14 April 2012 - Unique applications of NDVI and GOES dryness products

Bob Rabin from NSSL/UW-CIMSS provided me with a couple interesting images late last week in preparation for the upcoming events on Friday/Saturday. I thought I would share them here with you all to get a new perspective on a product that we used extensively within the Fire Weather Experiment last Fall to monitor vegetation and surface moisture. Bob Rabin gathers and generates NDVI composite imagery as well as GOES derived surface dryness values that we provide within SPC operations in support of their fire weather forecast desk. The products were mainly intended to monitor for dry vegetation and anomalously dry surface conditions that would be a potential hazard for fires. In these examples, Bob pointed out that the NDVI and GOES surface dryness products were both picking up on a very well defined dry / moist boundary across much of KS, OK and TX (see images below).

Continental US NDVI composite from 9 April 2012. Green areas indicate regions with significant green vegetation cover, while yellow and brown regions indicate decreased green vegetation cover. Note the pronounced gradient in green vegetation along a line extending from western KS and OK into central TX.

Continental US GOES surface dryness composite from 11 April 2012. Green areas indicate regions with significant surface moisture mesurements, while yellow and red regions indicate dry surface measurements. Note the pronounced gradient in surface moisture along a line extending from western OK into central TX. It would be interesting to examine how these surface moisture boundaries interacted to potentially enhance convective initiation set up by circulations due to differential heating. In fact, one SPC forecaster noted this in a Mesoscale Discussion issued on the 14th prior to convective initiation along the TX/OK border. In addition, it would be interesting to examine the interaction these surface moisture boundaries have on the evolution of the dryline. It is exciting to see applications of satellite imagery used to detect these features not easily observable from other systems in such a constant and relatively highly spatial manner.