Interactions of Diabatic Heating in Convective Superbursts with Energy Conversion Processes in the Genesis of Cape Verde Hurricanes from African Easterly Waves

• DOI: 10.1175/2011mwr3621.1
• Publication Date: 2011-09-15T23:55:21Z
• Authors: Robert S. Ross; T. N. Krishnamurti; S. Pattnaik
• Keywords: African easterly jet; Diabatic; Barotropic fluid; Cape verde; Mesoscale convective system; Tropical cyclogenesis

Abstract This paper defines a mechanism for the genesis of tropical cyclones from African easterly waves (AEWs) over eastern Atlantic, so-called Cape Verde storms. Convective “superbursts” produce strong diabatic heating, which then strengthens jet (AEJ), leading to enhanced barotropic energy conversions, occur at critical developmental stages system. Diabatic heating is calculated using Ertel isentropic potential vorticity (IPV) equation, while conversions are determined equations first derived by Lorenz. The developed studying Hurricane Bill (2009), as well Tropical Storm Debby, Helene, and nondeveloping AEW, all 2006 NASA Monsoon Multidisciplinary Analysis (NAMMA) field experiment, NCEP Final (FNL) analyses Advanced Research Weather Forecasting model (WRF-ARW) simulations. A striking singular maximum in due convective superburst shown precede 24–36 h pronounced positive conversion, demonstrated simultaneously with strengthening AEJ. conversion documented system, typically depression or early storm stages. physical explain how mesoscale can lead subsequently an synoptic-scale AEJ that mechanism. findings agree cited idealized studies other investigators who found moist AEWs grow 3 times stronger than dry result faster development larger conversions.