An Overview of Reanalysis-2


Masao Kanamitsu, Wesley Ebisuzaki

Climate Prediction Center, NCEP
Washington, DC

Jack Woolen

Environmental Modeling Center, NCEP
Washington, DC

Jerry Potter, Michael Fiorino

PCMDI, Lawrence Livermore National Laboratory
Livermore, CA


Attempt to correct known errors in the NCEP/NCAR reanalysis.

        1979-1993 completed. Monthly average data available on:


Model resolution, data and period:

Error fixes: New system components: Improvements to the model: Improved fixed fields: Improvement to the diagnostics: Archive and Distribution:

Updated Reanalysis for the satellite era.

Preliminary evaluation


Possible drawbacks: Major differences between R-1 and R-2: Other minor but notable differences:
Selected difference maps between R1, R2 (and ERA40).

1. Albedo over ocean :  Error fix in radiation

     Note that R1 has unrealistic albedo

2. Precipitation over south America : Effect of smoothed orography in R2.

  Note that R1 preciptation is noisy over Amazon basin.

3. Albedo over Africa : Improved desert albedo in R2

  Note that R2 has higher albedo over Sahara desert.

4. Land area averaged 2 m temperature (30N-60N) : Effect of corrected snow cover analysis.

  Note the peak difference in fall seasons.

5.  Soil moisture comparisons : Effect of using observed pentad precipitation in R2

   Note much larger interannual variability in R2

    5.1  Soil moisture over North America

           Dry condition in some of the years may not be accurate due to possible problems in  observed pentad precipitation.

    5.2  Soil moisture over Africa

    5.3  Soil moisture over South America

    5.4  Soil moisture over Eurasia polar region

          Note the very slow spin down in soil wetness over this region

6. Temperature at 100 hPa at the equator : Difference due to parameterization

          Note that difference between R1 and R2 is much smaller than the difference between R1, R2 and ERA.  This may be
              due to difference in model as well as to the way satellite data was used (NESDIS retrieval for R1, R2 and 1-D variational
              analysis for ERA).