{"@context":{"content":"http://purl.org/rss/1.0/modules/content/","dc":"http://purl.org/dc/terms/","foaf":"http://xmlns.com/foaf/0.1/","og":"http://ogp.me/ns#","rdfs":"http://www.w3.org/2000/01/rdf-schema#","sioc":"http://rdfs.org/sioc/ns#","sioct":"http://rdfs.org/sioc/types#","skos":"http://www.w3.org/2004/02/skos/core#","xsd":"http://www.w3.org/2001/XMLSchema#","owl":"http://www.w3.org/2002/07/owl#","rdf":"http://www.w3.org/1999/02/22-rdf-syntax-ns#","rss":"http://purl.org/rss/1.0/","site":"https://www.bco-dmo.org/ns#","odo":"http://ocean-data.org/schema/","emo":"http://ocean-data.org/schema/entity-matching#","bibo":"http://purl.org/ontology/bibo/","crypto":"http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions/","bcodmo":"http://lod.bco-dmo.org/id/","tw":"http://tw.rpi.edu/schema/","dcat":"http://www.w3.org/ns/dcat#","time":"http://www.w3.org/2006/time#","geo":"http://www.w3.org/2003/01/geo/wgs84_pos#","geosparql":"http://www.opengis.net/ont/geosparql#","sf":"http://www.opengis.net/ont/sf#","void":"http://rdfs.org/ns/void#","sd":"http://www.w3.org/ns/sparql-service-description#","dctype":"http://purl.org/dc/dcmitype/","prov":"http://www.w3.org/ns/prov#","schema":"http://schema.org/","geolink":"http://schema.geolink.org/1.0/base/main#","spdx":"http://spdx.org/rdf/terms#","bcodmo_vocab":"http://schema.bco-dmo.org/"},"@id":"http://lod.bco-dmo.org/id/dataset/674819#graph","@graph":[{"http://lod.bco-dmo.org/id/dataset/674819":{"@id":"http://lod.bco-dmo.org/id/dataset/674819","@type":["http://ocean-data.org/schema/DeploymentDatasetCollection","http://www.w3.org/ns/dcat#Dataset","http://ocean-data.org/schema/Dataset"],"http://ocean-data.org/schema/hasAcquisitionDescription":[{"@value":"
MODIS:
\nDates of fast ice movement were determined from visible-wavelength scenes from the MODIS\u00a0aboard the Aqua and Terra satellites.\u00a0 MODIS images are available only for the months when there is sunlight, generally October to April, and image resolution was 250 m.\u00a0 Figure A (see Supplemental Documents) shows the division of McMurdo Sound into six zones; fast ice areas were generated manually from clear-sky images by drawing polygons in GIS software, and pack ice was excluded from analysis. The fast ice in MODIS scenes was sometimes obscured by clouds, so for days with missing imagery we interpolated linearly between valid data.\u00a0 Areas of persistent multiyear ice or glaciers that were not considered in the analysis (white in the figure).\u00a0 Linear distance between McMurdo Station and the nearest open water on the day the ice reached the minimum extent for the season was also measured.
\nSSMI:
\nIn the SSM/I record, images were available for all months of the year, and image resolution was 25 km.\u00a0 Figure B \u00a0(see Supplemental Documents)\u00a0 shows the total of seven pixels in the 25 km polar stereographic projection that encompassed McMurdo Sound; for each pixel, daily or bi-daily fractional sea ice cover was extracted.\u00a0 SSM/I passive microwave sea ice observations do not distinguish between fast ice and pack ice. There are small amounts of land and ice shelf contamination in pixels 1, 2, 5 and 7.
This dataset contains dates relevant to sea ice movement including dates of initial ice retreat, final ice retreat, ice minimum, general ice minimum, ice minimum for the west of McMurdo Sound, ice minimum for the east of McMurdo Sound, and refreeze start.\u00a0 It also includes the minimum distance to the ice edge from McMurdo Station. \u00a0
\nDates were derived from Moderate-resolution Imaging Spectroradiometers (MODIS) collected between 2003 and 2015 and Scanning Multichannel Microwave Radiometer and Special Sensor Microwave Imager-family passive microwave sensors (SSM/I) imagery collected between 1978 and 2015.
The value \"notobs\" indicates the phenomena was not observed for two possible reasons; either the phenomena did not occur that\u00a0season or imagery was not available (e.g. MODIS visual imagery was only collected during daylit months).\u00a0 The value 'nd' indicates no data (e.g. SSM/I imagery was too\u00a0coarse to distinguish east\u00a0and west side minimums).
\nSSM/I:
\nData were processed using the bootstrap algorithm (National Snow and Ice Data Center, Comiso, 2000, Cavalieri et al. 2015) for the 1978/79-2014/15 seasons.
\nComiso, J (2000, updated 2015) Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS. Version 2, 1979-2015. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.
\nCavalieri DJ, Parkinson CL, Gloersen P, and Zwally HJ (2015) Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data, Version 1.1 Southern Hemisphere, 1978-2015. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. (doi:10.5067/8GQ8LZQVL0VL) Accessed 11 Dec 2015.
\nBCO-DMO Data Manager Processing Notes:
\n* added a conventional header with dataset name, PI name, version date
\n* modified parameter names to conform with BCO-DMO naming conventions
\n* blank values indicating no observed phenomena replaced with no data value 'nd'
\n* added approximate latitude and longitude of McMurdo Station
Data version 2 (2020-02-20)
\n*\u00a0\u00a0Data from data version 1 (2017-01-31)\u00a0updated.\u00a0Column values for \u201cedge_dist_min,\u00a0 ice_min_west_year,\u00a0 ice_min_west_month\u201d switched with \u201crefreeze_begin_year,\u00a0 refreeze_begin_month,\u00a0 refreeze_begin_day\u201d values where image_source was SSMI.