[Dart-users] updated adaptive localization and locations mods

Nancy Collins nancy at ucar.edu
Fri Feb 26 15:58:31 MST 2010


hello dart-users,

i've just committed the updated adaptive localization code.
adaptive localization is selected by setting a count in the
assim_tools_nml namelist.  if it's > 0, it sets a count of the
maximum number of observations within the localization
radius.  if it's exceeded, the radius will shrink proportionally
to the count.

the existing code did not discriminate between observation
types that were going to be assimilated and those types
which were either ignored, or evaluate only.   the updated
code now only counts assimilated types, so the count and
the resulting decreased radius should be more accurate.

thanks to ryan torn for pointing out the deficiency, and to glen
romine for providing the updated code.

there are 2 new namelist options in the &assim_tools_nml
namelist to control whether a diagnostic file is written out
with the location of the observation, the original radius,
and the updated radius value.  the filename can also be set.

this code update required some additional functions in the
locations module, so if you update your assim_tools directory
you will also need to update your location directory and
your obs_sequence directory.    all the models also have
updated default input.nml files with the new namelist vars.

the location modules have been heavily revised; see the log
message for any of the files in the locations directory for a
long and detailed message.  most of the changes are internal.
the most visible change is that writing out a location in ascii
will now have 2 more significant digits in the string.  this
should make writing and then reading in the ascii numbers
closer to the values obtained if written and read in binary.
but you will see bitwise differences between the original
code and the updated code for ascii location values, typically
confined to the least significant digit.

this code has been compiled and tested on several platforms,
but as always, if you run into problems or have questions let
me know.

thanks, and have a good weekend,
nancy



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