Snow Melt Onset Over Arctic Sea Ice from SMMR and SSM/I Brightness Temperatures, Version 2
Data set id:
NSIDC-0105
DOI: 10.5067/EBW7NSR7V1V4
There is a more recent version of these data.
Version Summary
Version Summary
The processing steps for Version 02 snow melt onset data were the same as for Version 01 with the exception of step 6.
Regarding further differences between the two versions, V01 processing had several problems with spurious brightness temperature values resulting in erroneous melt dates. Because the algorithm uses a threshold, it is particularly susceptible to the effects of spurious brightness temperatures. In V01, these spurious dates were corrected using a 9-point median filter. The cause of the spurious brightness temperatures was traced to an error in the input brightness temperature fields where bad scanlines of data were not properly flagged. The input brightness temperatures were reprocessed with the proper bad-data flags. The V02 melt product uses these reprocessed brightness temperatures. Because the spurious brightness temperatures were eliminated, the 9-point median filter was not needed and thus not implemented for the V02 melt product.
Regarding further differences between the two versions, V01 processing had several problems with spurious brightness temperature values resulting in erroneous melt dates. Because the algorithm uses a threshold, it is particularly susceptible to the effects of spurious brightness temperatures. In V01, these spurious dates were corrected using a 9-point median filter. The cause of the spurious brightness temperatures was traced to an error in the input brightness temperature fields where bad scanlines of data were not properly flagged. The input brightness temperatures were reprocessed with the proper bad-data flags. The V02 melt product uses these reprocessed brightness temperatures. Because the spurious brightness temperatures were eliminated, the 9-point median filter was not needed and thus not implemented for the V02 melt product.
Overview
Yearly snow melt onset dates over Arctic sea ice are derived from Scanning Multichannel Microwave Radiometer (SMMR) and Special Sensor Microwave/Imager (SSM/I) brightness temperatures. The introduction of liquid water to snow results in a sharp increase in the emissivity and hence brightness temperature of the snowpack. Snow melt onset is defined as the point in time when microwave brightness temperatures increase sharply due to the presence of liquid water in the snowpack.
Data cover the years 1979 through 2007, and are in a polar stereographic grid at 25 km resolution. Data files are tab-delimited ASCII files and GIF images.
Parameter(s):
SNOW MELT
Platform(s):
DMSP, DMSP 5D-2/F11, DMSP 5D-2/F13, DMSP 5D-2/F8, Nimbus-7
Sensor(s):
SMMR, SSM/I
Data Format(s):
GIF, Binary
Temporal Coverage:
1 January 1979 to 31 December 2007
Temporal Resolution:
- 1 year
Spatial Resolution:
- Not Specified
Spatial Coverage:
N:
90
S:
30
E:
180
W:
-180
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.
Data Access & Tools
This data set has been retired. There is a more recent version of these data.
Help Articles
How to Articles
Data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) can be accessed directly from our HTTPS file system. We provide basic command line Wget and curl instructions for HTTPS file system downloads below.