Global Precipitation Measurement
(GPM) Mission Data and Data Access
NASA Precipitation Processing System (PPS)
Erich Franz Stocker (erich.f.stocker@nasa.gov)
PPS Project Manager/Software Architect
GPM Deputy Project Scientist for Data
EGU 2014-Vienna Austria, April 30, 2014
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GPM Key Data Dates
• February 28, 2014 3:30AM (JST) GPM Core Observatory
launch from Tanegashima Space Center, Japan
• March 4, 2014 GMI commanded to science observation
mode and first data received
• March 8, 2014 DPR commanded to science observation
mode and first data received
• March 21, 2014 GMI L1, L2 near-realtime (NRT) and L1,
L2, L3 science standard data made available to set of early
data adopters
• April 2, 2014 DPR L2 NRT and L2 and L3 science
standard data made available to set of early data adopters
• April 2, 2014 Combined GMI/DPR L2 NRT and L2 and L3
science standard data made available to set of early data
adopters
• Current GMI, DPR and Combined data version is V01D
both NRT and standard science
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Data Release
• End of June 2014 GMI data release to the international
Precipitation Measurement Missions (PMM) science team
• End of July 2014 DPR data release to the international
PMM science team
• End of August 2014 General public release
• End of November 2014 General public release of new
merged radiometer product (IMERG)
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NRT GPM Core Data Products
Processing Sat/Inst/Alg
Level
Size
Latency
Key Parameters
1B
GPM/GMI
5 min
<= 1Hr 90%
Brightness Temperature-Tb
1C
GPM/GMI
5 min
<=1Hr ,90%
Tb (future 1C reference)
1CR
GPM/GMI
5 min
<- 1Hr, 90%
Intercalibrated Tb with
matched HF and LF pixels
2A
GPM/GMI/GPROF
5 min
<=1Hr 90%
Precipitation/TPW
2A Ku
GPM/DPR/Ku
30 min
<=180 min
Reflectivities/3D Precipitation
2A Ka
GPM/DPR/Ka
30 min
<=180 min
Reflectivities/3D Precipitation
2A DPR
GPM/DPR/DPR
30min
<= 180min
Dual Frequency retrievals:
reflectivities/3D precipitation
2B
GMI/DPR
GPM/GMI-DPR
30 min
<=180 min 90%
Combined GMI/DPR retrieval.
3D Precipitation
3
Merged Radiometers/IR
Halfhour
Early – 4 hours
Late – 8 hours
.1 deg x .1 deg global surface
precipitation
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1CR
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NRT Constellation Products
Processing
Level
Sat/Inst/Alg
Size
Latency
Key Parameters
1C
Metop B/MHS
Noaa 18/MHS
Noaa 19/MHS
As
received
Provider
dependent
Intercalibrated Tb
1C
MT/SAPHIR
As
received
Provider
Intercalibrated Tb
1C
NPP/ATMS
1 Hr
Provider
Intercalibrated Tb
1C
F16/SSMIS
F17/SSMIS
F18/SSMIS
As
received
Provider
Intercalibrated Tb
1C
TRMM/TMI
TDRSS
<=180 min
Reference Tb
1C
GCOM-W/AMSR2
orbit
~120min
Intercalibrated Tb
2A
GPROF /MHS
SAPHIR
ATMS
SSMIS
TMI
AMSR2
Same as
1C
Same as 1C
Precipitation/TPW
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Standard GPM Core Science Swath Products
Processing Sat/Inst/Alg
Level
Size
Key Parameters
1B
GPM/GMI
GPM orbit (Gorbit*)
Brightness Temperature-Tb
1C
GPM/GMI
Gorbit
Tb (future reference)
1CR
GPM/GMI
Gorbit
Tb with matched HF and LF
footprint
2A
GPM/GMI/GPROF
Gorbit
Precipitation/TPW
2A Ku
GPM/DPR/Ku
Gorbit
Reflectivities/3D
Precipitation
2A Ka
GPM/DPR/Ka
Gorbit
Reflectivities/3D
Precipitation
2A DPR
GPM/DPR/
Gorbit
Dual Frequency Retrievals.
3D precipitation
2B
GMI/DPR
GPM/GMI-DPR
Gorbit
GMI-DPR retrieval. 3D
Precipitation
* Gorbit is the GPM orbit calculated from the southern most point back to the
southern most point
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Standard GPM Core Gridded Products
Processing Sat/Inst/Alg
Level
Size
Key Parameters
3A
GPM/GMI/GPROF
0.25 deg x 0.25 deg
Daily/monthly
Precipitation
3A
GPM/DPR
0.25 deg x 0.25 deg
Daily
Precipitation
Ascending/Descending
separate
3A
GPM/DPR
0.25 deg x 0.25 deg
Monthly
Precipitation
3B
combined
GPM/GMI-DPR
0.25 deg x 0.25 deg
Daily/monthly
Precipitation
3B Merged
Merged Radiometers
0.10 deg x 0.10 deg
Half-hr/monthly
Gauge adjusted global
precipitation
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Standard Constellation Data Products
Processing Sat/Inst/Alg
Level
Size
Key Parameters
1C
Metop B/MHS
Noaa 18/MHS
Noaa 19/MHS
GPM
orbit
(Gorbit)
Intercalibrated Tb
1C
MT/SAPHIR
Gorbit
Intercalibrated Tb
1C
NPP/ATMS
Gorbit
Intercalibrated Tb
1C
F16/SSMIS
F17/SSMIS
F18/SSMIS
Gorbit
Intercalibrated Tb
1C
TRMM/TMI
Gorbit
Reference Tb
1C
GCOM-W/AMSR2
Gorbit
Intercalibrated Tb
2A
GPROF /MHS
SAPHIR
ATMS
SSMIS
TMI
AMSR2
Same as
1C
Precipitation/TPW
3A
All instruments with
GPROF 2A
Daily
monthly
0.25 deg x 0.25 deg
Precipitation
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Status of GPM Data Products-1
• Geolocation
– Location on the ground reported within requirements
– On April 19 Attitude Control System engineers reported an alignment error between
start tracker and spacecraft leading to ~0.3 degree peak to peak attitude error
(mostly roll)
• This does have an impact on incidence angles which affect Tb calculation
• New table scheduled to be uploaded April 25
• Data products will be adjusted as part of reprocessing for the PMM data release
• GMI L1 products
– Reasonably well calibrated (meets requirements specifications)
– Small calibration changes in April that included in version V01D
– Close to TMI calibration
– Some RFI issues in 10 GHz and 18GHz channels (approach to flag and mitigate
currently being examined.)
• GPROF retrieval products
– Saw more specific information in Dr. Kummerow’s presentation
– Currently using initial non GPM a priori databases
– New database approach for over land retrievals working reasonably well
– Currently producing GPROF retrieval for partner imagers and testing sounders
– Early state: some areas during really well and others not
– Will need about one year of stable GMI L1C and GMI-DPR Level 2B data to establish
physically based a priori databases for the GPROF retrievals for the radiometers
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Status of GPM Data Products -2
• Ku/Ka L1B –radar powers
– Have completed several external and internal calibrations
– Have verified phase shifter commands
– Reasonably well calibrated for this stage of the mission
– Providing acceptable input for the radar L2 algorithms
• Ku/Ka/DPR-retrievals
– L2 are providing reasonable retrievals again at the early stage where better in some
areas than in others
– Matching of Ku/Ka pixels working
– Some issues are being worked by JAXA engineers and DPR algorithm team
• Combined GMI-DPR
– Very early stage of development
– Working on dealing with data input issues
– Currently still in the experimental stage
• IMERG (merged radiometer product)
– Not being currently produced
– Need stable GPROF retrievals for sounders as well as imagers
– Currently in internal testing
– Usually lags 3 to 4 months after stable L2 GPROF retrievals.
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Sample Images of GMI and DPR
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GPM Special Products
• Daily gridded text products (like TRMM 3G68)
– 0.1 deg x 0.1 degree
– Contains:
• GMI GPROF surface precipitation
• Ku near-surface precipitation
• Ka near-surface precipitation
• DPR match swath near-surface precipitation
• GMI-DPR Combined surface precipition
– ASCII with line terminator being LF character
• GIS compatible files for IMERG
– TIFF (precipitation) with world files for metadata
– Precipitation in TIFF is scaled integer
– Half-hourly, 1day, 3 day and 7 day accumulations
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Accessing GPM Data
• Must register an email.
– registration.pps.eosdis.nasa.gov
– Receive an email and click to confirm
– Can specify interest in either standard science, NRT or both
• Can do ftp to the archive using your registered email as user name and password
• Can use a query/order web interface
– storm-pps.gsfc.nasa.gov or storm-pps.pps.eosdis.nasa.gov
– Can query, place orders for specific products, or establish standing orders which will
be fulfilled as products are generated
– Can subset swath products and get only the subsets specified
• Geographically
• Parameter (e.g. just include geolocation and surface precipitation)
• Or both together
• Currently limited as to the number orderable to keep within scope
– Can establish standing orders for subsets
– Can see browse images of the orbit to help in ordering decisions
– Can look through the data product online
• File specifications and algorithm theoretical basis documents (ATBD)
– pps.gsfc.nasa.gov/GPMprelimdocs.html
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Tools and Services
• THOR
– Tool for looking at GPM data products
– Includes functionality for making images including 3D images
– IDL based but IDL not required
– Available for: Linux, Windows, Mac OS
– http://pps.gsfc.nasa.gov/thorrelease.html
• Subsetting available for multiple years (STORM currently limits)
– erich.f.stocker@nasa.gov
– Carol.L.Archambeault@nasa.gov
– Includes setting up subsets to support field campaigns
• 3 Hr Presentation (Data and data access)
– Includes
• More detailed data description,strengths,limitations and status
• HDF5 format and tools for accessing
• Useful documentation
• Accessing data including the writing of scripts for automated access
• Use of THOR, STORM
– Can with planning offer the tutorial at Universities and agencies
– After a couple of presentations to get user feedback will package the presentation
– Contact: erich.f.stocker@nasa.gov
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