Lok Sabha Question No. 4291 (UNSTARRED), answered on 2019-12-13
Subject: Monsoon Predictions by Indian Meteorological Department
Ministry: EARTH SCIENCES
Asked by: Unmesh Bhaiyyasaheb Patil

## MINISTRY OF EARTH SCIENCES

## GOVERNMENT OF INDIA LOK SABHA

## UNSTARRED QUESTION No. 4291 TO BE ANSWERED ON FRIDAY, DECEMBER 13, 2019

## MONSOON PREDICTIONS BY INDIAN METEOROLOGICAL DEPARTMENT

## 4291. SHRI UNMESH BHAIYYASAHEB PATIL:

Will the Minister of EARTH SCIENCES be pleased to state:

- (a) whether the Indian Meteorological Department (IMD) has predicted normal  monsoon  during  the  current  season  and  if  so,  the  details thereof, region-wise;
- (b) whether  the  Government  is  aware  that  several  foreign  agencies including  the  Japanese  Meteorological Department  have  predicted below normal monsoon during the current season;
- (c) if so, the details thereof and the reaction of the Government thereto, agency-wise; and
- (d) whether average error in IMD, monsoon forecasts has come down during each of the last three years and if so, the details thereof?

## ANSWER

## MINISTER FOR MINISTRY OF SCIENCE AND TECHNOLOGY AND

## MINISTRY OF EARTH SCIENCES (DR. HARSH VARDHAN)

- (a) Yes  Sir. India  Meteorological  Department  (IMD)  had  predicted normal monsoon during the 2019 monsoon season. The long range forecast  for  the  2019  southwest  monsoon  rainfall  was  issued  in  3 stages.  The  first  stage  long  range  forecast  issued  on  15 th   April consisted of only forecast for season (June-September) rainfall over the country as a whole. In the second stage (31 st  May),  forecast for season rainfall over the four broad geographical regions (Northwest India, Central India, South Peninsula and Northeast India) and that for  monthly rainfall  over  the  country  as  a  whole  for the months of July and August were also issued. In the 3 rd  stage (1 st  August), the forecast  for  the  rainfall  during  the  second  half  of  the  monsoon season over the country as a whole was issued. Annexure- I gives the summary of the verification of the long-range forecasts issued for the 2019 Southwest monsoon.

The  first  stage  forecast  for  the  season  (June-September)  rainfall over the country as a whole issued in April was 96% of Long Period Average (LPA) with a model error of ± 5% of LPA.  The update issued in May for this forecast was (96% of LPA) with a model error of ± 4% of LPA. Both these forecasts were suggesting the normal category i.e. 96-104 % of LPA. The LPA of the season rainfall over the country as a whole for the period 1951-2000 is 89 cm.

Details of long-range rainfall forecasts issued by IMD for the 2019 southwest monsoon season (June- September) and realized rainfall during the season is at Annexure - I .

- (b)& (c) Yes  Sir.  IMD  keeps  track  of  forecasts  issued  by  various  foreign climate  agencies  including  that  of  Japan  Meteorological  Agency (JMA)  as  well  as  Japan  Agency  for  Marine-Earth  Science  and Technology  (JAMSTEC).  Inferences  derived  from  forecasts  from various centres for the 3 months periods of JJA and JAS of 2019 are given in Annexure II. The forecasts for 2019 monsoon season were issued  in  April/May  2019.  The  coupled  model  forecast  from  JMA indicated below normal precipitation over most parts of the country.

Inferences  derived  from  seasonal  forecasts  from  various  climate centers for the 2019 southwest monsoon season are at Annexure- II.

- (d) Yes Sir, there has been noticeable improvement in the skill of IMD seasonal forecast for the southwest monsoon season rainfall over the  country  as  a  whole.  The  average  absolute  error  (difference between forecast and actual rainfall) during the last 10 years (20102019) was 5.62% of LPA compared to the average absolute error of 8.84% of LPA during the previous 10 years (2000-2009).

Annexure - I

| Region          | Period              | Forecast (% of LPA)   | Forecast (% of LPA)   | Forecast (% of LPA)   | Actual              |
|-----------------|---------------------|-----------------------|-----------------------|-----------------------|---------------------|
|                 |                     | 15 th April           | 31 st May             | 1 st August           | Rainfall (% of LPA) |
| All India       | June to September   | 96± 5                 | 96± 4                 |                       | 110                 |
| Northwest India | June to September   |                       | 94± 8                 |                       | 98                  |
| Central India   | June to September   |                       | 100± 8                |                       | 129                 |
| Northeast India | June to September   |                       | 91± 8                 |                       | 88                  |
| South Peninsula | June to September   |                       | 97± 8                 |                       | 116                 |
| All India       | July                |                       | 95± 9                 |                       | 105                 |
| All India       | August              |                       | 99± 9                 |                       | 115                 |
| All India       | August to September |                       |                       | 100± 8                | 130                 |

## Annexure - II

| S. N o   | Centre issuing the Forecast                                    | Method                                               | Inference for 2019                                                                                                                                                                                                                                                                                                         |
|----------|----------------------------------------------------------------|------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 1.       | ECMWF, UK                                                      | Coupled Model                                        | JJA & JAS (Issued: May 2019): Normal rainfall is likely over most parts of India. Normal to below normal rainfall is likely over parts of eastern India and neighbouring regions near foothills of Himalaya.                                                                                                               |
|          |                                                                | EUROSIP Multi Model Ensemble (MME): 5 Coupled Models | JJA and JAS (Issued: May 2019): Normal to below normal rainfall is likely over the most parts of the country. However, there is slight possibility to have above normal rainfall over some of the west coastal region.                                                                                                     |
| 2.       | International Research Institute for Climate and Society, USA  | MME 7 Models (AGCM & CGCM)                           | JJA & JAS ( Issued: May 2019): Above normal rainfall is likely over some of the west central and eastern parts of India. Below normal rainfall is likely over some parts of south peninsular and north-eastern India. For the rest of the country climatological probabilities are likely.                                 |
| 3.       | Japan Agency for Marine-Earth Science and Technology (JAMSTEC) | Coupled Model                                        | JJA (Issued: May 2019): Positive rainfall anomalies are predicted over most parts of south, northeast and east coast region of India. Negative rainfall anomalies are predicted over remaining areas like west central, northwest and north India.                                                                         |
| 4.       | Asia-Pacific Economic Cooperation (APEC) Climate Center        | MME 6 Models (AGCM & CGCM)                           | June, July, August & September (Issued: May 2019): Normal to below normal rainfall is likely over parts of northwest India. Below normal rainfall is likely over parts of south India. Above normal rainfall likely over some parts of the eastern India. Climatological probabilities are likely for rest of the Country. |

|   5. | Met Office, UK                                                                                       | Coupled Model   | JJA & JAS (Issued: May 2019): Normal to below normal rainfall is likely over most parts of the country. However, above normal rainfall is likely over some of the north-eastern parts of the country.                                                                                                                                                                                                                                   |
|------|------------------------------------------------------------------------------------------------------|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|    6 | World Meteorological Organization (WMO)Long Range Forecast Mumti-Model Ensemble (LRFMME)             | AGCM & CGCM     | JJA (Issued: May 2019): Above normal rainfall is likely over the northernmost pars of the country. Below normal rainfall is likely over most parts of the country. Climatological probabilities are likely for rest of the Country. JJAS (Issued: May 2019): Positive rainfall anomalies are predicted over some of the north-eastern parts of the country. Indian region. Negative rainfall anomalies are predicted over most parts of |
|    7 | National Centers for Environmental Prediction (NCEP) coupled forecast system model version 2 (CFSv2) | Coupled Model   | JJA & JAS ( Issued: May 2019): Above normal rainfall is predicted over parts of west, south, northernmost and northeast India. Below normal rainfall is predicted over parts of eastern India and neighbouring central region. Normal rainfall is likely over remaining pats of India.                                                                                                                                                  |
|    8 | Japan Meteorological Agency (JMA)                                                                    | Coupled Model   | JJA (Issued: May 2019): Normal Precipitation is likely over some of the eastern costal parts of the country. Below normal precipitation is likely over most parts of the country. However, above normal precipitation is likely over northernmost parts of the country.                                                                                                                                                                 |