Measuring specific surface area of snow by near-infrared photography
نویسندگان
چکیده
منابع مشابه
Measuring specific surface area of snow by near-infrared photography
The specific surface area (SSA) is considered an essential microstructural parameter for the characterization of snow. Photography in the near-infrared (NIR) spectrum is sensitive to the SSA. We calculated the snow reflectance from calibrated NIR images of snow-pit walls and measured the SSA of samples obtained at the same locations. This new method is used to map the snow stratigraphy. The cor...
متن کاملThe physics of near-infrared photography
The physics behind the sometimes strange effects and ‘unnatural’ appearance of near-infrared (NIR) photographs is discussed in terms of reflection, absorption and transmission of NIR radiation with the respective objects. Besides discussing how NIR cameras work, several visible and NIR photograph pairs are presented, which include vegetation, natural water, clouds, the sky, and humans. In addit...
متن کاملMeasuring the specific surface area of snow with X-ray tomography and gas adsorption: comparison and implications for surface smoothness
Chemical and physical processes, such as heterogeneous chemical reactions, light scattering, and metamorphism occur in the natural snowpack. To model these processes in the snowpack, the specific surface area (SSA) is a key parameter. In this study, two methods, computed tomography and methane adsorption, which have intrinsically different effective resolutions – molecular and 30μm, respectivel...
متن کاملSensitivity of snow density and specific surface area measured by microtomography to different image processing algorithms
Microtomography can measure the X-ray attenuation coefficient in a 3-D volume of snow with a spatial resolution of a few microns. In order to extract quantitative characteristics of the microstructure, such as the specific surface area (SSA), from these data, the greyscale image first needs to be segmented into a binary image of ice and air. Different numerical algorithms can then be used to co...
متن کاملMeasurement of the specific surface area of snow using infrared reflectance in an integrating sphere at 1310 and 1550 nm
Even though the specific surface area (SSA) and the snow area index (SAI) of snow are crucial variables to determine the chemical and climatic impact of the snow cover, few data are available on the subject. We propose here a novel method to measure snow SSA and SAI. It is based on the measurement of the hemispherical infrared reflectance of snow samples using the DUFISSS instrument (DUal Frequ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Glaciology
سال: 2006
ISSN: 0022-1430,1727-5652
DOI: 10.3189/172756506781828412