WORLD METEOROLOGICAL ORGANIZATION
________________
MEETING OF EXPERT TEAM ON DATA
REPRESENTATION AND CODES
EUMETSAT, 23-27 April 2007
ET/DR&C/Doc. 3.1.5(1)
_______
(10.IV.2007)
ENGLISH ONLY
New Descriptors for GHRSST data
Submitted by Stan Kellett and John Stark (UK Met Office)
________________________________________________________________
Summary and Purpose of Document
New descriptors to be used for exchanging GHRSST data
________________________________________________________________
ACTION PROPOSED
The meeting is invited to discuss the content of this document.
1. Background
The Global Ocean Data Assimilation Experiment (GODAE) high-resolution sea surface temperature
pilot project (GHRSST-PP) provides a new generation of global high-resolution (<10km) SST data
products to the operational oceanographic, meteorological, climate and general scientific
community, in near real time and delayed mode. The project involves a wide range of international
participants who have invested a great deal in delivering high quality SST products.
There is a requirement to exchange GHRSST data between operational centers in a WMO
standard format. Although the GHRSST standard product is delivered in NetCDF, and is being
converted to BUFR at the Met Office for operational use. This necessitates the use of suitable
descriptors for the exchange of this data.
This document was submitted last year in Montreal and was rejected as the document needed to
pick some descriptors and required some corrections. This is the document that was subsequently
passed round the ETDRC group via email and accepted. These descriptors are now being used
operationally at the UK Met Office.
2. Proposal
The proposal is for the group to agree on descriptors for the following to be used when exchanging
GHRSST data:
Table
Reference
F X Y
0 25 037
0 14 035
0 25 022
0 25 023
0 25 024
0 01 028
0 01 024
0 01 029
0 01 038
0 25 038
0 22 046
Element name
BUFR
Unit
SST bias
Solar Radiation
Flux
GHRSST
Rejection Flag
GHRSST
Confidence Flag
GHRSST data
quality.
Aerosol optical
Depth (AOD)
source
Wind Speed
source
SSI Source
Source of Sea
Ice Fraction
Difference
between SST
and analysis
Sea Ice Fraction
Scale
CREX
Ref.
value
Data
width
(bits)
K
W/M2
2
1
-127
0
8
14
Flag
table
Flag
table
Code
table
Code
table
0
0
9
0
0
9
0
0
4
0
0
5
Code
Table
Code
Table
Code
Table
K
0
0
5
0
0
5
0
0
5
1
-127
8
Numeric
2
0
7
Table 1. Proposed BUFR and CREX codes.
0 25 022 - GHRSST Rejection Flag
Bit No.
1
Unprocessed
2
Unit
Scale
Data
width
(chars)
K
2
3
K
1
3
2
3
4
5
6
7
8
All 9
Land suspected.
Wind speed too large
Ice detected.
Rain detected (Microwave retrievals only)
Cloudy detected (Infra-red retrievals only)
Cosmetic value
SST out of range
Missing value
0 25 023 - GHRSST Confidence Flag
Bit No.
1
Default confidence value has been used.
2
Default bias and standard deviation has
been used.
3
Sun glint suspected
4
Sea ice retrieval for microwave data
5
High wind speed retrieval
6
Inaccurate SST due to low SST (< 285K).
(Only applies to the TMI instrument).
7
Relaxed rain contamination suspected
8
Potential side lobe contamination
All 9
Missing value
0 25 024 – GHRSST proximity confidence.
Code figure
0
1
2
3
4
5
6
7-9
10
11
12
13
14
15
Unprocessed infrared retrieval
Cloudy retrievals.
Bad: Data that are probably contaminated by cloud.
Suspect data.
Acceptable data.
Excellent data.
Cool skin suspected.
Reserved
Unprocessed microwave retrieval.
Questionable microwave retrieval that may be contaminated.
Acceptable microwave retrieval.
High probability of diurnal variability.
Reserved
Missing value
0 01 028 - Aerosol optical Depth (AOD) source
Code
figure
0
1
2
3
4
5
6-30
31
No AOD data available
NESDIS
NAVOCEANO
NAAPS
MERIS
AATSR
Reserved for future use
Missing value
0 01 024 - Wind Speed source
3
Code
figure
0
1
2
3
4
5
6
7
8-30
31
No wind speed data available
AMSR-E data
TMI data
NWP: ECMWF
NWP: UK Met Office
NWP: NCEP
Reference climatology
ERS_Scatterometer
Reserved for future use
Missing value
0 01 029 - SSI Source
Code figure
0
1
2
3
4
5
6
7-30
31
No SSI data available
MSG_SEVIRI
GOES East
GOES West
ECMWF
NCEP
UK Met Office
Reserved for future use
Missing value
0 01 038 - Source of Sea Ice Fraction
Code
figure
0
1
2
3
4
5
6-30
31
No sea ice set
NSIDC SSM/I Cavalieri et al (1992)
AMSR-E
ECMWF
CMS (France) cloud mask used by
Medspiration
EUMETSAT OSI-SAF
Reserved for future use
Missing value
Table of Acronyms
Acronym
AATSR
AMSR-E
AOD
BUFR
CMS
CREX
ECMWF
ERS
EUMETSAT
GHRSST-PP
GODAE
GOES
Expansion
Advanced Along-Track Scanning Radiometer.
Advanced Microwave Scanning Radiometer.
Aerosol optical depth.
Binary Universal Form for the Representation of meteorological data.
Centre de Meteorologie Spatiale (Lannion, France).
Character form for the Representation and Exchange of
meteorological and other data.
European Centre for Medium-range Weather Forecasts.
European Remote-sensing Satellite.
European organization for the exploitation of meteorological satellites.
GODAE High Resolution Sea Surface Temperature Pilot Project.
Global Ocean Data Assimilation Experiment.
Geostationary Operational Environment Satellite.
4
IR
MERIS
MSG
MW
NAAPS
NAVOCEANO
NCEP
NESDIS
NWP
OSI-SAF
RF
SEVIRI
SSI
TMI
Infra-red.
Medium Resolution Imaging Spectrometer.
Meteosat Second Generation.
Microwave.
Navy Aerosol Analysis and Prediction System.
Naval Oceanographic Office (United States of America).
National Centers for Environmental Prediction.
National Environmental Satellite, Data, and Information Service.
(United States of America).
Numerical weather prediction.
Ocean and Sea Ice Satellite Applications Facility.
Radio frequency.
Spinning Enhanced Visible and Infrared Imager
Surface Solar Irradiance.
Tropical Rainfall Measuring Mission (TRMM) Microwave Imager.
5