Identifying and spatio-temporal analysis of dust point sources in southwestern United States and applying robotics in wind erosion studies
| dc.contributor.committeeChair | Lee, Jeffrey A. | |
| dc.contributor.committeeMember | Mulligan, Kevin R. | |
| dc.contributor.committeeMember | Song, Xiaopeng | |
| dc.contributor.committeeMember | Ardon-Dryer, Karin | |
| dc.contributor.committeeMember | Gill, Thomas E. | |
| dc.contributor.committeeMember | Van Pelt, Robert S. | |
| dc.contributor.committeeMember | Zhu, Zhe | |
| dc.creator | Kandakji, Tarek | |
| dc.creator.orcid | 0000-0001-9173-5747 | |
| dc.date.accessioned | 2021-01-26T21:29:17Z | |
| dc.date.available | 2021-01-26T21:29:17Z | |
| dc.date.created | 2020-12 | |
| dc.date.issued | 2020-12 | |
| dc.date.submitted | December 2020 | |
| dc.date.updated | 2021-01-26T21:29:18Z | |
| dc.description.abstract | This dissertation is composed of three studies; two of them were published as scientific articles in two peer-reviewed academic journals. The first study is entitled “Identifying and Characterizing Dust Point Sources in the Southwestern United States using Remote Sensing and GIS” and it is published in Geomorphology. Appendix A is a screenshot of the first page of the published article showing Volume number and the related Digital Object Identifier (DOI). This study aimed to detect dust point sources in the Southern Great Plains and the Chihuahuan Desert of the United States (U.S.) between the years 2001 and 2016 using satellite images. The detected dust points were later characterized based on the geomorphology and the land use/land cover type of their emission source. A total of 1508 dust point sources were detected. The results showed that ephemeral lakes (i.e. playas) geomorphic class produce the most dust sources in proportion to their area. Cultivated croplands enclose 43% of the dust points, while shrublands and grasslands, combined, enclose 45% of the points. Results from this study confirm the importance of playas as a dynamic source of dust in southwestern U.S. Moreover, this study suggests that anthropogenic factors may be playing a major role in dust emission within southwestern U.S. The results of this study highlights the need to perform further spatio-temporal and quantitative analysis on the detected dust point sources to quantify the contribution of different land cover types on dust emission in the region. This suggestion was fulfilled in the second study of this dissertation. The second study is entitled “Drought and Land Use/Land Cover Impact on Dust Sources in Southern Great Plains and Chihuahuan Desert of the US: Inferring Anthropogenic Effect” and it is published in the Science of The Total Environment. Appendix B is a screenshot of the first page of the published manuscript showing the Volume number and the related DOI. The objective of this research was using the dust point sources dataset produced in the first study to test the hypothesis that there is a statistically significant association between drought level and land cover that may contribute to dust emission in the Southern Great Plains and Chihuahuan Desert regions of the U.S. To reach this objective, several analysis were conducted including spatio-temporal analysis and statistical analysis. The chi-square analysis results showed a significant association between land use type and drought level on dust emission (χ2 (6) = 45.54, р < 0.001), thus confirming the proposed hypothesis. Results from this study indicate that human activities in dust-prone regions will worsen the negative impacts of drought by changing land cover and making the soil more erodible in multiple ways. The third study of this dissertation is entitled “In Situ Measurement of Wind Shear Stress using the Rhex Hexapod Robot Platform”. In this work we used the rigid hexapod robot (RHex) to carry 3D sonic anemometers at two near surface heights to collect wind data. The rationale behind using a mobile senor in the field is to model wind and dust emission using a robust technique rather than using the traditional wind tunnels. The real conditions in the field are hard to simulate in a wind tunnel since it utilizes artificial wind stream flow that is restrained by the walls of the wind tunnel. Moreover, wind tunnel experiments fail to replicate air temperature and moisture content that affect momentum flux. Momentum flux within the boundary layer is an important factor in generating shear stress on the surface. Solar radiation in the open field can cause heating of the air at the surface, which will affect convective overturn and increase wind velocity. The robot scanned a 10 m × 10 m study area in an open field and collected wind and shear stress data as affected by four types of artificial roughness elements simulating a solid object like tree trunk and natural shrubs with different porosity and density. The shear stress and the wind speed data collected by the robot appear to be randomly distributed and does not follow any pattern, which reflects the complexity of real world conditions. These conditions are controlled by many factors, like wind gusts, surface heating, and resulting turbulence from convective overturn. However, the shading effect of solid object was observed, and its effect extends up to 0.5 m downwind of the object at 0.2 m height above the ground (midpoint between ground surface and anemometer mounted at 0.4 m). This study provides an important guideline for future studies, and highlights the potential of using RHex in further studies. Researchers in successive studies should try to fix the limitations of using RHex and improve the study design based on this work. | |
| dc.description.abstract | Embargo status: This title is currently under embargo. Request a copy through the form linked to the left, or by emailing lib.digitalcollections@ttu.edu. You can also contact the author directly. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | https://hdl.handle.net/2346/86787 | |
| dc.language.iso | eng | |
| dc.rights.availability | Restricted from online display. To be vetted for access, please click on Request a Copy on the left or contact the author directly. | |
| dc.subject | Blowing dust | |
| dc.subject | Drought level | |
| dc.subject | Chihuahuan Desert | |
| dc.subject | Southern Great Plains | |
| dc.subject | Land management | |
| dc.subject | Quantitative analysis | |
| dc.subject | Dust point sources | |
| dc.subject | Land use | |
| dc.subject | Geomorphology | |
| dc.subject | Robot | |
| dc.subject | RHex | |
| dc.subject | Wind erosion | |
| dc.subject | Remote sensing | |
| dc.subject | Geographic information system (GIS) | |
| dc.title | Identifying and spatio-temporal analysis of dust point sources in southwestern United States and applying robotics in wind erosion studies | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Geosciences | |
| thesis.degree.discipline | Geosciences | |
| thesis.degree.grantor | Texas Tech University | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy |