Developing a global data record of daily landscape freeze/thaw status using satellite passive microwave remote sensing

Youngwook Kim, John S. Kimball, Kyle C. McDonald, Joseph Glassy

Research output: Contribution to journalArticlepeer-review

164 Scopus citations


The landscape freeze-thaw (F/T) state parameter derived from satellite microwave remote sensing is closely linked to the surface energy budget, hydrological activity, vegetation growing season dynamics, terrestrial carbon budgets, and land-atmosphere trace gas exchange. Satellite microwave remote sensing is well suited for global F/T monitoring due to its insensitivity to atmospheric contamination and solar illumination effects, and its strong sensitivity to the relationship between landscape dielectric properties and predominantly frozen and thawed conditions. We investigated the utility of multifrequency and dual polarization brightness temperature (Tb) measurements from the Special Sensor Microwave Imager (SSM/I) to map global patterns and daily variations in terrestrial F/T cycles. We defined a global F/T classification domain by examining biophysical cold temperature constraints to vegetation growing seasons. We applied a temporal change classification algorithm based on a seasonal thresholding scheme to classify daily F/T states from time series Tb measurements. The SSM/I F/T classification accuracy was assessed using in situ air temperature measurements from the global WMO weather station network. A single-channel classification of 37 GHz, V-polarization Tb time series provided generally improved performance over other SSM/I frequencies, polarizations and channel combinations. Mean annual F/T classification accuracies were 92.2 ± 0.8 [SD] % and 85.0 ± 0.7 [SD] % for respective SSM/I time series of p.m. and a.m. orbital nodes over the global domain and a 20-year (19882007) satellite record. The resulting database provides a continuous and relatively long-term record of daily F/T dynamics for the global biosphere with well-defined accuracy.

Original languageEnglish
Article number5599863
Pages (from-to)949-960
Number of pages12
JournalIEEE Transactions on Geoscience and Remote Sensing
Issue number3
StatePublished - Mar 2011


Manuscript received March 29, 2010; revised June 15, 2010; accepted August 5, 2010. Date of publication October 14, 2010; date of current version February 25, 2011. This work is supported in part by the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) program under NNH06ZDA001N-MEaSUREs.

FundersFunder number
National Aeronautics and Space Administration


    • Earth system data record
    • Freeze/thaw
    • Making earth system data records for use in research environments
    • Passive microwave remote sensing
    • Radiometry
    • Soil moisture active passive
    • Special sensor microwave imager


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