Open AccessA statistical approach towards defining national-scale meteorological droughts in India using crop data
Author(s) -
Parmeshwar Udmale,
Yutaka Ichikawa,
Shaowei Ning,
Sangam Shrestha,
Indrajit Pal
Publication year - 2020
Publication title -
environmental research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.37
H-Index - 124
ISSN - 1748-9326
DOI - 10.1088/1748-9326/abacfa
Subject(s) - environmental science , evapotranspiration , precipitation , scale (ratio) , climatology , monsoon , index (typography) , crop , geography , meteorology , cartography , forestry , biology , ecology , geology , world wide web , computer science
In recent years, several drought indices have been developed and used to monitor local to regional scale droughts on various temporal scales. However, to our knowledge, these indices do not possess generalized criteria to define a threshold in which to declare a national-scale drought. We present a statistical methodology to identify national-scale meteorological drought years in India. We implement a Superposed Epoch Analysis and bootstrap analysis to estimate annual cereal crop production losses as a result of widespread meteorological drought events. For this purpose, the meteorological definition of drought based on the Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI), in combination with the country’s cropland area and cereal crops production, is used. The results demonstrate that a national-scale meteorological drought is defined if approximately 19% or more of India’s cropland is affected by meteorological drought (SPI3 and SPEI3 equal to or less than −1.00) throughout the monsoon season (June–September). According to this analysis, depending on the indicator data used, a total of 18to 20 national-scale meteorological droughts were identified in India during 1964–2015, causing a 3.61% to 3.93% composite decrease in cereal crops production. The years which were commonly identified as national scale meteorological droughts over cropland by using different approaches are 1965, 1972, 1987, 2002, and 2009. A similar statistical approach can also be used to define drought thresholds at various spatial scales using the drought indices most applicable to the purpose and scale of study.