In the just concluded three month pre monsoon season (March 1 to May 31, 2022) India received 130.6 mm rainfall, 1% below the normal rainfall of 131.7 mm as per the India Meteorological Department (IMD). In 2020[i] and 2021[ii] India received 158.5 mm and 155.2 mm or 20% and 18% above normal rainfall respectively. So this year, India has received much lower pre monsoon season rainfall compared to previous two years.
Month wise distribution However, when we look at the month-wise distribution of rainfall we find that in March 2022 there was just 8.9 mm (16.7 mm in March 2021) or 71% below normal rainfall when normal rainfall was supposed to be 30.4 mm. In April 2022, the rainfall was 38.3 mm (31 mm in April 2021), just 2.5% below normal rainfall of 39.3 mm. The lion’s share of rainfall of the season was in May 2022, at 83.4 mm (107.5 mm in May 2021), or 34.5 % above the normal rain of 62 mm. So near normal rainfall of the pre monsoon season rainfall actually hides the massive temporal disparity. Same is the case with spatial disparity as we can see below.
ALL INDIA State wise rainfall distribution As we can see the map of IMD showing state wise rainfall distribution during pre-monsoon season 2022, we see that Seven States (and Union Territories) had Large Excess (over 60% in excess of normal rainfall), five States and UTs had Excess (20-59% above normal rainfall), nine states had Normal (between 19% excess and 19% deficit compared to normal), Six states had Deficit (20 to 59% below normal rainfall), Nine states had Large Deficit (over 60% below normal) precipitation and one Union Territory (Dadar and Nagar Haveli) had NO rain during the entire three month pre monsoon season.
Meghalaya had the highest quantum of rainfall in this season at 1458.9 mm, 93% above normal rainfall. However, highest surplus % of rainfall was recorded by Karnataka at 121% above rainfall of 258.1 mm compared to normal rainfall of 116.8 mm.
ALL INDIA Sub Division wise Rainfall distribution As can be seen from the IMD map below, out of 36 meteorological sub divisions of IMD, Six had large Excess, Four had Excess, Eight had Normal, Ten had deficit rainfall and eight had large deficit rainfall in pre monsoon 2022 season.
South Interior Karnataka recorded the highest surplus % rainfall at 131% with rainfall of 324.5 mm compared to normal rainfall of 140.4 mm. Gujarat region recorded the highest deficit at 99% with almost nil rainfall compared to even low normal rainfall of 6.3 mm. With 909.3 mm rainfall, Assam and Meghalaya recorded the highest rainfall, which was 55% above normal.
ALL INDIA River Basin wise Rainfall Distribution As we have been highlighting for some years, IMD also provides River Basin wise rainfall distribution, though the quality of information provided by IMD in this case is very poor.
For Pre Monsoon 2022 season, as we can see from the IMD map, it is surprising that for a number of river basins, IMD has reported ZERO rainfall including: Narmada, Middle Yamuna, Lower Yamuna, Ganga (main stem in the central UP), Tons, Upper Brahmaputra, Barak, Imphal and Others, Sabarmati, Upper Godavari, Middle Godvari, Upper Bheema, Lower Bheema, Manjira and Vaippar Pamba. This seems clearly unlikely to be true for most of these basins, this only means that the IMD has been callous in collecting, calculating and reporting information about rainfall in river basins. Even from its district wise rainfall figures in the districts of these river basins, one can see that the IMD saying that these river Basins has had ZERO rainfall is absurd.
Strangely, IMD continues to report, like last year, NO DATA for a number of basins like Jhelum and Upper Indus.
STATE WISE DISTRICT WISE RAINFALL: NORTH ZONE: Jammu & Kashmir
EAST ZONE: Uttar Pradesh
NORTH EAST INDIA: Sikkim
WEST INDIA: Rajasthan
SOUTH INDIA: Andhra Pradesh