This directory contains files describing parts of the COSPAR
International Reference Atmosphere (CIRA-86)

The original CIRA-86 data are zonally averaged monthly mean
climatologies of several atmospheric parameters.

 * Temperatures, 
 * zonal winds, and 
 * geopotential heights 

are available on a grid with a resolution of 5 degrees in latitude and 0.25 
in log-pressure scale height. In addition, data sets of

 * temperatures, 
 * zonal winds, and 
 * pressures 

are accessible on a grid with a resolution of 10 degrees latitude and 5 km 
altitude.

Further information in the README file.

The files described in README were downloaded from the SPARC
data centre 2002-08-13 (www.sparc.sunysb.edu/html/fleming.html).


The files sht.dat and nht.dat have been used to create xml files
giving temperature and geometrical altitude as a function of pressure,
for different months. This was done by create_cira_xml.m, found in
this folder. The function modifies the data in some ways:

* Data for latitudes +-80 deg have been copied to +-90 deg, to
  cover all possible latitudes.

* CIRA does not contain temperatures for some low altitudes above
  Antarctica (no data available as always covered by ice). The
  temperature for lowest OK altitude has been copied to all "empty"
  positions".

* Altitudes have been calculated by *zt2p*, instead of using CIRA's
  own altitudes as they are only approximative (and geopotential
  instead of geometrical). For this calculation, water vapour is set
  to 50% RH for pressures > 350 hPa. A complete dry atmosphere is
  assumed for higher altitudes.

Patrick Eriksson
2007-11-01