scholarly journals Mesoscale precipitation characteristics near the Western Ghats during the Indian Summer Monsoon as simulated by a high-resolution regional model

2017 ◽  
Vol 143 (709) ◽  
pp. 3070-3084 ◽  
Author(s):  
Wendilyn J. Flynn ◽  
Stephen W. Nesbitt ◽  
Alison M. Anders ◽  
Piyush Garg
Keyword(s):  
High Resolution ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Western Ghats ◽  
Regional Model ◽  
Precipitation Characteristics ◽  
The Western Ghats

scholarly journals Statistical characteristics of raindrop size distribution over the Western Ghats of India: wet versus dry spells of the Indian summer monsoon

2021 ◽  
Vol 21 (6) ◽  
pp. 4741-4757
Author(s):  
Uriya Veerendra Murali Krishna ◽  
Subrata Kumar Das ◽  
Ezhilarasi Govindaraj Sulochana ◽  
Utsav Bhowmik ◽  
Sachin Madhukar Deshpande ◽  
...  
Keyword(s):  
Size Distribution ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Diurnal Cycle ◽  
Western Ghats ◽  
Raindrop Size Distribution ◽  
Dry Spells ◽  
Raindrop Size ◽  
The Western Ghats ◽  
Wet Spells

Abstract. The nature of raindrop size distribution (DSD) is analyzed for wet and dry spells of the Indian summer monsoon (ISM) in the Western Ghats (WG) region using Joss–Waldvogel disdrometer (JWD) measurements during the ISM period (June–September) in 2012–2015. The observed DSDs are fitted with a gamma distribution. Observations show a higher number of smaller drops in dry spells and more midsize and large drops in wet spells. The DSD spectra show distinct diurnal variation during wet and dry spells. The dry spells exhibit a strong diurnal cycle with two peaks, while the diurnal cycle is not very prominent in the wet spells. Results reveal the microphysical characteristics of warm rain during both wet and dry periods. However, the underlying dynamical parameters, such as moisture availability and vertical wind, cause the differences in DSD characteristics. The higher moisture and strong vertical winds can provide sufficient time for the raindrops to grow bigger in wet spells, whereas higher temperature may lead to evaporation and drop breakup processes in dry spells. In addition, the differences in DSD spectra with different rain rates are also observed. The DSD spectra are further analyzed by separating them into stratiform and convective rain types. Finally, an empirical relationship between the slope parameter λ and the shape parameter μ is derived by fitting the quadratic polynomial during wet and dry spells as well as for stratiform and convective types of rain. The μ–λ relations obtained in this work are slightly different compared to previous studies. These differences could be related to different rain microphysics such as collision–coalescence and breakup.

Precipitation modes over the Western Ghats orography during the summer monsoon season

2021 ◽  
Author(s):  
Jayesh Phadtare ◽  
Jennifer Fletcher ◽  
Andrew Ross ◽  
Andy Turner ◽  
Thorwald Stein ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
West Coast ◽  
Western Ghats ◽  
Monsoon Season ◽  
Radiosonde Data ◽  
Summer Monsoon Season ◽  
The West ◽  
Radiosonde Station ◽  
Westerly Flow ◽  
The Western Ghats

<p>Precipitation distribution around an orographic barrier is controlled by the Froude Number (Fr) of the impinging flow. Fr is essentially a ratio of kinetic energy and stratification of winds around the orography. For Fr > 1 (Fr <1), the flow is unblocked (blocked) and precipitation occurs over the mountain peaks and the lee region (upwind region). While idealized modelling studies have robustly established this relationship, its widespread real-world application is hampered by the dearth of relevant observations. Nevertheless, the data collected in the field campaigns give us an opportunity to explore this relationship and provide a testbed for numerical models. A realistic distribution of precipitation over a mountainous region in these models is necessary for flash-flood and landslide forecasting. The Western Ghats region is a classic example where the orographically induced precipitation leads to floods and landslides during the summer monsoon season. In the recent INCOMPASS field campaign, it was shown that the precipitation over the west coast of India occurred in alternate offshore and onshore phases. The Western Ghats received precipitation predominantly during the onshore phase which was characterized by a stronger westerly flow. Here, using the radiosonde data from a station over the Indian west coast and IMERG precipitation product, we show that climatologically, these phases can be mapped over an Fr-based classification of the monsoonal westerly flow. Classifying the flow as 'High Fr' (Fr >1), 'Moderate Fr' ( 0.5 < Fr ≤ 1) and 'Low Fr' ( Fr ≤ 0.5 ) gives three topographical modes of precipitation -- 'Orographic', 'Coastal' and 'Offshore', respectively.  Moreover, these modes are not sensitive to the choice of radiosonde station over the west coast.</p>

scholarly journals Statistical characteristics of raindrop size distribution over Western Ghats of India: wet versus dry spells of Indian Summer Monsoon

2019 ◽  
Author(s):  
Uriya Veerendra Murali Krishna ◽  
Subrata Kumar Das ◽  
Ezhilarasi Govindaraj Sulochana ◽  
Bhowmik Utsav ◽  
Sachin Madhukar Deshpande ◽  
...  
Keyword(s):  
Size Distribution ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Diurnal Cycle ◽  
Western Ghats ◽  
Warm Rain ◽  
Raindrop Size Distribution ◽  
Dry Spells ◽  
Western Ghats Of India ◽  
Raindrop Size

Abstract. The nature of raindrop size distribution (DSD) is analyzed during wet and dry spells of the Indian Summer Monsoon (ISM) over Western Ghats (WGs) using Joss-Waldvogel Disdrometer (JWD) measurements. The observed DSDs are fitted with gamma distribution, and the characteristic DSDs are studied during the summer monsoon seasons (June–September) of 2012–2015. The DSD spectra show distinct diurnal variation during wet and dry spells. The dry spells exhibit a strong diurnal cycle with two peaks, while the diurnal cycle is not prominent in the wet spells. The observational results reveal the microphysical characteristics of warm rain during both the wet and dry spells. Even though the warm rain processes are dominant over WGs during monsoon, the underlying dynamical processes cause the differences in DSD characteristics during wet and dry spells. In addition, the differences in DSD spectra with different rain rates are also observed during the wet and dry spells. The DSD spectra are further analyzed by separating into stratiform and convective types. Finally, an empirical relation between slope parameter, Λ and shape parameter, μ is derived by best fitting the quadratic polynomial for the observed data during both wet and dry spells as well as for the stratiform and convective types of precipitation. The Λ–μ relations obtained in the present study are slightly different in comparison with the earlier studies.

Changes in the Indian Summer Monsoon during the past 600 years: A high-resolution record from the Anshupa Lake, Upper Mahanadi Delta, Core Monsoon Zone of India

2021 ◽  
pp. 105048
Author(s):  
Chinmay Dash ◽  
Rajasekhariah Shankar ◽  
Pitambar Pati ◽  
Busnur Rachotappa Manjunatha ◽  
Rayees Ahmad Shah ◽  
...  
Keyword(s):  
High Resolution ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
The Past

scholarly journals Behavior of predicted convective clouds and precipitation in the high-resolution Unified Model over the Indian summer monsoon region

2017 ◽  
Vol 4 (5) ◽  
pp. 303-313 ◽  
Author(s):  
A. Jayakumar ◽  
Jisesh Sethunadh ◽  
R. Rakhi ◽  
T. Arulalan ◽  
Saji Mohandas ◽  
...  
Keyword(s):  
High Resolution ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Unified Model ◽  
Monsoon Region ◽  
Convective Clouds ◽  
Summer Monsoon Region
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