Five States in the country witnessed a decreasing trend in South-West monsoon rainfall during the three decades from 1989 to 2018.

In a written reply in the Lok Sabha on Wednesday, Kiren Rijiju, Union Earth Sciences Minister, said changes are observed in the rainfall pattern of the country. The India Meteorological Department (IMD) has carried out an analysis of observed monsoon rainfall variability and changes in 29 states and union territories at state and district levels based on the IMD’s observational data of 1989–2018 during the Southwest monsoon season from June to September.

He said Uttar Pradesh, Bihar, West Bengal, Meghalaya, and Nagaland have shown significant decreasing trends in Southwest monsoon rainfall during 1989–2018. The annual rainfall over these five States, along with Arunachal Pradesh and Himachal Pradesh, also shows significant decreasing trends, he said.

Referring to the district-wise rainfall, he said there are many districts in the country that show significant changes in the South-West monsoon and annual rainfall during the 1989–2018 period.

On the frequency of heavy rainfall days, the Minister said a significant increasing trend is observed over Saurashtra and Kutch, southeastern parts of Rajasthan, northern parts of Tamil Nadu, northern parts of Andhra Pradesh, and adjoining areas of southwest Odisha, many parts of Chhattisgarh, southwest Madhya Pradesh, West Bengal, Manipur and Mizoram, Konkan and Goa, and Uttarakhand.

Trend to continue

Associated with climate change due to global warming, temporal and spatial diversity in severe weather, including extremely heavy rainfall, has been observed in the country in recent years, in line with the increase in extreme events observed over various other parts of the globe.

He said the recent IPCC climate change report indicates that these trends will continue in the future and are not preventable.

To forewarn about such events, IMD issues forecasts and warnings related to severe weather to support disaster management activities and sectorial applications, he said.

Impact-based forecast

IMD has implemented an impact-based forecast (IBF) in the recent past that gives details of what the weather will do rather than what the weather will be. It contains the details of impacts expected from the severe weather elements and guidelines for the general public about do’s and don’ts while getting exposed to severe weather.

While issuing the warning, a suitable colour code is used to bring out the impact of the severe weather expected and to signal the disaster management about the course of action to be taken with respect to the impending disaster weather event.

Green colour corresponds to no warning, hence no action is needed; yellow colour corresponds to being watchful and getting updated information; orange corresponds to being alert and being prepared to take action; and red colour signals to take action, he said.

7 Apps launched

IMD has taken various initiatives for improvement in the dissemination of weather forecast and warning services based on the latest tools and technologies. In 2020, IMD launched seven of its services (current weather, nowcast, city forecast, rainfall information, tourism forecast, warnings, and cyclones) with the Umang mobile app for public use.

During the same year, IMD developed mobile apps “Mausam” for weather forecasting, “Meghdoot” for Agromet advisory dissemination, and “Damini” for lightning alert.