Passive microwave remote sensing of seasonal snow-covered sea ice

Abstract

The Arctic is thought to be an area where we can expect to see the fi rst and strongest signs of global-scale climate variability and change. We have already begun to see a reduction in: (1) the aerial extent of sea ice at about 3% per decade and (2) ice thickness at about 40%. At the current rate of reduction we can expect a seasonally ice-free Arctic by midway through this century given the current changes in thermodynamic processes controlling sea-ice freeze-up and decay. Many of the factors governing the thermodynamic processes of sea ice are strongly tied to the presence and geophysical state of snow on sea ice, yet snow on sea ice remains poorly studied. In this review, we provide a summary of the current state of knowledge pertaining to the geophysical, thermodynamic and dielectric properties of snow on sea ice. We fi rst give a detailed description of snow thermophysical properties such as thermal conductivity, diffusivity and specifi c heat and how snow geophysical/electrical properties and the seasonal surface energy balance affect them. We also review the different microwave emission and scattering mechanisms associated with snow-covered fi rst-year sea ice. Finally, we discuss the annual evolution of the Arctic system through snow thermodynamic (heat/mass transfer, metamorphism) and aeolian processes, with linkages to microwave remote sensing that have yet to be defi ned from an annual perspective in the Arctic.

Physical, dielectric, and C band microwave scattering properties of first‐year sea ice during advanced melt

“…While it is known that meteoric snow grain size and shape evolves as a function of radiation, temperature, and wind, and that these changes affect snow microwave backscatter and emission [ Langlois and Barber , 2007], the properties of disaggregated FYI ice grains that comprise the SL have not been fully examined. A GLM approach was used to assess the evolution of ice grain size and grain ratio over the data collection period of this study.…”

Impact of changing Arctic sea ice extent, sea ice age, and snow depth on sea salt aerosol from blowing snow and the open ocean for 1980-2017

“…This expression leads to very high salinities for thin snow cover, which generally occurs over newly formed sea ice in the Fall. Observations show that the surface of young sea ice is covered by a thin, highly saline layer of slush, thus the snow itself is highly saline but also contains large amounts of liquid (Drinkwater & Crocker, 1988;Langlois & Barber, 2007). This slushy brine-wetted snow is unlikely to be lifted by winds.…”

A review of satellite meteorology and climatology at the start of the twenty-first century

“…This is particularly evident over the oceans where the availability of moisture from the open ocean is signifi cantly reduced with the formation of sea ice. Langlois and Barber (2007) provide an overview of the remote sensing of sea ice from passive microwave observations. Over land regions both visible/infrared and microwave observations are used to derive snow parameters (Kelly et al, 2003).…”