Joint Observing System Simulation Experiment (JOSSE) Data set

at NASA/NCCS portal and NCAR


Updated in August 2016


Overview of the Nature run and credit


Description of the Nature Run data



The data set described in this manuscript contains the data required to conduct initial OSSEs.  The data set includes existing observations from the 2005-2006 Nature Run period and these data are considered as control observations to study the impact of additional observations.  These data are also useful for OSSE to evaluate data assimilation systems. A Nature Run on a low resolution regular grid for OSSE verification is also included.


The data set consists of (A) ECMWF Nature Run at low resolution pressure levels to verify OSSE experiments, (B) simulated and real observations for control experiments, and (C) cloud data for cloud evaluation.  


The complete Nature Run at model resolution and additional data are posted on the NASA/NCCS portal.  It is easier to view the data at NASA as the NCAR data are saved on tape, but it is easier to download large quantities of data from NCAR.


Data set names at NCAR are marked in green.  Currently the data are saved in the HPSS archive.  Individual files are viewable from the NASA/NCCS/portal.  The URL locations at the NASA portal are indicated in purple.


Contact about details of the data set

Michiko Masutani


Progress and update will be posted from




[NCAR data set]


Currently saved in HPSS  and must contact NCAR for access

Data ID:    ds621.0



NCAR Contact:

Chi-Fan Shih

Steven Worley


[NASA/NCCS portal]

(User ID and Password required)

Nature run data provided by EMCWF

Processed data including simulated observations



Ellen Salmon


The data are saved as individual file. 


User can down load the data using wget.
Sample line  for wget script would be

wget --no-check-certificate --user=<username> --password=<password> <path-to-file>


Please make sure to specify "--no-check-certificate"
Technical support: Bill McHale (