Dr. Timothy J. Lang

Tuesday, November 17, 2009

Radar Conference Presentations

Here are links to my presentations at the recent AMS radar conference:

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Wednesday, August 19, 2009

Real-Time vs. Post-Processed Impulse CMCs

Here is a scatterplot of real-time vs. post-processed impulse CMC (iCMC) values for 9 May and 20 June 2007. There is some decorrelation between the two, and a negative bias in the real-time values. However, the relationship is robust enough that we may be able to use bias-corrected, real-time data quantitatively with modest error.

As a bonus, here are real-time iCMC and post-processed continuing current CMC vs. total CMC for available 9 May and 20 June flashes. Real-time iCMC bears little relationship to total CMC, which is mainly driven by continuing current.

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Total Charge Moment Change Statistics: 20 June vs. 9 May 2007

I have processed the total charge moment change (CMC) data for the 20 June and 9 May 2007 storms. Here are some preliminary statistics on the differences between sprite-producing flashes between the two storms. Besides the obvious flash-altitude differences, which have been established long before now, there are some interesting charge and charge moment change differences. First of all, 20 June has larger impulse CMC and impulse charge; while 9 May features larger continuing current duration and charge, but also weaker current amplitude. In the sum, 9 May has the smaller total CMC but greater total charge. The latter result was inferred from previous work, prior to receiving the CMC data. However, these differences are not particularly significant, based on a rank-sum test. I am still thinking about the implications of these results.

(I apologize for the formatting; Blogger appears to not handle HTML tables seamlessly.)













Variable20 June 9 May 2007
Significance
Impulse CMC (C km)493.2268.1>99%
Height CMC (km AGL)7.55.7>99%
Impulse Charge (C)66.144.797%
Continuing Current (CC)
Duration (ms)
56129>99%
CC Amplitude (kA km)33.213.0>99%
CC Height (km AGL)7.85.7>99%
CC CMC (C km)1687.71558.952%
CC Charge (C)221.5278.391%
Total CMC (C km)2180.91801.684%
Height CMC (km AGL)7.75.7>99%
Total Charge (C)285.3322.676%


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