Selecting Good AIRS Channels
Thu, Mar 23, 2017
A reasonably well-defined way to select good AIRS channels (over long
time spans) is now available in
/asl/matlib/airs/find_good_airs_chans.m. The "airs" directory is
new in matlib and also contains code for frequency calibrating AIRS
(to be discussed in separate web post). The find_good_airs_chans.m
file is heavily commented, but is complicated since it uses AIRS
random and clear stats files to determine if a channel is good enough
to use for long-term studies.
The most common use of this code is to just load in
/asl/matlib/airs/good_chans_2016.mat and use the various indices in
that file for channel selection.
| Variable Name | Description |
|---|---|
| kg | good chans, ab can change |
| kg_fixed_ab | good chans, no ab changes |
| kg_ab0 | good chans, ab=0 (a+b) |
| kg_ab1 | good chans, ab=1 (a only) |
| kg_ab2 | good chans, ab=2 (b only) |
For general work, "kg' is probably OK to use. For long term trending, you should at the minimum use "kg_fixed_ab".
Time Variables
Note that I am using the Matlab "datetime" class for these files. It
is very convenient, most of the time. Please start to use it. Line
41 of find_good_airs_chans.m shows, for example, how to get the
years for each entry in mtime. Same goes for hours, minutes, etc.