November 16, 2004
Kdp in the 05 August 2004 NAME Storm
I am currently testing out Kdp calculation and thresholding with the NAME S-Pol radar data. Here is a nice example from the 05 August 2004 mesoscale convective system.
Here we see large Kdp values aloft, below the melting level - over 5.5 deg/km in fact! This is likely due to the presence of melting hail, and represents either the wet hailstones or shed water drops. Note the negative Zdr and high LDR values above the Kdp maximum, indicating large hail above the melting level. Interestingly, the Kdp values decline toward the ground. This could be partly due to some evaporation, but more likely there are some size distribution effects on Kdp. That is, a distribution of large water-coated ice particles may have inherently larger Kdp values than the same amount of water in drop form. Thus, as the water-coated hailstones further melt and form regular rain, Kdp values would be expected to decrease, as observed. This is a hypothesis that will be investigated using a T-matrix scattering model.
Posted by Timothy at 11:56 AM