185
9
MODIS-Based Snow
Cover Products,
Validation, and
Hydrologic Applications
Juraj Parajka and Günter Blöschl
9.1 INTRODUCTION
Water stored in the snowpack represents an important component of the hydrologic
balance in many regions of the world. Snow cover mapping is particularly important in mountains where an increased demand for water resources often leads to
intense competition for water between human society and freshwater ecosystems.
Monitoring and modeling of snow accumulation and snow melt are particularly difficult in some areas because of the large spatial variability of snow characteristics and,
often, limited availability of ground-based hydrologic data. Satellite imagery is an
attractive alternative relative to ground-based data, as the resolution and availability
do not depend much on the terrain characteristics.
Since the mid-1970s, a wide variety of remote sensing products has been used
to map the changes in snow cover from global to catchment scales. In recent years,
numerous applications of moderate resolution imaging spectroradiometer (MODIS)
snow cover products have demonstrated their high accuracy and consistency with
other satellite and ground-based snow observations or reanalyses of regional climate
models (Parajka and Blöschl 2008b). Many studies found MODIS snow cover products very useful in hydrologic applications of assessing the snow resources, even if
they give the spatial extent of the snow cover only (Blöschl et al. 1991). Regional
CONTENTS
9.1 Introduction .................................................................................................. 185
9.2 MODIS Snow Cover Products ...................................................................... 186
9.3 MODIS Snow Cover Validation ................................................................... 189
9.4 Methods for Cloud Impact Reduction .......................................................... 193
9.5 MODIS Applications in Watershed Hydrologic Modeling ........................... 198
9.6 Conclusions ...................................................................................................206
Acknowledgment ...................................................................................................206
References ..............................................................................................................206
9
MODIS-Based Snow
Cover Products,
Validation, and
Hydrologic Applications
Juraj Parajka and Günter Blöschl
9.1 INTRODUCTION
Water stored in the snowpack represents an important component of the hydrologic
balance in many regions of the world. Snow cover mapping is particularly important in mountains where an increased demand for water resources often leads to
intense competition for water between human society and freshwater ecosystems.
Monitoring and modeling of snow accumulation and snow melt are particularly difficult in some areas because of the large spatial variability of snow characteristics and,
often, limited availability of ground-based hydrologic data. Satellite imagery is an
attractive alternative relative to ground-based data, as the resolution and availability
do not depend much on the terrain characteristics.
Since the mid-1970s, a wide variety of remote sensing products has been used
to map the changes in snow cover from global to catchment scales. In recent years,
numerous applications of moderate resolution imaging spectroradiometer (MODIS)
snow cover products have demonstrated their high accuracy and consistency with
other satellite and ground-based snow observations or reanalyses of regional climate
models (Parajka and Blöschl 2008b). Many studies found MODIS snow cover products very useful in hydrologic applications of assessing the snow resources, even if
they give the spatial extent of the snow cover only (Blöschl et al. 1991). Regional
CONTENTS
9.1 Introduction .................................................................................................. 185
9.2 MODIS Snow Cover Products ...................................................................... 186
9.3 MODIS Snow Cover Validation ................................................................... 189
9.4 Methods for Cloud Impact Reduction .......................................................... 193
9.5 MODIS Applications in Watershed Hydrologic Modeling ........................... 198
9.6 Conclusions ...................................................................................................206
Acknowledgment ...................................................................................................206
References ..............................................................................................................206