Validation of operational AVHRR subpixel snow retrievals over the European Alps based on ASTER data

Snow is of great economic and social importance for the European Alps. Accurate monitoring of the alpine snow cover is a key component in studying regional climate change as well as in daily weather forecasting and snowmelt run‐off modelling. These applications require snow cover information on a high temporal resolution in near‐real time. For the European Alps, operational snow cover fraction maps are generated on a daily basis using data from the Advanced Very High Resolution Radiometer (AVHRR) on board the National Oceanic and Atmospheric Administration (NOAA) platforms. Snow cover distribution is inherently discontinuous and heterogeneous in this mountainous region. We have therefore implemented a straightforward multiple endmember unmixing approach to estimate fractional snow cover. Subpixel proportions are difficult to validate because similar products are not available and appropriate ground‐based observations do not exist. In this study, we validate AVHRR subpixel snow retrievals using binary classified data sets from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) to establish absolute errors of our operational approach at three test sites. Our analysis indicates that the AVHRR subpixel maps compare well with the aggregated ASTER data, showing an overall correlation of 0.78 and providing subpixel estimates with a mean absolute error of 10.4% fractional snow cover. Discrepancies between AVHRR and ASTER snow fraction maps can be attributed to varying snow conditions, terrain effects and density in forest cover.

[1]  Niklaus E. Zimmermann,et al.  Investigating the regional-scale pattern of agricultural land abandonment in the Swiss mountains: A spatial statistical modelling approach , 2007 .

[2]  Xiangming Xiao,et al.  Large-scale observations of alpine snow and ice cover in Asia: Using multi-temporal VEGETATION sensor data , 2002 .

[3]  Kokichi Sugihara,et al.  Why is the 3D Delaunay Triangulation Difficult to Construct , 1995, Inf. Process. Lett..

[4]  Yoram J. Kaufman,et al.  Remote sensing of subpixel snow cover using 0.66 and 2.1 μm channels , 2002 .

[5]  Thomas H. Painter,et al.  MULTISPECTRAL AND HYPERSPECTRAL REMOTE SENSING OF ALPINE SNOW PROPERTIES , 2004 .

[6]  M. Abrams.  The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER): Data products for the high spatial resolution imager on NASA's Terra platform , 2000 .

[7]  William H. Press,et al.  Numerical recipes in Fortran 77 : the art of scientificcomputing. , 1992 .

[8]  A. Klein,et al.  Improving snow cover mapping in forests through the use of a canopy reflectance model , 1998 .

[9]  Aisheng Wu,et al.  Effects of land cover type and greenness on advanced very high resolution radiometer bidirectional reflectances : analysis and removal , 1995 .

[10]  J. Settle,et al.  Linear mixing and the estimation of ground cover proportions , 1993 .

[11]  D. Roberts,et al.  Endmember selection for multiple endmember spectral mixture analysis using endmember average RMSE , 2003 .

[12]  N. DiGirolamo,et al.  MODIS snow-cover products , 2002 .

[13]  Jouni Pulliainen,et al.  Improved linear interpolation method for the estimation of snow-covered area from optical data , 2002 .

[14]  M. Bossard,et al.  CORINE land cover technical guide - Addendum 2000 , 2000 .

[15]  Curtis E. Woodcock,et al.  The effect of viewing geometry and topography on viewable gap fractions through forest canopies , 2004 .

[16]  S. Halldin,et al.  Snow accumulation in forests from ground and remote‐sensing data , 2004 .

[17]  C. Heunks,et al.  Land cover characterization and change detection for environmental monitoring of pan-Europe , 2000 .

[18]  G. Dedieu,et al.  SMAC: a simplified method for the atmospheric correction of satellite measurements in the solar spectrum , 1994 .

[19]  Umesh K. Haritashya,et al.  Mapping Dry/Wet Snow Cover in the Indian Himalayas using IRS Multispectral Imagery , 2005 .

[20]  James J. Simpson,et al.  Bidirectional anisotropic reflectance of snow and sea ice in AVHRR Channel 1 and 2 spectral regions. I. Theoretical analysis , 1999, IEEE Trans. Geosci. Remote. Sens..

[21]  Kari Luojus,et al.  From EO data to snow covered area (SCA) end products using automated processing system , 2005, Proceedings. 2005 IEEE International Geoscience and Remote Sensing Symposium, 2005. IGARSS '05..

[22]  Andrew G. Klein,et al.  Validation of daily MODIS snow cover maps of the Upper Rio Grande River Basin for the 2000–2001 snow year , 2003 .

[23]  T. Painter,et al.  Retrieval of subpixel snow-covered area and grain size from imaging spectrometer data , 2003 .

[24]  Jiancheng Shi.  Estimation of snow fraction using simulated ASTER image data , 2001 .

[25]  Jeff Dozier,et al.  Mapping alpine snow using a spectral mixture modeling technique , 1993, Annals of Glaciology.

[26]  Dorothy K. Hall,et al.  An approach to using snow areal depletion curves inferred from MODIS and its application to land surface modelling in Alaska , 2005 .

[27]  Rune Solberg,et al.  Snow-cover mapping in forests by constrained linear spectral unmixing of MODIS data , 2003 .

[28]  B. Ramsay,et al.  The interactive multisensor snow and ice mapping system , 1998 .

[29]  V. Salomonson,et al.  Estimating fractional snow cover from MODIS using the normalized difference snow index , 2004 .

[30]  Andreas Stoffel,et al.  Synergy of in situ and space borne observation for snow depth mapping in the Swiss Alps , 2007, Int. J. Appl. Earth Obs. Geoinformation.

[31]  M. Marquis,et al.  Accessing the MODIS snow and ice products at the NSIDC DAAC , 2000, IGARSS 2000. IEEE 2000 International Geoscience and Remote Sensing Symposium. Taking the Pulse of the Planet: The Role of Remote Sensing in Managing the Environment. Proceedings (Cat. No.00CH37120).

[32]  Anne W. Nolin,et al.  Towards retrieval of forest cover density over snow from the Multi‐angle Imaging SpectroRadiometer (MISR) , 2004 .

[33]  Rune Solberg,et al.  Subpixel mapping of snow cover in forests by optical remote sensing , 2003 .

[34]  Thomas H. Painter,et al.  The Effect of Grain Size on Spectral Mixture Analysis of Snow-Covered Area from AVIRIS Data , 1998 .

[35]  Dorothy K. Hall,et al.  Determination of actual snow-covered area using Landsat TM and digital elevation model data in Glacier National Park, Montana , 1995, Polar Record.

[36]  Dorothy K. Hall,et al.  Assessment of Snow-Cover Mapping Accuracy in a Variety of Vegetation-Cover Densities in Central Alaska , 1998 .

[37]  Dennis P. Lettenmaier,et al.  Evaluation of the snow‐covered area data product from MODIS , 2003 .

[38]  T. W. Ray,et al.  Nonlinear Spectral Mixing in Desert Vegetation , 1996 .

[39]  Jeff Dozier,et al.  Automated Mapping of Montane Snow Cover at Subpixel Resolution from the Landsat Thematic Mapper , 1996 .

[40]  S. Ekstrand,et al.  Landsat TM-based forest damage assessment : correction for topographic effects , 1996 .

[41]  W. Dulaney,et al.  Normalized difference vegetation index measurements from the Advanced Very High Resolution Radiometer , 1991 .

[42]  Rutger Dankers,et al.  Monitoring snow-cover dynamics in Northern Fennoscandia with SPOT VEGETATION images , 2004 .

[43]  Stefan Wunderle,et al.  Operational sub-pixel snow mapping over the Alps with NOAA AVHRR data , 2004, Annals of Glaciology.

[44]  Sari Metsämäki,et al.  A feasible method for fractional snow cover mapping in boreal zone based on a reflectance model , 2005 .

[45]  Dan Tarpley,et al.  Mapping and monitoring of the snow cover fraction over North America , 2003 .

[46]  Richard Fernandes,et al.  Validation of VEGETATION, MODIS, and GOES + SSM/I snow‐cover products over Canada based on surface snow depth observations , 2003 .

[47]  Jiancheng Shi,et al.  MODIS fraction snow mapping , 2002, IGARSS.

[48]  Yasushi Yamaguchi,et al.  Overview of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) , 1998, IEEE Trans. Geosci. Remote. Sens..

[49]  Zuhal Akyürek,et al.  Using MODIS snow cover maps in modeling snowmelt runoff process in the eastern part of Turkey , 2005 .

[50]  Weiyue Li,et al.  Comparison of methods of snow cover mapping by analysing the solar spectrum of satellite remote sensing data in China , 2003 .

[51]  Niklaus E. Zimmermann,et al.  Sensitivity assessment on continuous landscape variables to classify a discrete forest area , 2006 .

[52]  Paul E. Johnson,et al.  Spectral mixture modeling: A new analysis of rock and soil types at the Viking Lander 1 Site , 1986 .

[53]  R. Solberg,et al.  An automatic system for operational snow-cover monitoring in the Norwegian mountain regions , 1994, Proceedings of IGARSS '94 - 1994 IEEE International Geoscience and Remote Sensing Symposium.