Environmental Engineering Reference
In-Depth Information
Chapter 14
Snow Cover
Peter Romanov
Abstract Satellites present an important component of the global snow observing
system. Routine monitoring of the snow cover properties from space started in late
1960s. In this chapter, an overview is provided of techniques developed and used to
identify snow cover in satellite images and to generate maps of snow cover
distribution. The reviewed techniques include an interactive approach where
snow maps are manually generated by human analysts through a visual examination
of satellite imagery and automated algorithms that utilize satellite observations in
multiple bands in the optical, infrared, and microwave spectral range. Satellite-
based retrievals of the extent and the spatial distribution of snow cover are accu-
rately and spatially detailed. Estimates of bulk snow pack properties such as the
snow depth and the snow water equivalent are less reliable since they are strongly
dependent on other snow pack features, particularly on the snow grain size and the
snow pack stratification.
Keywords Snow cover extent • Satellite sensors • Remote sensing • Optical
microwave
14.1
Introduction
Terrestrial snow has the largest geographic extent of the cryosphere components.
It covers nearly 50 million km 2 of the Northern Hemisphere (NH) continent in
winter, affecting heavily populated mid-latitude regions as well as higher latitudes.
The extent of seasonal and perennial snow cover in the Southern Hemisphere is
smaller, up to about 1 million km 2 , but it still presents an important hydrological
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