MEaSUREs Global Record of Daily Landscape Freeze/Thaw Status, Version 3

The MEaSUREs Global Record of Daily Landscape Freeze/Thaw Status, Version 3 data set is a global record of the daily freeze/thaw (F/T) status of the landscape derived from satellite observations of radiometric brightness temperatures. Two F/T records are provided: one derived from Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave/Imager (SSM/I), and Special Sensor Microwave Imager/Sounder (SSMIS) data for the years 1979 to 2012; and a second derived from Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) data for the years 2002 to 2011.

Note: These data are considered provisional pending a review by the MEaSUREs program. Once the data have been reviewed, this statement will be removed from this documentation.

Table of Contents

  1. Contacts and Acknowledgments
  2. Detailed Data Description
  3. Data Access and Tools
  4. Data Acquisition and Processing
  5. References and Related Publications
  6. Document Information

Citing These Data

Data Citation

We kindly request that you cite the use of this data set in a publication using the following citation. For more information, see our Use and Copyright Web page.

Kim, Y., J. S. Kimball, J. Glassy, and K. C. McDonald. 2014. MEaSUREs Global Record of Daily Landscape Freeze/Thaw Status, Version 3, [indicate subset used]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center. doi:10.5067/MEASURES/CRYOSPHERE/nsidc-0477.003

Literature Citation

We kindly request that you acknowledge the use of this data set by referencing the following peer-reviewed publication.

Kim, Y., J. S. Kimball, K. Zhang, and K. C. McDonald. 2012. Satellite detection of increasing Northern Hemisphere non-frozen seasons from 1979 to 2008: Implications for regional vegetation growth. Remote Sensing of Environment 121: 472-487.

Overview

Platform

Nimbus 7
DMSP (Defense Meteorological Satellite Program)
Aqua (EOS PM-1)

Sensor

SMMR
SSM/I
SSMIS
AMSR-E

Spatial Coverage

Global

Spatial Resolution

25 km

Temporal Coverage

SMMR-SSM/I-SSMIS:

  • 01 January 1979 to 31 December 2012
AMSR-E:
  • 19 June 2002 to 27 September 2011

Temporal Resolution

Daily

Parameters

Daily AM F/T status
Daily PM F/T status
Daily Composite (combined AM and PM) F/T status
Daily Transitional F/T status
Daily Inverse Transitional F/T status
Daily F/T Status Accuracy Metric
Annual F/T Status Quality Assurance (QA) Maps

Data Format

HDF5 (.h5)
GeoTIFF (.tif)
GIF (.gif)

Metadata Access

View Metadata Record

Version

V3. See the Version History section of this document for version information.

Data Access

FTP

1. Contacts and Acknowledgments

Investigators

Dr. John Kimball, PI
Numerical Terradynamic Simulation Group (NTSG)
The University of Montana
Missoula, MT 59812

Dr. Youngwook Kim, Science Lead
Numerical Terradynamic Simulation Group (NTSG)
The University of Montana
Missoula, MT 59812

Joe Glassy, Software and Data Management Lead
Numerical Terradynamic Simulation Group (NTSG)
The University of Montana
Missoula, MT 59812

Dr. Kyle McDonald, Co-PI
Jet Propulsion Laboratory (JPL)
California Institute of Technology
Pasadena, CA 91109

Technical Contact

NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449  USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
e-mail: nsidc@nsidc.org

Acknowledgements

These data were generated through a grant from the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) program. Portions of this work were conducted at the University of Montana and Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA.

2. Detailed Data Description

The combined SMMR-SSM/I-SSMIS freeze/thaw record was derived from daily brightness temperature measurements at 37 GHz (vertical polarization) from the Scanning Multichannel Microwave Radiometer (1979-1986), Special Sensor Microwave Imager (1987-2008), and Special Sensor Microwave Imager/Sounder (2009-2012) sensor series. The AMSR-E (Advanced Microwave Scanning Radiometer for EOS) record was derived from daily (AM and PM overpass) 36.5 GHz (vertical polarization) brightness temperature retrievals encompassing the AMSR-E operational record.

Separate AM (morning), PM (afternoon), and CO (combined AM and PM) freeze/thaw status files are available as well as daily and annual quality assurance (QA) and accuracy metrics.

Formats

Data are provided in several formats:

  • HDF5
  • GeoTIFF
  • GIF

The sections below describe each format type and the parameters stored in that format.

HDF5

Freeze/Thaw Status

The following freeze/thaw status parameters are provided in HDF5 v1.8 formatted files.

  • Daily AM Freeze/Thaw status
  • Daily PM Freeze/Thaw status
  • Daily Composite (combined AM and PM) Freeze/Thaw status
  • Daily Transitional Freeze/Thaw status
  • Daily Inverse Transitional Freeze/Thaw status

HDF5 daily freeze/thaw status files for both the SMMR-SSM/I-SSMIS and AMSR-E records contain the following data fields:

Field Description Dimension Data Type
FT_status Daily global freeze/thaw status 1383 columns; 586 rows 8-bit unsigned integer
cell_lat Latitude 1383 columns; 586 rows 32-bit floating point
cell_lon Longitude 1383 columns; 586 rows 32-bit floating point

The cell_lat and cell_lon fields are included for CF v1.4 compliance, allowing users of common free software packages such as HDFView and Panoply to immediately view the data sets projected in a global geographic grid. In addition, the metadata for AM and PM HDF5 files includes an aggregate daily accuracy metric (Accuracy_Daily_Metric).

Quality Assurance

Annual F/T Status Quality Assurance (QA) maps are provided in an HDF5 file, one each for the SMMR-SSM/I-SSMIS and AMSR-E records, that contain one data field per year for each year in the corresponding instrument record. QA values are reported in a range from 0.0 (low, accuracy <70 percent) to 1.0 (best, accuracy >90 percent) and represent a relative index of data quality for each grid cell based on ancillary terrain and land cover heterogeneity, satellite data gaps, and daily F/T accuracy assessments. See Kim et al. 2011 for details.

HDF5 QA files contain the following data fields:

Field Description Dimension Data Type
FT_Annual_QA_[Year] QA 1383 columns; 586 rows 32-bit floating point
cell_lat Latitude 1383 columns; 586 rows 32-bit floating point
cell_lon Longitude 1383 columns; 586 rows 32-bit floating point
F/T Accuracy

Annual F/T accuracy data are provided in HDF5-formatted files for both the SMMR-SSM/I-SSMIS and AMSR-E records. These files consist of two data fields (AM and PM) per year for each year in the corresponding instrument record. Accuracy was assessed in relation to daily maximum and minimum air temperature measurements from the global WMO weather station network (see Kim et al. 2011 for details) and calculated as the percent of daily F/T retrievals per year that are consistent with in situ air temperature measurements. Values are reported in the range of 0.0 to 100.0.

HDF5 accuracy files contain the following data fields:

Field Description Dimension Data Type
FT_Accuracy_[AM/PM]_[Year] F/T accuracy value 1383 columns; 586 rows 32-bit floating point
cell_lat Latitude 1383 columns; 586 rows 32-bit floating point
cell_lon Longitude 1383 columns; 586 rows 32-bit floating point

GeoTIFF

Daily F/T status is also available for both the SMMR-SSM/I-SSMIS and AMSR-E records in GeoTIFF format with an ESRI projection file that facilitates viewing the data in ArcMap.

GIF

Annual F/T accuracy data for both the SMMR-SSM/I-SSMIS and AMSR-E records, derived from the PM overpass, are available as GIF image files. Browse images of the daily CO F/T status are also available to quickly evaluate the data visually.

File and Directory Structure

Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/nsidc0477_MEASURES_freeze_thaw_v03/ directory. At the top level of this directory, three folders contain daily F/T status files and a fourth contains the QA and accuracy data. Daily F/T status files are stored within /AMSRE/ and /SMMR_SSMI/ subdirectories in folders labeled by year. HDF5 QA and accuracy files are located at the top level of the /AMSRE/ and /SMMR_SSMI/ subdirectories within the QA and accuracy folder. Annual QA maps can be found in the folders labeled GIF.

Table 2 below describes the contents of the four folders at the top of the FTP directory:

Table 2. FTP Directory Description
Directory Description
DAILY_FT_GEOTIFF Global daily F/T status in GeoTIFF (.tif) file format. The ESRI projection (.prj) file resides at the top level of this directory.
DAILY_FT_BROWSE Global daily browse images of F/T status in GIF (.gif) file format
DAILY_FT_HDF5 Global daily F/T status in HDF5 (.h5) file format
QA_ACCURACY Annual QA maps and accuracy metrics in GIF and HDF5 formats. Also contains MD5 files (.md5) with checksum hash signatures.

File Naming Convention

Daily F/T Status HDF5 and GeoTIFF Files

This section explains the file naming convention for HDF5- and GeoTIFF-formatted daily F/T status files stored in the DAILY_FT_HDF5/[instrument]/ and DAILY_FT_GEOTIFF/[instrument]/ folders. Each daily F/T status product consists of three separate files: morning overpass (AM), afternoon overpass (PM), and a combined daily AM and PM (CO) classification. These data files utilize the following naming convention.

Example File Name: SSMI_37V_CO_FT_1993_day001.h5

[InstrumentLabel]_[Channel][Polarization]_[OverpassCode]_FT_[Year]_day[DOY].[FileExt]

Refer to Table 3 for the valid values for the file name variables listed above.

Table 3. Variables and Descriptions for Daily F/T Status Files
Variable Description
InstrumentLabel Sensor
Channel Frequency, GHz
Polarization V (Vertical)
OverpassCode Morning (AM), Afternoon (PM), or Combined AM and PM (CO)
Year Observation year
DOY Day of Year
FileExt .h5 (HDF5) or .tif (GeoTIFF)

Daily F/T Status GIF Browse Images

This section explains the file naming convention for the daily F/T status GIF browse images stored in the DAILY_FT_BROWSE/[instrument]/ folder.

Example File Name: SSMI_37V_CO_FT_1993_day001.gif

[InstrumentLabel]_[Channel][Polarization]_CO_FT_[Year]_day[DOY].gif

Refer to Table 4 for the valid values for the file name variables listed above.

Table 4. Variables and Descriptions for F/T Status Browse Images
Variable Description
InstrumentLabel Sensor
Channel Frequency, GHz
Polarization V (Vertical)
OverpassCode CO (combined AM and PM)
Year Observation year
DOY Day of Year

QA and Accuracy Files

This section explains the file naming convention for annual HDF QA and accuracy files stored in the QA_ACCURACY/[instrument]/ folder.

Example File Name: FT3_SMMR_SSMI_global_1979_2012_accuracy.h5

Refer to Table 5 for the valid values for the file name variables listed above.

[ProductVersion]_[InstrumentLabel]_global_[StartYear]_[EndYear]_[FileType].h5

Table 5. Variables and Descriptions for Annual QA and Accuracy Files
Variable Description
ProductVersion Freeze/Thaw Status, Version 3 (FT3)
InstrumentLabel Sensor
StartYear First year of data record
EndYear Last year of data record
FileType QA or accuracy

QA Maps

This section explains the file naming convention for the annual QA maps stored in the QA_ACCURACY/[instrument]/GIF/ folder.

Example File Name: SMMR_global_QA_1979_PM.gif

[InstrumentLabel]_global_QA_[Year]_[OverpassCode].gif

Refer to Table 6 for the valid values for the file name variables listed above.

Table 6. Variables and Descriptions for Annual QA Maps
Variable Description
InstrumentLabel Sensor
Year Year of data record
OverpassCode PM (afternoon)

File Size

Refer to Table 7 for file sizes corresponding to each file type.

Table 7. File Sizes by Type
File Type Size
Daily F/T Status Files 50 KB (.tif) - 200 KB (.h5)
Annual QA maps Approx. 25 KB
Browse Images Approx. 25 KB
QA and Accuracy Files 0.23 MB - 11.4 MB

Volume

The complete F/T dataset is approximately 13.3 GB. Each overpass code (AM, PM, or CO) represents approximately 4.4 GB of data. One year is approximately 125 MB per overpass code.

Spatial Coverage

Coverage is global:

  • Southernmost Latitude: -86.7167° S
  • Northernmost Latitude: 86.7167° N
  • Westernmost Longitude: -179.9999° W
  • Easternmost Longitude: 179.9999° E

Spatial Resolution

25 km

Projection and Grid Description

Each grid cell is projected in a global EASE-Grid format (Armstrong and Brodzik, 1995; Brodzik and Armstrong 2002) at 25km spatial resolution, with 1383 columns and 586 rows for a total of 810438 pixels per daily data product.

Temporal Coverage

SMMR-SSM/I-SSMIS

01 January 1979 to 31 December 2012

AMSR-E

19 June 2002 to 27 September 2011

Temporal Resolution

Daily

Parameter Description

Daily AM F/T status

Freeze/thaw status for the morning satellite overpass

Daily PM F/T Status

Freeze/thaw status for the afternoon satellite overpass

Daily Composite F/T Status

Combined freeze/thaw status for the morning and afternoon satellite overpasses

Daily Transitional F/T Status

AM frozen, PM thawed

Daily Inverse Transitional F/T Status

AM thawed, PM frozen

Daily F/T Status Accuracy Metric

Accuracy_Daily_Metric, stored as a metadata object in HDF5-formatted AM and PM files, provides an aggregate daily accuracy metric.

Annual F/T Status Quality Assurance (QA) Maps

Annual QA maps that provide a relative index of data quality derived from ancillary terrain and land cover heterogeneity information, satellite data gaps, and daily F/T accuracy assessments.

Parameter Range

F/T Status

Table 8 below describes the values used to classify F/T status in data files and images:

Table 8. F/T Classification Values
Classification   Browse Image Color Table
Value R G B
Frozen (AM/PM frozen) 0 000 000 255
Thawed (AM/PM thawed) 1 255 000 000
Transitional (AM frozen and PM thawed) 2 168 168 000
Inverse Transitional (PM frozen and AM thawed) 3 076 230 000
No F/T status available 251 255 255 255
Non-cold constraint area, but unmasked 252 255 255 255
Masked (permanent ice, non-vegetated, and urban area) 254 255 255 255
100 percent open water 255 255 255 255
Fill value 255 255 255 255

F/T Accuracy

Accuracy values are reported as a percent in the range 0.0 to 100.0. Missing values are indicated by -9999.

Sample Data Record

Figure 1 shows the SMMR-SSM/I-SSMIS daily combined AM/PM (CO) F/T status for 9 April 2004. Areas colored in gray lie outside of the F/T data set domain.

Sample Image

Figure 1. Daily CO SMMR-SSM/I-SSMIS F/T Status for 9 April 2004

3. Data Access and Tools

Data Access

Data are available via FTP.

Software and Tools

HDF5 data files may be accessed with HDFView, Panoply, or similar HDF5-compatible applications. GeoTIFF files may be viewed with ESRI ArcMap or similar Geographical Information System (GIS) software.

4. Data Acquisition and Processing

Theory of Measurements

The MEaSUREs Global Record of Daily Landscape Freeze/Thaw Status product, Version 3 allows F/T state dynamics to be quantified over vegetated land within a global domain where seasonally frozen temperatures are a major constraint to ecological processes. Satellite microwave remote sensing is well suited for monitoring global F/T status due to its relative insensitivity to atmospheric contamination, independence from solar illumination, and strong sensitivity to changes in landscape dielectric properties between frozen and thawed states. This freeze/thaw Earth System Data Record (F/T ESDR) is derived using daily radiometric brightness temperature measurement time series from two sources: overlapping SMMR-SSM/I-SSMIS time series and the AMSR-E operational record. The SMMR-SSM/I-SSMIS derived data represent a consistent, daily F/T global record that extends from 1979 to 2010, ensuring cross-sensor consistency through pixel-wise adjustment of the SMMR brightness temperature time series based on empirical analyses of overlapping SMMR, SSM/I, and SSMIS measurements. See Kim et al. 2011 for a detailed description of this data set's methods and validation scheme.

Data Acquisition Methods

The SMMR-SSM/I-SSMIS record was developed by merging the Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave Imager (SSM/I), and Special Sensor Microwave Imager/Sounder (SSMIS) 37 GHz frequency (vertical polarization) brightness temperature records (see Related Data Collections) and applying the same algorithms and protocols used to construct previous versions of this product. The record extends from 1979 to 2012 and encompasses large climate variations and longer-term trends in terrestrial F/T cycles which have been verified against global weather station air temperature records and other biophysical data, including satellite vegetation greenness and tower CO2 flux measurement networks (Kim et al. 2011, Kim et al. 2012). This data set also includes a freeze/thaw data record derived from 36V GHz daily (1:30 AM/PM equatorial crossing) brightness temperature records from the AMSR-E sensor on board NASA's Aqua space vehicle, for the years 2002 to 2011 inclusive. The F/T parameter derivation for AMSR-E is consistent with the SMMR-SSM/I-SSMIS methodology.

Derivation Techniques and Algorithms

The F/T ESDR was designed to have sufficient accuracy, resolution, and coverage to resolve physical processes that link Earth's water, energy, and carbon cycles. In addition, the data can resolve the F/T status of the composite landscape vegetation-snow-soil medium to a sufficient level to characterize the frozen temperature constraints to surface water mobility, vegetation productivity, ecosystem respiration, and land-atmosphere CO2 fluxes.

The F/T classification algorithm utilizes a seasonal threshold approach (STA); radiometric brightness temperature time-series are used to identify F/T transition sequences by exploiting the dynamic brightness temperature temporal response to differences in the aggregate landscape dielectric constant that occur as the landscape transitions between predominantly frozen and non-frozen conditions. These techniques are well-suited for resolving daily F/T state dynamics rather than single events or seasonally dominant transitions (Kim et al. 2011). F/T classification is further refined by using a modified single brightness temperature reference state STA algorithm for anomalous areas where the annual brightness temperature frozen reference state exceeds the brightness temperature non-frozen reference state; these areas, which include portions of northern Africa, Ethiopia and central Mexico, represent less than one percent of the F/T ESDR domain, and in general encompass dry climate areas where other environmental factors such as seasonal wetting events result in large brightness temperature changes similar to F/T transitions. Although these areas are still assigned a low QA value, the alternative single STA reference state F/T classification was found to markedly improve accuracy.

Satellite ascending and descending orbital data time series are processed separately to produce AM, PM, and composite daily (CO) F/T conditions. The F/T ESDR also identifies transitional (AM frozen and PM thawed) and inverse transitional (AM thawed and PM frozen) conditions. The global F/T ESDR domain encompasses unmasked vegetated land areas where low temperatures significantly constrain annual vegetation productivity as defined from climatological reanalysis data. Masked areas include permanent ice and snow, barren land, open water, and regions unconstrained by freezing temperatures. The F/T ESDR is projected in a global cylindrical Equal-Area Scalable Earth (EASE) grid (Brodzik and Armstrong 2002).

Quality Assessment

F/T accuracy is primarily assessed in relation to daily maximum and minimum air temperature measurements from the global World Meteorological Organization (WMO) weather station network (3,160 ±487 stations); mean annual F/T spatial classification accuracies are approximately 91.8 ±1.03 and 84.2 ±1.00 percent for respective F/T ESDR PM and AM retrievals over the global domain and long-term record. The AMSR-E portion of the F/T ESDR has similar spatial classification accuracy.

The F/T ESDR accuracy shows strong seasonal and annual variability and is reduced during active F/T transition periods when spatial heterogeneity in landscape F/T processes is maximized in relation to the relatively coarse (~25 km) satellite footprint (Kim et al. 2011). A daily F/T spatial classification accuracy data quality (QA) metric is included with each daily F/T global grid, defined from pixel-wise comparisons of F/T classification accuracy in relation to co-located global weather station network daily air temperature (minimum and maximum) measurements (Kim et al. 2011, Kim et al. 2012); spatial classification accuracy is defined as the proportion of global stations where the daily F/T classification is consistent with station air temperature measurement based F/T estimates. Additional data quality (QA/QC) metrics are included that provide more spatially explicit information on algorithm performance, including potential negative impacts of temporal gaps in sensor data time series, precipitation, open water and dry soil effects, terrain and land cover heterogeneity, and uncertainty associated with use of global reanalysis temperature data to define per grid-cell frozen and non-frozen reference state thresholds for the seasonal threshold algorithm (STA) based F/T classifications. The resulting F/T ESDR database provides a consistent and continuous multiyear record of daily (AM and PM) F/T dynamics for the global biosphere.

Annual QA maps represent a discrete metric for relative data quality ranging from low (estimated spatial classification accuracy < 70 percent) to best (accuracy > 90 percent. To produce the QA maps, stepwise linear regression was applied to a set of independent variables to estimate FT classification accuracy in relation to global temperature validation sites, where independent variables examined include temporal gaps in sensor brightness temperature data time series, identified active precipitation events, sub-grid (within each 25-km grid cell) open water inundation, and terrain and land cover heterogeneity. Mean annual QA maps are derived for each year of record. For a complete description of the methodology, see Kim et al. 2014.

The QA metrics provide an indicator of data quality for each grid cell within the global product domain. Refer to Figure 2. The dynamic QA information includes uncertainty associated with using reanalysis temperature data to define STA F/T thresholds; this metric was defined from the annual pixel-wise standard deviation of classified non-frozen periods derived from four global reanalysis based air temperature records: NCEP/NCAR, NCEP2, ERA-Interim, and MERRA. The dynamic QA information also includes the number of days per year with SMMR and SSM/I (and AMSR-E) brightness temperature data gaps and flagged precipitation events (Ferraro et al. 1996) and the average number of days per year with reanalysis air temperatures within ±3°C of 0.0°C. The static QA information integrates the potential effects of fractional open water cover defined from the finer scale (1 km resolution) MODIS 17-class IGBP global land cover product (Friedl et al. 2002); the static QA metric also accounts for complex topography (GLOBE, 1999) and heterogeneous land cover conditions defined from the 1 km resolution global land cover classification and digital elevation model.

Quality Assessment

Figure 2. Global F/T ESDR domain defined from a Cold Temperature Constraints Index (CCI, days per year) and GMAO model reanalysis-based daily Tmn over a 7-year (2000-2006) period. The F/T ESDR domain includes all vegetated land areas where the CCI ≥ 5 days per year.

Quality control (QC) metrics provide an indicator of F/T product quality for each grid cell within the F/T ESDR domain. Refer to Figure 3. The dynamic QC information includes the number of days per year with SSM/I radiometric brightness temperature data gaps and flagged precipitation events (Ferraro et al. 1996). The static QC information includes the potential effects of fractional open water cover (MODIS 17-class IGBP Global Land Cover Product, Friedl et al. 2002), complex topography (GLOBE, 1999) and heterogeneous land cover conditions defined from the 1 km resolution global land cover classification and Digital Elevation Model (DEM), and the average number of days (first year) with global model reanalysis air temperatures within ± 3 Celcius degrees of 0.0 Celcius degrees (Kim et al. 2011).

Quality Assessment

Figure 3. The QC scheme identifies regions of relative high to low quality F/T classification results, in relation to general climate and landscape features. The QC map pictured here ranges from low (estimated accuracy < 70 percent) to best (estimated accuracy > 90 percent). Areas in white lie outside the F/T ESDR domain.

Version History

Table 4 summarizes the version history for this data set.

Table 9. Description of Version Changes
Version Description of Changes
V3 (current)
  • Extended the SMMR-SSM/I-SSMIS F/T record through 2012;
  • Corrected land/ocean mask and F/T misclassification errors over some ocean dominated grid cells;
  • Revised the methodology used to produce data quality annual maps.
V2
  • Extended F/T record (1979 to 2010) by overlapping SMMR and SSM/I brightness temperature time series;
  • Added new AMSR-E derived F/T record (2002 to 2011);
  • Refined data quality annual maps;
  • Added GeoTIFF format option and quick-look GIF browse images.
V1 Original version of data set.

Sensor or Instrument Description

The Special Sensor Microwave/Imager (SSM/I) instruments used for this product were deployed on the DMSP F-8, F-11, and F-13 satellites. The SSM/I is a seven-channel, four-frequency, orthogonally polarized passive microwave radiometric system. The system measures combined atmosphere and surface radiances at 19.3 GHz, 22.2 GHz, 37.0 GHz, and 85.5 GHz. Please see NSIDC's Special Sensor Microwave/Imager Instrument Description Web page for more details.

The Special Sensor Microwave/Imager (SSMIS) used for this product is currently deployed on DSMP F-17. The instrument is a 24-channel, passive microwave radiometer designed to obtain a variety of polarized atmospheric temperature, moisture, and land variables under most weather conditions. Channel frequencies range from 19 GHz to 183 GHz and are obtained over a swath width of approximately 1707 km. Please see NSIDC's Special Sensor Microwave Imager/Sounder Instrument Description Web page for more details.

The Scanning Multichannel Microwave Radiometer (SMMR) operated on NASA's Nimbus-7 satellite from 26 October 1978 to 20 August 1987. SMMR was a ten-channel instrument capable of receiving both horizontally and vertically polarized radiation. A parabolic antenna 79 cm in diameter reflected microwave emissions into a five-frequency feed horn. The antenna beam maintained a constant nadir angle of 42 degrees, resulting in an incidence angle of 50.3 degrees at Earth's surface. The antenna was forward viewing and rotated equally ± 25 degrees about the satellite subtrack. The 50 degree scan provided a 780 km swath of the Earth's surface. Scan period was 4.096 seconds. See NSIDC's Scanning Multi-channel Microwave Radiometer (SMMR) Instrument Description Web page for more information.

The Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) is a twelve-channel, six-frequency, passive-microwave radiometer system on board the NASA Earth Oberserving System Aqua Satellite. The instrument measures horizontally and vertically polarized brightness temperatures at 6.9 GHz, 10.7 GHz, 18.7 GHz, 23.8 GHz, 36.5 GHz, and 89.0 GHz. Spatial resolution of the individual measurements varies from 5.4 km at 89 GHz to 56 km at 6.9 GHz. AMSR-E was developed and provided by the Japan Aerospace Exploration Agency (JAXA, Contractor: Mitsubishi Electric Corporation) with close cooperation of U.S. and Japanese scientists. The AMSR-E instrument onboard Aqua was modifed from the design used for AMSR, which flew on the Japanese ADEOS-2 satellite. See NSIDC's AMSR-E Instrument Description page for more information.

5. References and Related Publications

Armstrong, R. L., and M. J. Brodzik. 1995. An Earth-Gridded SSM/I Data Set for Cryospheric Studies and Global Change Monitoring. Advances in Space Research 16: 155-63.

Armstrong, R., K. Knowles, M. Brodzik, and M.A. Hardman, 1998, updated 2012. DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures. Version 2 [1987-2012]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.

Brodzik, M. J. and R. L. Armstrong. 2002. EASE-Grid: A Versatile Set of Equal-Area Rrojections and Grids. In M. Goodchild (Ed.), Discrete Global Grids. Santa Barbara, California USA: National Center for Geographic Information and Anlaysis.

Ferraro, R. R., F. Weng, N. C. Grody, and A. Basist. 1996. An Eight-Year (1987-1994) Time Series of Rainfall, Clouds, Water Vapor, Snow Cover, and Sea Ice Derived from SSM/I Measurements. Bulletin of the American Meteorological Society, 77(5), 891-905.

Friedl, M. A., D. K. McIver, J. C. F. Hodges, X. Y. Zhang, D. Muchoney, A. H. Strahler, C. E. Woodcock, S. Gopal, A. Schneider, A. Cooper, A. Baccini, F. Gao, and C. Schaaf. 2002. Global Land Cover Mapping from MODIS: Algorithms and Early Results. Remote Sensing of Environment, 83, 287-302

GLOBE Task Team and others (Hasting, D. A., P. K. Dunbar, G. M. Elphingstone et al.). 1999. The Global Land One-Kilometer Base Elevation (GLOBE) Digital Elevation Model, Version 1.0. National Oceanic and Atmospheric Administration, National Geophysical Data Center, 325 Broadway, Boulder, Colorado 80305-3328, U.S.A. Digital data base at http://www.ngdc.noaa.gov/mgg/topo/globe.html and CD-ROMs.

Jones, L.A., and J.S. Kimball, 2010. Daily Global Land Surface Parameters Derived from AMSR-E, Version 1.1. Boulder Colorado USA: NASA DAAC at the National Snow and Ice Data Center. http://nsidc.org/data/nsidc-0451.html.

Kim, Y., J.S. Kimball, K.C. McDonald and J. Glassy, 2010. MEaSUREs Global Record of Daily Landscape Freeze/Thaw Status, Version 1 [1988 to 2007]. Boulder Colorado USA: NASA DAAC at the National Snow and Ice Data Center. http://nsidc.org/data/nsidc-0477.html.

Kim, Y., J. S. Kimball, K. C. McDonald, and J. Glassy. 2011. Developing a Global Data Record of Daily Landscape Freeze/Thaw Status using Satellite Microwave Remote Sensing. IEEE Transactions on Geoscience and Remote Sensing.

Kim, Y., J.S. Kimball, K. Zhang, and K.C. McDonald, 2012. Satellite Detection of Increasing Northern Hemisphere Non-Frozen Seasons from 1979 to 2008: Implications for Regional Vegetation Growth. Remote Sensing of Environment 121, 472-487.

Kim, Y., J.S. Kimball, K. Zhang, K. Didan, I. Velicogna, and K.C. McDonald. 2014. Attribution of Divergent Northern Vegetation Growth Responses to Lengthening Non-Frozen Seasons using Satellite Optical-NIR and Microwave Remote Sensing. International Journal of Remote Sensing 35, 10, 3700-3721.

Knowles, K., M. Savoie, R. Armstrong, and M. Brodzik, 2006, updated 2011. AMSR-E/Aqua Daily EASE-Grid Brightness Temperatures [2002-2011]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.

Knowles, K., E.G. Njoku, R. Armstrong, and M. Brodzik, 2000. Nimbus-7 SMMR Pathfinder Daily EASE-Grid Brightness Temperatures [1979-1987]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.

McDonald, K.C, and J.S. Kimball, 2005. Hydrological Application of Remote Sensing: Freeze-thaw States Using both Active and Passive Microwave Sensors. Encyclopedia of Hydrological Sciences. Part 5. Remote Sensing. M.G. Anderson and J.J. McDonnell (Eds.), John Wiley & Sons Ltd. doi: 10.1002/0470848944.hsa059a.

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6.Document Information

Acronyms and Abbreviations

Acronyms and abbreviations used in this document are listed in Table 3.

Table 10. Acronyms and Abbreviations
Acronym Description
AMSR-E Advanced Microwave Scanning Radiometer - Earth Observing System
DEM Digital Elevation Model
DMSP Defense Meteorological Satellite Program
ESRI Environmental Systems Research Institute
EASE-Grid Equal-Area Scalable Earth Grid
F/T ESDR Freeze/Thaw Earth System Data Record
HDF5 Hierarchical Data Format - Version 5
JPL Jet Propulsion Laboratory
MEaSUREs Making Earth System Data Records for Use in Research Environments
NASA National Aeronautics and Space Administration
QA Quality Assurance
QC Quality Control
SMMR Scanning Multichannel Microwave Radiometer
SSM/I Special Sensor Microwave/Imager
SSMIS Special Sensor Microwave Imager/Sounder

Document Creation Date

July 2014

Document Revision Date

July 2014

Document URL

http://nsidc.org/data/docs/measures/nsidc-0477/index.html