by employing various drought indices. Larger co-efficient of variation (139 and 149 %) during the major growing seasons (Southwest and Northeast monsoon)evidenced high undependability of rainfall over Tamil Nadu. Drought Index (DI) analysis indicated a 51 per cent drought years in SWM and 48 per cent in NEM season, while Standardized Precipitation Index (SPI) exhibited 43 and 48 per cent of drought years in SWM and NEM respectively, indicating occurrence of drought once in every four years. More number of Consecutive Drought years (CDY) posed serious impacts on food production and livelihoods. Drought management framework as well as input for designing drought policy for Tamil Nadu.