Development of a calibrated proxy for thunderstorm occurrence using reanalysis and lightning data
P(severe storm) = P(storm initiation) x P(severe|storm initiation)
Our main goal is to find the best function P(storm initiation) in order to improve P(severe storm). To that aim we calculated several parameters related to instability, moisture or shear in Central Europe in the time period 2007-2013 from the ERA-Interim global atmospheric reanalysis. We investigated the relation between these parameters and the lightning occurrence using data from the EUropean Cooperation for LIghtning Detection (EUCLID).
Our results include the following three findings:
First, higher lightning probabilities can be observed with increasing CAPE values with a saturation, or even slight decrease setting in from approximately 800 J/kg, followed by strong increase at values in excess of 2500 J/kg.
Second, for a given CAPE value, lightning probability is relatively large both for very low (< 5 m/s) and high values (> 15 m/s) of 0-6 km bulk shear. Apparently there are two shear regimes that favor storm initiation and/or sustenance.
Last, high CAPE and low CIN values combine to highest lighting probabilities whereas for small CAPE values, higher probabilities are found in midrange CIN values. Last, lightning probabilities are highest for large CAPE and small CIN values but for small CAPE values, higher probabilities are found in midrange CIN values.