Upper-Level Structure of Oklahoma Tornadic Storms on 2 May 1979. II: Proposed Explanation of “V” Pattern and Internal Warm Region in Infrared Observations

Abstract

Abstract An analysis of the GOES measurements of a severe thunderstorm anvil on 2 May 1979 presented in Part I (Heymsfield et al.) showed a “V” shaped region of low infrared temperatures (TBB) and an internal region of high TBB. Several hypotheses have been given in the literature (e.g., dynamical and above-anvil cirrus) concerning the formation of the “V” pattern. In this paper, the radiative characteristics of the cirrus are examined as a partial explanation for the IR observations. Calculations are made relevant to the radiative properties using a plane parallel radiative transfer model which shows the sensitivity of TBB to ice water content (IWC), and an ice particle trajectory model which simulates the horizontal ice particle distribution. A variation in the horizontal distribution of IWC is postulated as an explanation for the “V” shaped area and internal warm region. The radiative model calculations support the hypothesis that the higher TBB values in the internal warm region may result from the ra...