Lightning and SSM/I-Ice-Scattering Mesoscale Convective Systems in the Global Tropics

Toracinta, E. Richard; Zipser, Edward J.

doi:10.1175/1520-0450(2001)040<0983:lasiis>2.0.co;2

Cited by 62 publications

(46 citation statements)

References 48 publications

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“…Sub-Saharan MCSs are faster and shorter lived than their counterparts over the East Atlantic (Hodges and Thorncroft 1997) and have significantly stronger 85 GHz ice-scattering signatures (Mohr et al 1999;Toracinta and Zipser 2001). Lightning-producing clouds are seven times more likely to occur over sub-Saharan Africa than over the Atlantic, while cell flash rates only vary by a factor of two (Boccippio et al 2000).…”

Section: Introductionsupporting

confidence: 93%

Stratiform precipitation production over sub‐Saharan Africa and the tropical East Atlantic as observed by TRMM

Schumacher

Houze

2006

Quart J Royal Meteoro Soc

114

111

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SUMMARYConvective systems over sub-Saharan Africa and the tropical East Atlantic have distinct geographical and seasonal variations in convective intensity and stratiform precipitation production as observed by the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar. Over the East Atlantic, convective rain rates are lower and the percentage of total rain that is stratiform is higher compared to over West Africa. In addition, the East Atlantic has more shallow precipitating convection and less non-precipitating anvil than sub-Saharan Africa. During the monsoon season, convective rain rates and the percentage of area covered by anvil decrease while the stratiform rain fraction and number of shallow convective cells increase in both regions compared to the pre-monsoon season. These observations suggest that convective sustainability, i.e. the ability of a region to continually support convection, helps determine whether a robust stratiform rain area or non-precipitating anvil forms.In addition to convective sustainability, wind shear and the Saharan Air Layer appear to play important roles in the formation and extent of the stratiform components of convective cloud systems. Strong winds associated with the African Easterly Jet and dry intrusions from the Sahara Desert may increase sublimation and evaporation at mid levels, resulting in less stratiform rain. Strong upper-level shear associated with the African Easterly Jet may further hinder stratiform rain production by displacing hydrometeors that form in the convective cells beyond the area of mesoscale rain formation. When the upper-level Tropical Easterly Jet strengthens during the monsoon season, upper-level shear is reduced dramatically and stratiform rain areas form in preference to non-raining anvil.

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Section: Introductionsupporting

confidence: 93%

Stratiform precipitation production over sub‐Saharan Africa and the tropical East Atlantic as observed by TRMM

Schumacher

Houze

2006

Quart J Royal Meteoro Soc

114

111

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“…While precipitating cloud systems occur throughout the Tropics, lightning has a strong land bias (Orville and Henderson 1986;Goodman and Christian 1993;Christian 1999;Toracinta and Zipser 2001). This has led many researchers to investigate the microphysical relationships between occurrence or absence of lightning and the structure and environment of tropical convective systems, often with the aid of remote sensing (radar or high-frequency passive microwave) techniques Rutledge et al 1992;Petersen et al 1996;Black and Hallett 1999;Cecil et al 2002;Cecil and Zipser 2002;Boccippio et al 2000;Carey and Rutledge 2000;Petersen and Rutledge 2001;Williams et al 2000;Toracinta and Zipser 2001).…”

Section: T O R a C I N T A E T A Lmentioning

confidence: 99%

Radar, Passive Microwave, and Lightning Characteristics of Precipitating Systems in the Tropics

Toracinta¹,

Cecil²,

Zipser³

et al. 2002

Mon. Wea. Rev.

Self Cite

148

137

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The bulk radar reflectivity structures, 85-and 37-GHz brightness temperatures, and lightning characteristics of precipitating systems in tropical Africa, South America, the east Pacific, and west Pacific are documented using data from the Tropical Rainfall Measuring Mission (TRMM) satellite during August, September, and October of 1998. The particular focus is on precipitation features [defined as a contiguous area Ն75 km 2 with either a near-surface reflectivity Ն20 dBZ or an 85-GHz polarization-corrected temperature (PCT) Յ 250 K] with appreciable rainfall, which account for the bulk of the total rainfall and lightning flash density in their respective regions. Systems over the tropical continents typically have greater magnitudes of reflectivity extending to higher altitudes than tropical oceanic systems. This is consistent with the observation of stronger ice scattering signatures (lower 85-and 37-GHz PCT) in the systems over land. However, when normalized by reflectivity heights, tropical continental features consistently have higher 85-GHz PCT than tropical oceanic features. It is inferred that greater supercooled water contents aloft in the tropical continental systems contribute to this brightness temperature difference.Lightning (as detected by the Lightning Imaging Sensor) is much more likely in tropical continental features than tropical oceanic features with similar brightness temperatures or similar reflectivity heights. Vertical profiles of radar reflectivity add additional information to the nonunique lightning-brightness temperature relationships showing that features with lightning tend to have greater magnitudes of reflectivity and smaller decreases of reflectivity with height above the freezing level than systems without detected lightning.Regional comparisons of the lightning, radar, and microwave signatures of precipitating features show that, over the oceans, the west Pacific has the highest frequency of intense precipitation features (by minimum PCT or maximum reflectivity height). Over land, the intense precipitation features occur more frequently in Africa. These observations are consistent with the relative differences in lightning flash density between the land and ocean regions. The quantitative database of land and ocean features presented here provides a substantial observational framework against which cloud and radiative transfer model results can be tested.

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“…There were studies of clouds conducted by grouping pixels with infrared brightness temperatures colder than certain criteria (e.g., Mapes and Houze 1992;Liu et al 1995;Chen et al 1996) and studies of precipitation systems by grouping pixels with cold microwave brightness temperature (e.g., Mohr and Zipser 1996;Toracinta and Zipser 2001) or by grouping pixels with valid precipitation radar echoes (e.g., Geerts 1998;Cifelli et al 2007). However, when several satellite instruments target the same object, different instruments and their measurands have their own characteristics and give different perspectives.…”

Section: Introductionmentioning

confidence: 99%

A Cloud and Precipitation Feature Database from Nine Years of TRMM Observations

Liu

Zipser

Cecil

et al. 2008

Journal of Applied Meteorology and Climatology

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344

315

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An event-based method of analyzing the measurements from multiple satellite sensors is presented by using observations of the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR), Microwave Imager (TMI), Visible and Infrared Scanner (VIRS), and Lightning Imaging System (LIS). First, the observations from PR, VIRS, TMI, and LIS are temporally and spatially collocated. Then the cloud and precipitation features are defined by grouping contiguous pixels using various criteria, including surface rain, cold infrared, or microwave brightness temperature. The characteristics of measurements from different sensors inside these features are summarized. Then, climatological descriptions of many properties of the identified features are generated. This analysis method condenses the original information of pixellevel measurements into the properties of events, which can greatly increase the efficiency of searching and sorting the observed historical events. Using the TRMM cloud and precipitation feature database, the regional variations of rainfall contribution by features with different size, intensity, and PR reflectivity vertical structure are shown. Above the freezing level, land storms tend to have larger 20-dBZ area and reach higher altitude than is the case for oceanic storms, especially those land storms over central Africa. Horizontal size and the maximum reflectivity of oceanic storms decrease with altitude. For land storms, these intensity measures increase with altitude between 2 km and the freezing level and decrease more slowly with altitude above the freezing level than for ocean storms.

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Lightning and SSM/I-Ice-Scattering Mesoscale Convective Systems in the Global Tropics

Cited by 62 publications

References 48 publications

Stratiform precipitation production over sub‐Saharan Africa and the tropical East Atlantic as observed by TRMM

Stratiform precipitation production over sub‐Saharan Africa and the tropical East Atlantic as observed by TRMM

Radar, Passive Microwave, and Lightning Characteristics of Precipitating Systems in the Tropics

A Cloud and Precipitation Feature Database from Nine Years of TRMM Observations

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