Prediction of landfalling Bay of Bengal cyclones during 2013 using the high resolution Weather Research and Forecasting model

Abstract

The present study investigated the capability of the Weather Research and Forecasting (WRF) model in the forecast/simulation of five landfalling Bay of Bengal (BoB) cyclones during 2013. A 3D variational (3DVar) method of data assimilation of the WRF model was used to assimilate the Global Telecommunication System and satellite radiances to improve the initial conditions. The results demonstrated that the model has the ability to simulate the cyclone track, intensity and structure. The study also indicates that predicted storm track, landfall and intensity improved with the 3DVar technique compared to without it. This was due to better initial conditions in the 3DVar experiment. The predicted track errors of the five storms were compared to available global and regional forecasting systems and the results show that the model has the capability for prediction of cyclones over the BoB region. The forecasted mean track errors were about 70, 114, 182 and 184 km; minimum centre pressure was about 8, 10, 13, 13 hPa and maximum surface wind was about 6, 10, 9, 8 m·s−1 on day 1 to day 4 forecast respectively. The study also presents some of the important predicted diagnostic parameters such as temperature anomaly, divergence, heating rate, frozen hydrometeors, vorticity field, equivalent potential temperature, maximum reflectivity, accumulated rainfall and horizontal wind fields compared to available observations for the extremely severe cyclonic storm Phailin. The warm core structure of the Phailin cyclone was resolved in the model between 9 and 15 km compared to satellite observations. The statistical analysis, distribution and magnitude of forecasted accumulated rainfall are also compared to the rainfall of 174 automatic weather stations.

Performance of High-Resolution WRF Modeling System in Simulation of Severe Tropical Cyclones over the Bay of Bengal Using IMDAA Regional Reanalysis Dataset

“…Amphan is considered at 00 UTC on 19 May 2020, Fani at 03 UTC on 02 May 2019, Hudhud at 12 UTC on 11 October 2014, Phailin at 12 UTC on 11 October 2013, and Sidr at 03 UTC on 15 November 2007. The positive (negative) anomaly indicates the temperature is warmer (cooler) than the normal temperature, and for the model, it is calculated using temperature at a given time minus the average temperature during the entire simulation period [58]. From satellite observation, it is noticed that in most cyclone cases, the maximum warm core varies from 9 km to 15 km in height.…”

The appraisal of tropical cyclones in the North Indian Ocean: An overview of different approaches and the involvement of Earth’s components

“…However, few studies focused on improving the vortex initialization by using better satellite and reanalysis data (Nadimpalli, 2020a;Nadimpalli, 2020b). In addition to SST, atmospheric high temperature and diabatic heating also plays a dominant role in the evolution of the intensity and determining the track of TC (Singh and Bhaskaran, 2020). Henceforth, many studies confirmed the direct correlation between seasonal changes and TC formation.…”

Tropical cyclone simulations over Bangladesh at convection permitting 4.4 km & 1.5 km resolution

“…They conclude that the downscaled model significantly improves the spatial distribution of rainfall, maximum vorticity evolution, wind, and temperature profiles for mature phase cyclones. Studies specifically examining the BoB simulations [8][9][10] typically make empirical comparisons of TC simulations at ~10 km resolution against observationally based data, but often with an India-centric domain that contains a larger number of landfalling events. By contrast, in this study we specifically focus on Bangladesh, with simulations at higher resolution.…”