scholarly journals Mesoscale Convective Systems in the Asian Monsoon Region From Advanced Himawari Imager: Algorithms and Preliminary Results

2019 ◽  
Vol 124 (4) ◽  
pp. 2210-2234 ◽  
Author(s):  
Dandan Chen ◽  
Jianping Guo ◽  
Dan Yao ◽  
Yanluan Lin ◽  
Chuanfeng Zhao ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
Mesoscale Convective Systems ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Preliminary Results ◽  
Convective Systems ◽  
Mesoscale Convective

scholarly journals Seasonal and Intraseasonal Variability of Mesoscale Convective Systems over the South Asian Monsoon Region

2016 ◽  
Vol 73 (12) ◽  
pp. 4753-4774 ◽  
Author(s):  
Katrina S. Virts ◽  
Robert A. Houze
Keyword(s):  
South Asian ◽  
Bay Of Bengal ◽  
Large Scale ◽  
Intraseasonal Variability ◽  
Intraseasonal Oscillation ◽  
Mesoscale Convective Systems ◽  
Asian Monsoon Region ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
Monsoon Depressions

Abstract Seasonal and intraseasonal differences in mesoscale convective systems (MCSs) over South Asia are examined using A-Train satellites, a ground-based lightning network, and reanalysis fields. Premonsoon (April–May) MCSs occur primarily over Bangladesh and the eastern Bay of Bengal. During the monsoon (June–September), small MCSs occur over the Meghalaya Plateau and northeast Himalayan notch, while large and connected MCSs are most widespread over the Bay of Bengal. Monsoon MCSs produce less lightning and exhibit more extensive stratiform and anvil reflectivity structures in CloudSat observations than do premonsoon MCSs. During the monsoon, Bay of Bengal and Meghalaya Plateau MCSs vary with the 30–60-day northward-propagating intraseasonal oscillation, while northeast Himalayan notch MCSs are associated with weak large-scale anomalies but locally enhanced CAPE. During intraseasonal active periods, a zone of enhanced large and connected MCSs, precipitation, and lightning extends from the northeastern Arabian Sea southeastward over India and the Bay of Bengal, flanked by suppressed anomalies. Spatial variability is observed within this enhancement zone: lightning is most enhanced where MCSs are less enhanced, and vice versa. Reanalysis composites indicate that Bay of Bengal MCSs are associated with monsoon depressions, which are frequent during active monsoon periods, while Meghalaya Plateau MCSs are most frequent at the end of break periods, as anomalous southwesterly winds strengthen moist advection toward the terrain. Over both regions, MCSs exhibit more extensive stratiform and anvil regions and less lightning when the large-scale environment is moister, and vice versa.

scholarly journals Comprehensive Pattern of Deep Convective Systems over the Tibetan Plateau–South Asian Monsoon Region Based on TRMM Data

2014 ◽  
Vol 27 (17) ◽  
pp. 6612-6626 ◽  
Author(s):  
Xiushu Qie ◽  
Xueke Wu ◽  
Tie Yuan ◽  
Jianchun Bian ◽  
Daren Lu
Keyword(s):  
Tibetan Plateau ◽  
South Asian ◽  
Asian Monsoon ◽  
South Asian Monsoon ◽  
The Tibetan Plateau ◽  
Lightning Flash ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Convective Systems ◽  
Deep Convective Systems

Abstract Diurnal and seasonal variation, intensity, and structure of deep convective systems (DCSs; with 20-dBZ echo tops exceeding 14 km) over the Tibetan Plateau–South Asian monsoon region from the Tibetan Plateau (TP) to the ocean are investigated using 14 yr of Tropical Rainfall Measuring Mission (TRMM) data. Four unique regions characterized by different orography are selected for comparison, including the TP, the southern Himalayan front (SHF), the South Asian subcontinent (SAS), and the ocean. DCSs and intense DCSs (IDCSs; with 40-dBZ echo tops exceeding 10 km) occur more frequently over the continent than over the ocean. About 23% of total DCSs develop into IDCSs in the SHF, followed by the TP (21%) and the SAS (15%), with the least over the ocean (2%). The average 20-dBZ echo-top height of IDCSs exceeds 16 km and 9% of them even exceed 18 km. DCSs and IDCSs are the most frequent over the SHF, especially in the westernmost SHF, where the intensity—in terms of strong radar echo-top (viz., 40 dBZ) height, ice-particle content, and lightning flash rate—is the strongest. DCSs over the TP are relatively weak in convective intensity and small in size but occur frequently. Oceanic DCSs possess the tallest cloud top (which mainly reflects small ice particles) and the largest size, but their convective intensity is markedly weaker. DCSs and IDCSs show a similar diurnal variation, mainly occurring in the afternoon with a peak at 1600 local time over land. Although most of both DCSs and IDCSs occur between April and October, DCSs have a peak in August, whereas IDCSs have a peak in May.

Radiative impacts of convective anvil outflow in the Asian monsoon region

2020 ◽  
Author(s):  
Sylvia Sullivan ◽  
Aiko Voigt ◽  
Martina Krämer ◽  
Annette Miltenberger ◽  
Sergey Khaykin ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
Radiative Heating ◽  
Specific Humidity ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Convective Systems ◽  
Radiative Impacts ◽  
Ice Water Content ◽  
Ice Water

<p>We investigate the radiative impacts of convectively detrained and in-situ formed ice crystals at uppermost altitudes with high-resolution ICON model runs in the Asian monsoon region. Radiatively, this area should be characterized by persistent longwave warming from thin and ubiquitous anvils and intermittent shortwave cooling from deep but infrequent convective systems. But how do different degrees of sophistication in the ice microphysics schemes modulate this picture? Three days coinciding with the StratoClim field campaign are simulated (6-9 August 2017), using two-moment microphysics, and in-situ ice water content (IWC) values and specific humidity profiles are used for validation. We calculate the shortwave and longwave radiative fluxes associated with IWC between 14 and 17 km over different timescales and examine the role of ambient dryness in anvil base radiative heating. We compare our results with the cloud-resolving Meso-NH simulation of Lee et al. ACP 2019 in which moist and ice layers were identified and tracked through the uppermost troposphere.</p>

scholarly journals Mesoscale convection system and occurrence of extreme low tropopause temperatures: observations over Asian summer monsoon region

2010 ◽  
Vol 28 (4) ◽  
pp. 927-940 ◽  
Author(s):  
A. R. Jain ◽  
V. Panwar ◽  
T. K. Mandal ◽  
V. R. Rao ◽  
A. Goel ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Asian Summer Monsoon ◽  
Wave Radiation ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
Using Data ◽  
Partial Overlap ◽  
Tropopause Temperature

Abstract. The present study examines the process of how tropospheric air enters the stratosphere, particularly in association with tropical mesoscale convective systems (TMCS) which are considered to be one of the causative mechanisms for the observation of extremely low tropopause temperature over the tropics. The association between the phenomena of convection and the observation of extreme low tropopause temperature events is, therefore, examined over the Asian monsoon region using data from multiple platforms. Satellite observations show that the area of low outgoing long wave radiation (OLR), which is a proxy for the enhanced convection, is embedded with high altitude clouds top temperatures (≤193 K). A detailed analysis of OLR and 100 hPa temperature shows that both are modulated by westward propagating Rossby waves with a period of ~15 days, indicating a close linkage between them. The process by which the tropospheric air enters the stratosphere may, in turn, be determined by how the areas of convection and low tropopause temperature (LTT) i.e. T≤191 K are spatially located. In this context, the relative spatial distribution of low OLR and LTT areas is examined. Though, the locations of low OLR and LTT are noticed in the same broad area, the two do not always overlap, except for partial overlap in some cases. When there are multiple low OLR areas, the LTT area generally appears in between the low OLR areas. Implications of these observations are also discussed. The present analysis also shows that the horizontal mean winds have a role in the spatial distribution of low OLR and LTT.

A five-year climatological lightning characteristics of linear mesoscale convective systems over North China

2021 ◽  
Vol 256 ◽  
pp. 105580
Author(s):  
Dongxia Liu ◽  
Mengyu Sun ◽  
Debin Su ◽  
Wenjing Xu ◽  
Han Yu ◽  
...  
Keyword(s):  
North China ◽  
Mesoscale Convective Systems ◽  
Convective Systems ◽  
Mesoscale Convective

scholarly journals An Observational Study of Mesoscale Convective Systems with Heavy Rainfall over the Korean Peninsula

2006 ◽  
Vol 21 (2) ◽  
pp. 125-148 ◽  
Author(s):  
Hyung Woo Kim ◽  
Dong Kyou Lee
Keyword(s):  
Observational Study ◽  
Korean Peninsula ◽  
Wind Shear ◽  
Heavy Rainfall ◽  
Vertical Wind Shear ◽  
Vertical Wind ◽  
Mesoscale Convective Systems ◽  
Low Level ◽  
Convective Systems ◽  
Mesoscale Convective

Abstract A heavy rainfall event induced by mesoscale convective systems (MCSs) occurred over the middle Korean Peninsula from 25 to 27 July 1996. This heavy rainfall caused a large loss of life and property damage as a result of flash floods and landslides. An observational study was conducted using Weather Surveillance Radar-1988 Doppler (WSR-88D) data from 0930 UTC 26 July to 0303 UTC 27 July 1996. Dominant synoptic features in this case had many similarities to those in previous studies, such as the presence of a quasi-stationary frontal system, a weak upper-level trough, sufficient moisture transportation by a low-level jet from a tropical storm landfall, strong potential and convective instability, and strong vertical wind shear. The thermodynamic characteristics and wind shear presented favorable conditions for a heavy rainfall occurrence. The early convective cells in the MCSs initiated over the coastal area, facilitated by the mesoscale boundaries of the land–sea contrast, rain–no rain regions, saturated–unsaturated soils, and steep horizontal pressure and thermal gradients. Two MCSs passed through the heavy rainfall regions during the investigation period. The first MCS initiated at 1000 UTC 26 July and had the characteristics of a supercell storm with small amounts of precipitation, the appearance of a mesocyclone with tilting storm, a rear-inflow jet at the midlevel of the storm, and fast forward propagation. The second MCS initiated over the upstream area of the first MCS at 1800 UTC 26 July and had the characteristics of a multicell storm, such as a broken areal-type squall line, slow or quasi-stationary backward propagation, heavy rainfall in a concentrated area due to the merging of the convective storms, and a stagnated cluster system. These systems merged and stagnated because their movement was blocked by the Taebaek Mountain Range, and they continued to develop because of the vertical wind shear resulting from a low-level easterly inflow.

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