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    • ABoVE: Passive Microwave-derived Annual Snowpack Main Melt Onset Date Maps, 1988-2023

    Metadata Updated: September 19, 2025

    This dataset provides the annual date of snowpack seasonal beginning melt (i.e., main melt onset date, MMOD) across northwest Canada, Alaska, US, and parts of far eastern Russia at 6.25-km resolution for the period 1988-2023. 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) stations, and compared to an established Freeze-Thaw ESDR (FT-ESDR) spring onset date record. The resulting MMOD data record is suitable for documenting the spatial-temporal impacts of MMOD variability in ecosystem services, wildlife movements, and hydrologic processes within the ABoVE (Arctic Boreal Vulnerability Experiment) 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). No coastal mask is used for the 2017-2023 data. The full data are included, and data users should be aware that values adjacent to large water bodies can be adversely affected.

    Access & Use Information

    Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

    Downloads & Resources

    Dates

    Metadata Created Date April 11, 2025
    Metadata Updated Date September 19, 2025

    Metadata Source

    Harvested from NASA Data.json

    Other Data Resources

    Additional Metadata

    Resource Type Dataset
    Metadata Created Date April 11, 2025
    Metadata Updated Date September 19, 2025
    Publisher ORNL_DAAC
    Maintainer
    Identifier 10.3334/ORNLDAAC/1841
    Data Last Modified 2025-09-10
    Category Earth Science
    Public Access Level public
    Bureau Code 026:00
    Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
    Schema Version https://project-open-data.cio.gov/v1.1/schema
    Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
    Harvest Object Id 8f34b99b-d423-4cf9-8497-4f2947dbe505
    Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
    Harvest Source Title NASA Data.json
    Homepage URL https://search.earthdata.nasa.gov/search?q=Main_Melt_Onset_Dates_1841&ac=true
    Old Spatial {"WestBoundingCoordinate":-180.0,"NorthBoundingCoordinate":72.4085,"EastBoundingCoordinate":-107.83,"SouthBoundingCoordinate":51.6089},"CARTESIAN"
    Program Code 026:000
    Source Datajson Identifier True
    Source Hash 92e848744787ada73aada85aa06fb90bd21d4083f25f45945af92648a3f7088c
    Source Schema Version 1.1
    Spatial
    Temporal 1988-02-09/1988-02-09

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