An assessment of the differences between three satellite snow cover mapping techniques

Abstract

Abstract:The National Operational Hydrologic Remote Sensing Center (NOHRSC) of the National Oceanic and Atmospheric Administration's (NOAA's) National Weather Service (NWS) provides daily satellite-derived snow cover maps to support the NWS Hydrologic Services Program covering the coterminous USA and Alaska. This study compared the NOHRSC snow cover maps with new automated snow cover maps produced by the National Environmental Satellite, Data, and Information Service (NESDIS) and the snow cover maps created from the Moderate Resolution Imaging Spectroradiometer (MODIS) imagery. The purpose of this paper is to demonstrate and account for the differences that occur between the three different snow cover mapping techniques. Because each of these snow cover products uses data from different sensors at different resolutions, the data were degraded to the coarsest relevant resolution. In both comparisons, forest canopy density was examined as a possible explanatory factor to account for those differences. NOHRSC snow cover maps were compared with NESDIS snow cover maps for 32 different dates from November 2000 to February 2001. NOHRSC snow cover maps were also compared with MODIS snow cover maps in the Pacific Northwest and the Great Plains for 18 days and 21 days, respectively, between March and June 2001. In the first comparison, where the NOHRSC product (¾1 km) was degraded to match the resolution of the NESDIS data (¾5 km), the two products showed an average agreement of 96%. Forest canopy density data provided only weak explanation for the differences between the NOHRSC and the NESDIS snow cover maps. In the second comparison, where the MODIS product (¾500 m) was degraded to match the resolution of the NOHRSC product for two sample areas, the agreement was 94% in the study area in the Pacific Northwest, and 95%

A review of global satellite-derived snow products

“…Despite the inherent difficulties, comparative studies to date have drawn some useful conclusions (Armstrong and Brodzik, 2001;Bitner et al, 2002;Brown et al, 2007Brown et al, , 2010Derksen et al, 2003;Drusch et al, 2004;Foster et al, 1997;Mialon et al, 2005;Mote et al, 2003;Savoie et al, 2007;Tait and Armstrong, 1996). For example, evaluations of NOAA visible and infrared versus passive microwave products find more disagreement during fall and spring than during midwinter, with particular differences under forest canopies, over complex terrain, in areas of persistent clouds, patchy snow, and wet snow (Armstrong and Brodzik, 2001;.…”

MODIS Snow and Sea Ice Products

“…From the standpoint of developing a climate-data record, this is more probiematic than maps derived from an automated algorithm (as in the case of the MODIS products) because even if snow maps derived from automated algorithms are later determined to be incorrect, they can be reprocessed in a uniform manner. Bitner et al (2002) compared NESDIS and MODIS snow maps with the NOHRSC map. NOHRSC snow cover maps were compared with MODIS snowcover maps in the Pacific Northwest and the Great Plains for 18 and 21 days, respectively, between March and June of 2001.…”

Elevation based correction of snow coverage retrieved from satellite images to improve model calibration

“…Several methodologies have been considered to improve the use of satellite images ranging from the field of numerical modelling and ground measurements of snow parameters (Dressler et al, 2006;Bitner et al, 2000;Lee et al, 2005;Ranzi et al, 1999, Tachner et al, 1998 to the development of empirical relationships between flow discharge and snow accumulation and melt (Martinec, 1960).…”