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Facilitating Access to Global Observing Systems Data and Information

Space Based Climate Observations for GCOS

Initial requirements for satellite observations for the Global Observing Systems (GTOS, GCOS and GOOS) were  developed jointly  by the AOPC, OOPC and TOPC with assistance from the Global Observing System Space Panel (GOSSP). GOSSP has since completed it's work and been disbanded. The detailed requirements of the three systems are maintained in a database operated by the WMO as a joint project with the Committee for Earth Observing Satellites (CEOS). The AOPC has specified the requirements for GCOS for the WMO/CEOS affiliates database.

The information contained in the table below is early version and should only be viewed as guidance at this point. The table also does not contain all the fields available in the CEOS database tables. It is presented here to provide a general view of the types of satellite observations required by the three observing systems.
 

Requirements for Satellite Observations for GCOS

The table below contains specifications developed by the AOPC for satellite observations in the atmosphere to meet GCOS needs. There are two sets of resolutions specified. The two resolutions and the column headings are explained in the second table below.
Parameter
Hor Res
UHor Res
HR Min
UHor Res
Vert Res
UVer Res
VR Min
UVer Res
Observing Cycle
UObs Cy
Accuracy
UAcc
Cloud cover
100
km
500
km
3
h
10
%
Cloud ice total column
100
km
500
km
3
h
g/m2
Cloud top height
100
km
500
km
3
h
0.5
km
Cloud water total column (<100 µm)
100
km
500
km
3
h
g/m2
Cloud water total column (>100 µm)
100
km
500
km
3
h
g/m2
Land surface temperature
100
km
500
km
3
h
1
K
Long-wave outgoing radiation at TOA
200
km
500
km
3
h
5
W/m2 - sd
Normalized Differential Vegetation Index (NDVI)
100
km
500
km
168
d
10
%
Precipitation rate at the ground (liquid)
100
km
500
km
3
h
0.6
mm/h
Precipitation rate at the ground (solid)
100
km
500
km
3
h
0.6
mm/h
Sea surface temperature
100
km
500
km
24
h
0.3
K - sd
Sea-ice cover
100
km
500
km
1
d
10
%
Short-wave outgoing radiation at TOA
200
km
500
km
3
h
5
W/m2 - sd
Significant wave height
100
km
250
km
3
h
0.5
m
Snow cover
100
km
500
km
1
d
10
%
Snow water equivalent
100
km
500
km
1
d
5
mm
Solar irradiance at TOA
0.125
d
5
W/m2 - sd
Specific humidity profile Higher troposphere
100
km
500
km
0.5
km
1
km
3
h
0.025
g/kg
Specific humidity profile Lower stratosphere
100
km
500
km
0.5
km
1
km
3
h
0.025
g/kg
Specific humidity profile Lower troposphere
100
km
500
km
0.1
km
2
km
3
h
0.25
g/kg
Specific humidity total column
100
km
500
km
3
h
1000
g/m2
Temperature profile Higher stratosphere/mesosphere
100
km
500
km
2
km
3
km
3
h
1
K
Temperature profile Higher troposphere
100
km
500
km
0.5
km
1
km
3
h
0.5
K
Temperature profile Lower stratosphere
100
km
500
km
0.5
km
1
km
3
h
0.5
K
Temperature profile Lower troposphere
100
km
500
km
0.1
km
2
km
3
h
0.5
K
Wind profile (horizontal component) Higher stratosphere/mesosphere
100
km
500
km
2
km
3
km
3
h
3
m/s
Wind profile (horizontal component) Higher troposphere
100
km
500
km
0.5
km
1
km
3
h
2
m/s
Wind profile (horizontal component) Lower stratosphere
100
km
500
km
0.5
km
1
km
3
h
2
m/s
Wind profile (horizontal component) Lower troposphere
100
km
500
km
0.1
km
2
km
3
h
2
m/s
Wind vector over sea surface (horizontal)
100
km
500
km
3
h
2
m/s

Explanation of the Columns in the Requirements Table
Parameter The variable that is being measured. It may be a profile or an integrated variable.
Hor Res The optimum horizontal resolution for observing the variable.
UHor Res The units of the horizontal resolution.
HR Min The minimum horizontal resolution for the observations to be useful for GCOS.
UHor Res The units of the horizontal resolution.
Vert Res The optimum vertical resolution for observing the variable.
UVer Res The units of the vertical resolution.
VR Min The minimum vertical resolution for the observations to be useful for GCOS.
UVer Res The units of the vertical resolution.
Observing Cycle The time interval between observations of the variable at the same point.
UObs Cy The units of the observing cycle.
Accuracy The accuracy required of the measurement of the variable.
UAcc The units of the accuracy.