scholarly journals Numerical Study of Physical Processes Controlling Summer Precipitation over the Western Ghats Region

2018 ◽  
Vol 31 (8) ◽  
pp. 3099-3115 ◽  
Author(s):  
Gang Zhang ◽  
Ronald B. Smith
Keyword(s):  
Western Ghats ◽  
Arabian Sea ◽  
Numerical Study ◽  
Deep Convection ◽  
Convective Available Potential Energy ◽  
Wrf Model ◽  
Summer Precipitation ◽  
Physical Processes ◽  
Convective Rainfall ◽  
The Western Ghats

Abstract Summer precipitation over the Western Ghats and its adjacent Arabian Sea is an important component of the Indian monsoon. To advance understanding of the physical processes controlling this regional precipitation, a series of high-resolution convection-permitting simulations were conducted using the Weather Research and Forecasting (WRF) Model. Convection simulated in the WRF Model agrees with TRMM and MODIS satellite estimates. Sensitivity simulations are conducted, by altering topography, latent heating, and sea surface temperature (SST), to quantify the effects of different physical forcing factors. It is helpful to put India’s west coast rainfall systems into three categories with different causes and characteristics. 1) Offshore rainfall is controlled by incoming convective available potential energy (CAPE), the entrainment of midtropospheric dry layer in the monsoon westerlies, and the latent heat flux and SST of the Arabian Sea. It is not triggered by the Western Ghats. When offshore convection is present, it reduces both CAPE and the downwind coastal rainfall. Strong (weak) offshore rainfall is associated with high (low) SSTs in the Arabian Sea, suggested by both observations and sensitivity simulations. 2) Coastal convective rainfall is forced by the coastline roughness, diurnal heating, and the Western Ghats topography. This localized convective rainfall ends abruptly beyond the Western Ghats, producing a rain shadow to the east of the mountains. This deep convection with mixed phase microphysics is the biggest overall rain producer. 3) Orographic stratiform warm rain and drizzle dominate the local precipitation on the crest of the Western Ghats.

scholarly journals Characteristics of Summer Precipitation around the Western Ghats and the Myanmar West Coast

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Dibas Shrestha ◽  
Rashila Deshar ◽  
Kenji Nakamura
Keyword(s):  
West Coast ◽  
Western Ghats ◽  
Large Scale ◽  
Summer Precipitation ◽  
Tropical Rainfall Measuring Mission ◽  
Precipitation Radar ◽  
Maximum Rainfall ◽  
Trmm Precipitation ◽  
The Western Ghats ◽  
Coastal Mountain

Characteristics of summer (June–August) precipitation over two coastal mountain regions in South Asia (Western Ghats: WG and Myanmar West Coast: MWC) with a focus on topographic impact are analyzed using the 13-year (1998–2010) high spatial resolution (0.05° × 0.05°) version 6 data obtained from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). A relationship between precipitation patterns and topography was observed in the coastal mountains. In both the WG and MWC, maximum rainfall along a tight line on the upwind side of the coastal mountains is primarily attributed to rain frequency. However, intense precipitation was observed over the offshore regions. Compared with the WG, deeper and large-scale precipitation systems develop over the MWC, producing more intense rainfall. It is suggested that insufficient humidity deters large-scale convection over the WG, and the atmosphere is sufficiently moist over the MWC.

Indian Monsoon Precipitation over Orography: Verification and Enhancement of understanding – Outcomes of the IMPROVE project

2021 ◽  
Author(s):  
Andrew Turner ◽  
Jennifer Fletcher ◽  
Kieran Hunt ◽  
Jayesh Phadtare ◽  
Stephen Griffiths ◽  
...  
Keyword(s):  
Diurnal Cycle ◽  
Extreme Events ◽  
Western Ghats ◽  
Large Scale ◽  
Wrf Model ◽  
Vital Role ◽  
Western Disturbances ◽  
Orographic Rainfall ◽  
The Impact ◽  
The Western Ghats

<p>IMPROVE is motivated by the effects of orography on Indian precipitation as part of the diurnal cycle of convection, contributing to water supply, as well as its role in extreme events.  IMPROVE considers two focal regions.  The Western Ghats, which intercept the monsoon flow across the Arabian Sea, receive some of the most frequent and heaviest rainfall during summer as well as being subject to extremes such as the 2018 Kerala floods.  Meanwhile, the Himalayas play a vital role in separating dry midlatitude flows from tropical airmasses and are subject to extremes during the summer monsoon, as well as in winter due to the passage of western disturbances.  This presentation summarizes the key results of IMPROVE.  Firstly, we examine the impact of orography on the observed convective diurnal cycle and assess its simulation in models at a range of resolutions including convection-permitting scales.  MetUM and WRF model experiments are used to identify key mechanisms and test their capability at simulating scale interactions between forcing at the large scale from the BSISO and newly identified regimes of on- and offshore convection near the Western Ghats.  An additional aspect to this work is the construction of a two-layer analytical model to test the behaviour of sheared flow perpendicular to a ridge analogous to the Western Ghats.  Secondly, the role of orography in extreme events is considered.  For the Western Ghats, this focuses on the interaction between monsoon low-pressure systems and the southwesterly flow in enhancing local rainfall.  For the Himalayas, we focus on characterising interactions between tropical lows and western disturbances in enhancing the orographic precipitation.  The work in IMPROVE works towards a deeper understanding of orographic rainfall and its extremes over India and uncovering why such mechanisms may be poorly represented in models.</p>

scholarly journals Numerical Study of the Impact of Complex Terrain and Soil Moisture on Convective Initiation

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 871
Author(s):  
Beilei Zan ◽  
Ye Yu ◽  
Longxiang Dong ◽  
Jianglin Li ◽  
Guo Zhao ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Complex Terrain ◽  
Numerical Study ◽  
Dominant Role ◽  
Deep Convection ◽  
Wrf Model ◽  
Weather Research And Forecasting ◽  
Local Circulation ◽  
Convective Initiation ◽  
The Impact

The relative importance of topography and soil moisture on the initiation of an afternoon deep convection under weak synoptic-scale forcing was investigated using the weather research and forecasting (WRF) model with high resolution (1.33 km). The convection occurred on 29 June 2017, over the Liupan Mountains, west of the Loess Plateau. The timing and location of the convective initiation (CI) simulated by the WRF model compared well with the radar observations. It showed that the warm and humid southerly airflow under 700 hPa was divided into east and west flows due to the blockage of the Liupan Mountains. The warm and humid air on the west side was forced to climb along the slope and enhanced the humidity near the ridge. The accumulation of unstable energy in the middle and north of the ridge led to a strong vertical convergence and triggered the convection. Sensitivity experiments showed that terrain played a dominant role in triggering the convection, while the spatial heterogeneity of soil moisture played an indirect role by affecting the local circulation and the partition of surface energy.

New locality records and call description of the Resplendent Shrub Frog Raorchestes resplendens (Amphibia: Anura: Rhacophoridae) from the Western Ghats, India

2020 ◽  
Vol 12 (11) ◽  
pp. 16502-16509
Author(s):  
Sandeep Das ◽  
K.P. Rajkumar ◽  
K.A. Sreejith ◽  
M. Royaltata ◽  
P.S. Easa
Keyword(s):  
Endangered Species ◽  
Western Ghats ◽  
Small Area ◽  
Grassland Ecosystem ◽  
Critically Endangered Species ◽  
Controlled Burning ◽  
New Locations ◽  
Southern Western Ghats ◽  
First Time ◽  
The Western Ghats

Abstract: The Resplendent Shrub Frog, Raorchestes resplendens Biju, Shouche, Dubois, Dutta, & Bossuyt, 2010 is a Critically Endangered species endemic to the Western Ghats and was considered to be restricted to a three-square kilometer patch atop Anamudi summit.  In this study, we report 36 new locations of the species from the Anamalai massif of the southern Western Ghats.  Niche-based prediction modelling suggests that the species is restricted to Anamalai massif.  The call description of this frog is also provided for the first time. The preferred microhabitat of the frog is Chrysopogon grass clumps in the marshy/swampy montane grassland ecosystem. Restricted to a small area with controlled burning management practiced in its habitat, R. resplendens needs immediate attention.

A Study of Essential Oil Constituents from Capsules, Physiological and Quality Parameters of Small Cardamom Ecotypes [Elettaria cardamomum (L.) Maton] Growing in the Western Ghats, India

2020 ◽  
Vol 23 (6) ◽  
pp. 1253-1264
Author(s):  
M. Alagupalamuthirsolai ◽  
R. Sivaranjani ◽  
S.J. Ankegowda ◽  
M. Murugan ◽  
K.S. Krishnamurthy ◽  
...  
Keyword(s):  
Essential Oil ◽  
Western Ghats ◽  
Quality Parameters ◽  
Elettaria Cardamomum ◽  
The Western Ghats

DNA barcoding of important fruit tree species of agronomic interest in the genus Garcinia L. from the Western Ghats

2021 ◽  
Author(s):  
Jayesh Anerao ◽  
Vikas Jha ◽  
Nishaat Shaikh ◽  
Apurva Shivalkar ◽  
Aishwarya Nityanand ◽  
...  
Keyword(s):  
Dna Barcoding ◽  
Tree Species ◽  
Western Ghats ◽  
Fruit Tree ◽  
The Western Ghats
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