IMDAA Regional Reanalysis: Performance Evaluation During Indian Summer Monsoon Season

The Indian Monsoon Data Assimilation and Analysis (IMDAA) is a regional high-resolution atmospheric reanalysis over the Indian subcontinent. This regional reanalysis over India is the first of its kind and is produced by the National Centre for Medium Range Weather Forecasting and Met Office, UK, in collaboration with the India Meteorological Department under the National Monsoon Mission project of the Ministry of Earth Sciences, Government of India. The reanalysis runs from 1979 to 2018, to span the era of modern meteorological satellites. This article briefly describes the IMDAA system and discusses the performance of the IMDAA during summer monsoon (June-September). This study provides evidence for substantial improvements seen in IMDAA compared to the ERA-Interim reanalysis fields over India. The evaluation is carried out for the period of 1979-1993 for all major features associated with the Indian Monsoon to highlight improvements compared to ERA-Interim and to document the biases. The study also demonstrates the potential use of the IMDAA data for applications such as wind resource assessment over India.