TEXAS STORMS
1 June 2001
imagery from GOES-8
Bob Rabin
NSSL & CIMSS
GOES-8
Visible loop
1
Window channel
(10.7 microns)
Water
vapor (6.7 microns)
Near
IR (3.9 microns)
Dirty
window (13.3 microns)
Window
- water vapor (10.7-6.7 microns)
The images have been remapped to
a equal latitude-longitude projection. The shift in the location
of the clouds with respect to the map is due to the effects of parallax,
which has not been taken into account here.
Unlike
the 9 Oct 2001 case, the brightness temperature difference (10.7 - 6.7
microns) is negative in local regions over the thunderstorm tops.
The observations are similar to that reported in previous studies using
METEOSAT (Schmetz et al., 1997). The brightness temperature in the water
vapor band was often observed to be warmer (by as much as 6-8 K) than in
the window band above cold top convective clouds. This observation was
explained by stratospheric water vapor which emits radiation at higher
stratospheric temperatures than the emitted radiation at cloud top. Their
results suggested that the magnitude of the difference in brightness temperature
depends on the lapse rate above the tropopause. Moreover, the greatest
differences are expected when cloud tops are located at the tropopause.
The most negative differences
(-2 degs C) exist above some of the coldest (presumably, higher than the
tropopause).
Schmetz, J., S.A. Tjemkes, M. Gube, L. van de
Berg, 1997: Monitoring deep convection and convective overshooting with
METEOSAT. Adv. Space Res., Vol. 19, No. 3, pp433-441.
Note that to animate the full time period requires
the download of 53 images. It may take a while before the movie is set
up and ready to run, depending on network speed & the amount of memory
available to your computer. The loops use a Java
Applet written by Tom Whittaker at the Cooperative Institute
for Meteorological Satellite Studies ( CIMSS
) at the University of Wisconsin-Madison.
Choose from the entries in Table 1 to compare individual
bands and brightness temperature differences at indicated times (UTC).
GOES-8 & GOES-8 comparisons are available when available. .
Table 1