Lok Sabha Question No. 5365 (UNSTARRED), answered on 2023-04-05
Subject: Seamless Modeling Systems
Ministry: EARTH SCIENCES
Asked by: Balashowry Vallabbhaneni

## GOVERNMENT OF INDIA MINISTRY OF EARTH SCIENCES LOK SABHA UNSTARRED QUESTION NO. 5365

## TO BE ANSWERED ON WEDNESDAY, 5 TH  APRIL, 2023

## SEAMLESS MODELING SYSTEMS

## 5365.  SHRI BALASHOWRY VALLABHANENI:

Will the Minister of EARTH SCIENCES be pleased to state:

- (a) the seamless modeling systems being adopted by the Ministry;
- (b) the extent to which these systems help in weather forecasting; and
- (c) the manner in which these are different and efficient when compared to similar systems being adopted in other advanced countries?

## ANSWER

## THE MINISTER OF STATE (INDEPENDENT CHARGE) FOR MINISTRY OF SCIENCE AND TECHNOLOGY AND EARTH SCIENCES (DR. JITENDRA SINGH)

- (a) India Meteorological Department  (IMD)  issues  various outlook/forecast/warning at various time and spatial scales for Public as well as Disaster Management Authorities for the  preparedness  of  extreme  weather  events.  India  is  now  having  one  of  the  best dynamical prediction systems for supporting early warning. IMD has developed capability for  generating  real  time  forecasts  and  warnings  in  all  spatial  scales  from  a  location  to Block, district, meteorological subdivisions and homogeneous regions and temporal scales of a few hours (nowcast), 3 days (short range forecast), 4-7 days (medium range forecast) 1-4 weeks (extended range forecast) and one month to a season (long range forecast).

IMD  follows  a  seamless  forecasting  strategy.  The  long-range  forecasts  (for  the  whole season) issued are being followed with extended range forecast issued on every Thursday with a validity period of four weeks. To follow up the extended range forecast, IMD issues short  to  medium  range  forecast  and  warnings  at  36  meteorological  sub-divisions  levels daily four times valid up to next five days with an outlook for subsequent two days. The short to medium range forecast and warning at district and station level are issued by state level  Meteorological  Centres  (MCs)/Regional  Meteorological  Centres  (RMCs)  with  a validity of next five days and are updated twice a day. The short to medium range forecast is followed by very short range forecast of severe weather up to three hours (nowcast) for all the districts and 1089 cities and towns. These nowcasts are updated every three hours.

A suite of numerical weather prediction (NWP) models of different temporal and spatial scales are run routinely to support operational forecast activities.

- (b) NWP model guidance is one of the most important inputs utilized in weather forecasting. The deterministic as well as probabilistic guidance from various NWP modeling systems implemented at National Centre for Medium Range Weather Forecasting (NCMRWF) and Indian  Institute  of  Tropical  Meteorology  (IITM)  facilitate  IMD  forecasters  to  provide efficient weather and climate services including sectoral application.
- (c) Many  advanced  countries  in  the  world  are  using  a  combination  of  different  Numerical models  for  operational  weather  forecasting.  These  numerical  models  are  based  on seamless/unified modelling techniques as well as on different models at individual level. The unified  seamless  modelling  system  has  its  own  advantages  and  disadvantages.  The seamless modelling system removes all boundaries between meso-scale prediction (short range),  synoptic  scale  prediction  (medium  range),  extended  range  prediction,  seasonal prediction and/or climate studies.  However, this also reduces the flexibility with respect to practical considerations in terms of development, inherent complexity of the modelling system, computing resource requirement, performance variability with space (regions) and time scale and targeting a specific sector. Although the predictions on different temporal scales are interlinked and weather events across different time scales interact seamlessly, a lot  of  advancement  and  initiatives  have  taken  place  for  the  transition  towards  a  unified seamless framework.

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