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NRT Sounding Data Products

The main parameters in the NRT sounding data products are:
  • Refractivity (GRM-01)
  • Temperature (GRM-02)
  • Specific humidity (GRM-03)
  • Pressure (GRM-04)
  • Surface pressure (GRM-05)
In addition, various supporting data and selected parameters from the level 1b data products (with some post-processing applied) are included with the level 2 NRT sounding data products. The NRT products are delivered less than three hours after measurement, making them the choice for NWP users.

Refractivity profile (GRM-01)
Quantity Values Remarks
Units Refractivity units (N) Neutral atmosphere
Domain 0-50 km Surface to 1 hPa
Range 0-450 N-units
Precision 0.1 N-units
Vertical resolution 150-250 m
Target accuracy 0.6-2 %, 0.6 %, 0.03 N-units0-5 km, 5-30 km, 30-50 km
Temperature profile (GRM-02)
Quantity Values Remarks
Units Kelvin (K)
Domain 0-50 km Surface to 1 hPa
Range 180-350 K
Precision 0.1 K
Vertical resolution250-500 m depends on background pressure levels
Target accuracy2-3 K, 1 K, 1-5 K, 5-10 K0-5 km, 5-30 km, 30-40 km, 40-50 km
Specific humidity profile (GRM-03)
Quantity Values Remarks
Units kg/kg Specific humidity
Domain 0-15 km Surface to 100 hPa
Range 0-50 g/kg
Precision 0.001 g/kg
Vertical resolution 250-500 m depends on background pressure levels
Target accuracy 10 % or 0.2 g/kg whichever is greater
Pressure profile (GRM-04)
Quantity Values Remarks
Units hectopascals (hPa)
Domain 0-50km Surface to 1 hPa
Range 0.01-1100 hPa
Precision 0.001 hPa
Vertical resolution 250-500 m depends on background pressure levels
Target accuracy 0.2 % or 2 hPa whichever is greater
Surface pressure (GRM-05)
Quantity Values Remarks
Units hectopascals (hPa)
Domain SurfaceHorizontal location nominally at the ellipsoid tangent point location of the straight line connecting GPS and MetOp
Range 900-1100 hPa
Precision 0.001 hPa
Vertical resolution N/A
Target accuracy 2 hPa

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