Original scientific paper

Improving IMD operational Limited Area Model forecasts

S.K. Roy Bhowmik ; India Meteorological Department, New Delhi, India
K Prasad ; SAARC Meteorological Research Centre, Dhaka, Bangladesh

Abstract

India Meteorological Department (IMD) has been using a Limited Area Model (LAM) on operational basis for the forecast up to 48 hours with the first guess fields for objective analysis and lateral boundary conditions from the global spectral model (T–80) run of the National Center for Medium Range Weather Forecasting (NCMRWF), New Delhi. In this paper the model code has been modified and made more flexible, delinking it from the NCMRWF (T–80). This has allowed the use of initial and boundary conditions directly from the NCEP Global Forecast System (GFS) products available at the resolution of 1° x 1° lat./long. The main interest in this study is to improve the analysis and forecast in the short range time scale (up to 72 hours) by improving the model (LAM) resolution and using better Initial and boundary conditions from the NCEP GFS instead of the NCMRWF T–80 model. Simulation experiments are performed on wide variety of synoptic situations which occur very often over the Indian sub-continent. The performance evaluation in terms of qualitative comparison between the model simulated outputs against actual observations and the outputs of the operational model indicates that the modified version of the model is capable to provide a improved numerical guidance on the occurrence of heavy rainfall in the 48–72 hours forecast scale.

Keywords

Limited Area Model; monsoon depression; first guess; lateral boundary condition

Hrčak ID:

31008

URI

https://hrcak.srce.hr/31008

Publication date:

31.12.2008.

Article data in other languages: croatian

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