Medspiration – System Requirements Document - Data User Element

Medspiration MED-SOC-RS-001_1
System Requirements Document Issue F
Page Table, fig. Reference ID Text from reference documents
SR entry
62 WP-ID2.2.2.5 TMI SST retrieval below 285 K
62 WP2-203 TMI retrieves SST primarily from the 10.7 GHz channel, which has decreased sensitivity (and therefore increased error) at
CFD.0160
SSTs below 285K. Although the bias at lower temperatures is negligible, the standard deviation increases (as reflected in
the SSES). TMI data having retrievals below 285K must be flagged according to the following GDS rule:
62 Rule
WP2-204
· Rule 2.2.2.5: If a TRMM TMI SST measurement value is less than 285K, bit 2 of the L2P confidence data variable
CFD.0160
2.2.2.5
MW_SST_flags should be set.
62 WP-ID2.2.2.6 High Wind retrieval, above 12 ms -1
62 WP2-205 Uncertainties in the emissivity model at high winds and increased errors in the directional model, result in larger errors
CFD.0170
above 12 ms -1 . These errors should not vary temporally or spatially since they are due to uncertainty in the estimate of
emissivity. Although this increased error will be reflected in the SSES, some data users may chose to simply exclude these
retrievals as suspect.
62 The GDS specifies the following rule:
62 Rule
WP2-206
· Rule 2.2.2.6a: If a microwave wind speed measurement contemporaneous with a microwave SST measurement is
CFD.0170
2.2.2.6a
greater than 12 ms -1 , bit 3 of the L2P confidence data variable MW_SST_flags should be set.
62 Rule
WP2-207
· Rule 2.2.2.6b: If a contemporaneous microwave wind speed measurement is unavailable, the nearest NWP analysis
CFD.0180
2.2.2.6b
in space and time toi the SST measurement should be used to evaluate Rule 2.2.2.6a.
62 WP-ID2.2.2.7 Derive a Microwave Proximity Confidence Value (MPCF)
62 WP2-208 MPCV data are analogous to Infrared Proximity Confidence Values (IPCV) and provide a method to better understand the
CFD0210
character of microwave SST and their relationship to the SST1m. Microwave SST measurements are known to be of a
reduced quality when they are in close proximity to clearly flagged rainfall, due to side lobe contamination in the proximity
of land and sea ice. Also, at wind speeds < 2 ms -1 , a cool skin effect may also exist whereas at high wind speeds the
emissivity model used to derive SST is poorly defined. These factors may be used to derive a Proximity_Confidence
© 2004 SOC Page 154 of 193