Abstract
AbstractThe penetration depth of broad spectrum solar irradiation over the wavelength range 300–1,100 nm has been experimentally measured for water and carbon dioxide ices of different grain size ranges. Both of these ice compositions are found on the surface of Mars and have been observed as surface frosts, snow deposits, and ice sheets. The e‐folding scale of snow and slab ice has been previously measured, but understanding the behavior between these end‐member states is important for modeling the thermal behavior and surface processes associated with ice deposits on Mars, such as grain growth and slab formation via sintering, and carbon dioxide jetting leading to the formation of araneiforms. We find the penetration depth increases in a predictable way with grain size, and an empirical model is given to fit these data, varying with both ice composition and grain size.
Highlights
Previous studies have reported the penetration depth of broad‐spectrum solar irradiation in CO2 ice in its most massive form (Chinnery et al, 2018) and at its finest, as CO2 snow (Chinnery et al, 2019), but how do these two measurements relate to each other, and what is the behavior exhibited in between these two end‐members? Is this same behavior seen for water ice? Measurements of light penetration in water ices have been undertaken in the past, but these have used naturally occurring Antarctic snow and sea ice with all associated contaminants (e.g. Beaglehole et al, 1998; Brandt & Warren, 1993; Datt et al, 2015; Perovich, 1996), impure snow (Kaufmann & Hagermann, 2015), or the measurements were made using narrower wavelength ranges, such as France et al (2010)
We present our findings on how the e‐folding scale varies with grain size for both water and carbon dioxide ices
The penetration depth of broad‐spectrum (300–1100 nm) solar irradiation in granular ice has been calculated from light intensity measurements through water and carbon dioxide ices of different grain sizes
Summary
Previous studies have reported the penetration depth of broad‐spectrum solar irradiation in CO2 ice in its most massive form (Chinnery et al, 2018) and at its finest, as CO2 snow (Chinnery et al, 2019), but how do these two measurements relate to each other, and what is the behavior exhibited in between these two end‐members? Is this same behavior seen for water ice? Measurements of light penetration in water ices have been undertaken in the past, but these have used naturally occurring Antarctic snow and sea ice with all associated contaminants (e.g. Beaglehole et al, 1998; Brandt & Warren, 1993; Datt et al, 2015; Perovich, 1996), impure snow (Kaufmann & Hagermann, 2015), or the measurements were made using narrower wavelength ranges, such as France et al (2010). The penetration depth, or e‐folding scale, is defined as the depth of required to reduce the intensity of incident light to 1/e (~37%), of its initial intensity. It is an important but currently poorly constrained control on the extent of a “Solid‐State Greenhouse Effect” (SSGE) induced in a surface ice deposit (Möhlmann, 2010). We present our findings on how the e‐folding scale varies with grain size for both water and carbon dioxide ices This has significant implications for understanding the evolution of the Martian seasonal and permanent polar caps, which incorporate both ice compositions in varying proportions over a wide range of grain sizes, which vary with time. The sintering process causes grain growth and densification over time, and so the penetration depth of that ice deposit will increase as the ice becomes more translucent
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
