New Delhi: An experimental radar-based rainfall estimating system has been developed by India Meteorological Department (IMD) to not only alert people about the possibility of rain in their area, but also predict the amount of rainfall in a particular region even if no weather stations exist there.
Earlier, IMD could only give rainfall statistics from their existing stations. However, now readings from locations where no stations exist would be available with the help of a Doppler Weather Radar (DWR) system. Currently, two such systems are being utilised to display rainfall occurring in Uttar Pradesh and Delhi, in addition to the existing observatories.
Kuldeep Srivastava, scientist at IMD and head of Regional Weather Forecasting Centre, who developed the model, said earlier scientists had to rely on readings from the nearest weather station. However, with rainfall often varying substantially in a small area, the data was not accurate.
“We will base the data on the readings of a nearby area, but radar usage will allow us to track the direction from where the clouds are coming and the locations they may have impacted majorly. This will allow us to give a rainfall estimate without a weather station,” added Srivastava.
In Srivastava’s research, rainfall at desired locations was estimated from the precipitation accumulation product of DWR using image processing based on a python-based computer algorithm. After this, a linear regression model using the least square method was developed in R language.
Estimated and observed rainfall data of July, August and September 2018 was used to train the model. After this, the model was tested on rainfall data of July, August and September 2019 and validated. The paper has been published in Journal of Atmospheric Science Research.
While the system was in use last year too, it’s now being displayed on IMD’s regional website for Delhi to allow people to find out about the estimated rainfall occurring in their neighbourhood. IMD said it aims to refine this further before the next monsoon.
“Chances of rain reduce during winter, but we can still use this period to improve the system. By next monsoon, we will be able to get accurate estimates of the areas impacted more by rain and the locations that received the most rainfall,” said Srivastava, adding that 35 locations across the NCR would be displayed on the website daily. More locations across Delhi can be added to the list.
Delhi’s base weather is measured by the Safdarjung observatory. The four oldest stations are Palam, Ridge, Aya Nagar and Lodhi Road generally representing central, south and southwest Delhi. While more stations exist in the capital, including Delhi University, Jafarpur, Pusa, Pitampura, Sports Complex in east Delhi and Mungeshpur, data is not always available at these locations.
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