Identifying the climate zones shifts of Indian meteorological subdivisions: insights from historical records

Abstract

The climate zones of meteorological subdivisions of India consist of six climate classes based on the Köppen-Geiger climate classification. Recently, these climate zones have undergone significant changes due to long-term climate variability. Present study assesses the changes in Indian meteorological subdivisions using the observed rainfall, and maximum and minimum temperatures in the period of 1951-2020. The 30-year moving climatological mean is updated every decade revealing that there have been major changes in the Arid Steppe-hot and Temperate climate in the historical periods 1961-1990 and 1991-2020. The area of the Indian homogeneous region depicts a shift to the drier climate zone in North West India and North East India from Temperate to Arid steppe hot and Tropical savannah to Temperate climate respectively. The change is nearly 7% of the total area of India due to an increasing trend in temperature and a decreasing trend in rainfall which controlled by the negative phase of Victoria Mode (VM) decrease in moisture transport and divergence over Northern India Indo-Gangetic Plane. This climate zone shift could adversely impact the agriculture in the Northern India Agro-Climatic Zone in the future. Overall, this study enhances the knowledge about climate zone change and therefore the IMD forecasting system.