18/04/2020 - Geography

KEY POINTS

·         The forecast by the India Meteorological Department (IMD) of a normal monsoon this year has come as a silver lining in the general atmosphere of despondency created by the Covid-19 outbreak. 

·         The agriculture and allied activities sector, which seems set to grow at 3.5 per cent in 2019-20, regardless of the of Covid-19 onslaught towards the end of the rabi season, can be expected to sustain or excel this level of growth in 2020-21 as well.

·         Significantly, the IMD has also outlined the revised “normal dates” for the onset, progress, and withdrawal of the monsoon in different regions, based on the experience of the past few decades, thus, virtually altering the country’s monsoon-dictated cropping calendar.

·         Yet it manages to cover the entire country, including the northwest, by July 8, nearly a week earlier than the previously deemed normal time of mid-July. The reworked date of the monsoon’s complete withdrawal from the country is now October 15, instead of September-end.

·         That said, the truth also is that the IMD’s long-period weather predictions are yet to acquire the kind of credibility that its short- and medium-term forecasts have managed to do. Its preliminary monsoon projections, issued around this time every year, most often, go wrong.

·         At times, even the updated versions and the region-wise forecasts released later on also prove incorrect. The indication about the distribution of the rainfall, which matters more for agriculture than the amount of precipitation, comes only when the rainy season is already underway and the bulk of the crop sowing has taken place.

The Indian Meteorological Department(IMD) issues a two stage forecast on Monsoon,the first forecast in the month of April and the second one in the last week of May.The April forecast states that India is more likely to get Normal Monsoon i.e. around 88 cm.

Importance of monsoon prediction:

1.Monsoons are lifeline for Indian farmers as majority of Indian farmers depend on monsoonal rainfall.As per the predictions made by IMD,the farmers make decisions about sowing illustrates the importance of monsoon prediction.

2.Government takes stand on developmental activities like construction of roads,irrigation projects etc on the basis of monsoon prediction.

Forecasting models employed by IMD at present :

IMD employed two models for weather forecast.They are 1.Statistical Model 2.Dynamic model.

Statistical Model : 

Statistical model is based on identifying climate parameters linked to the performance of monsoon.Climate parameters include sea surface temperature gradient between North Atlantic and North Pacific,the volume of warm water in the equatorial pacific,the Eurasian snow cover.These parameters are correlated to the previous years parameters for the prediction of Monsoon for that year.

Dynamic Model :

This model is also known an Monsoon Mission Coupled Forecast System.This model relies on super computers where mathematical simulation of physics of ocean and atmosphere is done to get the forecast.

Efficiency of these models :

Last year IMD predicted the below normal rainfall due to ElNino concerns,but the rainfall is above normal shows that monsoons are difficult to predict.

The probabilities of normal rainfall this year are 43% and 70% as per statistical and dynamic models respectively explains the difficulty in the prediction of monsoon.

Wayforward :

1.IMD can employ artificial intelligence linked models to increase the efficiency in its prediction of monsoons.

2.Indian Government can enhance funds towards research projects related to weather forecast.

3.Collaboration of IMD with different countries meteorological departments may result in the development of efficient models.

4.Geography learning can be enhanced in school level which can motivate students to opt this area for research and development.

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