This data set contains static pressure values for Antarctica using the Paroscientific Pressure Altimeter. The data were collected by scientists working on the Investigating the Cryospheric Evolution of the Central Antarctic Plate (ICECAP) project, which is funded by the National Science Foundation (NSF) and the Natural Environment Research Council (NERC) with additional support from NASA Operation IceBridge.
Operation IceBridge products may include test flight data that are not useful for research and scientific analysis. Test flights usually occur at the beginning of campaigns. Users should read flight reports for the flights that collected any of the data they intend to use. Check IceBridge campaign Flight Reports for dates and information about test flights.
We kindly request that you cite the use of this data set in a publication using the following citation. For more information, see our Use and Copyright Web page.
Donald D. Blankenship, Scott D. Kempf, Thomas G. Richter, and Duncan A. Young. 2012, updated 2014. IceBridge Paroscientific L1B Pressure Altimeter Time-Tagged Air Pressure. [indicate subset used]. Boulder, Colorado USA: NASA DAAC at NSIDC. http://dx.doi.org/10.5067/N1F4NBFMIREJ.
Paroscientific Pressure Altimeter
29 December 2008 to present
ASCII text (.txt) and XML (.xml)
Donald D. Blankenship, Scott D. Kempf, Thomas G. Richter, and Duncan A. Young
University of Texas at Austin
Institute for Geophysics
Austin, TX, 78759-8500
NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449 USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
Funding: NASA's Operation Ice Bridge (grant NNX09AR52G, contract NNG10HP06C (American Recovery and Reinvestment Act), and grant NNX11AD33G) to the University of Texas at Austin. NSF's International Polar Year activities (grant ANT-0733025) to the University of Texas at Austin, the Antarctic Ecosystems and Climate Collaborative Research Center at the University of Tasmania, and the UK's NERC grant NE/D003733/1 to University of Edinburgh. See data file header for funding information for each transect.
The data files are in space-delimited ASCII text format, with a header offset by # leading characters, corresponding to the NASA Aerogeophysical ASCII data standard. Each data file is paired with an associated XML file. The XML files contain location, platform, and instrument metadata.
Data are available on the FTP site in the ftp://n5eil10u.ecs.nsidc.org/SAN2/ICEBRIDGE/IAPRS1B.001/ directory. Within this directory are folders organized by date, for example /2013.01.26/.
Data stored in the /2008.12.29/ and /2008.12.31/ folders were collected as part of the 2009 campaign.
Files are named according to the following convention and as described in Table 1:
|IAPRS1B||Short name for IceBridge Paroscientific L1B Pressure Altimeter Time-Tagged Air Pressure|
|YYYY||Four-digit year of survey|
|DOY||Day of year of survey|
|XXXX||Geographic track line|
|.xxx||Indicates ASCII text file (.txt), or XML file (.xml)|
The data files range from approximately 10 KB to 5 MB.
XML files range from approximately 10 KB to 63 KB.
The entire data set is approximately 933 MB.
Spatial coverage for this data set is Antarctica, represented by this extent:
Southernmost Latitude: 90° S
Northernmost Latitude: 53° S
Westernmost Longitude: 180° W
Easternmost Longitude: 180° E
20 meters along track. 150 meters along track for late 2011 field season.
WGS-84 ellipsoid; ITRF 2008
These data were collected from 29 December 2008 to the present as part of ICECAP, NSF, NERC, and Operation IceBridge funded campaigns. Data collected in late December 2008 are part of the 2009 campaign.
ICECAP campaigns were conducted on an annual basis. East Antarctic campaigns for this data set typically extend from November to early January.
The L1B Pressure Altimeter Time-Tagged Air Pressure data files contain fields as described in Table 2.
|YEAR||Year of survey||UTC|
|DOY||Day of Year of survey||UTC|
|SOD||Second of day||UTC|
|SEC||Packet Sequence Number||n/a|
|LON||Longitude||Decimal degrees WGS-84|
|LAT||Latitude||Decimal degrees WGS-84|
|AC_ELEVATION||Aircraft elevation||Meters WGS-84|
|ROLL||Roll, right wing down positive||Degrees|
|PITCH||Pitch, nose up positive||Degrees|
|HEADING||Heading w.r.t north||Degrees|
Note: Positions are interpolated from the real time GPS feed and have an accuracy of several meters.
Figure 1 shows the first ten records from the data file IAPRS1B_2013025_ICP5_JKB2h_RIGGS1c_pressure.txt.
Data are available via FTP.
No special tools are required for the ASCII text files.
Outside air pressure is directed into a commercial off the shelf pressure transducer (Paroscientific). The pressure transducer internally digitizes the pressure measurements and outputs a serial data packet at regular intervals. This data set is acquired to assist with atmospheric corrections for laser altimetry, and to validate vertical acceleration data.
Static air was piped from a port on the exterior right side of the cockpit, via a sealed rubber hose to the pressure transducer. RS-232 packets are output at a rate of 4 Hz with the calibrated pressure value in millibars to the ELSA acquisition system.
The only processing was to time register the samples and to convert the units to International System (SI) units (kiloPascals).
Trajectory and attitude data were interpolated to this product from the IceBridge GPS L1B Time-Tagged Real-Time Position and Attitude Solution (IPUTN1B) product.
Missing values have been replaced by "nan".
On 02 May 2012, V01 2011 Antarctica data were replaced by V01.1. In V01.1, additional fields were added containing low-precision real-time position and orientation data resampled to match the times of the existing geophysical samples.
On 26 April 2013, the 2009, 2010, and 2011 Antarctica data were replaced. The format of 2009 and 2010 Antarctica data was revised to that of the 2011 Antarctica data, ensuring the time stamps are UTC year, day, and time, and adding georeferencing fields including real time position, roll, pitch and heading. For some campaigns V01.2 includes more flights than V01.1.
Resolution on the instrument data is 1 Pa (Pascal); observed jitter between consecutive samples is on the order of 1.3 Pa. Total range of the instrument is 0 to 103.4 kPa; the vendors quoted uncertainty is 10 Pa.
During the late 2011 field season, the raw output unit of the sensor was set to pounds per square inch, and the sample rate was set to 0.67 Hz.
Paroscientific Pressure Altimeters consist of a Digiquartz pressure transducer and a digital interface board in an integral package. Commands and data requests are sent via two-way RS-232 serial interfaces. Digital outputs are provided directly in engineering units with typical accuracy of 0.01 per cent over a wide temperature range. Output pressure is fully thermally compensated using a quartz crystal temperature signal. All intelligent transmitters are pre-programmed with calibration coefficients for full plug-in interchangeability
The acronyms used in this document are listed in Table 3.
|ASCII||American Standard Code for Information Interchange|
|CIRES||Cooperative Institute for Research in Environmental Science|
|FTP||File Transfer Protocol|
|ITRF||International Terrestrial Reference Frame|
|ICECAP||Investigating the Cryospheric Evolution of the Central Antarctic Plate|
|IMU||Inertial Measurement Unit|
|NASA||National Aeronautics and Space Administration|
|NERC||Natural Environment Research Council|
|NSF||National Science Foundation|
|NSIDC||National Snow and Ice Data Center|
|URL||Uniform Resource Locator|
|UTC||Universal Time Code|
|WGS-84||World Geodetic System 1984|
10 December 2014