The Impact of Mesoscale Convective Systems on Regional Visibility and Oxidant Distributions during Persistent Elevated Pollution Episodes

1986 ◽  
Vol 25 (11) ◽  
pp. 1518-1531 ◽  
Author(s):  
Walter A. Lyons ◽  
Rebecca H. Calby ◽  
Cecil S. Keen
Keyword(s):  
Mesoscale Convective Systems ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
The Impact ◽  
Pollution Episodes

scholarly journals Macrophysical, Microphysical, and Radiative Properties of Tropical Mesoscale Convective Systems over Their Life Cycle

2016 ◽  
Vol 29 (9) ◽  
pp. 3353-3371 ◽  
Author(s):  
Dominique Bouniol ◽  
Rémy Roca ◽  
Thomas Fiolleau ◽  
D. Emmanuel Poan
Keyword(s):  
Life Cycle ◽  
Large Scale ◽  
Radiative Heating ◽  
Radiative Properties ◽  
Mesoscale Convective Systems ◽  
Cloud Base ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
Polar Orbiting Satellite ◽  
The Impact

Abstract Mesoscale convective systems (MCSs) are important drivers of the atmospheric large-scale circulation through their associated diabatic heating profile. Taking advantage of recent tracking techniques, this study investigates the evolution of macrophysical, microphysical, and radiative properties over the MCS life cycle by merging geostationary and polar-orbiting satellite data. These observations are performed in three major convective areas: continental West Africa, the adjacent Atlantic Ocean, and the open Indian Ocean. MCS properties are also investigated according to internal subregions (convective, stratiform, and nonprecipitating anvil). Continental MCSs show a specific life cycle, with more intense convection at the beginning. Larger and denser hydrometeors are thus found at higher altitudes, as well as up to the cirriform subregion. Oceanic MCSs have more constant reflectivity values, suggesting a less intense convective updraft, but more persistent intensity. A layer of small crystals is found in all subregions, but with a depth that varies according to the MCS subregion and life cycle. Radiative properties are also examined. It appears that the evolution of large and dense hydrometeors tends to control the evolution of the cloud albedo and the outgoing longwave radiation. The impact of dense hydrometeors, detrained from the convective towers, is also seen in the radiative heating profiles, in particular in the shortwave domain. A dipole of cooling near the cloud top and heating near the cloud base is found in the longwave; this cooling intensifies near the end of the life cycle.

scholarly journals Evidence of mineral dust altering cloud microphysics and precipitation

2008 ◽  
Vol 8 (6) ◽  
pp. 18893-18910 ◽  
Author(s):  
Q.-L. Min ◽  
R. Li ◽  
B. Lin ◽  
E. Joseph ◽  
S. Wang ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Heavy Precipitation ◽  
Cloud Microphysics ◽  
Mesoscale Convective Systems ◽  
Size Spectrum ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
Cloud Ice ◽  
The Impact ◽  
Light Precipitation

Abstract. Multi-platform and multi-sensor observations are employed to investigate the impact of mineral dust on cloud microphysical and precipitation processes in mesoscale convective systems. It is clearly evident that for a given convection strength,small hydrometeors were more prevalent in the stratiform rain regions with dust than in those regions that were dust free. Evidence of abundant cloud ice particles in the dust sector, particularly at altitudes where heterogeneous nucleation process of mineral dust prevails, further supports the observed changes of precipitation. The consequences of the microphysical effects of the dust aerosols were to shift the precipitation size spectrum from heavy precipitation to light precipitation and ultimately suppressing precipitation.

scholarly journals Dry soils can intensify mesoscale convective systems

2020 ◽  
Vol 117 (35) ◽  
pp. 21132-21137 ◽  
Author(s):  
Cornelia Klein ◽  
Christopher M. Taylor
Keyword(s):  
Soil Moisture ◽  
Positive Impact ◽  
Surface Fluxes ◽  
Mesoscale Convective Systems ◽  
Convective Systems ◽  
The World ◽  
Mesoscale Convective ◽  
Moisture State ◽  
Favorable Conditions ◽  
The Impact

Soil moisture can feed back on rainfall through the impact of surface fluxes on the environment in which convection develops. The vast majority of previous research has focused on the initiation of convection, but in many regions of the world, the majority of rain comes from remotely triggered mesoscale convective systems (MCSs). Here we conduct a systematic observational analysis of soil moisture feedbacks on propagating MCSs anywhere in the world and show a strong positive impact of drier soils on convection within mature MCSs. From thousands of storms captured in satellite imagery over the Sahel, we find that convective cores within MCSs are favored on the downstream side of dry patches ≥200 km across. The effect is particularly strong during the afternoon–evening transition when convection reaches its diurnal peak in intensity and frequency, with dry soils accounting for an additional one in five convective cores. Dry soil patterns intensify MCSs through a combination of convergence, increased instability, and wind shear, all factors that strengthen organized convection. These favorable conditions tend to occur in the vicinity of a surface-induced anomalous displacement of the Sahelian dry line/intertropical discontinuity, suggesting a strong link between dry line dynamics and soil moisture state. Our results have important implications for nowcasting of severe weather in the Sahel and potentially in other MCS hotspot regions of the world.

scholarly journals Evidence of mineral dust altering cloud microphysics and precipitation

2009 ◽  
Vol 9 (9) ◽  
pp. 3223-3231 ◽  
Author(s):  
Q.-L. Min ◽  
R. Li ◽  
B. Lin ◽  
E. Joseph ◽  
S. Wang ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Heavy Precipitation ◽  
Cloud Microphysics ◽  
Mesoscale Convective Systems ◽  
Size Spectrum ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
Cloud Ice ◽  
The Impact ◽  
Light Precipitation

Abstract. Multi-platform and multi-sensor observations are employed to investigate the impact of mineral dust on cloud microphysical and precipitation processes in mesoscale convective systems. For a given convective strength, small hydrometeors were more prevalent in the stratiform rain regions with dust than in those regions that were dust free. Evidence of abundant cloud ice particles in the dust sector, particularly at altitudes where heterogeneous nucleation of mineral dust prevails, further supports the observed changes of precipitation. The consequences of the microphysical effects of the dust aerosols were to shift the precipitation size spectrum from heavy precipitation to light precipitation and ultimately suppressing precipitation.

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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