bc55df03-cac4-4384-bfa7-57b65d969b48 eng utf8 dataset dataset NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom polardatacentre@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact 2019-11-25 ISO 19115 Geographic Information - Metadata ISO 19115:2003(E) European Petroleum Survey Group (EPSG) Geodetic Parameter Registry 2008-11-12 publication European Petroleum Survey Group EPSGadministrator@iogp.org https://www.epsg-registry.org/ EPSG Geodetic Parameter Dataset The EPSG Geodetic Parameter Dataset is a structured dataset of Coordinate Reference Systems and Coordinate Transformations, accessible through this online registry. information publisher urn:ogc:def:crs:EPSG::3031 6.18.3 Processed line aerogravity data over the Institute and Moller region (2010/11 season) 2019-11-25 creation 2019-11-25 revision 2019-11-25 publication 2019-11-25 released 1.0 https://doi.org/10.5285/bc55df03-cac4-4384-bfa7-57b65d969b48 doi GB/NERC/BAS/PDC/01261 https://data.bas.ac.uk/ NE/G013071/1 award Please cite this item as: Jordan, T., Ferraccioli, F., Ross, N., Corr, H., Leat, P., Bingham, R., Rippin, D., Le Brocq, A., & Siegert, M. (2020). Processed line aerogravity data over the Institute and Moller region (2010/11 season) (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/bc55df03-cac4-4384-bfa7-57b65d969b48 During the 2010/2011 Antarctic field season a collaborative NERC AFI (Antarctic Funding Initiative) project studying the basal boundary conditions of the Institute & Moller ice streams, West Antarctica, collected ~25,000 km of new high quality aerogravity data. Data were acquired using Lacoste and Romberg air-sea gravity meter S83, mounted in the BAS aerogeophysically equipped Twin Otter "Bravo Lima". Data are provided as XYZ ASCII line data. Data were collected as part of the UK Natural Environment Research Council AFI grant NE/G013071/1. No credit. completed Jordan, Tom British Antarctic Survey Researcher author Ferraccioli, Fausto British Antarctic Survey Researcher author Ross, Neil Newcastle University Researcher author Corr, Hugh British Antarctic Survey Researcher author Leat, Philip British Antarctic Survey Researcher author Bingham, Rob British Antarctic Survey Researcher author Rippin, David University of Leeds Researcher author Le Brocq, Anne Exeter University Researcher author Siegert, Martin Bristol Glaciology Centre, University of Bristol Researcher author NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact asNeeded completed EARTH SCIENCE > Solid Earth > Geodetics/Gravity > Gravity theme Global Change Master Directory (GCMD) Science Keywords 2026-01-27 publication 23 Global Change Data Center, Science and Exploration Directorate, Goddard Space Flight Center (GSFC) National Aeronautics and Space Administration (NASA) Greenbelt MD United States of America https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords Global Change Master Directory (GCMD) Keywords The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. information publisher Aerogeophysical Antarctic Gravity theme The Institute and Moller Glacier Antarctica place Geology theme GEMET - INSPIRE themes, version 1.0 2021-01-06 revision otherRestrictions no limitations to public access otherRestrictions no limitations license Open Government Licence v3.0 otherRestrictions This data is governed by the NERC Data Policy: https://www.ukri.org/who-we-are/nerc/our-policies-and-standards/nerc-data-policy/ otherRestrictions Further by downloading this data the user acknowledges that they agree with the NERC data policy (), and the following conditions: 1. To cite the data in any publication as follows: Jordan, T., Ferraccioli, F., Ross, N., Corr, H., Leat, P., Bingham, R., Rippin, D., Le Brocq, A., & Siegert, M. (2020). Processed line aerogravity data over the Institute and Moller region (2010/11 season) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/BC55DF03-CAC4-4384-BFA7-57B65D969B48 2. The user recognizes the limitations of data. Use of the data is at the users' own risk, and there is no warranty as to the quality or accuracy of any data, or the fitness of the data for your intended use. The data are not necessarily fully quality assured and cannot be expected to be free from measurement uncertainty, systematic biases, or errors of interpretation or analysis, and may include inaccuracies in error margins quoted with the data. doi doi crossReference doi doi crossReference doi doi crossReference doi doi crossReference doi doi crossReference url url largerWorkCitation url url crossReference url url crossReference url url crossReference textTable eng utf8 geoscientificInformation -108.9 -58.7 -84.11 -78.9 2010-12-20 2011-01-09 It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk. NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information distributor text/plain bytes 362807296 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=bc55df03-cac4-4384-bfa7-57b65d969b48 WWW:LINK-1.0-http--link Get Data Download data download dataset Methodology: Airborne gravity are presented in Jordan et al., (2012) along with further details on data collection. The dataset available here includes all channels from raw through to filtered and upward continued free air anomalies. All data is provided in the "by flight" database. Data processing steps: 1/ Calculate observed gravity. True spring tension (ST_real) is calculated from the posted spring tension (ST) correcting for the fact that for this survey the true spring tension approaches the posted value at 38 mGal per second. Beam velocity (Beam_vel) is derived from raw beam position (RB) assuming a centred difference approximation. Relative gravity (rec_grav) = (Spr_tens_real+((beam_vel)*k_fac)+CC)*scale_value, k_fac=30, meter scale value =0.9966. Still readings (Still) are in mGal and were calculating assuming a 2nd order best fit to the approximately linear drift of the meter observed at the tie down points. Airborne absolute gravity values (Abs_grav) = Rec_grav- Still + Base 2/ Corrections to derive free air anomalies (disturbances). Vertical acceleration (VaccCor) is calculated as 2nd derivative of flight altitude (Height_WGS1984), with a 3 point mean filter applied after differencing to reduce short wavelength noise. Eotvos correction (EotvosCor) follows (Harlan, 1968). Latitude correction (LatCor) = 978.03185(1+0.005278895 sin2Lat- 0.000023462 sin4Lat) (IUGG 1967). Free air correction (FaCor) = 0.3086*Height_WGS1984. NOTE subsequent free air values are defined as gravity disturbances in geodesy, as they are referred to the ellipsoid (Hackney and Featherstone, 2003). Horizontal acceleration correction (HaccCor). For this survey the approximation of (Swain, 1996) was used, assuming a damping factor of 0.707, and a platform period of 4 minutes. 3/ Free air anomaly and filtering. Free air anomaly (Free_air) = Abs_grav-VaccCor+EotvosCor+FaCor-LatCor-(0.5*HaccCor) Filtered free air anomaly (FAA_filt) used 9 km 1/2 wavelength space domain kernel filter (Holt et al., 2006). Final free air data (FAA_clip) was produced by manually masking turns, start and end of lines, and other regions of noisy data. Levelling correction (level_cor) includes both statistical (line and tie) and microleveling (line only) of free air data. FAA_level includes data after levelling. Upward continued free air anomaly (FAA_2600) was produced by upward continuing free air data from the collected flight altitude to 2600 m. Channel description: Basic Channels Date UTC date (YYYY/MM/DD) Time UTC time (HH:MM:SS.SS) FlightID Sequential flight number and survey ID e.g. W12 Line_no Line Number e.g. LW200.1:12 Lon Longitude WGS 1984 Lat Latitude WGS 1984 x x projected meters * y y projected meters * Height_WGS1984 Aircraft altitude (meters) in WGS 1984 Raw gravity Channels ST Spring Tension (meter units) CC Cross Coupling (meter units) RB Raw beam position (Mv) XACC Cross axis accelerometer (Mv) LACC Long axis accelerometer (Mv) Still Airborne meter still reading value (mGal) Base Absolute gravity reference, from land gravity (mGal) Calculation Channels St_real True Spring tension value (meter units) Beam_vel Gravity meter beam velocity (Mv/sec) Rec_grav Recalculated relative gravity (mGal) Abs_grav Calculated absolute gravity (mGal) VaccCor Vertical acceleration correction (mGal) EotvosCor Eotvos correction (mGal) LatCor Latitude correction (mGal) FaCor Free air correction (mGal) HaccCor Horizontal acceleration correction (mGal) Free air Channels Free_air Un-filtered free air anomaly (mGal) FAA_filt Filtered free air anomaly (mGal) FAA_clip Filtered free air anomaly masked (mGal) FAA_level Filtered, masked and levelled free air anomaly (mGal) FA_2600m Upward continued free air anomal...(5) Data quality: 7.5 km line spacing survey. asNeeded completed