Data Management Plan
IceBridge Data Management Plan (pdf)
Check the ESDIS Doc Server at https://ops1-cm.ems.eosdis.nasa.gov/cm2 to verify that this is the correct version prior to use.
Earth Science Data and Information System Project, Code 423
August 2018
Expires: End of project, 2020
Reviewed by:
Jeanne Behnke
ESDIS Deputy – Operations
GSFC – Code 423
Steve Tanner
NSIDC DAAC Operation IceBridge
Manager
National Snow and Ice Data Center
Approved by:
Andy Mitchell
ESDIE Project Manager
GSFC – Code 423
Joseph Macgregor
Operation IceBridge Project Scientist
GSFC – Code 615
Amanda Leon
NSIDC DAAC Manager
National Snow and Ice Data Center
Preface
This document is under ESDIS Project configuration control. Once this document is approved, ESDIS approved changes are handled in accordance with Class I and Class II change control requirements described in the ESDIS Configuration Management Procedures, and changes to this document shall be made by document change notice (DCN) or by complete revision.
This document contains information pertaining to the Operation IceBridge Data Management Plan.
Any questions should be addressed to:
ESDIS Configuration Management Office
NASA/GSFC
Code 423
Greenbelt, Md. 20771
Abstract
This document is a detailed plan for all management of Operation IceBridge data throughout its project lifecycle ending in 2020. Its content is applicable to all data providers and all data sets unless specific exceptions are made.
Keywords: IceBridge, NSIDC DAAC, CReSIS, LIDAR, WFF, GSFC, NSERC, CIRRUS, UARC, DMS, Lamont-Doherty, WISE
Table of Contents
1 INTRODUCTION
1.1 SCOPE
1.2 MISSION DESCRIPTION
2 REQUIREMENTS
2.1 SCIENCE DATA GENERATION AND DOCUMENTATION
2.2 SCIENCE DATA FORMAT AND METADATA
3 PROVIDERS, PRODUCTS, AND DEADLINES
3.1 UNIVERSITY OF KANSAS CENTER FOR REMOTE SENSING OF ICE SHEETS (CRESIS)
3.1.1 Instruments and Science Data Products
3.1.1.1 Accumulation Radar
3.1.1.2 Ku-Band Radar Altimeter
3.1.1.3 Multichannel Coherent Radar Depth Sounder (MCoRDS)
3.1.1.4 Snow Radar
3.2 NASA WALLOPS FLIGHT FACILITY
3.2.1 Instruments and Science Data Products
3.2.1.1 Airborne Topographic Mapper (ATM)
3.2.1.2 Narrow Swath Airborne Topographic Mapper (ATM)
3.2.1.3 Continuous Airborne Mapping By Optical Translator (CAMBOT)
3.2.1.4 KT19 Infrared Radiation Pyrometer
3.3 NASA GODDARD SPACE FLIGHT CENTER
3.3.1 Instruments and Science Data Products
3.3.1.1 Land, Vegetation, and Ice Sensor (LVIS)
3.4 NATIONAL SUBORBITAL EDUCATION AND RESEARCH CENTER (NSERC)
3.4.1 Instruments and Science Data Products
3.4.1.1 On-board Meteorology Suite
3.5 CIRRUS DIGITAL SYSTEMS
3.5.1 Instruments and Science Data Products
3.5.1.1 Cirrus CIR Camera
3.6 UNIVERSITY AFFILIATED RESEARCH CENTER (UARC)
3.6.1 Instruments and Science Data Products
3.6.1.1 Digital Mapping System Camera (DMS)
3.7 LAMONT-DOHERTY EARTH OBSERVATORY
3.7.1 Instruments and Science Data Products
3.7.1.1 Magnetometer
3.7.1.2 Gravimeter
3.8 UNIVERSITY OF TEXAS
3.8.1 Instruments and Science Data Products
3.8.1.1 GPS / Inertial Measurements
3.8.1.2 Gravimeter
3.8.1.3 High Capability Radar Sounder (HiCARS)
3.8.1.4 Laser Altimeter
3.8.1.5 Scanning Lidar
3.8.1.6 Magnetometer
3.8.1.7 Pressure Altimeter
3.9 UNIVERSITY OF ALASKA FAIRBANKS
3.9.1 Instruments and Science Data Products
3.9.1.1 Glacier Lidar
3.10 UNIVERSITY OF CALIFORNIA IRVINE
3.10.1 Instruments and Science Data Products
3.10.1.1 WISE
3.11 UNIVERSITY OF COLORADO/CULPIS-X
3.11.1 Instruments and Science Data Products
3.12 MISCELLANEOUS
3.12.1 Data Products
3.12.1.1 Flight Reports
3.12.1.2 Derived Products
4 DATA STEWARDSHIP
4.1 ACCEPTANCE OF NEW DATA SETS
4.2 DATA SUBMISSION PROCESS
4.3 NAMING CONVENTIONS
5 ABBREVIATIONS AND ACRONYMS
1. Introduction
1.1 Scope
This document outlines a detailed plan for all aspects of Operation IceBridge data management throughout its project lifecycle until 2020. Its content is applicable to all data providers and all data sets unless specific exceptions are made.
1.2 Mission Description
The Operation IceBridge mission, initiated in 2009, collects airborne remote sensing measurements to bridge the gap between NASA’s Ice, Cloud and Land Elevation Satellite (ICESat) mission and the upcoming ICESat-2 mission. Operation IceBridge survey areas include the Greenland and Antarctic ice sheets, Canadian ice caps, Alaskan glaciers, and sea ice in the Arctic and Southern oceans.
Operation IceBridge combines multiple instruments to map ice surface topography, bedrock topography beneath the ice sheets, grounding line position, ice and snow thickness, and sea ice distribution and freeboard. Data from laser altimeters and radar sounders are paired with gravimeter, magnetometer, mapping camera, and other data to provide dynamic, high-value, repeat measurements of rapidly changing portions of land and sea ice.
2. Requirements
2.1 Science Data Generation and Documentation
2.1.1 All Operation IceBridge data products shall conform to the terms and conditions of the NASA Earth Science Data and Information Policy, which can be found at: http://science.nasa.gov/earth-science/earth-science-data/data-information-policy/.
2.1.2 Operation IceBridge data providers shall be assigned the responsibility of producing data products for their respective instruments.
2.1.3 To keep end-to-end consistency, Operation IceBridge data providers shall reprocess any given data product (in its entirety, including data from earlier IceBridge campaigns) that requires an algorithm change.
2.1.4 To keep end-to-end consistency, Operation IceBridge data providers shall reformat any given data product (in its entirety, including data from earlier campaigns) that requires a format change.
2.1.5 By the end of mission, Operation IceBridge data providers shall provide all documentation necessary for final archival purposes as spelled out in the NASA Earth Science preservation document at: https://earthdata.nasa.gov/user-resources/standards-and-references/preservation-content-spec
2.1.6 Operation IceBridge data providers shall provide documentation, as specified by NASA/NSIDC documentation content requirements to facilitate users’ understanding and use of their data products. NSIDC User Services will provide template documentation upon request and will work with data providers to develop appropriate documentation.
2.1.7 Operation IceBridge data providers shall submit product documentation to the NSIDC DAAC as early as possible before the first delivery of a new product, and be available to work with NSIDC technical writers, to facilitate establishment of the new product. For subsequent data deliveries, data providers shall submit updates to documentation within one week after the submission of data to the NSIDC DAAC for ingest, archive and distribution.
2.1.8 Operation IceBridge L1B and L2 data products shall be organized and partitioned temporally, following each flight’s trajectory.
2.2 Science Data Format and Metadata
2.2.1 Operation IceBridge data product formats, with the exception of Level 0 or raw data, shall conform to one of the NASA Earth Science Division (ESD) approved Data System standards. The formats will be selected in collaboration with the ESDIS Project and documented in Section 4 of this Data Management Plan. The list of existing approved standards, along with guidelines for approval of new standards, can be found at: https://earthdata.nasa.gov/user-resources/standards-and-references. Once decided upon and agreed to, a data set’s format should be kept consistent for all future deliveries, unless renegotiated with a plan for reprocessing of existing data.
2.2.1 All data submissions to the NSIDC DAAC shall have accompanying spatial, temporal, and product metadata that adhere to ESD-approved specifications at: https://earthdata.nasa.gov/user-resources/standards-and-references.
3. Providers, Products, and Deadlines
This section describes each of the individual data providers, their instruments, the data products that they generate, and their associated submission deadlines. For each data product, the following information is provided.
- Product collection short name
- A brief product description
- Data processing level
- Data format
- Estimated data volume per campaign (GB)
- Submission schedule
- Provider contact information
- Delivery mechanism
3.1 NASA Wallops Flight Facility
NASA Goddard Space Flight Center’s Wallops Flight Facility, located on Virginia’s Eastern Shore, was established in 1945 by the National Advisory Committee for Aeronautics, as a center for aeronautic research. The research and responsibilities of Wallops Flight Facility are centered on the philosophy of providing a fast, low cost, highly flexible and safe response to meet the needs of the United States’ aerospace technology interests and science research.
Provider POCs | Email Address |
---|---|
Michael Studinger | Michael.Studinger@nasa.gov |
Jim Yungel | James.K.Yungel@nasa.gov |
3.1.1 Instruments and Science Data Products
3.1.1.1 Airborne Topographic Mapper (ATM)
The ATM is a scanning Laser Imaging Detection and Ranging (LIDAR) developed and used by NASA for observing the Earth’s topography for several scientific applications, foremost of which is the measurement of changing Arctic and Antarctic ice sheets and glaciers. It typically flies on aircraft at an altitude between 400 and 800 meters above ground level, and measures topography to an accuracy better than ten centimeters by incorporating measurements from global positioning system (GPS) receivers and inertial navigation system (INS) attitude sensors.
Table 3.5. ATM Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
ILATM0 | IceBridge ATM L0 Raw Ranges | 0 | Binary | 175 | 6 months | FTP or equivalent |
ILATM1B | IceBridge ATM L1B Qfit Elevation and Return Strength | 1B | HDF5 | 500 | 6 months following deployment end | FTP or equivalent |
ILATMW1B | IceBridge ATM L1B Elevation and Return Strength with Waveforms | 1B | HDF5 | 75 | 6 months following deployment end | FTP or equivalent |
ILATM2 | IceBridge ATM L2 Icessn Elevation, Slope, and Roughness | 2 | Fixed format ASCII | 2 | 6 months following deployment end | FTP or equivalent |
IDHDT4 | IceBridge ATM L4 dh/dt | 4 | Fixed format ASCII | 0.2 | 6 months following deployment end | FTP or equivalent |
3.1.1.2 Narrow Swath Airborne Topographic Mapper
The NASA IceBridge Narrow Swath ATM Level-1B Qfit Elevation and Return Strength (ILNSA1B) data set contains spot elevation measurements of Greenland, Arctic, and Antarctic sea ice acquired using the NASA ATM 4CT3 narrow scan instrumentation
Table 3.6. Narrow Swath ATM Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
ILNSA1B | IceBridge Narrow Swath ATM L1B Qfit Elevation and Return Strength | 1B | HDF5 | 30 | 6 months following deployment end | FTP or equivalent |
3.1.1.3 Continuous Airborne Mapping By Optical Translator (CAMBOT)
The NASA IceBridge CAMBOT L1B Geolocated Images data set contains images taken over Antarctica and Greenland. The data set contains original CAMBOT files and full size Joint Pictures Expert Group (JPEG) images, with associated Keyhole Markup Language (KML) files, rotated and reduced-resolution Portable Network Graphics (PNG) image files, and position, altitude and trajectory files.
Table 3.7. CAMBOT Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IOCAM1B | IceBridge CAMBOT L1B Geolocated Images | 1B | jpeg | 500 | 6 months following deployment end | Hard drive |
3.1.1.4 KT-19 Infrared Radiation Pyrometer
The NASA IceBridge KT-19 IR Surface Temperature data set contains surface temperature measurements of Arctic sea ice and land ice acquired using the Heitronics KT19.85 Series II Infrared Radiation Pyrometer alongside the NASA ATM instrument.
Table 3.8. KT19 Infrared Radiation Pyrometer Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IAKST1B | IceBridge KT19 IR Surface Temperature | 1B | Fixed format ASCII | 0.5 | 6 months following deployment end | FTP to NSIDC |
3.1.1.5 Pathfinder Advanced Radar Ice Sounder (PARIS)
The IceBridge PARIS data set contains Greenland ice thickness measurements acquired using the Pathfinder Advanced Radar Ice Sounder (PARIS). The transmit waveform of this radar sounder is a 5 MHz bandwidth chirp generated by a commercial Direct-Digital Synthesizer (DDS) chip. The chip also applies a trapezoidal envelope to the pulse, minimizing unwanted sidebands. The 250 W amplifier uses a class AB mode of operation to ensure high linearity and thus preserve the pulse’s low sidebands. Bench tests of the amplifier demonstrated a two-tone third-order inter-modulation of better than -20 dBc measured at PO = 250 W
Table 3.9. PARIS Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IAKST1B | IceBridge KT19 IR Surface Temperature | 1B | Fixed format ASCII | 0.5 | 6 months following deployment end | FTP to NSIDC |
3.2 University of Kansas Center for Remote Sensing of Ice Sheets (CReSIS)
The Center for Remote Sensing of Ice Sheets (CReSIS) is a Science and Technology Center established by the National Science Foundation (NSF)in 2005, with the mission of developing new technologies and computer models to measure and predict the response of sea level change to the mass balance of ice sheets in Greenland and Antarctica. The NSF’s Science and Technology Center (STC) program combines the efforts of scientists and engineers to respond to problems of global significance, supporting the intense, sustained, collaborative work that is required to achieve progress in these areas. NSF STC support ended in 2015, but CReSIS continues to operate with other external awards and university support.
Provider POCs | Email Address |
---|---|
Carl Leuschen | leuschen@cresis.ku.edu |
John Paden | paden@ku.edu |
3.2.1 Instruments and Science Data Products
3.2.1.3 Multichannel Coherent Radar Depth Sounder (MCoRDS)
This radar typically operates over the frequency range from 180 to 210 MHz on the NASA P-3 and 165 to 215 MHz on the NASA DC-8 with multiple receivers developed for airborne sounding and imaging of ice sheets. Multiple receivers permit digital beam-steering for suppressing cross-track surface clutter that can mask weak ice–bed echoes and strip-map synthetic aperture radar (SAR) images of the ice-bed interface. With 1225 W of peak transmit power on the P-3 and a peak transmit power of 6000 W on the DC-8, a loop sensitivity of >230 dB is achieved.
Table 3.3. MCoRDS Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IRMCR1B | IceBridge MCoRDS L1B Geolocated Radar Echo Strength Profiles | 1B | NetCDF | 100 | 6 months | FTP |
IRMCR2 | IceBridge MCoRDS L2 IceThickness | 2 | CSV | 1 | 6 months | FTP |
IRMCR3 | IceBridge MCoRDS L3Gridded IceThickness, Surface, and Bottom | 3 | ASCII | 1 | 6 months | FTP |
* IRMCR3 volume per campaign is dependent on availability of flight grids and community need for gridded products.
3.2.1.2 Snow Radar
This ultra-wideband radar operates over the frequency from 2 to 8 GHz to map near-surface internal layers in polar firn with fine vertical resolution. Starting in 2017 the Snow Radar was replaced with a single system which operates from 2-18 GHz, sub-band processing of the data will be done to provide simulated data from the historic 2-8 GHz system. The radar also measures the thickness of snow over sea ice. Information about snow thickness is essential to estimate sea ice thickness from ice freeboard measurements performed with satellite radar and laser altimeters.
Table 3.4. Snow Radar Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IRSNO1B | IceBridge Snow Radar L1B Geolocated Radar Echo Strength Profiles | 1B | NetCDF | 250 | 6 months | FTP |
3.2.1.3 Accumulation Radar
This radar provides fine depth resolution profiling of the top 100 m of the ice column. It is designed to map variations in the snow accumulation rate. When operated from aircraft, it operates from 600 to 900 MHz providing 28-cm depth resolution in ice.
Table 3.1. Accumulation Radar Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IRACC1B | IceBridge Accumulation Radar L1B Geolocated Radar Echo Strength Profiles | 1B | NetCDF | 150 | 6 months | FTP, SFTP or SCP |
3.2.1.4 Ku-Band Radar Altimeter
This wideband radar altimeter operates over the frequency range from 12 to 18 GHz. The primary purpose of this radar is high precision surface elevation measurements over polar ice sheets. The data collected with this radar can be analyzed in conjunction with laser-altimeter data to determine thickness of snow over sea ice. Starting in 2017, the Ku Radar was replaced with a single system which operates from 2-18 GHz (3.2.1.2), sub-band processing of the data will be done to provide simulated data from the historic 12-18 GHz system.
Table 3.2. Ku-Band Radar Altimeter Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IRKUB1B | IceBridge Ku-Band Radar L1B Geolocated Radar Echo Strength Profiles | 1B | NetCDF | 250 | 6 months | FTP |
3.3 NASA Goddard Space Flight Center
NASA’s Land, Vegetation and Ice Sensor (LVIS), which also includes data from an integrated inertial navigation system (INS) and GPS, is designed, developed and operated by the Laser Remote Sensing Laboratory, at NASA’s Goddard Space Flight Center.
Provider POCs | Email Address |
---|---|
Bryan Blair | James.B.Blair@nasa.gov |
Michelle Hofton | mhofton@umd.edu |
Emily Wilson | emily.l.wilson@nasa.gov |
Shar Etemad | shahriar.etemad@nasa.gov |
3.3.1 Instruments and Science Data Products
3.3.1.1 Land, Vegetationand Ice Sensor
LVIS is a scanning laser altimeter instrument that is flown, by aircraft, over target areas to collect data on surface topography, surface roughness, and vegetation coverage. LVIS has a scan angle of 12º, which produces a 2-km wide swath from a 10-km flight altitude. LVIS is a full-waveform laser altimeter, and, as such, the transmit and return waveforms are collected for each laser shot and released as the LVIS L1B product.
Table 3.9. LVIS Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
ILVIS0 | IceBridge LVIS L0 Raw Ranges | 0 | Binary | 500 | 1 month following deployment end | Hard drive |
ILVGH1B | IceBridge LVIS GH L1B Geolocated Return Energy Waveforms | 1B | HDF5 | 300 | 6 months following deployment end | FTP |
ILVGH2 | IceBridge LVIS GH L2Geolocated Surface Elevation Product | 2 | Fixed format ASCII | 30 | 6 months following deployment end | FTP |
ILVIS1B | IceBridge LVIS L1B Geolocated Return Energy Waveforms | 1B | HDF5 | 300 | 6 months following deployment end | FTP |
ILVIS2 | IceBridge LVIS L2Geolocated SurfaceElevation Product | 2 | Fixed format ASCII | 30 | 6 months following deployment end | FTP |
IPPLV1B | IceBridge LVIS POS/AV L1B Corrected Position and Attitude Data | 1B | sbet | 20 | 6 months following deployment end | FTP |
3.4 National Suborbital Education and Research Center (NSERC)
The NSERC is the product of a cooperative agreement between NASA and the University of North Dakota. NSERC supports science mission operations and aircraft deployments for Earth science research campaigns conducted by the NASA Airborne Science Program. NSERC provides payload integration engineering, data display and networking, and facility instrumentation for NASA’s fleet of research aircraft, including the DC-8 and P-3B airborne laboratories, the WB-57 high altitude platform, and the Global Hawk Uninhabited Aerial Vehicle, among others.
NSERC is also responsible for education and outreach activities for the Airborne Science Program, including organization and operation of the Student Airborne Research Program (SARP), a college-level summer internship that provides hands-on research experience in airborne science using NASA’s flying laboratories.
Provider POCs | Email Address |
---|---|
David van Gilst | d.vangilst@nserc.und.edu |
3.4.1 Instruments and Science Data Products
3.4.1.1 On-board Meteorology Suite
This is a collection of airborne in-flight meteorological and in-cabin measurements, and thermal emission measurements of near-nadir surface skin temperature. Instruments flown over Antarctica include cabin pressure transducer, 3-stage hygrometer, 2-stage hygrometer, total air temperature sensor, and infrared surface temperature pyrometer. The data files contain measurements for 36 meteorological, surface characteristic, and positional variables.
Table 3.10. On-board Meteorology Suite Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IAMET1B | IceBridge NSERC L1B Geolocated Meteorologic and Surface Temperature Data | 1B | ICARTT | <1 | 1 month after deployment | FTP |
3.5 The Airborne Sensor Facility (ASF)
The Airborne Sensor Facility at NASA Ames and Armstrong Research Centers provides data system development and operations, and payload integration services for the Airborne Science Program. It is also responsible for the development and operation of remote sensing instruments for the NASA Earth Observing System Project Science Office, that are used for satellite calibration and validation, process studies, and algorithm development. This includes field operations, data processing, and the operation of a NIST-traceable calibration laboratory
Provider POCs | Email Address |
---|---|
Rose Dominguez | roseanne.dominguez@nasa.gov |
Jeffrey Myers | jeffrey.s.myers@nasa.gov |
3.5.1 Instruments and Science Data Products
3.5.1.1 Digital Mapping System Camera
The DMS is an airborne digital camera that acquires high resolution natural color and panchromatic imagery from low and medium altitude research aircraft. Data acquired by DMS are used by a variety of scientific programs to monitor variation in environmental conditions, assess global change, and respond to natural disasters.
The DMS instrument is maintained and operated by the Airborne Sensor Facility (ASF) located at the NASA Ames Research Center in Mountain View, California, under the oversight of the Earth Observing System (EOS) Project Science Office at NASA Goddard.
Table 3.12. Digital Mapping System Camera
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IODCC0 | IceBridge DMS L0 Camera Calibration | 0 | 1 | 90 days | Hard Drive | |
IODMS0 | IceBridge DMS L0 Raw Imagery | 0 | jpg | 5120 | 90 days | Hard Drive |
IODMS1B | IceBridge DMS L1B Geolocated and Orthorectified Images | 1B | geotiff | 9216 | 90 days | Hard Drive |
IPAPP1B | IceBridge POS/AV L1B Corrected Position and Attitude Data | 1B | sbet | 35 | 90 days | FTP |
3.6 Cirrus Digital Systems (UARC)
Cirrus Digital Systems is a California based company that processes Digital Mapping System (DMS) stereographic imagery and ATM Lidar into a Level 3 Hybrid Surface Model (HSM). The HSM possesses the elevation accuracy of ATM and visual realism and surface resolution of DMS imagery.
Provider POCs | Email Address |
---|---|
John Arvesen | arvesen@cirrus-designs.com |
Ryan Dotson | rdotson@fireballit.com |
3.6.1 Instruments and Science Data Products
3.6.1.1 Cirrus HSM
Table 3.11. Cirrus HSM
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IODMS0 | IceBridge DMS L3 Photogrammetric DEM | 3 | Geotiff | ~2000 | 6 months (requires L1B ATM data) | Hard drive or BD-ROM |
3.7 Lamont-Doherty Earth Observatory
Lamont-Doherty Earth Observatory seeks fundamental knowledge about the origin, evolution and future of the natural world. Its scientists study the planet from its deepest interior to the outer reaches of its atmosphere, on every continent and in every ocean, providing a rational basis for the difficult choices facing humanity.
Provider POCs | Email Address |
---|---|
Kirsty Tinto | tinto@ldeo.columbia.edu |
3.7.1 Instruments and Science Data Products
3.7.1.1 Magnetometer
The NASA IceBridge Scintrex CS-3 Cesium Magnetometer records magnetic field readings and fluxgate values.
Table 3.13. Magnetometer
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IMCS30 | IceBridge Scintrex CS-3 Cesium Magnetometer L0 Raw Magnetic Field | 0 | ASCII | 20 | 5 Months after campaign | FTP |
IMCS31B | IceBridge Scintrex CS-3 Cesium Magnetometer L1B Geolocated Magnetic Anomalies | 2 | ICARTT | 4 | 5 Months after campaign | FTP |
3.7.1.2 Gravimeter
This gravimeter is a Sander Geophysics AIRGrav airborne gravity system. The AIRGrav data consist of measurements of aircraft attitude and acceleration. Aircraft attitude is provided as one file per flight. Gravity data include latitude and Eötvös corrected values, and the free air correction at various along-flight-line spatial filtering scales. Gravity data are organized temporally.
Table 3.14. Gravimeter
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IGGRV1B | IceBridge Sander AIRGrav L1B Geolocated Free Air Gravity Anomalies | 2 | ICARTT | 4 | 5 Months after campaign | FTP |
IGBTH3 | IceBridge Sander AIRGrav L3 Bathymetry | 4 | ASCII | 1 | 1 year | FTP |
IGBTH4 | IceBridge Sander AIRGrav L4 Bathymetry | 4 | ASCII | 2 | 1 year | FTP |
3.8 University of Texas
The University of Texas Institute for Geophysics (UTIG) is an academic research center best known for projects with an international scope. Prominent research areas include marine geology and geophysics, tectonics, terrestrial and lunar seismology, quantitative and exploration geophysics, and geophysical studies of ice sheets and of climate.
Provider POCs | Email Address |
---|---|
Don Blankenship | blank@ig.utexas.edu |
Duncan Young | duncan@utig.ig.utexas.edu |
3.8.1 Instruments and Science Data Products
3.8.1.1 GPS / Inertial Measurements
Two GPS-aided Inertial Measurement Units (IMU) are included in this suite. One is standalone and one is integrated with the Scanning Lidar.
Table 3.15. GPS / IMU
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IPUTG0 | IceBridge GPS L0 Raw Satellite Navigation Data | 0 | ELSA/ NMEA | 1 | 2 months post field; non critical | FTP |
IPUTI0 | IceBridge IMU L0 Raw Inertial Measurement Unit Data | 0 | ELSA/ MMQ-50/ Novatel | 1 | 2 months post field; non critical | FTP |
IPUTG1B | IceBridge GPS/IMU L1B Primary Position and Attitude Solution | 1B | ASCII | <1 | 4 months post field | FTP |
IPUTN1B | IceBridge GPS L1B Time-Tagged Real-Time Position and Attitude Solution | 1B | ASCII | <1 | 2 months post field | FTP |
ITKTC0 | IceBridge L0 Raw Kinematics GPS Time Codes | 0 | ELSA/ ASCII time stamps | <1 | 2 months post field; non critical | FTP |
3.8.1.2 Gravimeter
Three gravimeters have been used by Texas for Operation IceBridge: a Bell Aerospace BGM-3 (#203); a ZLS Corporation ZLS (#S-83); and a Canadian Microgravity GT-1A (#3).
Table 3.16. Gravimeter
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IGBGM0 | IceBridge BGM-3 Gravimeter L0 Raw Accelerations | 0 | ELSA/ Counts per second | <1 | 2 months post field; non critical (retired after AN11) | FTP |
IGBGM1B | IceBridge BGM-3 Gravimeter L1B Time-Tagged Accelerations | 1B | ASCII | <1 | 2 months post field; (retired after AN11) | FTP |
IGBGM2 | IceBridge BGM-3 Gravimeter L2 Geolocated Free-Air Anomalies | 2 | ASCII | <1 | 4 months post field; (retired after AN11) | FTP |
IGZLS1B | IceBridge ZLS Dynamic Gravity Meter Time-Registered L1B Vertical Accelerations | 1B | ASCII | <1 | 2 months post field; (only used for AN11) | FTP |
IGCMG1B | IceBridge CMG 1A Dynamic Gravity Meter Time Time-Tagged L1B Vertical Accelerations | 1B | ASCII | <1 | 2 months post field;<p(only used for<pAN12) | FTP |
IGCMG2 | IceBridge CMG GT-1A Gravimeter L2 Geolocated Free-Air Gravity Disturbances | 2 | ASCII | <1 | 4 months post field; (only used for AN12) | FTP |
3.8.1.3 High Capability Radar Sounder (HiCARS)
This is a Very High Frequency (VHF) ice-penetrating radar which operates in frequency-chirped mode from 52.5 to 67.5 MHz. HiCARS allows for phase coherent recording of radar returns for advanced processing. For antennas the system uses twin flat dipoles, one mounted under each aircraft wing providing approximately 18 dB of two-way antenna gain. The peak instantaneous output power is 8kW.
Table 3.17. HiCARS
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IR1HI0 | IceBridge HiCARS 1 L0 Raw Return Energy Amplitudes | 0 | 16-bit offset video Binary | 1500 | 2 months post field; non critical (retired after AN10) | Hard drive |
IR1HIB | IceBridge HiCARS 1 L1B Time-Tagged Echo Strength Profiles | 1B | NetCDF | 120 | 2 months post field; (retired after AN10; format pending NSIDC approval) | Hard drive |
IR1HI2 | IceBridge HiCARS 1 L2 Geolocated Ice Thickness | 2 | ASCII | <1G | 4 months post field;<p(retired after AN10) | FTP |
IR2HI0 | IceBridge HiCARS 2 L0 Raw Return Energy Amplitudes | 0 | 16-bit offset video Binary | 1500 | 2 months post field; non critical (used after AN10) | Hard drive |
IR2HI1B | IceBridge HiCARS 2 L1B Time-Tagged Echo Strength Profiles | 1B | NetCDF | 120 | 2 months post field; (used after AN10; format pending NSIDC approval) | Hard drive |
IR2HI2 | IceBridge HiCARS 2 L2 Geolocated Ice Thickness | 2 | ASCII | <1 | 4 months post field; (retired after AN10) | FTP |
3.8.1.4 Laser Altimeter
This is a fixed, nadir pointing Riegl laser altimeter, which is the predecessor to the scanning, Sigma Space lidar.
Table 3.18. Laser Altimeter
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
ILUTP0 | IceBridge Riegl Laser Altimeter L0 Raw Ranges | 0 | ELSA/ Riegl | <1 | 2 months post field; non critical | FTP |
ILUTP1B | IceBridge Riegl Laser Altimeter L1B Time-Tagged Laser Ranges | 1B | ASCII | <1 | 2 months post field | FTP |
ILUTP2 | IceBridge Riegl Laser Altimeter L2 Geolocated Surface Elevation Triplets | 2 | ASCII | <1 | 4 months post field | FTP |
3.8.1.5 Scanning Lidar
This is a multi-beam, scanning photon-counting lidar built by Sigma Space. It images the surface below the aircraft with one hundred laser beamlets. This system is mechanically scanned in a swath either side of the flight path. A one hundred channel photon counting receiver captures return photons and records time of flight and time tag data allowing a three-dimensional reconstruction of the surface. At a survey altitude of 800 m, swath width is around 400 m.
Table 3.19. Scanning Lidar
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
ILSSP0 | IceBridge Sigma Space Prototype L0 Raw Time-of-Flight Data | 0 | Sigma Space binary | ~1000 to 3000 | 2 months post field; non critical (Retired after AN09) | Hard drive |
ILSIG0 | IceBridge Sigma Space Lidar L0 Raw Time-of-Flight Data | 0 | Sigma Space binary | ~1000 to 3000 | 2 months post field; non critical | Hard drive |
ILSIG1B | IceBridge Photon Counting Lidar L1B Uncorrected Geolocated Photon Elevations | 1B | HDF(details TBD) | 250 | 4 months | Hard drive |
ILSNP1B | IceBridge Sigma Space Photon Counting Lidar L1B Time-Tagged Nadir Photon Ranges | 1B | HDF5 (details TBD) | ~1000 | 4 months post field | Hard drive |
ILSNP4 | IceBridge Merged Photon Counting Lidar/Profiler L4 Surface Slope and Elevations | 4 | HDF | <1 | 4 months post field | FTP |
3.8.1.6 Magnetometer
There are two magnetometers used for these products. One is a cesium vapor magnetometer used for scalar geomagnetic field strength measurements. The other is a three-axis fluxgate magnetometer used to provide vector magnetic field data for use by the cesium magnetometer.
Table 3.20. Magnetometer
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IMFGM0 | IceBridge Flux Gate Magnetometer L0 Raw Magnetic Field | 0 | ELSA/3 channel voltages (HEX) | <1 | 2 months post field; non critical | FTP |
IMGEO0 | IceBridge Geometrics 823A Cesium Magnetometer L0 Raw Magnetic Field | 0 | ELSA/ Geometrics | <1 | 2 months post field; non critical | FTP |
IMGEO1B | IceBridge Geometrics 823A Cesium Magnetometer L1B Time-Tagged Magnetic Field | 1B | ASCII | <1 | 2 months post field | FTP |
IMGEO2 | IceBridge Geometrics 823A Cesium Magnetometer L2 Geolocated Magnetic Anomalies | 2 | ASCII | <1 | 2 months post field | FTP |
3.8.1.7 Pressure Altimeter
This instrument measures air pressure via a Paroscientific S-1000 Digiquartz Transmitter.
Table 3.21. Pressure Altimeter
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IAPRS0 | IceBridge Paroscientific S-1000 L0 Pressure Altimeter Raw Air Pressure | 0 | ELSA | <1 | 2 months post field; non critical | FTP |
IAPRS1B | IceBridge Paroscientific S-1000 L1B Pressure Altimeter Time-Tagged Air Pressure | 1B | ASCII | <1 | 2 months post field | FTP |
3.9 University of Alaska Fairbanks
The University of Alaska Fairbanks (UAF) is a public research university home to seven major research areas. The Geophysical Institute is one of the seven that conducts research into space physics, atmospheric science, seismology, tectonics, and sedimentation.
Provider POCs | Email Address |
Chris Larsen | cflarsen@alaska.edu |
3.9.1 Instruments and Science Data Products
3.9.1.1 Glacier Lidar
Table 3.22. Glacier Lidar
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
ILAKP1B | IceBridge UAF Lidar Profiler L1B Geolocated Surface Elevation Triplets | 1B | Binary | 20 | 3 months | FTP |
ILAKS1B | IceBridge UAF Lidar Scanner L1B Geolocated Surface Elevation Triplets | 1B | LAS | 135 | 3 months after campaign | FTP |
IPUAF1B | IceBridge UAF GPS/IMU L1B Corrected Position and Attitude Data | 1B | ASCII | 1 | 3 months after campaign | FTP |
3.10 University of California Irvine
The University of California Irvine’s (UCI) department of Earth System Science supports the Rignot Research Group. Relative to Operation IceBridge, the group measures ice thickness with an airborne ground penetrating radar called the Warm Ice Sounding Explorer (WISE) which operates at a center frequency of 2.5 MHz and is optimized to probe temperate ice.
Provider POCs | Email Address |
Eric Rignot | eric.j.rignot@jpl.nasa.gov |
Jeremie Mouginot | jmougino@uci.edu |
Bernd Scheuchl | bscheuch@uci.edu |
3.10.1 Instruments and Science Data Products
3.10.1.1 WISE
This sounder uses 120-mlong wavelengths to penetrate past rough ice surfaces, voids, water pockets, water-filled cracks, and temperate ice (ice at the in-situ-pressure melting point) before they are reflected by the interface between ice and the glacier bed. This makes the system well suited for the study of outlet glaciers with challenging internal structure, i.e. highly absorptive or scattering heterogeneities associated with the presence of liquid water pockets within the ice.
Table 3.23. WISE
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IRWIS2 | IceBridge WISE L2 Geolocated Ice Thickness and Surface Elevation | 2 | ASCII | 14 | 6 months | FTP |
3.11 Miscellaneous
3.11.1 Data Products
3.11.1.1 Flight Reports
Table 3.24. Flight Reports
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IFLTRPT | IceBridge Mission Flight Reports | n/a | ASCII and PDF | 1 | 6 months | FTP |
3.11.1.2 Derived Products
The NASA IceBridge Sea Ice Freeboard, Snow Depth, and Thickness (IDCSI4) data set contains derived geophysical data products including sea ice freeboard, snow depth, and sea ice thickness measurements in Greenland and Antarctica retrieved from IceBridge Snow Radar, DMS, CAMBOT, and ATM data sets. The data were collected as part of Operation IceBridge funded campaigns, are stored in American Standard Code for Information Interchange (ASCII) text files, and are available via File Transfer Protocol (FTP) for periodic, ongoing campaigns from 31 March 2009 to the present.
Provider POCs | Email Address |
Nathan Kurtz | nathan.t.kurtz@nasa.gov |
Table 3.25. Sea Ice Science Data Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IDCSI2 | IceBridge Sea Ice Freeboard, Snow Depth, and Thickness | 2 | ASCII | < 1 | 12 month following deployment end | FTP |
IDCSI4 | IceBridge L4 Sea Ice Freeboard, Snow Depth, and Thickness | 4 | ASCII | < 1 | 12 months | FTP |
The Bed Machine data set contains a bed topography/bathymetric map of Greenland based on mass conservation, multi-beam data, and other techniques. The data set also includes surface elevation, ice thickness and an ice/ocean/land mask
Provider POCs | Email Address |
Mathieu Morlighem | mathieu.morlighem@uci.edu |
Table 3.26. Bed Machine Data Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IDBMG4 | IceBridge BedMachine Greenland | 4 | NetCDF | 3 | 12 month | FTP |
The following Tomographic derived products were developed by NASA Jet Propulsion Laboratory (JPL) for swath ice sounding. Data was collected by the MCoRDs instrument and processed into bedmap products: ice thickness maps, ice thickness error maps, basal elevation maps, and basal reflectivity maps.
Provider POCs | Email Address |
Xiaoqing Wu | Xiaoqing.Wu@jpl.nasa.gov |
Table 3.27. Tomographic Products
Short Name | Product Description | Data Level | Format | Volume per Campaign (GB) | Submission Schedule | Delivery Mechanism |
---|---|---|---|---|---|---|
IRTIT | IceBridge Radar L3 Tomographic Ice Thickness | 3 | HDF5 | 2 | 12 Months | FTP |
IRTTE3 | IceBridge Radar L3 Tomographic Ice Thickness Error | 3 | HDF5 | 2 | 12 Months | FTP |
4. Data Stewardship
The NSIDC DAAC, with support from the ESDIS Project, is responsible for ingest, archive, and distribution of all IceBridge data products. This includes Level 0 data (where specified), higher level products, ancillary data, metadata, algorithm source code, documentation, and other information in accordance with EOS Data and Information System (EOSDIS) archive policies. Responsibilities also include the distribution of the above-mentioned products to users in accordance with the IceBridge mission and EOSDIS data distribution policies. Public release of these data shall conform to the NASA Earth Science Data and Information Policy, which can be found at: https://science.nasa.gov/earth-science/earth-science-data/data-information-policy/”>science/earth-science-data/data-information-policy/.
Previously, NSIDC used an abbreviated ingest process (“fasttrack”) which circumvented the approved NASA processes and standards in order to make data available as quickly as possible, and enabled data providers to deliver data with minimal metadata and documentation. That process will no longer be available. All data will be delivered to NSIDC using the steps described below unless ESDIS and the IceBridge Project Science Office grant specific exceptions.
In order to ensure that NASA’s expectations for data preservation and usability are met, NSIDC may delay publication of any data set that is not delivered with full documentation (as specified in the NASA documentation content specifications) or that does not meet delivery requirements.
4.1 Acceptance of New Data Sets
Before a new IceBridge data product is sent to the NSIDC DAAC, the following steps must first be implemented:
4.1.1 A description of the data product in question will be documented by the provider and sent to the Operation IceBridge Project Science Office, the ESDIS Project, and the NSIDC DAAC. This description will include:
- A description of the science content of the data product and its relevance to Operation IceBridge science requirements
- Level of product (0-4)
- Expected data volume (per life of mission)
- Current archive location
4.1.2 Review by ESDIS and the Project Science Office. Any new product that is proposed will be reviewed by ESDIS and the Operation IceBridge Project Science Office to make sure that the product is scientifically relevant, within the scope of the Operation IceBridge mission objectives, and that sufficient resources are available to support it. An evaluation of its current archive status will be made to determine if the product can be “brokered”, or linked, from its existing location rather than ingested into NSIDC’s data archive. Only when data is judged to be safely archived and sufficiently documented will a brokering arrangement be considered. In the case of brokering, NSIDC enables discovery of the data through appropriate links, but bears no further responsibility to the data.
4.1.3 Create appropriate short names and long names for each data product. NSIDC will do this in conjunction with the provider.
4.1.4 ESDIS will update this Data Management Plan.
4.2 Data Submission Process
This process applies to all IceBridge data sets that are not currently archived in NSIDC’s Earth Core System (ECS) system (unless ESDIS and the IceBridge Project Science Office grant an exception). As of March 2013, only UARC has been granted said exception for the DMS data sets.
As part of each new submission, each provider must provide NSIDC with the information required to create and validate an Earth Science Data Type (ESDT) that defines the structure of the data set. Once created, the ESDT is maintained as long as the data set structure does not change.
The provider is responsible for providing NSIDC with information required for any updates to the ESDT and notifying NSIDC if changes are planned to the content or structure of the data set. The ESDT must be consistent with the content of expected data delivery.
In order to efficiently ingest data into NSIDC’s ECS system, ESDIS has created (through its ECS contractor) a generic tool for creation of necessary metadata and associated files. This tool, called “SIPSMetGen”, is given to each provider along with associated configuration files for its correct operation.
Details of how to run the SIPSMetGen tool will be included with the tool package. Details of how data ingestion to NSIDC will now work using SIPSMetGen can be found in the IceBridge Science Investigator-led Processing System (SIPS) Operational Concept Document located at:
https://n5eil01u.ecs.nsidc.org/PullDir/OIB_SIPSMetGen/latest/SIPSMetGen_2.0.1_UserGuide.pdf.
The providers retain full responsibility for data and control over metadata quality. This process is simply a mechanism for automated ingest to NSIDC.
4.2.1 Before the first submission, the provider is responsible for performing integration testing with NSIDC to ensure that data will routinely be ingested successfully without excessive manual intervention by NSIDC’s Operations staff.
4.2.2 The provider is responsible for running the SIPSMetGen tool and creating the necessary metadata and Product Delivery Record (PDR) files before each data submission. After receipt of ingest status notices from ECS, the provider (with support from NSIDC and the ECS contractor) is responsible for all error correction and re-delivery.
4.3 Naming Conventions
Science data files and their associated supporting files (such as browse, quality assurance, preliminary metadata (“premet”), and spatial files) must use a standard naming convention. A file and its associated files should use the same name; the file extension distinguishes the data file from the associated files. File names should include the ESDT shortname, date and time of data collection, version identification, and any additional information that might be needed to uniquely identify the data file.
Example, for ATM L1B data:
Data file: ILATM1B_V01_04212010_04452366_A.h5
Premet file: ILATM1B_V01_04212010_04452366_A.premet
Spatial file: ILATM1B_V01_04212010_04452366_A.spatial
Abbreviations and Acronyms
AK | Alaska |
ASCII | American Standard Code for Information Interchange |
ASF | Airborne Sensor Facility |
ATM | Airborne Topographic Mapper |
CAMBOT | Continuous Airborne Mapping by Optical Translator |
CCAR | Colorado Center for Astrodynamics Research |
CReSIS | Center for Remote Sensing of Ice Sheets |
CSV | Comma Separated Value |
CULPIS-X | CU Lidar Profilometer and Imaging System – extended |
DAAC | Distributed Active Archive Center |
dB | Decibel |
DCN | Document Change Notice |
DMS | Digital Mapping System |
ECS | EOSDIS Core System |
EED | EOSDIS Evolution and Development |
ELSA | Environment for Linked Stream Acquisition |
EOS | Earth Observing System |
EOSDIS | EOS Data and Information System |
ESD | Earth Science Division |
ESDIS | Earth Science Data and Information System |
ESDT | Earth Science Data Type |
FTP | File Transfer Protocol |
GB | Giga (109) Byte |
GHZ | Giga Hertz |
GPS | Global Positioning System |
GSFC | Goddard Space Flight Center |
HDF | Hierarchical Data Format |
HEX | Hexadecimal |
HiCARS | High Capability Radar Sounder |
HSM | Hybrid Surface Model |
ICARTT | International Consortium for Atmospheric Research on Transport and Transformation |
ICESat | Ice, Cloud and Land Elevation Satellite |
IMU | Inertial Measurement Units |
INS | Inertial Navigation System |
JPEG | Joint Pictures Expert Group |
JPL | Jet Propulsion Laboratory |
Km | Kilometers |
KML | Keyhole Markup Language |
L0 – L4 | Level 0 through Level 4 |
LAS | Live Access Server |
LIDAR | Laser Imaging Detection and Ranging |
LVIS | Land, Vegetation, and Ice Sensor |
MB | Mega Byte 106 bytes |
Mbps | Mega bits per second |
MCoRDS | Multichannel Coherent Radar Depth Sounder |
MHz | Mega Hertz |
NASA | National Aeronautics and Space Administration |
NMEA | National Marine Electronics Association |
NetCDF | Network Common Data Form |
NSERC | National Suborbital Education and Research Center |
NSF | National Science Foundation |
NSIDC | National Snow and Ice Data Center |
PDR | Product Delivery Record |
PNG | Portable Network Graphics |
POC | Point of Contact |
POS | Product Order Status |
SAR | Synthetic Aperture Radar |
SARP | Student Airborne Research Program |
SIPS | Science Investigator-led Processing System |
STC | Science and Technology Center |
TBD | To Be Determined |
UAF | University of Alaska Fairbanks |
UARC | University Affiliated Research Center |
UC | University of California |
UCI | University of California Irvine |
UTIG | University of Texas Institute for Geophysics |
VHF | Very High Frequency |
WISE | Warm Ice Sounding Explorer |
ZLS | Zero-Length Spring Corporation |