Climate of India: Blog by Dr. Satyaban B Ratna

The India Meteorological Department released the December 2022 monthly climate summary. As per the report, the all-India mean temperature for December 2022 is the highest on record (21.49 ºC) since 1901. Similarly, the average maximum temperature for December 2022 is the second highest (27.32 ºC) after the year 2016 (27.75 ºC) while the average minimum temperature is also the second highest (15.65 ºC) after the year 2008 (15.69 ºC) since records began in 1901 (Table 1). The all-India spatial patterns of maximum, minimum and mean temperature for December 2022 is given in Figure 1. Coincidently, all three years (2008, 2016 and 2022) happened to be La Nina years (Figure 2) with December Nino3.4 index values of -0.90 ºC, -0.51ºC and -0.90 ºC respectively. Table 1: The observed temperatures during December 2022 for all India and four homogeneous regions with its ranks since 1901. Values are rounded off to nearest two decimal. [Source: IMD] Figure 1: Observed spatial tempe...

As the year 2022 has come to an end, a season from October to December, known as the post-monsoon season for India or the northeast monsoon season over south-peninsula India, also have come to an end. South Peninsular India, consisting of five meteorological subdivisions (Tamil Nadu, Coastal Andhra Pradesh, Rayalaseema, Kerala, and South Interior Karnataka), receives about 30% of its annual rainfall during the Northeast monsoon season. The re-establishment of northeasterly trade-wind regime associated with the southward movement of the Inter Tropical Convergence Zone (ITCZ) ushers-in the northeast monsoon, bringing much needed rainfall to the southern parts of India. However, the predictability of northeast monsoon is limited to some extent due to the strong day to day atmospheric variability caused by the passage of the synoptic scale weather systems such as easterly waves, lows, depressions, cyclones etc. The seasonal predictability of the northeast monsoon ov...

In the first section the observed Sea Surface Temperature (SST) and rainfall anomaly for the month of November 2022 are discussed. Next, the present status, evolution, 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 presented. Apart from this the observed weather conditions over India during the month of November 2022 also discussed. Global patterns of SST and Rainfall The global observed anomalies of Sea surface temperature (degree C) and rainfall (mm/day) for the previous month (November 2022) is given in Figure 1. The SST anomaly in the equatorial Pacific indicating the existence of La Niña. However, major parts of the global Oceans were with above normal SST anomaly. There was below normal rainfall in the central equatorial Pacific. north Australia and parts of southern Africa and South America in February 2022. Above normal rainfall was observed over equatorial...

 In the first section the observed Sea Surface Temperature (SST) and rainfall anomaly for the month of October 2022 are discussed. Next, the present status, evolution, 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 presented. Apart from this the observed weather conditions over India during the month of October 2022 also discussed. Global patterns of SST and Rainfall Figure 1:   Sea surface temperature (SST) anomaly (C) and Precipitation Anomaly (mm/day) for October 2022. [SST data: NOAA ERSSTv5, Precipitation data: GPCPv2.3, Climatology: 1991-2020] El Niño–Southern Oscillation (ENSO): Present Status Figure 2 : Tropical Pacific Sea surface temperature (SST) anomalies (Left Panel) and changes in the SST anomalies (degree C) from the previous month (Right Panel) during August - October 2022.  [SST data: NOAA ERSSTv5, Climatology: 1991-2020] Figure ...

The Indian summer monsoon rainfall (ISMR) during June-September in 2022 was above normal with respect to its climatology. Rainfall during the 2022 Southwest Monsoon Season was above normal. The all-India monsoon seasonal rainfall during 1 June to 30 September was 925.0 mm compared to its climatology value 868.6 mm based on 1971-2020 data (Fig. 1 and Fig.2). It can be seen that although all India rainfall was above normal, the Indo-Gangetic plains ( Nagaland, Manipur, Mizoram & Tripura, Gangetic West Bengal, Jharkhand, Bihar, and east & west Uttar Pradesh)  received severe deficient rainfall.  Rainfall averaged over All India was the fifth highest since 2001 after the years 2019(970.8 mm), 2007(966.6 mm), 2020 (959.3 mm), and 2013 (943.4 mm).  The ISMR was above normal three out of the last four years (2018-2022) comes after normal to below normal ISMR for five years during 2014-2018 (Fig. 2) Figure 1:    Observed (left), climatology (middle), and anomaly...