IceBridge Paroscientific L1B Pressure Altimeter Time-Tagged Air Pressure

This data set contains static pressure values for Antarctica using the Paroscientific Digiquartz Transmitter. 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.

Table of Contents

  1. Contacts and Acknowledgments
  2. Detailed Data Description
  3. Data Access and Tools
  4. Data Acquisition and Processing
  5. References and Related Publications
  6. Document Information

Citing These Data

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://nsidc.org/data/iaprs1b.html.

Overview

Platform

BT-67 DC-3T

Sensor

Paroscientific Pressure Altimeter

Spatial Coverage

Antarctica

Spatial Resolution

20 meters

Temporal Coverage

29 December 2008 to present

Temporal Resolution

Seasonal

Parameters

Static pressure

Data Format

ASCII text (.txt) and XML (.xml)

Metadata Access

View Metadata Record

Data Access

FTP

1. Contacts and Acknowledgments

Investigator(s) Name and Title

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

Technical Contact

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
e-mail: nsidc@nsidc.org

Acknowledgements

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.

2. Detailed Data Description

Format

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.

File and Directory Structure

Data are available on the FTP site in the ftp://n5eil10u.ecs.nsidc.org/SAN2/ICEBRIDGE/IAPRS1B.001/ directory. This directory is organized by date, for example /2013.01.26/.

File Naming Convention

Files are named according to the following convention and as described in Table 1:

IAPRS1B_2013025_ICP5_JKB2h_RIGGS1c_pressure.txt
IAPRS1B_2013025_ICP5_JKB2h_RIGGS1c_pressure.txt.xml

IAPRS1B_YYYYDOY_AAAA_JKBnx_XXXX_pressure.xxx

Where:

Table 1. Naming Convention
Variable Description
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
AAAA Geographic area
JKBnx Host platform
XXXX Geographic track line
pressure Static pressure
.xxx Indicates ASCII text file (.txt), or XML file (.xml)

File Size

The data files range from approximately 10 KB to 5 MB.

XML files range from approximately 10 KB to 63 KB.

Volume

The entire data set is approximately 933 MB.

Spatial Coverage

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

Spatial Resolution

20 meters along track. 150 meters along track for late 2011 field season.

Projection and Grid Description

WGS-84 ellipsoid; ITRF 2008

Temporal Coverage

These data were collected from 29 December 2008 to the present as part of ICECAP, NSF, NERC, and Operation IceBridge funded campaigns.

Temporal Resolution

ICECAP campaigns were conducted on an annual basis. East Antarctic campaigns for this data set typically extend from November to early January.

Parameter or Variable

Parameter Description

The L1B Pressure Altimeter Time-Tagged Air Pressure data files contain fields as described in Table 2.

Table 2. File Parameter Description
Parameter Description Units
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
PRESSURE Static pressure kiloPascals

Note: Positions are interpolated from the real time GPS feed and have an accuracy of several meters.

Sample Data Record

Figure 1 shows the first ten records from the data file IAPRS1B_2013025_ICP5_JKB2h_RIGGS1c_pressure.txt.

sample data record

3. Data Access and Tools

Data Access

Data are available via FTP.

Software and Tools

No special tools are required for the ASCII text files.

4. Data Acquisition and Processing

Theory of Measurements

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.

Data Acquisition Methods

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.

Derivation Techniques and Algorithms

The only processing was to time register the samples and to convert the units to International System (SI) units (kiloPascals).

Trajectory and Attitude Data

Trajectory and attitude data were interpolated to this product from the IceBridge GPS L1B Time-Tagged Real-Time Position and Attitude Solution (IPUTN1B) product.

Processing Steps

Missing values have been replaced by "nan".

Version History

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.

Error Sources

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.

Sensor or Instrument Description

Paroscientific Intelligent Transmitters 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

5. References and Related Publications

Related Data Collections

Related Web Sites

6. Document Information

Acronyms and Abbreviations

The acronyms used in this document are listed in Table 3.

Table 3. Acronyms and Abbreviations
Acronym Description
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
L1B Processing Level-1B
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

Document Creation Date

10 December 2014

Document Revision Date

.....

Document URL

http://nsidc.org/data/docs/daac/icebridge/iaprs1b/index.html