scholarly journals Mesoscale Convective Systems as a source of electromagnetic signals registered by ground-based system and DEMETER satellite

2020 ◽  
Author(s):  
Karol Martynski ◽  
Jan Blecki ◽  
Roman Wronowski ◽  
Andrzej Kulak ◽  
Janusz Mlynarczyk ◽  
...  
Keyword(s):  
Mesoscale Convective Systems ◽  
Atmospheric Conditions ◽  
The West ◽  
Low Frequencies ◽  
Air Masses ◽  
Convective Systems ◽  
Demeter Satellite ◽  
Mesoscale Convective ◽  
Electromagnetic Signals ◽  
Maritime Air

Abstract. Mesoscale Convective Systems (MCS) are especially visible in the summertime, when there is an advection of warm maritime air from the West. Advection of air masses is enriched by water vapour, which source can be found over the Mediterranean Sea. In propitious atmospheric conditions, thus significant convection, atmospheric instability or strong vertical thermal gradient, lead to the development of strong thunderstorm systems. In this paper we discuss one case of MCS, which generated a significant amount of +CG, -CG and IC discharges. We have focused on the ELF (Extremely Low Frequencies,

scholarly journals Mesoscale convective systems as a source of electromagnetic signals registered by ground-based system and DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite

2021 ◽  
Vol 39 (2) ◽  
pp. 321-326
Author(s):  
Karol Martynski ◽  
Jan Blecki ◽  
Roman Wronowski ◽  
Andrzej Kulak ◽  
Janusz Mlynarczyk ◽  
...  
Keyword(s):  
Low Frequency ◽  
Field Measurements ◽  
Mesoscale Convective Systems ◽  
Atmospheric Conditions ◽  
Very High Frequency ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
Electromagnetic Signals ◽  
Electro Magnetic ◽  
Atmospheric Discharges

Abstract. Mesoscale convective systems (MCSs) are especially visible in the summertime when there is an advection of warm maritime air from the west. Advection of air masses is enriched by water vapour, the source of which can be found over the Mediterranean Sea. In propitious atmospheric conditions, and thus significant convection, atmospheric instability or strong vertical thermal gradient leads to the development of strong thunderstorm systems. In this paper, we discuss one case of MCSs, which generated a significant amount of +CG (cloud-to-ground), −CG and intracloud (IC) discharges. We have focused on the ELF (extremely low frequency; < 1 kHz) electromagnetic field measurements, since they allow us to compute the charge moments of atmospheric discharges. Identification of the MCSs is a complex process, due to many variables which have to be taken into account. For our research, we took into consideration a few tools, such as cloud reflectivity, atmospheric soundings and data provided by PERUN (Polish system of the discharge localisation system), which operates in a very high frequency (VHF) range (113.5–114.5 MHz). Combining the above-described measurement systems and tools, we identified a MCS which occurred in Poland on 23 July 2009. Furthermore, it fulfilled our requirements since the thunderstorm crossed the path of the DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) overpass.

Stochastic tracking of mesoscale convective systems: evaluation in the West African Sahel

2015 ◽  
Vol 30 (2) ◽  
pp. 681-691 ◽  
Author(s):  
Alexandros Makris ◽  
Clémentine Prieur ◽  
Théo Vischel ◽  
Guillaume Quantin ◽  
Thierry Lebel ◽  
...  
Keyword(s):  
West African ◽  
Mesoscale Convective Systems ◽  
The West ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
West African Sahel ◽  
African Sahel

scholarly journals Tropical Atlantic Hurricanes, Easterly Waves, and West African Mesoscale Convective Systems

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Yves K. Kouadio ◽  
Luiz A. T. Machado ◽  
Jacques Servain
Keyword(s):  
West Africa ◽  
West African ◽  
Mesoscale Convective Systems ◽  
Tropical Atlantic ◽  
Atmospheric Conditions ◽  
Easterly Waves ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
Sst Anomaly ◽  
Atlantic Hurricanes

The relationship between tropical Atlantic hurricanes (Hs), atmospheric easterly waves (AEWs), and West African mesoscale convective systems (MCSs) is investigated. It points out atmospheric conditions over West Africa before hurricane formation. The analysis was performed for two periods, June–November in 2004 and 2005, during which 12 hurricanes (seven in 2004, five in 2005) were selected. Using the AEW signature in the 700 hPa vorticity, a backward trajectory was performed to the African coast, starting from the date and position of each hurricane, when and where it was catalogued as a tropical depression. At this step, using the Meteosat-7 satellite dataset, we selected all the MCSs around this time and region, and tracked them from their initiation until their dissipation. This procedure allowed us to relate each of the selected Hs with AEWs and a succession of MCSs that occurred a few times over West Africa before initiation of the hurricane. Finally, a dipole in sea surface temperature (SST) was observed with a positive SST anomaly within the region of H generation and a negative SST anomaly within the Gulf of Guinea. This SST anomaly dipole could contribute to enhance the continental convergence associated with the monsoon that impacts on the West African MCSs formation.

scholarly journals Analysis of Strengthening and Dissipating Mesoscale Convective Systems Propagating off the West African Coast

2014 ◽  
Vol 142 (12) ◽  
pp. 4600-4623 ◽  
Author(s):  
Abdou L. Dieng ◽  
Laurence Eymard ◽  
Saidou M. Sall ◽  
Alban Lazar ◽  
Marion Leduc-Leballeur
Keyword(s):  
Radar Data ◽  
West African ◽  
Mesoscale Convective Systems ◽  
The West ◽  
Convective Systems ◽  
Wave Trough ◽  
West African Coast ◽  
African Coast ◽  
Mesoscale Convective ◽  
Tropical Depressions

Abstract A large number of Atlantic tropical depressions are generated in the eastern basin in relation to the African easterly wave (AEW) and embedded mesoscale convective systems (MCSs) coming from the African continent. In this paper, the structures of strengthening and dissipating MCSs evolving near the West African coast are analyzed, including the role of the ocean surface conditions in their evolution. Satellite infrared brightness temperature and meteorological radar data over seven summer seasons between 1993 and 2006 are used to subjectively select 20 cases of strengthening and dissipating MCSs in the vicinity of the Senegal coast. With these observed MCSs, a lagged composite analysis is then performed using Interim ECMWF Re-Analysis (ERA-Interim) and Climate Forecast System Reanalysis (CFSR). It is shown that the strengthening MCS is generally preceded by prior passage of an AEW near the West African coast. This previous wave trough is associated with a convective cyclonic circulation in the low and middle troposphere, which enhances the southwesterly flow and then provides humidity to the strengthening MCS, located in the vicinity of the subsequent AEW trough. This is favored by the contraction of the wavelength associated with the two troughs. The sea surface contributes to the MCS enhancement through surface evaporation flux. But this contribution is found to be less important than advection of humidity from the previous wave trough. These conditions are almost not found in the dissipating MCS cases, which dissipate in a dry environment dominated by a subsident and anticyclonic circulation, with generally no interaction with a previous wave trough.

scholarly journals Mesoscale Convective Systems Monitoring on the Basis of MSG Data – Case Studies

2015 ◽  
Vol 50 (2) ◽  
pp. 91-103
Author(s):  
K. Szafranek ◽  
B. Jakubiak ◽  
R. Lech ◽  
M. Tomczuk
Keyword(s):  
System Development ◽  
Weather Conditions ◽  
Radar Data ◽  
Mesoscale Convective Systems ◽  
Temperature Threshold ◽  
The European Union ◽  
Atmospheric Conditions ◽  
Development Fund ◽  
Convective Systems ◽  
Mesoscale Convective

Abstract Analysis described in the paper were made in the frame of the PROZA (Operational decisionmaking based on atmospheric conditions, http://projekt-proza.pl/) project co-financed by the European Union through the European Regional Development Fund. One of its tasks was to develop an operational forecast system, which is going to support different economies branches like forestry or fruit farming by reducing the risk of economic decisions with taking into consideration weather conditions. The main purpose of the paper is to describe the method of the MCSs (Mesoscale Convective Systems) tracking on the basis of the MSG (Meteosat Second Generation) data. Until now several tests were performed. The Meteosat satellite images in selected spectral channels collected for Central Europe Region for May 2010 were used to detect and track cloud systems recognized as MCSs in Poland. The ISIS tracking method was applied here. First the cloud objects are defined using the temperature threshold and next the selected cells are tracked using principle of overlapping position on consecutive images. The main benefit of using a temperature threshold to define cells is its efficiency. During the tracking process the algorithm links the cells of the image at time t to the one of the following image at time t+dt that correspond to the same cloud system. Selected cases present phenomena, which appeared at the territory of Poland. They were compared to the weather radar data and UKMO UM (United Kingdom MetOffice Unified Model) forecasts. The paper presents analysis of exemplary MCSs in the context of near realtime prediction system development and proves that developed tool can be helpful in MCSs monitoring.

A 10-Year Climatology of Mesoscale Convective Systems and Their Synoptic Circulations in the Southwest Mountain Area of China

2021 ◽  
Vol 22 (1) ◽  
pp. 23-41
Author(s):  
Yanan Meng ◽  
Jianhua Sun ◽  
Yuanchun Zhang ◽  
Shenming Fu
Keyword(s):  
Tibetan Plateau ◽  
Temperature Data ◽  
Mesoscale Convective Systems ◽  
The Tibetan Plateau ◽  
Contribution Rate ◽  
Indochina Peninsula ◽  
The West ◽  
Mountain Area ◽  
Convective Systems ◽  
Mesoscale Convective

AbstractHourly blackbody temperature data from the warm seasons (May–September) of 2009–18 were used to detect mesoscale convective systems (MCSs) generated in the southwest mountain area (elevation ≥ 500 m) of China. A total of 3059 MCSs were grouped into four categories (C1, C2, C3, and C4) according to their generation positions using K-means clustering. Major characteristics of the four types of MCSs and their synoptic environmental conditions were investigated. The MCSs had a peak in July and a minimum in May, and usually lasted from 3 to 21 h. The C1 MCSs generated in the northeast of the Tibetan Plateau developed faster, were largest, and had a longer lifespan. The C2 and C4 MCSs had greater intensity and were initiated in the southeast of the Tibetan Plateau and the west of the Yungui Plateau, and near the Wuling and Xuefeng Mountains, respectively. The C3 MCSs initiated in the Qinling, Ta-pa, and Wushan Mountains were smallest. The C1 and C2 MCSs contributed more than 30% to total precipitation, which was more than the C3 and C4 MCSs (<25%), and the contribution rate of MCSs to short-duration heavy rainfall affected by local MCSs was over 60%. Composite synoptic circulations of the four types of MCSs showed several factors, including the locations and intensities of cyclones in the Bay of Bengal and high pressure in the Indochina Peninsula in the low-to-middle troposphere, and vortexes or southwesterly winds in the low-level troposphere, regulate the location and intensity of convection.

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