NIR photography results from the 2009 Ground Passive and Active Snow (GAPS) Experiment (Invited)

Seasonal snow-cover plays a key role in the global water and energy cycle and its monitoring is crucial for managing water resources and understanding its effect on Earth’s climate. Snow falls over bare ground at the beginning of the snow season, it will undergo melting and refreezing cycles as a consequence of fluctuations in surface temperatures above and below the melting point. This produces drastic changes in snowpack properties, in particular grain size and density. Near-infrared digital photography (NIDP) is an innovative and recently proposed method that can quantitatively measure snowpack properties along its vertical profile while greatly reducing the errors associated with more classical methodologies. There are many fields that can ultimately benefit from NIDP, among which are estimates of snow water equivalent (SWE) and snow depth from passive microwave observations. On February 11th - 17th, 2009 a multi-sensor experiment, the Ground Passive and Active Snow (GAPS) Experiment, was carried out nearby Stanley, Idaho. Among other things, passive microwave data were collected concurrently with data of snow parameters along the vertical profile through conventional techniques and a NIR-based approach. Grain size were also photographed and measured along the vertical direction with a microscopic system for comparison with grain size retrieved from NIR photography and refinement of the technique. In this talk, we will report the first results regarding the results from GAPS09 regarding NIDP, the comparison between SSA and grain size derived with the conventional and NIDP techniques and, eventually, a discussion on the use of NIDP data for modeling measured passive microwave data.