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Description
Remote sensing in visible to near-infrared wavelengths is an important tool for identifying and understanding compositional differences on planetary surfaces. Electronic transitions produce broad absorption bands that are often due to the presence of iron cations in crystalline mineral structures or amorphous phases. Mars’ iron-rich and variably oxidized surface provides an ideal environment for detecting spectral variations that can be related to differences in surface dust cover or the composition of the underlying bedrock. Several imaging cameras sent to Mars include the capability to selectively filter incoming light to discriminate between surface materials.
At the coarse spatial resolution provided by the wide-angle Mars Color Imager (MARCI) camera aboard the Mars Reconnaissance Orbiter (MRO), regional scale differences in reflectance at all wavelengths are dominated by the presence or absence of Fe3+-rich dust. The dust cover in many regions is highly variable, often with strong seasonal dependence although major storm events can redistribute dust in ways that significantly alter the albedo of large-scale regions outside of the normal annual cycle. Surface dust reservoirs represent an important part of the martian climate system and may play a critical role in the growth of regional dust storms to planet-wide scales. Detailed investigation of seasonal and secular changes permitted by repeated MARCI imaging coverage have allowed the surface dust coverage of the planet at large to be described and have revealed multiannual replenishing of regions historically associated with the growth of storms.
From the ground, rover-based multispectral imaging acquired by the Mastcam cameras allows compositional discrimination between bedrock units and float material encountered along the Curiosity rover’s traverse across crater floor and lower Mt. Sharp units. Mastcam spectra indicate differences in primary mineralogy, the presence of iron-bearing alteration phases, and variations in iron oxidation state, which occur at specific locations along the rover’s traverse. These changes represent differences in the primary depositional environment and the action of later alteration by fluids circulating through fractures in the bedrock. Loose float rocks sample materials brought into the crater by fluvial or other processes. Mastcam observations provide important constraints on the geologic history of the Gale Crater site.
At the coarse spatial resolution provided by the wide-angle Mars Color Imager (MARCI) camera aboard the Mars Reconnaissance Orbiter (MRO), regional scale differences in reflectance at all wavelengths are dominated by the presence or absence of Fe3+-rich dust. The dust cover in many regions is highly variable, often with strong seasonal dependence although major storm events can redistribute dust in ways that significantly alter the albedo of large-scale regions outside of the normal annual cycle. Surface dust reservoirs represent an important part of the martian climate system and may play a critical role in the growth of regional dust storms to planet-wide scales. Detailed investigation of seasonal and secular changes permitted by repeated MARCI imaging coverage have allowed the surface dust coverage of the planet at large to be described and have revealed multiannual replenishing of regions historically associated with the growth of storms.
From the ground, rover-based multispectral imaging acquired by the Mastcam cameras allows compositional discrimination between bedrock units and float material encountered along the Curiosity rover’s traverse across crater floor and lower Mt. Sharp units. Mastcam spectra indicate differences in primary mineralogy, the presence of iron-bearing alteration phases, and variations in iron oxidation state, which occur at specific locations along the rover’s traverse. These changes represent differences in the primary depositional environment and the action of later alteration by fluids circulating through fractures in the bedrock. Loose float rocks sample materials brought into the crater by fluvial or other processes. Mastcam observations provide important constraints on the geologic history of the Gale Crater site.
ContributorsWellington, Danika (Author) / Bell Iii, James F (Thesis advisor) / Christensen, Philip R. (Committee member) / Robinson, Mark S (Committee member) / Sharp, Thomas G (Committee member) / Till, Christy B. (Committee member) / Arizona State University (Publisher)
Created2018
Description
Research has shown roofing systems with high solar reflectance and thermal emissivity lead to less heat absorption, a consequential reduction in cooling load demand, and a resultant reduction on energy expenditure. Studies on energy savings from cool roof coatings have been conducted for decades and when compared to more traditional roofing systems have demonstrated energy savings ranging from 2-40%, with average savings estimated at 20%. The 20% average is widely used by cool roof industry professionals, designers, and contractors to market and sell the technology in the commercial sector to owners and owner representatives researching new roofs. While the 20% energy savings is a documented average, unfortunately there is no average roof. Each roof is unique considering size, materials, and location to name a few. In addition, the ability of the cool roof to maintain the original solar reflectance is integral to realizing energy savings. The case study calculated project payback for a 20-year cool roof design using both 30% and 20% estimated annual energy savings. In addition, building material specifications and solar reflectance attenuation in respect to reductions in cooling energy were projected into the payback calculations. Lastly, the cost impact of cleaning maintenance was added to the calculations to provide an analysis on affect to anticipated payback schedules. The results showed cleaning costs only added 1 year to project paybacks and saved over 262,244 kWh over 20 years.
ContributorsHaverstic, Preston (Author) / Sullivan, Kenneth (Thesis advisor) / Okamura, Patrick (Committee member) / Slife, Curtis (Committee member) / Arizona State University (Publisher)
Created2016