Survey of hail forecasting possibility by using radar data

Subject Areas : Marine Physics

A. Saneei ¹ (Dep. of Meteorology, Faculty of Marine Science & Technology, Islamic Azad University Tehran North Branch)
F. Arkian ² (Dep. of Meteorology, Faculty of Marine Science & Technology, Islamic Azad University Tehran North Branch)
P. S. Katiraeie ³ (Dep. of Meteorology, Faculty of Marine Science & Technology, Islamic Azad University Tehran North Branch)
M. Raihani Parvari ⁴ (Dep. of Radar, Iran Meteorological Organization)

Received: 2011-07-20 Accepted : 2012-10-18 Published : 2013-02-19

Keywords: Hail detection, echo tops45dBZ reflectivity, freezing level, zhail, waldvogel,

Abstract :

Hail related to summertime thunderstorms is a small-scale phenomenon, and it often has short time duration. Hail will be produced by a thunderstorm for typically a fraction of an hour, and the width of the track of hail can be as narrow as a few hundred meters. In this research, radar data were analyzed for severe thunderstorms that produced hail across Tehran, Ahvaz and East Khazar radar stations of the Iran during the 2008–2010. A dataset containing 6 reports of hail that sounding, radar and synoptic stations covering them simultaneously. There are several methods for the detection of hail using single polarizationRadar. The methods with high accuracy of detection hail occurrence and warning threshold have been selected.this method is based on criterion of the Waldvogel hail algorithm that uses the maximum altitude at which a reflectivity of 45dBZ is found in relation to the height of the freezing level. The results show that for height difference greater than 4.5 km, the probability of hail detection is 100%. This value depending on warm and cold climate can be varied up to 1 km.