Practical Predictability of the 17 December 2014 Heavy Rainfall Event over East Coast of Peninsular Malaysia using WRF Model

It is difficult to forecast hourly rainfall locally even using the latest meteorological models, although hourly rainfall averaged spatially to some extent can be used for calculating practical rainfall. This study conducts numerical experiments with triple nesting on the 2012 heavy rainfall event in northern Kyushu using the weather research and forecasting (WRF) model and examines the features of hourly rainfall averaged spatially. The dependence of rainfall is averaged spatially on a spatial averaging scale and clarified by comparing rainfall calculated by simulation using the WRF model with radar/AMeDAS precipitation analysis data. This study’s findings indicate the effective spatial averaging scale making relative error of calculated values to the observed ones minimum.

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Convection-Permitting Simulation of a Heavy Rainfall Event in Armenia Using the WRF Model

Journal of Geophysical Research Atmospheres ◽

10.1029/2017jd028247 ◽

2018 ◽

Vol 123 (19) ◽

pp. 11,008-11,029

Author(s):

Artur Gevorgyan

Keyword(s):

Heavy Rainfall ◽

Wrf Model ◽

Rainfall Event ◽

Heavy Rainfall Event

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Simulation of heavy rainfall event along east coast of India using WRF modeling system: impact of 3DVAR data assimilation

Modeling Earth Systems and Environment ◽

10.1007/s40808-018-0531-0 ◽

2018 ◽

Vol 5 (1) ◽

pp. 245-256 ◽

Cited By ~ 2

Author(s):

Shilpi Kalra ◽

Sushil Kumar ◽

A. Routray

Keyword(s):

Data Assimilation ◽

Heavy Rainfall ◽

East Coast ◽

Rainfall Event ◽

Heavy Rainfall Event ◽

East Coast Of India ◽

Wrf Modeling ◽

System Impact

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Understanding the Dynamics of a Heavy Rainfall Event using Multivariate Ensemble Sensitivity Analysis

10.5194/egusphere-egu21-11954 ◽

2021 ◽

Author(s):

Babitha George ◽

Govindan Kutty

Keyword(s):

Sensitivity Analysis ◽

Covariance Matrix ◽

Heavy Rainfall ◽

Initial Conditions ◽

Wrf Model ◽

Control Area ◽

Rainfall Event ◽

Heavy Rainfall Event ◽

Ensemble Forecasts ◽

The Impact

<p>Ensemble forecasts have proven useful for investigating the dynamics in a wide variety of atmospheric systems and they might be useful for diagnosing the source of forecast uncertainty in multi-scale flows. Ensemble Sensitivity Analysis (ESA) uses ensemble forecasts to evaluate the impact of changes in initial conditions on subsequent forecasts. ESA leads to a simple univariate regression by approximating the analysis covariance matrix with the corresponding diagonal matrix. On the contrary, the multivariate ensemble sensitivity computes sensitivity based on a more general multivariate regression that retains the full covariance matrix. The purpose of this study is to examine the performance of multivariate ensemble sensitivity over univariate by applying it to a heavy rainfall event that happened over the Himalayan foothills in June 2013. The ensemble forecasts and analyses are generated using the Advanced Research version of the Weather Research and Forecasting (WRF) model DART based Ensemble Kalman Filter. Initial results are promising and the sensitivity shows similar patterns for both univariate and multivariate methods. The reflectivity forecast for both methods are characterized by lower temperatures and increased moisture in the control area at 850 hPa level. Compared to multivariate, univariate ensemble sensitivity overestimates the magnitude of sensitivity for temperature. But the sensitivity for the moisture is the same in both methods.</p>

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The Role of Local Orography on the Development of a Severe Rainfall Event over Western Peninsular Malaysia: A Case Study

Monthly Weather Review ◽

10.1175/mwr-d-18-0413.1 ◽

2020 ◽

Vol 148 (5) ◽

pp. 2191-2209

Author(s):

Mohd Fadzil Firdzaus Mohd Nor ◽

Christopher E. Holloway ◽

Peter M. Inness

Keyword(s):

Heavy Rainfall ◽

Flash Floods ◽

Peninsular Malaysia ◽

Rainfall Event ◽

Heavy Rainfall Event ◽

Limited Area ◽

Rainfall Events ◽

Low Level ◽

Sumatra Island ◽

Strait Of Malacca

Abstract Severe rainfall events are common in western Peninsular Malaysia. They are usually short and intense, and occasionally cause flash floods and landslides. Forecasting these local events is difficult and understanding the mechanisms of the rainfall events is vital for the advancement of tropical weather forecasting. This study investigates the mechanisms responsible for a local heavy rainfall event on 2 May 2012 that caused flash floods and landslides using both observations and simulations with the limited-area high-resolution Met Office Unified Model (MetUM). Results suggest that previous day rainfalls over Peninsular Malaysia and Sumatra Island influenced the development of overnight rainfall over the Strait of Malacca by low-level flow convergence. Afternoon convection over the Titiwangsa Mountains over Peninsular Malaysia then induced rainfall development and the combination of these two events influenced the development of severe convective storm over western Peninsular Malaysia. Additionally, anomalously strong low-level northwesterlies also contributed to this event. Sensitivity studies were carried out to investigate the influence of the local orography on this event. Flattened Peninsular Malaysia orography causes a lack of rainfall over the central part of Peninsular Malaysia and Sumatra Island and produces a weaker overnight rainfall over the Strait of Malacca. By removing Sumatra Island in the final experiment, the western and inland parts of Peninsular Malaysia would receive more rainfall, as this region is more influenced by the westerly wind from the Indian Ocean. These results suggest the importance of the interaction between landmasses, orography, low-level flow, and the diurnal cycle on the development of heavy rainfall events.

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Synoptic Analysis of a Heavy Rainfall Event over Southeast Region of Bangladesh Using WRF Model

Journal of Scientific Research ◽

10.3329/jsr.v5i3.13171 ◽

2013 ◽

Vol 5 (3) ◽

pp. 421-434 ◽

Cited By ~ 3

Author(s):

M. N. Ahasan ◽

M. A. Mannan ◽

S. K. Debsarma

Keyword(s):

Wind Shear ◽

Heavy Rainfall ◽

Large Scale ◽

Model Simulation ◽

Wrf Model ◽

Rainfall Event ◽

Horizontal Wind ◽

Heavy Rainfall Event ◽

Southeast Region ◽

Synoptic Analysis

Synoptic analysis of the heavy rainfall event of 7 September 2011 was carried out using the Weather Research and Forecasting (WRF) Model. This extraordinary rainfall event was localized over the southeast region of Bangladesh and recorded rainfall was 331 mm at Chittagong and 226 mm at Sandwip within a span of 24-h. The model was run at 9 km horizontal resolution using KF CPS with YSU PBL scheme. The model performance was evaluated by examining the different predicted parameters like mean sea level pressure, upper and lower level circulations, wind shear, relative vorticity, convergence, moisture and rainfall. The rainfall was validated with TRMM 3B42RT and observed rainfall data. The results indicate that the WRF model was able to simulate the heavy rainfall event, and associated synoptic features reasonably well, though there are some biases in the rainfall pattern. The results suggest that the highly localized heavy rain over southeast Bangladesh was the result of an interaction of the large scale monsoon system with cyclonic disturbances and required moisture have been supplied from the Bay of Bengal. The low level flow facilitated strong convergence over the region due to horizontal wind shear, which resulted in maintenance of the storms. Keywords: Heavy Rainfall; WRF Model; Simulation; Validation; TRMM. © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v5i3.13171 J. Sci. Res. 5 (3), 421-434 (2013)

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