Reanalysis generate not only analysis fields but also quality information on each observation (O-A and O-F statistics, and bias estimation, etc).

Reanalysis now goes towards end of third generation of comprehensive global reanalysis.

Should balance be enforced or used as a diagnostic? Validation by comparison with other re-analyses becomes usual. Validation with O-A and O-B statistics, and diagnostics with analysis tendency is

useful. Next generation re-analyses are required improve hydrological cycle,

stratosphere, polar region, uncertainty estimates, Reducing trend jump and analysis increments, Earth system analysis.

Ensemble based analysis can generate information of uncertainty. 20th century reanalysis with Ps and sst will start Reprocessed observation data (ex, AMV and CSR, etc) are useful. Background error for non-satellite era is useful. Ultimately the accuracy of a reanalysis is limited by observations. New data for ocean analysis: GRADE, SMOS. Atmosphere and ocean coupled reanalysis.

1. KEYNOTE

2. MERRA and Beyond

3. NCEP

4.SIRCA

5. JRA55

6. ECMWF

7. Ocean