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Description
A wide range of types of activity in mid-latitude Martian gullies has been observed over the last decade (Malin et al., 2006; Harrison et al., 2009, 2015; Diniega et al., 2010; Dundas et al., 2010, 2012, 2015, 2017) with some activity constrained temporally to occur in the coldest times of year (winter and spring; Harrison et al., 2009; Diniega et al., 2010; Dundas et al., 2010, 2012, 2015, 2017), suggesting that surficial frosts that form seasonally and diurnally might play a key role in this present-day activity. Frost formation is highly dependent on two key factors: (1) surface temperature and (2) the atmospheric partial pressure of the condensable gas (Kieffer, 1968). The Martian atmosphere is primarily composed of CO2and CO2 frost formation is not diffusion-limited (unlike H2O). Hence, for temperatures less than the local frost point of CO2, (~ 148 K at a surface pressure of 610 Pa) frost is always present (Piqueux et al., 2016). Typically, these frosts are dominated volumetrically by CO2, although small amounts of H2O frosts are also present, and typically precede CO2 frost deposition (due to water’s higher condensation temperature (Schorghofer and Edgett, 2006)). Here we use the Thermal Emission Imaging System (THEMIS) and the Thermal Emission Spectrometer (TES) onboard Mars Odyssey and Mars Global Surveyor, respectively, to explore the global spatial and temporal variation of temperatures conducive to CO2 and H2O frost formation on Mars, and assess their distribution with gully landforms. CO2 frost temperatures are observed at all latitudes and are strongly correlated with dusty, low thermal inertia regions near the equator. Modeling results suggest that frost formation is restricted to the surface due to near-surface radiative effects. About 49 % of all gullies lie within THEMIS frost framelets. In terms of active gullies, 54 % of active gullies lie within THEMIS framelets, with 14.3% in the north and 54% in the south.
Relatively small amounts of H2O frost (~ 10–100 μm) are also likely to form diurnally and seasonally. The global H2O frost point distribution follows water vapor column abundance closely, with a weak correlation with local surface pressure. There is a strong hemispherical dependence on the frost point temperature—with the northern hemisphere having a higher frost point (in general) than the southern hemisphere—likely due to elevation differences. Unlike the distribution of CO2 frost temperatures, there is little to no correlation with surface thermophysical properties (thermal inertia, albedo, etc.). Modeling suggests H2O frosts can briefly attain melting point temperatures for a few hours if present under thin layers of dust, and can perhaps play a role in present-day equatorial mass-wasting events (eg. McEwen et al., 2018).
Based on seasonal constraints on gully activity timing, preliminary field studies, frost presence from visible imagery, spectral data and thermal data (this work), it is likely that most present-day activity can be explained by frosts (primarily CO2, and possibly H2O). We predict that the conditions necessary for significant present-day activity include formation of sufficient amounts of frost (> ~20 cm/year) within loose, unconsolidated sediments (I < ~ 350) on available slopes. However, whether or not present-day gully activity is representative of gully formation as a whole is still open to debate, and the details on CO2 frost-induced gully formation mechanisms remain unresolved.
Relatively small amounts of H2O frost (~ 10–100 μm) are also likely to form diurnally and seasonally. The global H2O frost point distribution follows water vapor column abundance closely, with a weak correlation with local surface pressure. There is a strong hemispherical dependence on the frost point temperature—with the northern hemisphere having a higher frost point (in general) than the southern hemisphere—likely due to elevation differences. Unlike the distribution of CO2 frost temperatures, there is little to no correlation with surface thermophysical properties (thermal inertia, albedo, etc.). Modeling suggests H2O frosts can briefly attain melting point temperatures for a few hours if present under thin layers of dust, and can perhaps play a role in present-day equatorial mass-wasting events (eg. McEwen et al., 2018).
Based on seasonal constraints on gully activity timing, preliminary field studies, frost presence from visible imagery, spectral data and thermal data (this work), it is likely that most present-day activity can be explained by frosts (primarily CO2, and possibly H2O). We predict that the conditions necessary for significant present-day activity include formation of sufficient amounts of frost (> ~20 cm/year) within loose, unconsolidated sediments (I < ~ 350) on available slopes. However, whether or not present-day gully activity is representative of gully formation as a whole is still open to debate, and the details on CO2 frost-induced gully formation mechanisms remain unresolved.
ContributorsKhuller, Aditya Rai (Author) / Christensen, Philip (Thesis director) / Harrison, Tanya (Committee member) / Diniega, Serina (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Due to recent changes in climate, hurricanes have become more violent and destructive in the tropical region of the Caribbean. Extreme weather events have destroyed freshwater sources in many islands, affecting the overall food and water security of the region. More resilient forms of collecting freshwater for citizens and agriculture must be proposed in order to mitigate future weather impacts and increase future water security. Rainwater harvesting is an ideal and sustainable source of freshwater that can be adapted into existing households to help ease reliance on city water sources. Rainwater harvesting systems are effective sources of supplemental freshwater because they are easy to incorporate and inexpensive compared to other sources of freshwater. Dennis McClung, founder and owner of global charity, Garden Pool, has created the Climate Smart Farm, an agriculture system that incorporates rainwater harvesting to help create a more climate resilient farm. The Climate Smart Farm is adaptable and can be customized to incorporate solar energy, vertical gardening, aquaponics, hydroponics, plant propagation techniques, and more to grow crops in a more sustainable fashion. The system has recently been installed in the island of Barbuda, which was badly affected by the hurricanes in the summer of 2017. The system has been positively accepted by the country due to its ability to make agriculture simple and sustainable. It can be built with local materials, making the building process economy friendly. And with the addition of plant propagation techniques, the Climate Smart Farm can extend growing seasons and increase overall yields.
ContributorsLeung, Karyn Mae (Author) / Eakin, Hallie (Thesis director) / McClung, Dennis (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
As we already know, fresh water is essential to human life as it sustains and replenishes our bodies. Water sustainability is clearly an important issue that need to be addressed in our world of growing demand and shrinking resources. The ASU Future H2O program seeks to make a difference in the development of water sustainability programs by performing experiments that convert urine into reusable water. The goal is to make reusable water processes become inexpensive and easily accessible to local businesses. This promises a significant environmental impact. In order to make the process of development more efficient we can combine engineering technology with scientific experimentation. As an engineering student and an advocate of water sustainability, I have a chance to design the front-end platform that will use IoT to make the experimental process more accessible and effective. In this paper, I will document the entire process involved in the designing process and what I have learned.
ContributorsTran, Phung Thien (Author) / Boscovic, Dragan (Thesis director) / Boyer, Treavor (Committee member) / School of Earth and Space Exploration (Contributor) / Computer Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Despite similar climate, ecosystem, and population size, the cities of Hermosillo, Mexico and Mesa, USA manage their water very differently. Mesa has a stable and resilient system organized around state and federal regulations. Hermosillo, after rapidly industrializing, has not been able to cope with climate change and long-term drought conditions. Water distribution statistics, stakeholders, policy structure, and government organization were combined in an organizational framework to compare the practices of the two cities. These inputs were weighed against the outcomes and the sustainability of each system. While Mesa is part of a massive metropolitan area, Hermosillo is still developing into a metropolitan center and does not have access to the same infrastructure and resources. In Hermosillo local needs are frequently discounted in favor of broad political goals.
ContributorsMoe, Rud Lamb (Author) / Chhetri, Netra (Thesis director) / White, Dave (Committee member) / Robles-Morua, Agustin (Committee member) / Barrett, The Honors College (Contributor) / School of Earth and Space Exploration (Contributor) / School of Sustainability (Contributor) / School of Geographical Sciences and Urban Planning (Contributor)
Created2013-05
Description
Over the last few decades, sustainability has become a great focus for individuals as well as businesses globally. The focus of this study was to understand why businesses purchase certain office supplies and why they may not be choosing to purchase the most sustainable options. The research question asked, “why are certain businesses reluctant to make positive, sustainable changes to their usage of office materials in their workplace environments?” Most companies do not look for alternatives that would benefit the environment when purchasing products for their office space. The reasons behind this hesitancy to change was studied through current literature on the topic as well as interviews conducted with Office Managers of several different businesses. Comparisons were made between each businesses’ decision patterns in order to find the root cause or causes of why companies do not choose more sustainable options when purchasing products for their workspaces. The interviews revealed that cost and quality are the most important factors these businesses take into consideration when purchasing office supplies. While some companies have looked into alternative products for their supplies, they ultimately choose to still purchase the less sustainable option. This is because the less sustainable option is often cheaper, and the company knows what quality to expect for the item. Overall, all of the Office Managers who were interviewed acknowledged some sort of sustainable practice that their company was taking part in, even if it did not directly relate to the types of office supplies that they purchase. This inclusion of general sustainable practices demonstrates how businesses are making efforts one way or another towards a more sustainable future. Therefore, this awareness to sustainability suggests that most, if not all businesses will eventually end up purchasing sustainable alternatives for their office supplies. However, the timeframe for which this occurs for each company will likely vary.
ContributorsOberlander, Rachel Lynn (Author) / Kappes, Janelle (Thesis director) / Augustin-Behravesh, Shirley-Ann (Committee member) / Dean, W.P. Carey School of Business (Contributor) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
This paper addresses many of the problems that will be encountered when travelling to Mars and discusses the possibility of different solutions. Protection from radiation, oxygen production, and water sources are some of the major problems and the solution to these problems are vital for the success of future space travel. By utilizing technology that has already been used in space travel and implementing the use of technology that is successful on Earth, humans will be able to live on Mars successfully.
ContributorsWebber, Kaitlin Brooke (Author) / Culbertson, Robert (Thesis director) / Foy, Joseph (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
This project focuses on using Neutral Gas and Ion Mass Spectrometer (NGIMS) density data for carbon dioxide, oxygen, carbon monoxide, and nitrogen during deep dip campaigns 5, 6, and 8. Density profiles obtained from NGIMS were plotted against simulated density profiles from the Mars Global Ionosphere-Thermosphere Model (MGITM). Averaged temperature profiles were also plotted for the three deep dip campaigns, using NGIMS data and MGITM output. MGITM was also used as a tool to uncover potential heat balance terms needed to reproduce the mean density and temperature profiles measured by NGIMS.
This method of using NGIMS data as a validation tool for MGITM simulations has been tested previously using dayside data from deep dip campaigns 2 and 8. In those cases, MGITM was able to accurately reproduce the measured density and temperature profiles; however, in the deep dip 5 and 6 campaigns, the results are not quite the same, due to the highly variable nature of the nightside thermosphere. MGITM was able to fairly accurately reproduce the density and temperature profiles for deep dip 5, but the deep dip 6 model output showed unexpected significant variation. The deep dip 6 results reveal possible changes to be made to MGITM to more accurately reflect the observed structure of the nighttime thermosphere. In particular, upgrading the model to incorporate a suitable gravity wave parameterization should better capture the role of global winds in maintaining the nighttime thermospheric structure.
This project reveals that there still exist many unknowns about the structure and dynamics of the night side of the Martian atmosphere, as well as significant diurnal variations in density. Further study is needed to uncover these unknowns and their role in atmospheric mass loss.
This method of using NGIMS data as a validation tool for MGITM simulations has been tested previously using dayside data from deep dip campaigns 2 and 8. In those cases, MGITM was able to accurately reproduce the measured density and temperature profiles; however, in the deep dip 5 and 6 campaigns, the results are not quite the same, due to the highly variable nature of the nightside thermosphere. MGITM was able to fairly accurately reproduce the density and temperature profiles for deep dip 5, but the deep dip 6 model output showed unexpected significant variation. The deep dip 6 results reveal possible changes to be made to MGITM to more accurately reflect the observed structure of the nighttime thermosphere. In particular, upgrading the model to incorporate a suitable gravity wave parameterization should better capture the role of global winds in maintaining the nighttime thermospheric structure.
This project reveals that there still exist many unknowns about the structure and dynamics of the night side of the Martian atmosphere, as well as significant diurnal variations in density. Further study is needed to uncover these unknowns and their role in atmospheric mass loss.
ContributorsRobinson, Jenna (Author) / Desch, Steven (Thesis director) / Hervig, Richard (Committee member) / School of Earth and Space Exploration (Contributor) / School for the Future of Innovation in Society (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05