Level 2B, 2C

 GRM-02/41 NRT T  GRM-03/42 NRT Q  GRM-04/43 NRT P  GRM-05/44 NRT SP
 GRM-10/48 Offline T  GRM-11/49 Offline Q  GRM-12/50 Offline P  GRM-13/51 Offline SP

GRM-03/42: NRT Specific Humidity Profile

_Values Remarks
Unitsg/kgSpecific humidity
Domain0-15 km Surface to
~100 hPa
Range0-50 g/kg_
on target
0.2 g/kg
10 %
Whichever is greater
on vertical
250-500 m Depends on back-
ground pressure levels
GRM-03 status Operational Metop-A
GRM-42 status Operational Metop-B
Current product version (GRM-03): 1.0
Current product version (GRM-42): 1.0

Product description

The NRT specific humidity product contains a profile of specific humidity as a function of height (geometric and geopotential) above the EGM-96 geoid.

Algorithm description

Each product profile is the result of one radio occultation. Signals from the occulting GPS satellite are measured by the GRAS receiver onboard the EPS/Metop satellite, downlinked, and processed by the ROM SAF into refractivity. More details can be found in the Algorithm Theoretical Baseline Document, on the Radio Occultation Theory page, and in the Validation Report for GRM-03 and GRM-42.

Data characteristics

GRAS measures about 700 GPS occultations per day. The product is output in both NetCDF and BUFR format, and disseminated via GTS/RMDCN (BUFR) and EUMETCast (NetCDF and BUFR). NetCDF files are also stored in the ROM SAF Product Archive.

Product validation and monitoring

Accuracy of the current version of the product will be described in a future Validation Report. Daily monitoring of the processing and dissemination can be seen on the Monitoring Page.

Product documentation

All ROM SAF NRT and Offline products are described in the Product User Manual.
This product will be made available at the Product Archive.

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