Radar Conference Presentations

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

• Talk on 3-D structure of convection in NAME
• Poster on statistical analysis of the STEPS lightning and radar dataset

Richard Heene et al. (2008)

Richard Heene, the father of "Balloon Boy" Falcon Heene, was the lead author of a study published in National Weather Digest, entitled "Electromagnetic Fields Recorded in Mesocyclones" (sorry, NWD does not provide online links to articles). While the non-existent balloon journey of Falcon is now potentially a hoax, I thought it would be interesting to examine his father's sole scientific publication to date.

Richard Heene is a proponent of an electromagnetic explanation for atmospheric vortices such as tornadoes, dust devils, and tropical cyclones. This is in contrast to the predominant view within the scientific community, which favors a fluid dynamics explanation (i.e., air pressure changes, inherent spin or vorticity of air, etc.). For example, in the Vortex 2 tornado-chasing campaign last summer, no electromagnetic observations of any kind were made. The scientific community does not need to invoke electromagnetism because, based on numerous experiments and observations, as well as theoretical modeling, fluid dynamics is seen as an adequate explanation for tornadoes. The same goes for things like dust devils and hurricanes. In essence, the electromagnetic folks have a "solution" in search of a problem. We already understand tornadoes pretty well in the context of wind, pressure, and temperature. We don't need to add electricity and magnetism to the mix.

In the paper, Heene and his colleagues show some magnetic field measurements near dust devils, rotating thunderstorms, and a hurricane. Unsurprisingly, they find enhanced magnetic fields near these phenomena. This is because we already know from decades of research that dust devils, thunderstorms, and hurricanes can be electrified. Due to winds in these storms, the electric charges move, thereby creating a magnetic field. What Heene et al. fail to show is that the magnetic fields have anything to do with the formation of the vortex phenomena they studied. The main problem is that they don't demonstrate that these magnetic fields are strong enough to cause vortices on their own. This has been a constant problem for electromagnetism proponents for decades.

Electromagnetism proponents like Heene and colleagues need to first demonstrate the weaknesses of fluid dynamics theory in explaining tornadoes, etc., and then they need to demonstrate how electromagnetism can fill those holes. Demonstrating that storms can have magnetic fields, and properly describing those fields, is scientifically interesting. But there is very little evidence to support the idea that magnetic fields cause tornadoes and like phenomena, especially in contrast to fluid dynamics.

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.

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.)

Variable	20 June	9 May 2007	Significance
Impulse CMC (C km)	493.2	268.1	>99%
Height CMC (km AGL)	7.5	5.7	>99%
Impulse Charge (C)	66.1	44.7	97%
Continuing Current (CC) Duration (ms)	56	129	>99%
CC Amplitude (kA km)	33.2	13.0	>99%
CC Height (km AGL)	7.8	5.7	>99%
CC CMC (C km)	1687.7	1558.9	52%
CC Charge (C)	221.5	278.3	91%
Total CMC (C km)	2180.9	1801.6	84%
Height CMC (km AGL)	7.7	5.7	>99%
Total Charge (C)	285.3	322.6	76%

NAME grant report contribution

Using the three-dimensional S-Pol radar grids, we have been analyzing the intraseasonal variability in the microphysical structure of convection during NAME 2004.  In the Lang et al. (2007) study, two meteorological regimes were identified: A, in which there is enhanced rainfall over the Gulf of California and coastal plain; and B, in which there is enhanced northward propagation of precipitating systems.  These regimes often overlapped, and were distinct from the usual no-regime scenario which featured the diurnally forced convection only over the Sierra Madre Occidental (SMO).

During the intersection of Regimes A and B (henceforth called Regime AB), convection contains enhanced ice and water mass over the coastal plain and Gulf, but there is little change in these parameters over the SMO.  In addition, the heaviest rains over the Gulf feature smaller raindrop median volume diameters during Regime AB.  These drop-size distribution changes are significant enough to manifest themselves as changes in reflectivity-rainfall relationships, particularly over the Gulf.  Overall, the results support the conclusion that variability in meteorological regime affects the microphysical structure of convection in the NAME region, particularly at low elevations.

Journal Reference Updates

Lang, T. J., et al., 2009: On the correction of partial beam blockage in polarimetric radar data. Journal of Atmospheric and Oceanic Technology, 26, 943-957.

Nesbitt, S. W., D. Gochis, and T. J. Lang, 2008: The diurnal cycle of clouds and precipitation along the Sierra Madre Occidental during NAME-2004: Implications for warm season precipitation estimation in complex terrain. Journal of Hydrometeorology, 9, 728-743. (this is an update to our previous reference for this paper)

Conference Paper Updates

Lang, T. J., et al., 2008: Polarimetric radar analysis of convection in northwestern Mexico. 28th Conference on Hurricanes and Tropical Meteorology, American Meteorological Society, Orlando, FL.

Lang, T. J., et al., 2007: Polarimetric radar analysis of convection in the complex topography of northwestern Mexico during NAME 2004. 6th Conference of Mesoscale Meteorology and Typhoon in East Asia, Taipei, Taiwan.

Website

http://radarmet.atmos.colostate.edu/name

Heavy rain and flooding in Taiwan

Typhoon Morakot did a number on Taiwan over the weekend, with the NASA TRMM satellite estimating 100 cm or more of rain over a 7-day period.  Some locations appear to have received far more than this, but the limited resolution of the TRMM satellite would not have been able to see that.  Of course, the flooding was catastrophic.  Taiwan is especially vulnerable to tropical cyclone landfalls, as the central mountain range provides orographic enhancement of rainfall.  These orographic processes were a central focus of the TiMREX experiment in 2008, which featured the National Center for Atmospheric Research's S-Pol radar.  Some CSU Radarmet students also participated in this project, and our own Angela Rowe has started analysis of some select cases. 

Reviews Today

Getting backed up on reviews.  Got four to do in the next few weeks, so going to try to bang some out today.  This year has just been crazy for review requests.  I am already over my annual record for new reviews, and it's only August!  I have to start saying no sometime ...