SMAP Enhanced L3 Radiometer Global and Northern Hemisphere Daily 9 km EASE-Grid Freeze/Thaw State, Version 3
Data set id:
SPL3FTP_E
DOI: 10.5067/ZV08T8J395JB
There is a more recent version of these data.
Version Summary
Version Summary
Changes to this version include:
- Adjusted the freeze/thaw reference states for the normalized polarization ratio (NPR) algorithm per the improved Level-1 brightness temperature recalibration. The freezing reference averages from 2016-2020 and the thaw reference averages from 2015-2019.
- Adjusted the reference states for the Single-Channel V (SCV) algorithm per the update of the GEOS-FP surface and soil temperature profiles.
- Improved the never frozen/never thawed masks for false-flag mitigation by:
* extending the temporal extent of the AMSR-E source data to include data through 2019
* blending in a GEOS-FP temperature climatology for 2015-2020 using a loose ±10 ºC criterion for fully-frozen or fully-thawed conditions.
- The product data structure, content, and processor code are otherwise unchanged from the previous version.
For the full major and minor version history, go to https://nsidc.org/data/smap/version-history
- Adjusted the freeze/thaw reference states for the normalized polarization ratio (NPR) algorithm per the improved Level-1 brightness temperature recalibration. The freezing reference averages from 2016-2020 and the thaw reference averages from 2015-2019.
- Adjusted the reference states for the Single-Channel V (SCV) algorithm per the update of the GEOS-FP surface and soil temperature profiles.
- Improved the never frozen/never thawed masks for false-flag mitigation by:
* extending the temporal extent of the AMSR-E source data to include data through 2019
* blending in a GEOS-FP temperature climatology for 2015-2020 using a loose ±10 ºC criterion for fully-frozen or fully-thawed conditions.
- The product data structure, content, and processor code are otherwise unchanged from the previous version.
For the full major and minor version history, go to https://nsidc.org/data/smap/version-history
Overview
This enhanced Level-3 (L3) product provides a daily composite of global and Northern Hemisphere landscape freeze/thaw conditions retrieved by the Soil Moisture Active Passive (SMAP) radiometer from 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. This product is derived from SMAP enhanced Level-1C brightness temperatures (SPL1CTB_E). Backus-Gilbert optimal interpolation techniques are used to extract maximum information from SMAP antenna temperatures and convert them to brightness temperatures. The data are then posted to two 9 km Earth-fixed, Equal-Area Scalable Earth Grids, Version 2.0 (EASE-Grid 2.0): a global cylindrical and a Northern Hemisphere azimuthal.
Parameter(s):
BRIGHTNESS TEMPERATUREFREEZE/THAWTRANSITION DIRECTION
Platform(s):
SMAP
Sensor(s):
SMAP L-BAND RADIOMETER
Data Format(s):
HDF5
Temporal Coverage:
31 March 2015 to present
Temporal Resolution:
- 1 day
Spatial Resolution:
- 9 km
- 9 km
Spatial Reference System(s):
WGS 84 / NSIDC EASE-Grid 2.0 North
EPSG:6931
WGS 84 / NSIDC EASE-Grid 2.0 Global
EPSG:6933
Spatial Coverage:
N:
85.044
S:
-85.044
E:
180
W:
-180
N:
85.044
S:
45
E:
180
W:
-180
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.
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General Questions & FAQs
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How to Articles
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