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      https://www.ias.ac.in/article/fulltext/jess/131/0114

    • Keywords

       

      Tropical cyclone forecast; unified model; NCUM; model veriBcation; track error; intensity prediction; landfall prediction.

    • Abstract

       

      Operational forecasting of tropical cyclone (TC) track and intensity in the India Meteorological Department (IMD) relies more and more on the numerical weather prediction (NWP) model guidance from national and international agencies particularly, on the medium range (24–120 h). Any improvement in TC forecasts by the NWPmodels enhances the operational forecaster’s confidence and capability. The real-time information from the National Centre for Medium Range Weather Forecasting (NCMRWF) global NWP model (NCUM-G) is routinely used by operational forecasters at IMD as model guidance. The present study documents the improved skill of NCUM-G in forecasting the North Indian Ocean (NIO) TCs during 2015–2019, based on a collection of 1810 forecasts involving 22 TC cases. The study highlights three significant changes in the modelling system during the recent five years, namely (i) increased grid resolution from 17 to 12 km, (ii) use of hybrid 4D-Var data assimilation (DA), and (iii) increased volume of assimilated data. The study results indicate a consistent improvement in the NCUM-G model forecasts during the premonsoon (April–May,AM)and post-monsoon (October–December,OND)TCseasons. In addition to a 44% reduction in the initial position error, the study also reports a statistically significant decrease in the direct position error (DPE) and error in the intensity forecast, resulting in a forecast gain of 24 hrs. Comparing NWP models with IMDs official track error shows that NCUM-G and ECMWF model forecasts feature lower DPE than IMD in 2019, particularly at higher (96, 108, and 120 h) lead times.

    • Author Affiliations

       

      SUSHANT KUMAR1 ANUMEHA DUBE1 SUMIT KUMAR1 S INDIRA RANI1 KULDEEP SHARMA2 S KARUNASAGAR3 SAJI MOHANDAS1 RAGHAVENDRA ASHRIT1 JOHN P GEORGE1 ASHIS K MITRA1

      1. National Centre for Medium Range Weather Forecasting, Ministry of Earth Sciences (MoES), A-50, Institutional Area Phase-II, Sec-62, Noida 201 307, India.
      2. Centre for Climate Research Singapore (CCRS), Meteorological Service Singapore, Singapore, Singapore.
      3. India Meteorological Department, Ministry of Earth Sciences, Noida, India.
    • Dates

       
  • Journal of Earth System Science | News

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