The Split Window Difference (10.3 µm – 12.3 µm) field can be used to identify moisture gradients in clear skies. This is because of the different absorptive properties by water vapor of energy at those two wavelengths.

This Lab (pdf format) can be used to guide students as they explore the Split Window Difference in clear skies over Kansas. (When I’ve used this lab, after the students have used SIFT to examine fields, I have them stand in front of class and talk about the scene while I run SIFT — and I have them consider these questions, among others).

NetCDF files to be used with this lab (i.e., to be uploaded into SIFT) are available at this ftp site. ( ftp://ftp.ssec.wisc.edu/pub/sift/data/SIFTLab/Preconvective/ )

NetCDF files that show what happened shortly after the scenes examined in the lab are here. ( ftp://ftp.ssec.wisc.edu/pub/sift/data/SIFTLab/Initiation/ )

SPC Storm Report for this day are here.