Climate of India: Blog by Dr. Satyaban B Ratna

India Meteorological Department classifies the heavy rainfall events received in a day, during the 24 hours period as per the following criteria: Heavy Rainfall event: 64.5 to 115.5 mm Very Heavy Rainfall event: 115.6 to 204.4 mm Extremely Heavy Rainfall events: >204.4 mm Heavy Rainfall Events: January 2022 During January 2022, there were  89 stations reported heavy rainfall (64.5 to 115.5 mm), nine stations reported very heavy rainfall (115.6 to 204.4 mm), one station received extremely heavy rainfall ( >204.4 mm). The locations of these stations are given in Figure 1. Figure 1: The locations of heavy rainfall events, very heavy rainfall events, and extremely heavy rainfall events in the month of January 2022 [Source: India Meteorological Department] Some of the stations over India also received record daily rainfall during the 24-hour period as per the given table.

In this page, the current status and prediction of the large-scale climate modes such as El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) that primarily influence the Indian climate are discussed.  The current status is based on the evolution of climate variables during the recent three months and their prediction is based on that issued by various international centres. The global observed anomalies of Sea surface temperature (degree C) and precipitation (mm/day) for the latest month of January 2022 are given in Figure 1. Figure 1:   Sea surface temperature (SST) anomaly (C) and Precipitation Anomaly (mm/day) for January 2022. [SST data: NOAA ERSSTv5, Precipitation data: GPCPv2.3, Climatology: 1991-2020] ENSO (El Niño–Southern Oscillation) In November 2021, La Niña is present in the Pacific Ocean, where cooler than normal SSTs were observed across central and eastern equatorial Pacific and warmer than normal SSTs were observed over west tropical Pacific Ocean (Fig. 2)

In this blog, the observed climate conditions for the month of January 2022 over India are presented.  Rainfall The country India received 39.6mm rainfall during the month of January 2022. The long period average (LPA), also known as climatology (1961-2010) rainfall over the country as a whole for the month of January was 17.3mm. Accordingly, the percentage departure of rainfall compared to the climatology was 129%, so, the country received higher rainfall compared to the climatology during the month of January 2022. The spatial rainfall patterns over India for the month of January 2022 (Figure 1, right panel) indicates that most parts of the country received above normal rainfall compared to the climatology. As per the India Meteorological Department (IMD)'s report, out of 36 meteorological sub-divisions, 23 received large excess, 2 excess, 4 normal, 1 deficient and 6 sub-divisions received large deficient rainfall. Figure 1: Spatial rainfall pattern over India for observed (left

  El Niño–Southern Oscillation indices El Niño and La Niña events (referred as El Niño–Southern Oscillation or ENSO) are driven by changes in the Sea surface temperature and atmosphere in the equatorial Pacific Ocean. During El Niño, sea surface temperatures in the central and eastern Pacific Ocean become warmer than average, while La Niña is characterised by cooler than average sea surface temperatures in the same regions. To monitor the signs of El Niño or La Niña, several sea surface temperature (SST) indices are being used. These indices simply refer to the difference in sea surface temperature from the long-term mean (here 1991–2020) in several regions located along the equatorial Pacific. These regions are called NINO1 and NINO2, NINO3, and NINO3.4 and NINO4. The Niño regions cover the following areas: Nino1+2: 10°S-0, 90°W-80°W        (-10 to 0, 270 to 280) Nino3    : 5°S-5°N, 150°W-90°W    (  -5 to 5, 210 to 270) Nino3.4 : 5°N-5°S, 170°W-120°W  (  -5 to 5, 190 to 240) Nino4