scholarly journals Sensitivity Analysis of PBL Physics Schemes of WRF-ARW Model in Simulating the Tropical Cyclone ‘TITLI’ (2018) Over the Bay of Bengal

2021 ◽  
Vol 13 (3) ◽  
pp. 851-867
Author(s):  
- Saifullah ◽  
M. I. Ali
Keyword(s):  
Heat Flux ◽  
Tropical Cyclone ◽  
India Meteorological Department ◽  
Moisture Flux ◽  
Medium Range Forecast ◽  
Weather Phenomenon ◽  
Arw Model ◽  
Level 3 ◽  
Pressure Maximum ◽  
Environmental Prediction

Tropical Cyclone (TC) is the most destructive weather phenomenon in the Indian sub-continent. To mitigate the destruction due to TC better prediction is needed. So, the study of sensitivity of different physical schemes in WRF-ARW model with intensification and track of TC is important. In this study, sensitivity of Yonsei University (YSU), Asymmetric Convective Model version 2 (ACM2), Bougeault-Lacarrere (Boulac), Medium-Range Forecast (MRF), Mellor-Yamada Nakanishi and Niino Level 2.5 (MYNN2.5) and Level 3 (MYNN3) Planetary Boundary Layer (PBL) schemes are used to simulate the TC ‘Titli’ which made land fall near Palasa in North Andrha Pradesh and South Odhisha coasts at 0000 UTC of 11th October. National center for environmental prediction Global Final Reanalysis (FNL) data have been used as an initial and lateral boundary conditions. Variation of heat flux, latent heat flux and moisture flux with time for these schemes are shown which are responsible to intensify the TC. Model simulated intensity i.e., minimum central pressure, maximum sustained wind speed at the surface (10 m) and track are compared with the India Meteorological Department (IMD) estimated value. It can be specified that the Boulac, MYNN2.5 and MYNN3 schemes simulate the better intensity and track of TC ‘Titli’.  

Tropical cyclone simulations over Bay of Bengal with ARW model: Sensitivity to cloud microphysics schemes

2019 ◽  
Vol 230 ◽  
pp. 104651 ◽  
Author(s):  
P. Reshmi Mohan ◽  
C. Venkata Srinivas ◽  
V. Yesubabu ◽  
R. Baskaran ◽  
B. Venkatraman
Keyword(s):  
Tropical Cyclone ◽  
Bay Of Bengal ◽  
Cloud Microphysics ◽  
Model Sensitivity ◽  
Arw Model

scholarly journals The Impact of Convective Momentum Transport on Tropical Cyclone Track Forecasts Using the Emanuel Cumulus Parameterization

2007 ◽  
Vol 135 (4) ◽  
pp. 1195-1207 ◽  
Author(s):  
Timothy F. Hogan ◽  
Randal L. Pauley
Keyword(s):  
Tropical Cyclone ◽  
Data Assimilation ◽  
Tropical Cyclones ◽  
Momentum Transport ◽  
Cumulus Parameterization ◽  
Transport Parameter ◽  
Medium Range Forecast ◽  
Medium Range ◽  
Convective Momentum Transport ◽  
The Impact

Abstract The influence of convective momentum transport (CMT) on tropical cyclone (TC) track forecasts is examined in the Navy Operational Global Atmospheric Prediction System (NOGAPS) with the Emanuel cumulus parameterization. Data assimilation and medium-range forecast experiments show that for 35 tropical cyclones during August and September 2004 the inclusion of CMT in the cumulus parameterization significantly improves the TC track forecasts. The tests show that the track forecasts are very sensitive to the magnitude of the Emanuel parameterization’s convective momentum transport parameter, which controls the CMT tendency returned by the parameterization. While the overall effect of this formulation of CMT in NOGAPS data assimilation/medium-range forecasts results in the surface pressure of tropical cyclones being less intense (and more consistent with the analysis), the parameterization is not equivalent to a simple diffusion of winds in the presence of convection. This is demonstrated by two data assimilation/medium-range forecast tests in which a vertical diffusion algorithm replaces the CMT. Two additional data assimilation/medium-range forecast experiments were conducted to test whether the skill increase primarily comes from the CMT in the immediate vicinity of the tropical cyclones. The results show that the inclusion of the CMT calculation in the vicinity of the TC makes the largest contribution to the increase in forecast skill, but the general contribution of CMT away from the TC also plays an important role.

Prediction of August Atlantic Basin Hurricane Activity

10.1175/814.1 ◽  
2004 ◽  
Vol 19 (6) ◽  
pp. 1044-1060 ◽  
Author(s):  
Eric S. Blake ◽  
William M. Gray
Keyword(s):  
Tropical Cyclone ◽  
Subtropical High ◽  
Northwest Pacific ◽  
Seasonal Forecasts ◽  
Reanalysis Dataset ◽  
Atlantic Basin ◽  
The North ◽  
Hurricane Activity ◽  
Environmental Prediction ◽  
The Bering Sea

Abstract Although skillful seasonal hurricane forecasts for the Atlantic basin are now a reality, large gaps remain in our understanding of observed variations in the distribution of activity within the hurricane season. The month of August roughly spans the first third of the climatologically most active part of the season, but activity during the month is quite variable. This paper reports on an initial investigation into forecasting year-to-year variability of August tropical cyclone (TC) activity using the National Centers for Environmental Prediction–National Center for Atmospheric Research reanalysis dataset. It is shown that 55%–75% of the variance of August TC activity can be hindcast using a combination of 4–5 global predictors chosen from a 12-predictor pool with each of the predictors showing precursor associations with TC activity. The most prominent predictive signal is the equatorial July 200-mb wind off the west coast of South America. When this wind is anomalously strong from the northeast during July, Atlantic TC activity in August is almost always enhanced. Other July conditions associated with active Augusts include a weak subtropical high in the North Atlantic, an enhanced subtropical high in the northwest Pacific, and low pressure in the Bering Sea region. The most important application of the August-only forecast is that predicted net tropical cyclone (NTC) activity in August has a significant relationship with the incidence of U.S. August TC landfall events. Better understanding of August-only TC variability will allow for a more complete perspective of total seasonal variability and, as such, assist in making better seasonal forecasts.

scholarly journals Tropical Cyclone Outflow-Layer Structure and Balanced Response to Eddy Forcings

2017 ◽  
Vol 74 (1) ◽  
pp. 133-149 ◽  
Author(s):  
Sarah D. Ditchek ◽  
John Molinari ◽  
David Vollaro
Keyword(s):  
Heat Flux ◽  
Tropical Cyclone ◽  
Momentum Flux ◽  
Layer Structure ◽  
Secondary Circulation ◽  
Intensity Change ◽  
Upper Troposphere ◽  
Eddy Heat Flux ◽  
Momentum Fluxes

Abstract The ERA-Interim is used to generate azimuthally averaged composites of Atlantic basin tropical cyclones from 1979 to 2014. Both the mean state and the eddy forcing terms exhibited similar radial–vertical structure for all storm intensities, varying only in magnitude. Thus, only major hurricanes are described in detail. Radial inflow and outflow extended beyond the 2000-km radius. Warm anomalies reached 2000 km in the outflow layer. Composite eddy momentum fluxes within the outflow layer were 2.5 times larger than mean momentum fluxes, highlighting the importance of outflow–environment interactions. A balanced vortex equation was applied to understand the role of eddy heat and momentum fluxes. Dominant terms were the lateral eddy heat flux convergence, lateral eddy momentum flux, and eddy Coriolis torque. Each acted to enhance the secondary circulation. The eddy momentum flux terms produced about twice the response of heat flux terms. The circulation created by the eddy Coriolis torque arises from a vertical gradient of mean storm-relative meridional wind in the upper troposphere at outer radii. It is produced by background inertial stability variations that allow stronger outflow on the equatorward side. Overall, the fluxes drive a strengthened secondary circulation that extends to outer radii. Balanced vertical motion is strongest in the upper troposphere in the storm core. A method is proposed for evaluating the role of environmental interaction on tropical cyclone intensity change.

scholarly journals Tropical Cyclone Intensity Change and Axisymmetricity Deduced from GSMaP

2017 ◽  
Vol 145 (3) ◽  
pp. 1003-1017 ◽  
Author(s):  
Udai Shimada ◽  
Kazumasa Aonashi ◽  
Yoshiaki Miyamoto
Keyword(s):  
Tropical Cyclone ◽  
Development Stage ◽  
Mean Value ◽  
Current Intensity ◽  
Intensity Change ◽  
Current Time ◽  
Cyclone Intensity ◽  
Asymmetric Component ◽  
Pressure Maximum ◽  
Relationship Of

The relationship of tropical cyclone (TC) future intensity change to current intensity and current axisymmetricity deduced from hourly Global Satellite Mapping of Precipitation (GSMaP) data was investigated. Axisymmetricity is a metric that correlates positively with the magnitude of the axisymmetric component of the rainfall rate and negatively with the magnitude of the asymmetric component. The samples used were all of the TCs that existed in the western North Pacific basin during the years 2000–15. The results showed that, during the development stage, the intensification rate at the current time, and 6 and 12 h after the current time was strongly related to both the current intensity and axisymmetricity. On average, the higher the axisymmetricity, the larger the intensity change in the next 24 h for TCs with a current central pressure (maximum sustained wind) between 945 and 995 hPa (85 and 40 kt). The mean value of the axisymmetricity for TCs experiencing rapid intensification (RI) was much higher than that for non-RI TCs for current intensities of 960–990 hPa. The new observational evidence for the intensification process presented here is consistent with the findings of previous theoretical studies emphasizing the role of the axisymmetric component of diabatic heating.

scholarly journals Performance of IMD multi-model ensemble and WRF (ARW) model for sub-basin wise rainfall forecast during monsoon 2012

MAUSAM ◽  
2021 ◽  
Vol 67 (2) ◽  
pp. 323-332
Author(s):  
ASHOK KUMAR DAS ◽  
SURINDER KAUR
Keyword(s):  
Prediction Models ◽  
Weather Prediction ◽  
India Meteorological Department ◽  
Precipitation Forecast ◽  
False Alarms ◽  
Model Ensemble ◽  
Rainfall Forecast ◽  
Quantitative Precipitation Forecast ◽  
Arw Model ◽  
Nwp Model

The Numerical Weather Prediction models, Multi-model Ensemble (MME) (27 km × 27 km) and WRF (ARW) (9 km × 9 km) operationally run by India Meteorological Department (IMD) have been utilized to estimate sub-basin wise rainfall forecast. The sub-basin wise operational Quantitative Precipitation Forecast (QPF) have been issued by 10 field offices named Flood Meteorological Offices (FMOs) of IMD located at different flood prone areas of the country. The daily sub-basin wise NWP model rainfall forecast for 122 sub basins under these 10 FMOs for the flood season 2012 have been estimated on operational basis which are used by forecasters at FMOs as a guidance for the issue of operational sub-basin QPF for flood forecasting purposes. The performance of the MME and WRF (ARW) models rainfall at the sub-basin level have been studied in detail. The performance of WRF (ARW) and MME models is compared in the heavy rainfall case over the river basins (Mahanadi etc.) falls under FMO, Bhubaneswar and it is found that WRF (ARW) model gives better result than MME. It is also found that performance of WRF (ARW) is little better than MME when compared over all the flood prone river sub basins of India. For high rainfall categories (51-100,  >100 mm), generally these leads to floods, the success rate of model rainfall forecasts are less and false alarms are more. The NWP models are able to capture the rainfall events but there is difference in magnitudes of sub basin wise rainfall estimates.

scholarly journals Study of tropical cyclone "Fanoos" using MM5 model – a case study

2009 ◽  
Vol 9 (1) ◽  
pp. 43-51 ◽  
Author(s):  
S. Ramalingeswara Rao ◽  
K. Muni Krishna ◽  
O. S. R. U. Bhanu Kumar
Keyword(s):  
Tropical Cyclone ◽  
East Coast ◽  
Mesoscale Model ◽  
India Meteorological Department ◽  
Cumulus Parameterization ◽  
Cumulus Parameterization Scheme ◽  
Sea Level Pressure ◽  
Mm5 Model ◽  
Made In

Abstract. Tropical cyclones are one of the most intense weather hazards over east coast of India and create a lot of devastation through gale winds and torrential floods while they cross the coast. So an attempt is made in this study to simulate track and intensity of tropical cyclone "Fanoos", which is formed over the Bay of Bengal during 5–10 December 2005 by using mesoscale model MM5. The simulated results are compared with the observed results of India Meteorological Department (IMD); results show that the cumulus parameterization scheme, Kain-Fritsch (KF) is more accurately simulated both in track and intensity than the other Betts-Miller (BM) and Grell Schemes. The reason for better performance of KF-1 scheme may be due to inclusion of updrafts and downdrafts. The model could predict the minimum Central Sea Level Pressure (CSLP) as 983 hPa as compared to the IMD reports of 984 hPa and the wind speed is simulated at maximum 63 m/s compared to the IMD estimates of 65 m/s. Secondly "Fanoos" development from the lagrangian stand point in terms of vertical distribution of Potential Vorticity (PV) is also carried out around cyclone centre.

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