Whether northern ground is frozen or thawed (SMAP, 3 km, daily)
What it measures. A daily yes-or-no style map of whether the land surface across the Northern Hemisphere is frozen or thawed, at 3 km resolution.
How it's made. Derived from L-band radar echoes off the ground collected by NASA's SMAP satellite during its morning and evening passes, then resampled onto an equal-area 3 km grid.
How & where you'd use it. Helps track the start and end of the growing season, soil freeze-thaw cycles, and seasonal changes in northern landscapes important for ecosystems and the carbon cycle.
What's measured
Coverage & cadence
- Time span2015-04-13 → 2015-07-07
- Measured bySMAP (SMAP L-BAND RADAR)
- Processing levelLevel 3
- Spatial extent-180, 45, 180, 85.044
- FormatsHDF5
- StatusCOMPLETE
What you can do with it
- Measure sea ice, snow cover and glaciers
- Watch ice-sheet elevation change
- Track freeze/thaw and permafrost
Official description
This Level-3 (L3) product provides a daily composite of Northern Hemisphere landscape freeze/thaw conditions retrieved by the Soil Moisture Active Passive (SMAP) radar from 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. SMAP L-band backscatter data are used to derive freeze/thaw data, which are then resampled to an Earth-fixed, Northern Hemisphere azimuthal 3 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0).
Get the data
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="SPL3FTA",
version="003",
bounding_box=(-122.5, 37.2, -121.8, 37.9), # your area (W,S,E,N)
temporal=("2024-01-01", "2024-12-31"), # your dates
)
files = earthaccess.open(results) # stream straight from NSIDC_CPRDBrowsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package. Official links
- Search and order NASA Earth Science data using spatial and temporal filters. Reformatting, reprojecting, and subsetting options are available for some data sets. GET DATA
- Quickly download a few files using a web browser, or access data through a command-line utility such as WGET. GET DATA
- Search data by spatial and/or temporal ranges or file name. Choose from various download options, including a Python script. GET DATA
- A Python library to search and access NASA Earth science data with just a few lines of code GET DATA
- Find more data access options and help resources. VIEW RELATED INFORMATION
- SMAP L3 Radar Northern Hemisphere Daily 3 km EASE-Grid Freeze/Thaw State, Version 3 User Guide VIEW RELATED INFORMATION
- SMAP Post-Recovery Advisory Note 23 July 2019 VIEW RELATED INFORMATION
- SMAP Ancillary Data Report: Landcover Classification [2013] VIEW RELATED INFORMATION