Assistant Technical Representative: John E. Janowiak

Contributors: Robert J. Joyce

Period of Performance: December 10-14, 2001

1. WORK PERFORMED DURING THE PAST WEEK

A. The goal this week was to compare temporal interpolation of advection vectors derived from the same satellite (created from full coverage, even and odd satellite configuration data sets) to simultaneous vectors (no temporal interpolation) derived from overlapping coverage satellites to compensate for gaps created from potential dropout periods such as equinox. Both vector data sets are compared to simultaneously derived vectors from the initial satellite. The new vectors used in both comparisons contain no carryover of vectors from one half-hourly period into the next, and possess the increased positive zonal maximum advection rate (6-to-12 pixels). Correlation, bias, amplitude, and normalized RMS are produced (and stored in the data/rjoyce/temporal-interp_vectors directory on the ftp.ncep.noaa.gov server) so that a direct comparison at each temporal interpolation interval is made to relationships already determined between temporally simultaneous vectors derived from two different satellites. For all satellite overlap regions, the statistical comparisons of 6 hourly or less temporal vector interpolations are far superior to simultaneous vectors derived from overlapping satellites. The multi-satellite advection vectors will only be useful over the single satellite temporal interpolation method for gaps larger than equinox periods (~6 hours). This work completes the 2nd and 3rd sections of the WORK PLANNED for the December 3 - 7 report.

B. However we still need to look at the decay of correlation and accuracy of determining half-
hourly advection vectors from images further apart than the standard 30 minute period (1st section of the WORK PLANNED for the December 3 - 7 report). This is required for instances such a determining vectors from the GMS satellite which operationally images only on a hourly basis. Began developing software for this study.

2. WORK PLANNED FOR NEXT WEEK

A. The overall goal is to get the best half hourly global advection field, at all locations.

1. The assumption that this must begin with preforming spatial lag correlations at lag of only a half hour between successive images (or hourly only in GMS domain) must be proved. Show the decay in correlation and other statistics by increasing the temporal lag between successive images.

2. Repeat procedure tallying all IR images per day at 5.0 degree latitude/longitude region for the dominant satellite (#1 Work Performed Past Week) by including all satellites observing the region.

3. Change the absolute inter-satellite calibration from the mean of the two GOES to the GOES-8 (East) for both CPC full resolution, half hourly, globally merged geostationary satellite IR and GPCP, 1 degree, 3 hourly IR histogram software.