scholarly journals Mesoscale convective systems over the Amazon basin. Part I: climatological aspects

2017 ◽  
Vol 38 (1) ◽  
pp. 215-229 ◽  
Author(s):  
Amanda Rehbein ◽  
Tercio Ambrizzi ◽  
Carlos Roberto Mechoso
Keyword(s):  
Amazon Basin ◽  
Mesoscale Convective Systems ◽  
Convective Systems ◽  
Mesoscale Convective

Synoptic Wave Perturbations and Convective Systems over Equatorial Africa

2008 ◽  
Vol 21 (23) ◽  
pp. 6372-6388 ◽  
Author(s):  
Hanh Nguyen ◽  
Jean-Philippe Duvel
Keyword(s):  
Amazon Basin ◽  
Spectral Characteristics ◽  
Congo Basin ◽  
Mesoscale Convective Systems ◽  
Kelvin Wave ◽  
Equatorial Atlantic ◽  
Periodic Behavior ◽  
Convective Systems ◽  
Equatorial Africa ◽  
Mesoscale Convective

Abstract Spectral analysis of the outgoing longwave radiation (OLR) time series over equatorial Africa reveals large oscillations of the convection with periods of between 3 and 6 days. In March and April, when the intertropical convergence zone (ITCZ) migrates northward and crosses equatorial Africa, this periodic behavior is most pronounced with a marked peak at 5–6 days. Robust horizontal and vertical patterns, consistent with a convectively coupled Kelvin wave, can be extracted by a simple composite technique based only on the phase of the convective oscillations over equatorial Africa. The composite reveals differences between continental and adjacent oceanic regions. Over the continent, the stronger oscillation of the convection is associated with larger temperature and moisture anomalies near the surface, suggesting an influence of diabatic processes on the amplitude of the perturbations. Some convective events over equatorial Africa are triggered by waves propagating eastward over the equatorial Atlantic. However, this cannot explain the robust periodic behavior observed over equatorial Africa because the convective variability over the Amazon basin and the equatorial Atlantic have different spectral characteristics with no marked peak at 5–6 days in March and April. The mesoscale convective systems embedded in these synoptic disturbances are studied using satellite brightness temperature at higher spatial (0.5°) and temporal (3 h) resolution than the OLR (respectively, 2.5° and daily average). The diurnal and the wave modulations of occurrence, size, and life cycle of the mesoscale convective systems are inspected. These systems are generated preferentially over the western slopes of the Rift Valley highlands. They propagate west-southwestward over the Congo basin where they reach their maximum size. The 5–6-day perturbations do not modify the diurnal triggering of convective systems notably, but the perturbations do modify their development into larger organized convection, especially over the Congo basin. The implication of these results for understanding the physical source of these 5–6-day perturbations is discussed.

scholarly journals Biomass burning CCN enhance the dynamics of a mesoscale convective system over the La Plata Basin: a numerical approach

2018 ◽  
Vol 18 (3) ◽  
pp. 2081-2096
Author(s):  
Gláuber Camponogara ◽  
Maria Assunção Faus da Silva Dias ◽  
Gustavo G. Carrió
Keyword(s):  
Biomass Burning ◽  
Amazon Basin ◽  
Cloud Condensation Nuclei ◽  
Mesoscale Convective System ◽  
Mesoscale Convective Systems ◽  
Convective System ◽  
La Plata ◽  
Convective Systems ◽  
La Plata Basin ◽  
Mesoscale Convective

Abstract. High aerosol loadings are discharged into the atmosphere every year by biomass burning in the Amazon and central Brazil during the dry season (July–December). These particles, suspended in the atmosphere, can be carried via a low-level jet toward the La Plata Basin, one of the largest hydrographic basins in the world. Once they reach this region, the aerosols can affect mesoscale convective systems (MCSs), whose frequency is higher during the spring and summer over the basin. The present study is one of the first that seeks to understand the microphysical effects of biomass burning aerosols from the Amazon Basin on mesoscale convective systems over the La Plata Basin. We performed numerical simulations initialized with idealized cloud condensation nuclei (CCN) profiles for an MCS case observed over the La Plata Basin on 21 September 2010. The experiments reveal an important link between CCN number concentration and MCS dynamics, where stronger downdrafts were observed under higher amounts of aerosols, generating more updraft cells in response. Moreover, the simulations show higher amounts of precipitation as the CCN concentration increases. Despite the model's uncertainties and limitations, these results represent an important step toward the understanding of possible impacts on the Amazon biomass burning aerosols over neighboring regions such as the La Plata Basin.

scholarly journals Biomass burning CCNs enhance the dynamics of a Mesoscale Convective System over the La Plata Basin: a numerical approach

2017 ◽  
Author(s):  
Gláuber Camponogara ◽  
Maria Assunção Faus Silva Dias ◽  
Gustavo G. Carrió
Keyword(s):  
Biomass Burning ◽  
Amazon Basin ◽  
Mesoscale Convective System ◽  
Numerical Approach ◽  
Mesoscale Convective Systems ◽  
Convective System ◽  
La Plata ◽  
Convective Systems ◽  
La Plata Basin ◽  
Mesoscale Convective

Abstract. High aerosol loadings are discharged into the atmosphere every year by biomass burning in the Amazon and Central Brazil during the dry season (July–December). These particles, suspended in the atmosphere, can be carried via a low level jet toward the La Plata Basin, one of the largest hydrographic basins in the world. Once they reach this region, the aerosols can affect mesoscale convective systems (MCS), whose frequency is higher during the spring and summer over the basin. The present study is one of the first that seeks to understand the microphysical effects of biomass burning aerosols from the Amazon Basin on mesoscale convective systems over the La Plata Basin. We performed numerical simulations initialized with idealized CCN profiles for an MCS case observed over the La Plata Basin on 21 September 2010. The experiments reveal an important link between CCN number concentration and MCS dynamics, where stronger downdrafts were observed under higher amounts of aerosols, generating more updraft cells in response. Moreover, the simulations show higher amounts of precipitation as the CCN concentration increases. Despite the model’s uncertainties and limitations, these results represent an important step toward the understanding of possible impacts on the Amazon biomass burning aerosols over neighboring regions such as the La Plata Basin.

scholarly journals Mesoscale convective systems over the Amazon basin: The GoAmazon2014/5 program

2019 ◽  
Vol 39 (15) ◽  
pp. 5599-5618 ◽  
Author(s):  
Amanda Rehbein ◽  
Tercio Ambrizzi ◽  
Carlos R. Mechoso ◽  
Sergio A. I. Espinosa ◽  
Timothy A. Myers
Keyword(s):  
Amazon Basin ◽  
Mesoscale Convective Systems ◽  
Convective Systems ◽  
Mesoscale Convective

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.

Precipitation charge and size measurements in the stratiform region of two mesoscale convective systems

1995 ◽  
Vol 100 (D8) ◽  
pp. 16341 ◽  
Author(s):  
Monte G. Bateman ◽  
W. David Rust ◽  
Bradley F. Smull ◽  
Thomas C. Marshall
Keyword(s):  
Mesoscale Convective Systems ◽  
Convective Systems ◽  
Stratiform Region ◽  
Mesoscale Convective
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