Example of a DIF

Entry_ID: PODAAC_TPMGDRB_PRODUCT068
Entry_Title: TOPEX/POSEIDON Altimeter Merged Geophysical Data Record Generation B (NASA/PO.DAAC), Product 068
Group: Personnel
Role: Investigator
First_Name: LEE-LUENG
Last_Name: FU
Email: podaac@podaac.jpl.nasa.gov
Phone: (818) 354-8167
FAX: (818) 393-6720
Group: Address
MS 300-323
Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109
USA
End_Group
End_Group
Group: Personnel
Role: Technical Contact
First_Name: PLEASE CONTACT
Last_Name: JPL DAAC USER SERVICES
Email: jpl@eos.nasa.gov
Email: podaac@podaac.jpl.nasa.gov
Phone: (818) 354-9890
FAX: (818) 393-2718
FAX: (818) 393-6720
Group: Address
MS 300-320
Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109
USA
End_Group
End_Group
Group: Personnel
Role: DIF Author
First_Name: VICTOR
Last_Name: ZLOTNICKI
Email: vz@pacific.jpl.nasa.gov
Phone: (818) 354-5519
FAX: (818) 393-6720
Group: Address
MS 300-323
Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109
USA
End_Group
End_Group
Discipline: EARTH SCIENCE
Group: Parameters
Category: EARTH SCIENCE
Topic: ATMOSPHERE
Term: ATMOSPHERIC WATER VAPOR
Variable: PRECIPITABLE WATER
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: ATMOSPHERE
Term: ATMOSPHERIC WINDS
Variable: SURFACE WINDS
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: ATMOSPHERE
Term: CLOUDS
Variable: CLOUD PRECIPITABLE WATER
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: COASTAL PROCESSES
Variable: SEA LEVEL RISE
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: COASTAL PROCESSES
Variable: SEA SURFACE HEIGHT
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: MARINE GEOPHYSICS
Variable: MARINE GRAVITY FIELD
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: OCEAN CIRCULATION
Variable: OCEAN CURRENTS
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: OCEAN CIRCULATION
Variable: VORTICITY
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: OCEAN CIRCULATION
Variable: WIND-DRIVEN CIRCULATION
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: OCEAN WAVES
Variable: SEA STATE
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: OCEAN WAVES
Variable: SIGNIFICANT WAVE HEIGHT
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: OCEAN WAVES
Variable: WAVE HEIGHT
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: OCEAN WAVES
Variable: WIND WAVES
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: OCEAN WINDS
Variable: SURFACE WINDS
Detailed_Variable:
End_Group
Group: Parameters
Category: EARTH SCIENCE
Topic: OCEANS
Term: SEA SURFACE HEIGHT
Variable: SEA SURFACE HEIGHT
Detailed_Variable:
End_Group
Sensor_Name: ALT (TOPEX) > TOPEX Radar Altimeter
Sensor_Name: ALTIMETERS
Sensor_Name: MICROWAVE RADIOMETER
Sensor_Name: RADAR ALTIMETERS
Sensor_Name: RADIOMETERS
Sensor_Name: SSALT > POSEIDON Solid State Radar Altimeter
Sensor_Name: TMR > TOPEX Microwave Radiometer
Source_Name: TOPEX/POSEIDON > Ocean Topography Experiment
Group: Temporal_Coverage
Start_Date: 1992-09-22
End_Group
Data_Set_Progress: IN WORK
Group: Spatial_Coverage
Southernmost_Latitude: 66S
Northernmost_Latitude: 66N
Westernmost_Longitude: 180W
Easternmost_Longitude: 180E
End_Group
Location: BOUNDARY LAYER
Location: IONOSPHERE
Location: SEA SURFACE
Location: TROPOSPHERE
Group: Data_Resolution
Latitude_Resolution: 0.05 deg
Longitude_Resolution: 3 deg
Temporal_Resolution: 1 sec
End_Group
Project: WOCE > World Ocean Circulation Experiment
Group: Quality
Sea surface height above ellipsoid to better than 5 cm for a single 1
sec point
End_Group
Group: Use_Constraints
This product is research data, both because of its form and content. The
data consist entirely of files comprising headers and data records with
over a hundred parameters for each second. It is organized along the
satellite's track, not gridded. There are no images. Read software is
contained on the CD-ROM. Both calculation of sea surface height from the
altimeter range and environmental corrections as well as analysis software
are the responsibility of the user.
End_Group
Originating_Center: JPL
Group: Data_Center
Data_Center_Name: JPL/PODAAC > Physical Oceanography Distributed Active Archive Center
Data_Center_URL: http://podaac.jpl.nasa.gov
Data_Set_ID: Product 068
Group: Personnel
Role: Data Center Contact
First_Name: PLEASE CONTACT
Last_Name: JPL DAAC USER SERVICES
Email: jpl@eos.nasa.gov
Email: podaac@podaac.jpl.nasa.gov
Phone: (818) 354-9890
FAX: (818) 393-2718
FAX: (818) 393-6720
Group: Address
MS 300-320
Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109
USA
End_Group
End_Group
End_Group
Group: Distribution
Distribution_Media: CD-ROM
Distribution_Format: VAX binary Integer words
Fees: free
End_Group
Group: Reference
Benada, R., PO.DAAC Merged GDR (TOPEX/POSEIDON)-B Users Handbook,
Rep. JPL D-11007, Jet Propulsion Laboratory, Pasadena, CA, 1997.

Callahan, P., TOPEX/POSEIDON Project GDR Users Handbook, Rep. JPL
D-8944, Rev. A, Jet Propulsion Laboratory, Pasadena, CA, 1993.

TOPEX Project, TOPEX Ground System Software Interface
Specification, Volume 2: Design (SIS-2) Geophysical Data Record (GDR) - GDR
Data, Interim Geophysical Data Record (IGDR) - GDR Data, Rep. JPL D-8590,
Rev. C,Jet Propulsion Laboratory, Pasadena, CA, 1993.

TOPEX/POSEIDON Project, Mission Plan, Rep. JPL D-6862, Rev., Jet
Propulsion Laboratory, Pasadena, CA, 1991.

Fu, L.-L., et al., TOPEX/POSEIDON Mission Overview, J. Geophys.
Res., 99, 24,369-24,381, 1994.

End_Group
Group: Summary
The TOPEX/POSEIDON MGDR-B (Merged Geophysical Data Record-B) dataset
contains altimeter and microwave radiometer data from the TOPEX/POSEIDON
mission, a joint endeavour of NASA and the French space agency CNES (Centre
National d' Etudes Spatiales). This data set (MGDR-B) has generation B
algorithms, and replaces the generation A dataset identified as JPL PO.DAAC
Product 028.

The data start September 22, 1992, and continue as of this writing
(1997-07-12). The spatial coverage is global between latitudes +/-66
degrees. The temporal sampling is once every 1 second along the satellite
track; the groundtrack pattern repeats within +/- 1 km every 9.9156 days
(127 orbits around the Earth). The spatial sampling is about 6 km along the
tracks, with maximum gaps between neighbouring tracks of 315 km at the
Equator.

The data product includes measurements from the NASA dual frequency
altimeter (Ku and C band, 13.6 and 5.3 Ghz) which is ON 90% of the time,
the French (CNES) solid-state altimeter (Ku band) which is ON 10% of the
time, and the Topex Microwave Radiometer (TMR, 18, 21, and 37 Ghz) which is
ON all the time.

The main parameters included in the dataset are: sea surface height
above the ellipsoid, 1-sec average; significant wave height; wind
speed; atmospheric total water vapor; ionospheric electron content;
tidal height (from a model); time-mean sea surface height above the
ellipsoid (from a model); geoid height above the ellipsoid (from a
model). In addition a number of engineering parameters and quality flags
are included. No waveform data are included in the MGDR. Some coverage and
quality control plots are also included.

The present product is research data, in intent, form and content. It
consists entirely of files with over a hundred parameters for each 1-second
data record. They are organized along the satellite's track, not mapped.
There are no images. Although read software is contained on the CD-ROM,
software to calculate sea surface height from the altimeter range and
environmental corrections as well as analysis software are the
responsibility of the user.

The MGDR-B are distributed on CD-ROMs (ISO 9660), 1 CD-ROM holds 30
days worth of data. All data values are VAX binary integers, with some
headers in ASCII text, but the software allows the binary data to be
converted to other representations.

Availability: All data from the start of mission through November 1997
are available except cycles 1, 2 and 3. The remainder of the data through
January 1998 will be available by the end of April 1998.
After that, CD-ROMS will be produced with 1-2 month delay from
observation time. Software, documentation and data for cycles 1-142
are available via FTP from podaac.jpl.nasa.gov, but users are
requested to restict access to a few files because of the large file
sizes. Each file is GnuZipped, and a cycle occupies approximately 95
MB/cycle. Assuming an average 10 KB/sec ftp transfer rate, this
translates as 2.7 hours/cycle. The MGDR-B data is JPL Product 068 and
can be ordered at "http://podaac.jpl.nasa.gov". The TOPEX/POSEIDON
Project maintains web pages at "http://topex-www.jpl.nasa.gov".

As opposed to MGDR-A, this product does not include crossover files in
the CDs. The crossovers will be released as a separate data product.
Recently produced tide models (see
"http://podaac.jpl.nasa.gov/tides.shtml") are available as a separate
product on CD-ROM (Product 055:
"http://podaac.jpl.nasa.gov/cdrom/tide/index.htm"). T/P waveform data
are provided in Product 035, the TOPEX altimeter sensor data record.

The main references are:

Benada, R., PO.DAAC Merged GDR (TOPEX/POSEIDON)-B Users Handbook, Rep.
JPL D-11007, Jet Propulsion Laboratory, Pasadena, CA, 1997.

Fu, L.-L., et al., TOPEX/POSEIDON Mission Overview, J. Geophys. Res.,
99, 24,369-24,381, 1994.

End_Group
IDN_Node: USA/NASA
Last_DIF_Revision_Date: 1998-03-16

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