VIIRS Snow (VNP10)¶

VIIRS Snow Cover Version 2 (VNP10 Suomi NPP, VJ110 NOAA-20, VJ210 NOAA-21) — NDSI-based 375 m snow cover continuing the MODIS record, including cloud-gap-filled maps

Available

At a glance¶

Note on period: VNP10 (Suomi NPP) starts on 2012-01-19, VJ110 (NOAA-20) on 2018-01-05 and VJ210 (NOAA-21) on 2023-02-10 (per CMR). No new VNP10 data are expected after 2 November 2026, and production stopped during the Suomi NPP anomaly of 10–21 July 2026.

Overview¶

Global snow cover from VIIRS, produced by the NASA snow team with an approach developed alongside the MODIS Collection 6 snow algorithm and almost identical to it (NDSI plus data screens), so that the MODIS snow record begun in 2000 can continue. Using the VIIRS imagery bands I1 (0.64 µm) and I3 (1.61 µm), it has a finer 375 m resolution than MODIS (500 m), and provides daily snow cover (A1), cloud-gap-filled daily snow cover (A1F), 0.05° snow cover percentage (C1) and a 375 m global cloud-gap-filled map (D1F) for each satellite (VNP10, VJ110, VJ210).

What changes with the successor¶

VIIRS Snow Cover Version 1 (VNP10 C1) → VIIRS Snow Cover Version 2 (C2)¶

Transition: 2024-06

A version with improved algorithms, cloud masking and noise detection that added NOAA-20 (VJ110) products. Version 1 (Suomi NPP only) stopped production on 17 June 2024, and NOAA-21 (VJ210) products were added in January 2026.

Sources: NSIDC — VIIRS Version 1 (Collection 1) cease forward processing notice · NSIDC VNP10A1 V2 User Guide (version history)

Available variables¶

Layer names from the NSIDC Version 2 user guides. Files are HDF-EOS5 (HDF5, CF-1.6); group paths can differ by satellite and product, so check your downloaded files. NDSI_Snow_Cover values 0–100 are NDSI × 100; 201 no decision, 211 night, 237 lake/inland water, 239 ocean, 250 cloud, 251 missing L1B, 252 failed calibration, 253 bowtie trim, 254 L1B fill, 255 L2 fill.

instantaneous mean accumulated maximum minimum static — instantaneous: value at the time stamp · mean/accumulated/maximum/minimum: over the indicated interval · static: does not change with time

Daily snow cover, 375 m (VNP10A1 / VJ110A1 / VJ210A1)¶

Cloud-gap-filled daily snow cover, 375 m (VNP10A1F / VJ110A1F / VJ210A1F)¶

0.05° CMG snow cover percentage (VNP10C1 / VJ110C1 / VJ210C1)¶

375 m global cloud-gap-filled map (VNP10D1F / VJ110D1F / VJ210D1F)¶

The full variable list is in the official documentation.

How to get the data¶

• NSIDC DAAC data set page (VNP10A1 V2) — NSIDC Data Access Tool / HTTPS (Earthdata Cloud) / documentation
  • NOAA-20 is VJ110A1 and NOAA-21 is VJ210A1. The VIIRS data set list and announcements are at https://nsidc.org/data/viirs.
• NASA Earthdata Search and earthaccess (Earthdata Cloud) — Web search and download / earthaccess / AWS S3 (in us-west-2 only)
  • CMR short names are VNP10A1, VJ110A1, VJ210A1 and so on, with version 2. A free Earthdata Login is required.
• NASA AppEEARS — Point and area extraction with reprojection
  • Supports VNP10A1 and VJ110A1 (375 m daily snow cover) since March 2026.

Example code¶

Downloads one day of NOAA-20 (VJ110A1F) cloud-gap-filled snow cover with earthaccess and reads it (pip install earthaccess h5py numpy). Variables are located by name, so you do not need to know the HDF-EOS5 group path.

import earthaccess
import h5py
import numpy as np

earthaccess.login()  # free NASA Earthdata account
results = earthaccess.search_data(
    short_name="VJ110A1F", version="2",
    temporal=("2024-01-15", "2024-01-15"),
    bounding_box=(124, 33, 132, 39),   # (west, south, east, north)
)
files = earthaccess.download(results, "vj110a1f")

def find(h5, name):
    hits = []
    h5.visititems(lambda k, v: hits.append(k) if k.endswith("/" + name) else None)
    return h5[hits[0]]

for f in files:
    with h5py.File(f, "r") as h5:
        ndsi = find(h5, "CGF_NDSI_Snow_Cover")[:].astype("float32")
        cp = find(h5, "Cloud_Persistence")[:]
    ndsi[ndsi > 100] = np.nan          # 201+ are codes for night, water, cloud, missing
    snow = ndsi > 0                     # example: treat NDSI snow cover 1-100 as snow (tune for your study)
    print(f, np.nanmean(snow), (cp == 0).mean())

Practical tips¶

• Delivery of Suomi NPP data (VNP10) ends on 2 November 2026. Switch the short names in your scripts to VJ110 (NOAA-20) or VJ210 (NOAA-21) and check for offsets where the satellite changes.
• NDSI_Snow_Cover values 0–100 are NDSI, not fractional snow cover. Choose your own snow/no-snow threshold and report it in your paper.
• Codes differ from MODIS: VIIRS has 251 (missing L1B), 252 (failed calibration), 253 (bowtie trim) and so on instead of 200 (missing), and the NDSI scale_factor is 0.001 (MODIS 0.0001). Quality variable names also differ (Basic_QA, Algorithm_bit_flags_QA).
• There are no VIIRS equivalents of the MODIS 8-day (A2) and monthly (CM) products or of the snow albedo layer. Composite the daily data yourself if needed.
• Users reported that the PROJ string in the NSIDC user guide (WGS84 ellipsoid) does not georeference correctly in GIS, and NSIDC confirmed that the MODIS sphere (+proj=sinu +R=6371007.181) is correct. Set coordinates from the XDim and YDim variables.
• Known issues include erroneous snow-free areas on the Antarctic Peninsula (difficult cloud detection), weave and stitching patterns at swath edges, day-to-day lake position wobble, and errors over warm surfaces, bright surfaces and lake ice.
• Hall et al. (2024) report that VIIRS maps slightly more snow than MODIS (a less conservative cloud mask and different overpass time). Check the difference over the overlap period before joining with the MODIS record.

Notices and change history¶

References for your paper¶

Dataset citation¶

VJ110A1 V2 (NOAA-20 daily, 375 m) — DOI 10.5067/UAJGR7WVWDDI

@misc{vj110a1_v2,
  author    = {Riggs, George A. and Hall, Dorothy K.},
  title     = {{VIIRS/JPSS1 Snow Cover Daily L3 Global 375m SIN Grid, Version 2}},
  year      = {2023},
  publisher = {NASA National Snow and Ice Data Center Distributed Active Archive Center},
  address   = {Boulder, Colorado USA},
  doi       = {10.5067/UAJGR7WVWDDI}
}

VNP10A1 V2 (Suomi NPP daily, 375 m) — DOI 10.5067/45VDCKJBXWEE

@misc{vnp10a1_v2,
  author    = {Riggs, George A. and Hall, Dorothy K.},
  title     = {{VIIRS/NPP Snow Cover Daily L3 Global 375m SIN Grid, Version 2}},
  year      = {2023},
  publisher = {NASA National Snow and Ice Data Center Distributed Active Archive Center},
  address   = {Boulder, Colorado USA},
  doi       = {10.5067/45VDCKJBXWEE}
}

VNP10A1F V2 (Suomi NPP cloud-gap-filled daily, 375 m) — DOI 10.5067/PN50Y51IVNLE

@misc{vnp10a1f_v2,
  author    = {Riggs, George A. and Hall, Dorothy K.},
  title     = {{VIIRS/NPP CGF Snow Cover Daily L3 Global 375m SIN Grid, Version 2}},
  year      = {2022},
  publisher = {NASA National Snow and Ice Data Center Distributed Active Archive Center},
  address   = {Boulder, Colorado USA},
  doi       = {10.5067/PN50Y51IVNLE}
}

VJ210A1 V2 (NOAA-21 daily, 375 m) — DOI 10.5067/IX3NQYYS3MOV

@misc{vj210a1_v2,
  author    = {Riggs, George A. and Hall, Dorothy K.},
  title     = {{VIIRS/JPSS2 Snow Cover Daily L3 Global 375m SIN Grid, Version 2}},
  year      = {2026},
  publisher = {NASA National Snow and Ice Data Center Distributed Active Archive Center},
  address   = {Boulder, Colorado USA},
  doi       = {10.5067/IX3NQYYS3MOV}
}

Reference papers¶

Overview of the MODIS and VIIRS snow records — DOI 10.5194/essd-9-765-2017

@article{riggs2017snow,
  author  = {Riggs, George A. and Hall, Dorothy K. and Rom{\'a}n, Miguel O.},
  title   = {Overview of {NASA}'s {MODIS} and {Visible Infrared Imaging Radiometer Suite} ({VIIRS}) snow-cover {Earth System Data Records}},
  journal = {Earth System Science Data},
  volume  = {9},
  number  = {2},
  pages   = {765--777},
  year    = {2017},
  doi     = {10.5194/essd-9-765-2017}
}

Comparison of MODIS and VIIRS snow products for a climate data record — DOI 10.3390/rs16163029

@article{hall2024modisviirs,
  author  = {Hall, Dorothy K. and Riggs, George A. and DiGirolamo, Nicolo E.},
  title   = {Comparison of the {NASA} Standard {MODerate-Resolution Imaging Spectroradiometer} and {Visible Infrared Imaging Radiometer Suite} Snow-Cover Products for Creation of a Climate Data Record: A Case Study in the {Great Basin} of the Western {United States}},
  journal = {Remote Sensing},
  volume  = {16},
  number  = {16},
  pages   = {3029},
  year    = {2024},
  doi     = {10.3390/rs16163029}
}

Acknowledgements¶

Follow the citation on each NSIDC data set page (authors, year, title, version, DOI, access date and a description of any subset used). Every satellite and product has its own DOI (e.g. VJ110A1F 10.5067/2YJ7GZPW2NNB, VJ210A1F 10.5067/YAWW1AIS887J, VNP10C1 10.5067/PHOQ2G589HCC, VJ110C1 10.5067/DNC2SNXE6HJB, VNP10D1F 10.5067/F3VW9TYIK26A, VJ110D1F 10.5067/FPB0B5CD1RVA).

Information on the datasets used in this study was compiled with the help of the Korean Climate Data Navigator (KCDN) (Sim, 2026; https://doi.org/10.5281/zenodo.23300923).

Links¶

• VNP10A1, VJ110A1, VJ210A1 V2 User Guide (PDF)
• VNP10A1F cloud-gap-filled V2 User Guide (PDF)
• VNP10C1 0.05° CMG V2 User Guide (PDF)
• NSIDC VIIRS data sets and announcements
• Earthdata Forum — answer on the VIIRS snow L3 CRS issue (2025)