Tropical Cyclone Satellite Studies
High resolution IR image data sets: In support of the GOES-R Algorithm Working Group (AWG) project, data sets are being assembled with 1-km Mercator remapped 2560x1920 images. All available good quality IR window images are being collected for the following Atlantic hurricanes: Lili-02, Isabel-03, Emily-05, Katrina-05, Rita-05, Wilma-05, Stan-05, Alpha-05, Beta-05, and Ernesto-06; along with 2005 eastern Pacific hurricane Hilary. The data sets are nearly complete and include data from the two MODIS satellites (Terra and Aqua), and AVHRR from satellites NOAA-12, 14, 15, 16, 17, and 18. Not all passes provide good quality images since coverage at the limb is not satisfactory and 1-km resolution data from AVHRR does not have global coverage. Nevertheless, with hurricanes near the US, 8-12 good quality images per day are often available. The 1-km IR resolution provides feature detail not well depicted in lower resolution geostationary images. One example of Hurricane Rita is shown in the figure, with the entire image along with a zoomed in view. (R. Zehr)
Figure 1. 1-km resolution IR image of Hurricane Rita at 1835 UTC, 20 September 2005, from MODIS Aqua.
Automated methods have been developed to retrieve, decode and archive COSMIC (Constellation Observing System for Meteorological, Ionosphere and Climate) GPS-based soundings produced via radio occultation, which are derived from the Taiwanese FORMOSAT-3 Satellite. Example coverage is shown in Figure 2 and example soundings of temperature and water vapor pressure from 14.5N 123.4E on 8 November 2006 are shown in Figure 3 and Figure 4. It is hoped that these data will be useful for the study of the thermodynamic environment of tropical cyclones and other studies that need high vertical resolution sounding. These data are freely available in netcdf format from NCAR once the user has registered. (J. Knaff)
Figure 2: Locations of COSMIC GPS-based soundings 8 November 2006
Figure 3: Temperature sounding example at 14.5N, 123.4E taken at 13UTC on 8 November. Note the x-axis is log scale.
Figure 4: Same as Figure 3 except for water vapor pressure and the vertical axis extends only to 100 hPa.
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