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ABoVE: Passive Microwave-derived Annual Snowpack Main Melt Onset Date Maps, 1988-2018

Published by ORNL_DAAC | National Aeronautics and Space Administration | Catalog Last Checked: March 07, 2026 at 08:01 PM | Dataset Last Updated: April 23, 2025
This dataset provides the annual date of snowpack seasonal beginning melt (i.e., main melt onset date, MMOD) across northwest Canada; Alaska, U.S.; and parts of far eastern Russia at 6.25 km resolution for the period 1988-2018. MMOD was derived from the daily 19V (K-band) and 37V (Ka-band) GHz bands from the Making Earth Science Data Records for Use in Research Environments (MEaSUREs) Calibrated Enhanced-Resolution Passive Microwave (PMW) EASE-Grid Brightness Temperature (Tb) Earth System Data Record (ESDR). The PMW MMOD dataset was validated using the transition date from Freeze Degree Days (FDD) to Thaw Degree Days (TDD) from in situ air temperature observations from 31 SNOw TELemetry network (SNOTEL) observations, and compared to the established Freeze-Thaw ESDR (FT-ESDR) spring onset date. The resulting MMOD data record is suitable for documenting the spatial-temporal impacts of MMOD variability in ecosystem services, wildlife movements, and hydrologic processes across the ABoVE domain. The data from 1988-2016 included a coastal mask removing coastal pixels due to potential water contamination from coarse brightness temperature observations (Dersken et al., 2012). There is not a coastal mask for the 2017-2018 data. The full data are included, and data users should be aware that coastal values can be adversely affected by adjacent water bodies.

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Complete Metadata
@type dcat:Dataset
accessLevel public
bureauCode 
[
  "026:00"
]
contactPoint 
{
  "fn": "undefined",
  "@type": "vcard:Contact",
  "hasEmail": "mailto:uso@daac.ornl.gov"
}
description This dataset provides the annual date of snowpack seasonal beginning melt (i.e., main melt onset date, MMOD) across northwest Canada; Alaska, U.S.; and parts of far eastern Russia at 6.25 km resolution for the period 1988-2018. MMOD was derived from the daily 19V (K-band) and 37V (Ka-band) GHz bands from the Making Earth Science Data Records for Use in Research Environments (MEaSUREs) Calibrated Enhanced-Resolution Passive Microwave (PMW) EASE-Grid Brightness Temperature (Tb) Earth System Data Record (ESDR). The PMW MMOD dataset was validated using the transition date from Freeze Degree Days (FDD) to Thaw Degree Days (TDD) from in situ air temperature observations from 31 SNOw TELemetry network (SNOTEL) observations, and compared to the established Freeze-Thaw ESDR (FT-ESDR) spring onset date. The resulting MMOD data record is suitable for documenting the spatial-temporal impacts of MMOD variability in ecosystem services, wildlife movements, and hydrologic processes across the ABoVE domain. The data from 1988-2016 included a coastal mask removing coastal pixels due to potential water contamination from coarse brightness temperature observations (Dersken et al., 2012). There is not a coastal mask for the 2017-2018 data. The full data are included, and data users should be aware that coastal values can be adversely affected by adjacent water bodies.
distribution 
[
  {
    "@type": "dcat:Distribution",
    "title": "The dataset's project home page",
    "format": "HTML",
    "mediaType": "text/html",
    "description": "ABoVE project site",
    "downloadURL": "https://above.nasa.gov"
  },
  {
    "@type": "dcat:Distribution",
    "title": "View documentation related to this dataset",
    "format": "PDF",
    "mediaType": "application/pdf",
    "description": "ABoVE: Passive Microwave-derived Annual Snowpack Main Melt Onset Date Maps, 1988-2018: Main_Melt_Onset_Dates.pdf",
    "downloadURL": "https://data.ornldaac.earthdata.nasa.gov/public/above/Main_Melt_Onset_Dates/comp/Main_Melt_Onset_Dates.pdf"
  },
  {
    "@type": "dcat:Distribution",
    "title": "This dataset's landing page",
    "format": "HTML",
    "mediaType": "text/html",
    "description": "Data set Landing Page DOI URL",
    "downloadURL": "https://doi.org/10.3334/ORNLDAAC/1841"
  },
  {
    "@type": "dcat:Distribution",
    "title": "View documentation related to this dataset",
    "format": "HTML",
    "mediaType": "text/html",
    "description": "ORNL DAAC Data Set Documentation",
    "downloadURL": "https://daac.ornl.gov/ABOVE/guides/Main_Melt_Onset_Dates.html"
  },
  {
    "@type": "dcat:Distribution",
    "title": "Google Scholar search results",
    "format": "HTML",
    "mediaType": "text/html",
    "description": "Search results for publications that cite this dataset by its DOI.",
    "downloadURL": "https://scholar.google.com/scholar?q=10.3334%2FORNLDAAC%2F1841"
  },
  {
    "@type": "dcat:Distribution",
    "title": "Get a related visualization",
    "format": "JPEG",
    "mediaType": "image/jpeg",
    "description": "Spatial extent of snowpack main melt onset dataset (MMOD) extending from the Russian Far East across Alaska into Canada's Northwest Territories and British Columbia. The map also includes the GRDC river gauging locations (blue diamonds) used at Eagle, Stevens Village, and Pilot basins (black outlines). Locations of river ice breakup observations (white circles), the World Meteorological Organization (WMO) stations (orange triangles), and SNOw TELemetry network (SNOTEL) stations (purple triangles) are shown. Source: Pan et al. (2021)",
    "downloadURL": "https://daac.ornl.gov/ABOVE/guides/Main_Melt_Onset_Dates_Fig1.jpg"
  },
  {
    "@type": "dcat:Distribution",
    "title": "Download this dataset",
    "format": "HTML",
    "mediaType": "text/html",
    "description": "This link allows direct data access via Earthdata login",
    "downloadURL": "https://daac.ornl.gov/daacdata/above/Main_Melt_Onset_Dates/"
  }
]
identifier C2143401742-ORNL_CLOUD
issued 2024-05-01
keyword 
[
  "climate-indicators",
  "cryosphere",
  "cryospheric-indicators",
  "earth-science",
  "snow-ice",
  "terrestrial-hydrosphere"
]
landingPage https://doi.org/10.3334/ORNLDAAC/1841
language 
[
  "en-US"
]
modified 2025-04-23
programCode 
[
  "026:001"
]
publisher 
{
  "name": "ORNL_DAAC",
  "@type": "org:Organization"
}
spatial -180.0 51.61 -107.83 72.41
temporal 1988-02-09T00:00:00Z/2018-02-10T23:59:59Z
theme 
[
  "ABoVE",
  "geospatial"
]
title ABoVE: Passive Microwave-derived Annual Snowpack Main Melt Onset Date Maps, 1988-2018

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