scholarly journals Synoptic Control of Convective Rainfall Rates and Cloud-to-Ground Lightning Frequencies in Warm-Season Mesoscale Convective Systems over North China

2018 ◽  
Vol 146 (3) ◽  
pp. 813-831 ◽  
Author(s):  
Rudi Xia ◽  
Da-Lin Zhang ◽  
Cuihong Zhang ◽  
Yongqing Wang
Keyword(s):  
Environmental Conditions ◽  
North China ◽  
Convective Available Potential Energy ◽  
Cloud Microphysics ◽  
Small Sample ◽  
Mesoscale Convective Systems ◽  
Convective Rainfall ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
Cg Lightning

Abstract This study examines whether environmental conditions can control convective rainfall rates and cloud-to-ground (CG) lightning frequencies in mesoscale convective systems (MCSs) over north China (NC). A total of 60 identified MCSs over NC during June–August of 2008–13 were classified into 4 categories based on their high/low convective rainfall rates (HR/LR) and high/low CG lightning frequencies (HL/LL) (i.e., HRHL, HRLL, LRHL, and LRLL MCSs). MCSs with HR (HL) occurred most frequently in July (August), while those with LR or LL occurred most frequently in June; they followed closely seasonal changes. All MCSs were apt to form during afternoon hours. HRLL MCSs also formed during evening hours while HRHL MCSs could occur at any time of a day. A composite analysis of environmental conditions shows obvious differences and similarities among the HRHL, HRLL, and LRLL categories, while the LRHL MCSs exhibited little differences from the climatological mean because of its small sample size. Both the HRHL and HRLL MCSs occurred in the presence of upper-level anomalous divergence, a midlevel trough, and the lower-tropospheric southwesterly transport of tropical moist air. In contrast, LRLL MCSs took place as a result of daytime heating over mountainous regions, with little midlevel forcing over NC. The HRHL, HRLL, LRHL, and LRLL categories exhibited orders of the highest-to-smallest convective available potential energy and precipitable water but the smallest-to-largest convective inhibition and lifted indices. It is concluded that environmental conditions determine to some extent convective rainfall rates and CG lightning activity, although some other processes (e.g., cloud microphysics) also play certain roles, especially in CG lightning production.

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 Lightning and precipitation produced by severe weather systems over Belém, Brazil

2014 ◽  
Vol 29 (spe) ◽  
pp. 41-59 ◽  
Author(s):  
Wanda Maria do Nascimento Ribeiro ◽  
José Ricardo Santos Souza ◽  
Márcio Nirlando Gomes Lopes ◽  
Renata Kelen Cardoso Câmara ◽  
Edson José Paulino Rocha ◽  
...  
Keyword(s):  
Large Scale ◽  
Electric Activity ◽  
Weather Conditions ◽  
Rain Gauge ◽  
Mesoscale Convective Systems ◽  
Major Influence ◽  
Rainfall Events ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
Cg Lightning

CG Lightning flashes events monitored by a LDN of the Amazon Protection System, which included 12 LPATS IV VAISALA sensors distributed over eastern Amazonia, were analyzed during four severe rainstorm occurrences in Belem-PA-Brazil, in the 2006-2007 period. These selected case studies referred to rainfall events, which produced more than 25 mm/hour, or more than 40 mm/ 2 hours of precipitation rate totals, registered by a tipping bucket automatic high-resolution rain gauge, located at 1º 47' 53" S and 48º 30' 16" W. Centered at this location, a 30 ,10 and 5 km radius circles were drawn by means of a geographic information system, and the data from lightning occurrences within this larger area, were set apart for analysis. During these severe storms the CG lightning events, occurred almost randomly over the surrounding defined circle, previously covered by mesoscale convective systems, for all cases studied. This work also showed that the interaction between large-scale and mesoscale weather conditions have a major influence on the intensity of the storms studied cases. In addition to the enhancement of the lightning and precipitation rates, the electric activity within the larger circles can precede the rainfall at central point of the areas

Physical Processes Associated with Heavy Flooding Rainfall in Nashville, Tennessee, and Vicinity during 1–2 May 2010: The Role of an Atmospheric River and Mesoscale Convective Systems

2012 ◽  
Vol 140 (2) ◽  
pp. 358-378 ◽  
Author(s):  
Benjamin J. Moore ◽  
Paul J. Neiman ◽  
F. Martin Ralph ◽  
Faye E. Barthold
Keyword(s):  
Water Vapor ◽  
Heavy Rainfall ◽  
Convective Available Potential Energy ◽  
Mesoscale Convective Systems ◽  
Water Vapor Transport ◽  
Mississippi Valley ◽  
Physical Processes ◽  
Convective Systems ◽  
Atmospheric River ◽  
Mesoscale Convective

A multiscale analysis is conducted in order to examine the physical processes that resulted in prolonged heavy rainfall and devastating flash flooding across western and central Tennessee and Kentucky on 1–2 May 2010, during which Nashville, Tennessee, received 344.7 mm of rainfall and incurred 11 flood-related fatalities. On the synoptic scale, heavy rainfall was supported by a persistent corridor of strong water vapor transport rooted in the tropics that was manifested as an atmospheric river (AR). This AR developed as water vapor was extracted from the eastern tropical Pacific and the Caribbean Sea and transported into the central Mississippi Valley by a strong southerly low-level jet (LLJ) positioned between a stationary lee trough along the eastern Mexico coast and a broad, stationary subtropical ridge positioned over the southeastern United States and the subtropical Atlantic. The AR, associated with substantial water vapor content and moderate convective available potential energy, supported the successive development of two quasi-stationary mesoscale convective systems (MCSs) on 1 and 2 May, respectively. These MCSs were both linearly organized and exhibited back-building and echo-training, processes that afforded the repeated movement of convective cells over the same area of western and central Tennessee and Kentucky, resulting in a narrow band of rainfall totals of 200–400 mm. Mesoscale analyses reveal that the MCSs developed on the warm side of a slow-moving cold front and that the interaction between the southerly LLJ and convectively generated outflow boundaries was fundamental for generating convection.

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.

Lightning and Storm Type in Central Alabama

2017 ◽  
Vol 8 (4) ◽  
pp. 30-46
Author(s):  
Morgan Willis ◽  
Jason Senkbeil
Keyword(s):  
Decision Making ◽  
Mesoscale Convective Systems ◽  
Convective Systems ◽  
Mesoscale Convective ◽  
The Relationship ◽  
Cg Lightning

This study assessed the relationship between cloud-to-ground (CG) lightning and storm type on high-lightning days in Central Alabama during 2007 – 2011 with an emphasis on identifying which types of storms produce the most lightning. Five variables were used to classify high-lightning thunderstorms into 4 types. The storm types include: 1) spring linear events with high CG flash rates; 2) summer airmass events with a high percentage of area above 40 dBZ; 3) spring weak events representing several thunderstorm modes and; 4) summer Mesoscale Convective Systems with high flash rates and the highest percentage of areas above 40 dBZ. This research has the potential to aid forecasters in decision making by associating lightning potential with storm type characteristics observed on days with frequent lightning.

scholarly journals Precipitation and Mesoscale Convective Systems: Radiative Impact of Dust over Northern Africa

2018 ◽  
Vol 146 (9) ◽  
pp. 3011-3029 ◽  
Author(s):  
Irene Reinares Martínez ◽  
Jean-Pierre Chaboureau
Keyword(s):  
Convective Available Potential Energy ◽  
Dust Emission ◽  
Northern Africa ◽  
Mesoscale Convective Systems ◽  
Lower Atmosphere ◽  
Radiative Effect ◽  
Near Surface ◽  
Convective Systems ◽  
African Easterly Jet ◽  
Mesoscale Convective

Abstract The radiative effect of dust on precipitation and mesoscale convective systems (MCSs) is examined during a case of dust emission and transport from 9 to 14 June 2006 over northern Africa. The same method to identify and track different cloud types is applied to satellite observations and two convection-permitting simulations (with grid mesh of 2.5 km), with and without the radiative effect of dust, performed with the MesoNH model. The MCSs produce most of the observed total precipitation (66%), and the long-lived systems (lasting 6 h or more) are responsible for 55% of the total. Both simulations reproduce the observed distribution of precipitation between the cloud categories but differ due to the radiative effects of dust. The overall impacts of dust are a warming of the midtroposphere; a cooling of the near surface, primarily in the western parts of northern Africa; and a decrease in precipitation due to a too-low number of long-lived MCSs. The drop in their number is due to the stabilization of the lower atmosphere, which inhibits the triggering of convection. The long-lived MCSs are a little longer lived, faster, and more efficient in rainfall production when accounting for the dust–radiation interaction. This higher degree of organization is due to the larger convective available potential energy and an intensified African easterly jet. The latter is, in turn, a response to the variation in the meridional gradient of the temperature induced by the dust.

scholarly journals Relative influence of meteorological conditions and aerosols on the lifetime of mesoscale convective systems

2016 ◽  
Vol 113 (27) ◽  
pp. 7426-7431 ◽  
Author(s):  
Sudip Chakraborty ◽  
Rong Fu ◽  
Steven T. Massie ◽  
Graeme Stephens
Keyword(s):  
Large Scale ◽  
Convective Available Potential Energy ◽  
Vertical Wind Shear ◽  
Meteorological Conditions ◽  
Relative Influence ◽  
Mesoscale Convective Systems ◽  
Total Variance ◽  
Decay Phase ◽  
Convective Systems ◽  
Mesoscale Convective

Using collocated measurements from geostationary and polar-orbital satellites over tropical continents, we provide a large-scale statistical assessment of the relative influence of aerosols and meteorological conditions on the lifetime of mesoscale convective systems (MCSs). Our results show that MCSs’ lifetime increases by 3–24 h when vertical wind shear (VWS) and convective available potential energy (CAPE) are moderate to high and ambient aerosol optical depth (AOD) increases by 1 SD (1σ). However, this influence is not as strong as that of CAPE, relative humidity, and VWS, which increase MCSs’ lifetime by 3–30 h, 3–27 h, and 3–30 h per 1σ of these variables and explain up to 36%, 45%, and 34%, respectively, of the variance of the MCSs’ lifetime. AOD explains up to 24% of the total variance of MCSs’ lifetime during the decay phase. This result is physically consistent with that of the variation of the MCSs’ ice water content (IWC) with aerosols, which accounts for 35% and 27% of the total variance of the IWC in convective cores and anvil, respectively, during the decay phase. The effect of aerosols on MCSs’ lifetime varies between different continents. AOD appears to explain up to 20–22% of the total variance of MCSs’ lifetime over equatorial South America compared with 8% over equatorial Africa. Aerosols over the Indian Ocean can explain 20% of total variance of MCSs’ lifetime over South Asia because such MCSs form and develop over the ocean. These regional differences of aerosol impacts may be linked to different meteorological conditions.

Forecasting the Maintenance of Quasi-Linear Mesoscale Convective Systems

2007 ◽  
Vol 22 (3) ◽  
pp. 556-570 ◽  
Author(s):  
Michael C. Coniglio ◽  
Harold E. Brooks ◽  
Steven J. Weiss ◽  
Stephen F. Corfidi
Keyword(s):  
Convective Available Potential Energy ◽  
Warm Season ◽  
Value Added ◽  
Convective Cloud ◽  
Mesoscale Convective Systems ◽  
Linear Discriminant ◽  
Convective Systems ◽  
Shear Component ◽  
Mesoscale Convective ◽  
Deep Layers

Abstract The problem of forecasting the maintenance of mesoscale convective systems (MCSs) is investigated through an examination of observed proximity soundings. Furthermore, environmental variables that are statistically different between mature and weakening MCSs are input into a logistic regression procedure to develop probabilistic guidance on MCS maintenance, focusing on warm-season quasi-linear systems that persist for several hours. Between the mature and weakening MCSs, shear vector magnitudes over very deep layers are the best discriminators among hundreds of kinematic and thermodynamic variables. An analysis of the shear profiles reveals that the shear component perpendicular to MCS motion (usually parallel to the leading line) accounts for much of this difference in low levels and the shear component parallel to MCS motion accounts for much of this difference in mid- to upper levels. The lapse rates over a significant portion of the convective cloud layer, the convective available potential energy, and the deep-layer mean wind speed are also very good discriminators and collectively provide a high level of discrimination between the mature and dissipation soundings as revealed by linear discriminant analysis. Probabilistic equations developed from these variables used with short-term numerical model output show utility in forecasting the transition of an MCS with a solid line of 50+ dBZ echoes to a more disorganized system with unsteady changes in structure and propagation. This study shows that empirical forecast tools based on environmental relationships still have the potential to provide forecasters with improved information on the qualitative characteristics of MCS structure and longevity. This is especially important since the current and near-term value added by explicit numerical forecasts of convection is still uncertain.

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.

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