Regional variation of morphology of organized convection in the tropics and subtropics

Abstract

[1] Properties of organized convection with large horizontal area (> 1000 km 2 ) and with different horizontal structures in the tropics and subtropics are investigated by using 14 years of Tropical Rainfall Measuring Mission observations. First, the convective features (CFs) are defined as contiguous areas of convective precipitation detected by the Tropical Rainfall Measuring Mission precipitation radar. Using the minor and major axes of fitted ellipses, the morphology of the CFs are described as closer to a circular or a line shape. Regional variations and the properties of organized convection are examined with CFs with area > 1000 km 2 after categorizing them by their shapes. Organized convection tends to have larger extent and a higher fraction of near-circular shapes over land than over ocean. Shallow organized convection with maximum radar echo top height below 4.5 km is found mainly over ocean and some coastal regions. Of all tropical oceans, most shallow organized convection is found over the east Pacific. The fraction of line shaped organized convection is higher over the ocean than over land, and is higher in the subtropics than in the tropics. More convective lines are found in winter than in summer over oceans, but more in summer over land. Organized convective lines are slightly less convectively intense indicated by lower 30 dBZ echo top heights and warmer 37 GHz brightness temperatures than those with near-circular shapes. Orientations of organized convective lines are often aligned with fronts, dry lines, warm ocean currents, coastlines, and mountain slopes. Over the subtropics, organized convective lines are tilted more east-west over land, and more north-south over oceans. The largest and the most intense convective lines are found over central Africa, Argentina, and southeast U.S. over land, and over several warm currents in subtropical oceans.

Rain characteristics and large‐scale environments of precipitation objects with extreme rain volumes from TRMM observations

“…PFs in the top 1% span from middle congestus to deep convection, with consistent maximum height and minimum IR and land regions showing higher concentrations of deeper convection. Note that shallow systems with large VRR do occur over several specific regions of frequent deep convection such as the East Pacific ITCZ [ Liu and Zipser , , ].…”

Mesoscale marine tropical precipitation varies independently from the spatial arrangement of its convective cells

“…In agreement with the known more frequent occurrence of MCSs over land than over ocean (e.g., Nesbitt et al ., ), the convection appears much more clustered over land (Figure ) than over ocean (Figure ) in our analysis as well. The systems should be larger over land than over ocean (Liu and Zipser, ), which remains true in our analysis, even if we split precipitation objects in their individual cells. This leads to a rather triangular – N phase space over land, in contrast to the squared population of the phase space over ocean.…”

Characteristics of Mesoscale Convective Systems over China and Its Vicinity Using Geostationary Satellite FY2

“…The availability of multiple satellite observations in recent years provides an opportunity to describe in detail the properties and characteristics of MCSs (e.g., Houze 2007;Romatschke et al 2010;Luo et al 2011;Xu and Zipser 2011;Xu 2013;Liu and Zipser 2013;Wu et al 2013;Qie et al 2014). The findings are particularly helpful to understand the structures of MCSs and their relationships with the environments as they evolve.…”

“…MCSs may take on different organizations in regions with different environmental conditions (e.g., Carbone et al 2002;Johnson et al 2005;Houze 2004Houze , 2007. As a result, in addition to having different scales (meso-a, meso-b, and meso-g) as in Orlanski (1975), they may also appear with different morphologies, sometimes as a quasi-circular-shaped, long-lasting mesoscale convective complex (MCC; e.g., Maddox 1980), as a persistent elongated convective system (PECS; e.g., Anderson and Arritt 1998), or as a convective line (e.g., Houze 1977;Zipser 1977;Parker and Johnson 2000;Meng et al 2013;Zheng et al 2013;Liu and Zipser 2013).…”

“…Severe weather phenomena produced by frequent convective activity are often associated with mesoscale convective systems (MCSs). Although MCSs usually consist of regions with convective and stratiform precipitation and nonprecipitating regions with anvil cloud, a variety of precipitation and cloud structures can be exhibited (e.g., McAnelly and Cotton 1989;Johnson et al 2005;Liu and Zipser 2013). MCSs may take on different organizations in regions with different environmental conditions (e.g., Carbone et al 2002;Johnson et al 2005;Houze 2004Houze , 2007.…”