Obs4MIPs- SatelliteObservations
Rehosted forGCMModelEvaluation
Obs4MIPs
RobertFerraro
Jet Propulsion Laboratory
This project is collaboration between NASA and DOE, and is
overseen by an International Task Team constituted under the
WCRP Data Advisory Council
JetPropulsionLaboratory
CaliforniaInstituteofTechnology
InitialSentimentsBehindobs4MIPS
Under-ExploitedObservationsforModelEvaluation
How to bring as much
observational scrutiny as possible
to the CMIP/IPCC process?
How to best utilize the wealth
of satellite observations for the
CMIP/IPCC process?
ModelandObservationOverlap
Taylor et al. 2008
~120 ocean
~60 land
~90 atmos
~50 cryosphere
Example: NASA – Current Missions ~14
Total Missions Flown ~ 60
Many with multiple instruments
Most with multiple products (e.g. 10-100s)
Many cases with the same products
Over 300 Variables in
(monthly) CMIP Database
Over 1000 satellitederived quantities
What’stheProblem?
Formats
• ModelerstypicallyuseNetCDF,globallygriddedoutput
• Satellitedatacomesinlotsofformats:HDF,NetCDF,binary,etc;Different
processinglevels(L2– Swath,L3– gridded,L4– analysis),withvoids,fills,and
flags
Metadata
• ModelerstypicallyusetheCFconvention
• SatellitedatamaybeNASAEOScompliant,CFcompliant,orfollownospecific
convention– metadatamaynotactuallybeimbeddedinthedatafiles…
Experience
• Modelers(notall)knowverylittleaboutsatellitedata,don’tunderstand
retrievals,biases– Findingdataisstillhardandtheyseemultipleproductsfor
the“same”variableanddon’tknowhowtochoose
• Satellitedataprovidersproducedocumentationforthemselves,whichisoften
impenetrablefornon-observationalscientists
• Mappingbetweenmodeloutputandobservationsisnotalwaysobvious
obs4MIPs:The4Commandments
Target Quantities
1. Use the CMIP5/6 simulation protocol as
guideline for selecting observations.
Model
Output
Variables
Satellite
Retrieval
Variables
2. Observations to be formatted the same
as CMIP Model output (e.g. NetCDF
files, CF Convention)
3. Include a Technical Note for each
variable describing observation and use
for model evaluation (at graduate
student level).
4. Hosted on the ESGF with CMIP model
output, using the same search and
download facilities, (and in the future,
online analysis capabilities)
Modelers
Observation
Experts
Analysis
Community
Target Community
obs4MIPs“TechnicalNote”
Every dataset must include a Technical Note, which is hosted with the dataset on the ESGF
The Tech Note is limited to about 6 – 8 pages, with figures
Content should summarize important information in a way that a graduate student can
understand
References to more complete documentation, and journal articles, are included at the end
Technical note content is mandatory, and is review by the task team before it is published
• Intent of the Document
An uncertainty estimate is
• Data Field Description (CF name, units)
required, and more detailed
• Point Of Contact (name, email address)
error information (zonal, point
• Data Origin
by point) is encouraged
• Validation and Uncertainty Estimate
• Considerations for use in Model Evaluation
For example:
Sun Synchronicity
• Instrument Overview
Diurnal Sampling
• References
Sampling Bias
• Revision History
Effect of cloud contamination
The objective is to place all of the relevant information needed to make use of the dataset in
one document next to the data holding itself
DataandDocumentationTogether
Technoteis
advertisedinthe
searchresults
Manywaysto
download
obs4MIPs:CurrentSetofObservations
https://www.earthsystemcog.org/projects/obs4mips/satellite_products
(CF)VariableLongName(#Datasets)
AirTemperature(3)
AmbientAerosolOpticalThicknessat550
nm(2)
CALIPSO3DClearfraction(3)
CALIPSO3DUndefinedfraction(3)
CALIPSOClearCloudFraction(3)
CALIPSOCloudFraction(3)
CALIPSOHighLevelCloudFraction(3)
CALIPSOLow-LevelCloudFraction(3)
CALIPSOMidLevelCloudFraction(3)
CALIPSOScatteringRatio(6)
CALIPSOTotalCloudFraction(3)
CloudFractionretrievedbyMISR(1)
EastwardNear-SurfaceWind(1)
EastwardWind(1)
FractionofAbsorbedPhotosynthetically
ActiveRadiation(1)
GeopotentialHeight(1)
ISCCPCloudAreaFraction(Jointhistogramof
opticalthicknessandcloudtoppressure)
(1)
ISCCPMeanCloudAlbedo(Cloud-fraction
weighted&daytimeonly)(1)
ISCCPMeanCloudAlbedo(Unweighted&
daytimeonly)(1)
ISCCPMeanCloudTopPressure(Cloudfractionweighted&daytimeonly)(1)
ISCCPMeanCloudTopPressure
(Unweighted,daytimeonly)(1)
ISCCPMeanCloudTopTemperature(Cloudfractionweighted&daytimeonly)(1)
ISCCPMeanCloudTopTemperature
(Unweighted&daytimeonly)(1)
ISCCPTotalCloudFraction(daytimeonly)(1)
LeafAreaIndex(1)
MassFractionofCloudIce(1)
MoleFractionofO3(1)
MonthlyAverageNear-SurfaceWindSpeed
(1)
Near-SurfaceWindSpeed(1)
NorthwardNear-SurfaceWind(1)
NorthwardWind(1)
Precipitation(4)
SeaIceAreaFraction(4)
SeaSurfaceHeightAboveGeoid(1)
SeaSurfaceTemperature(3)
SpecificHumidity(2)
SurfaceDownwellingClear-SkyLongwave
Radiation(1)
SurfaceDownwellingClear-SkyShortwave
Radiation(1)
SurfaceDownwellingLongwaveRadiation(1)
SurfaceDownwellingShortwaveRadiation
(1)
SurfaceUpwellingClear-SkyShortwave
Radiation(1)
SurfaceUpwellingLongwaveRadiation(1)
SurfaceUpwellingShortwaveRadiation(1)
TOAIncidentShortwaveRadiation(1)
TOAOutgoingClear-SkyLongwaveRadiation
(1)
TOAOutgoingClear-SkyShortwaveRadiation
(1)
TOAOutgoingLongwaveRadiation(3)
TOAOutgoingShortwaveRadiation(1)
TotalCloudFraction(1)
WaterVaporPath(1)
aerosolopticalthicknessat550nm(1)
column-averagedry-airmolefractionof
atmosphericcarbondioxide(1)
column-averagedry-airmolefractionof
atmosphericmethane(1)
monthlyaverageatmospherewatervapor
contentoverice-freeoceans(1)
seasurfacetemperature(1)
ConcludingRemarks
Intheory,automatedtranslationamongfileformatsandmetadata
conventionsispossible
Inpractice,it’snotsoeasy– regridding isatouchysubject…
Anddocumentationforthenon-expertislargelynon-existant
Wethinkthatprovidingdataanddocumentationtailoredtothe
customer isthebestwaytoincreaseitsutility
Obs4MIPsisevolvingundertheguidanceoftheWDACTaskTeam
Manyissuestosortoutgoingforward…Likehowtohandleinsitu
data…
Findobs4MIPsat
https://www.earthsystemcog.org/projects/obs4mips/
OrGoogle“obs4MIPs”
Acknowledgements
Obs4MIPsTaskTeamMembers
•
•
•
•
•
•
•
•
•
•
•
•
•
PeterGleckler,co-chair,PCMDI/DOE
DuaneWaliser,co-chair,JPL/NASA
SandrineBony,IPSL
MikeBosilovich,GSFC/NASA.
HeleneChepfer,IPSL
Veronika Erying,DLR
RobertFerraro,JPL/NASA
Pierre-Phillipe Mathieu(ESA)
RogerSaunders,UKMO
Jörg Schulz,EUMETSAT
KarlTaylor,PCMDI/DOE
Jean-NoëlThépaut,ECMWF
JerryPotter,PCMDI/DOE,GSFC/NASA
Ex-Officio
•
•
•
•
•
TsengdarLee,NASA
Renu Joseph,DOE
Pierre-PhilippeMathieu,ESA
MichelRixen,WMO
OtisBrown,WDAC
PartofthisworkwasperformedattheJetPropulsionLaboratory,CaliforniaInstituteofTechnology
underacontractfromNASA