Level 2A

 GRM-01 N  GRM-40 N  GRM-09/47 N

GRM-09/47: Offline Refractivity Profile
(ORPMEA/ORPMEB)

_Values Remarks
Units Refractivity units (N-units) Neutral atmosphere
Domain 0-50 km Surface to
~1 hPa
Range0-450 N-units_
Requirement
on target
accuracy
0-5 km: 0.5%-2%
5-30 km: 0.5%
30-50 km: 0.02 N-units
_
Requirement
on vertical
resolution
150-250 m_
GRM-09 status Development Metop-A
GRM-47 status Development Metop-B
 Current product version: N/A_

Product description

The Offline refractivity product contains a profile of neutral refractivity 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 a future validation report.

Data characteristics

GRAS measures about 700 GPS occultations per day. The product is produced in both NetCDF and BUFR format, and will be 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 will be made available at 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.

DMI's logo IEEC's logo Met Office's logo
ECMWF's logo