JISAO data
Selected NCEP / NCAR Reanalysis fields
4-times daily, daily, and monthly averages of the NCEP/NCAR reanalysis are available from the NOAA Climate Diagnostics Center. The present WWW page provides selected fields that we have calculated for research purposes at JISAO.






Pentad | Monthly data









Climatological-mean and standard deviation of DJF 500 hPa geopotential height, 1979-95

Image of 
Northern Hemisphere extratropics.



Contours are drawn for the 546 and 528 dam geopotentials, and shading
indicates regions with standard deviations > 60 m.  Climatological ridges are 
located on the west coasts of North America and Europe, with the largest variability upstream of the ridges.








Pentad-mean data:

At JISAO, the data resides at /home/disk/tao/data/ncep_reanalysis/pentad/


200mb geopotential height, 1948-99 (80 Mb)


Tropopaus pressure, 1948-99 (80 Mb)


500mb geopotential height, 1958-99 (64 Mb)


500mb zonal wind, 1948 - June 2002 (84 Mb)


500mb meridional wind, 1948 - June 2002 (84 Mb)


600mb omega, 1958-97 (61 Mb)



850 hPa air temperature, 1948-2000 (81 Mbytes)


925mb zonal wind, 1948-99 (80 Mb)


925mb meridional wind, 1948-99 (80 Mb)


0.995 sigma (lowest model level)
air temperature, 1948-2002 (84 Mb)


sea-level pressure, 1948-2002 (84 Mb)



All errors in the calculation and writing of the pentad-mean fields
are due to Todd Mitchell and Dan Vimont.  For leap years, the twelfth pentad
(February 25 through March 1) is the average of six days.  The
pentad-means are calculated from daily-average data obtained at
various times from the NCEP / NCAR
reanalysis project archive at the NOAA Climate Diagnostics Center.  On some of the files
the "history" variable ("ncdump -h filename.nc") says when the daily
data was obtained.  Users are encouraged
to visit the NOAA CDC site to become more familiar with the data available and the problems identified with this product.


Other pentad-mean data sets:

NCEP outgoing
longwave radiation

Pingping Xie offers an "experimental" version of the Xie and Arkin rainfall data for 1979-96.








Monthly-mean data:

At JISAO, the data resides at home/disk/tao/data/ncep_reanalysis/monthly/


1000 mb zonal and meridional wind climatologies for
1950-79.  Each file is 0.3 Mbyte in size.  (Maps 1-12: 
individual calendar months; Map 13: annual mean; Maps 14-17 seasonal
means for DJF, MAM, JJA, SON)







Reference:

Kistler, R., E. Kalnay, W. Collins, S. Saha, G. White, J. Woollen,
M. Chelliah, W. Ebisuzaki, M. Kanamitsu, V. Kousky, H. van den Dool,
R. Jenne,  M. Fiorino, 2001: The NCEP-NCAR 50-Year
      Reanalysis: Monthly Means CD-ROM and
      Documentation. Bull. Amer. Meteor. Soc., 82, 247-268.










February 2003


Todd Mitchell (mitchell@atmos.washington.edu)


JISAO  data