Browsing by Author "Gibson, Glen R."

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    An Analysis of Shoreline Change at Little Lagoon, Alabama
    Gibson, Glen R. (Virginia Tech, 2006-06-20)
    In Alabama, the term "coastal shoreline" applies to the Gulf shoreline and the shorelines of estuaries, bays, and sounds connected to the Gulf of Mexico and subject to its tides. However, Alabama shoreline studies have yet to include Little Lagoon, which has been connected to the Gulf of Mexico for most of the last 200 years, according to historical charts. This study used historical nautical charts, aerial photographs, and LIDAR derived shorelines from 1917 to 2004 to analyze shoreline change on Little Lagoon and its adjacent Gulf shoreline. The high water line was used as the common reference feature, and all shorelines were georeferenced, projected, and digitized in a Geographic In-formation System. Between 1917 and 2001, the Gulf shoreline eroded an average of 40 m over 12.7 km, with some transects eroding almost 120 m while others accreted almost 60 m. The greatest changes to the Gulf shoreline were found near natural inlets, downdrift of jetties, and coincident with nourishment projects. Between 1955 and 1997, Little Lagoon shrank 0.5%, or 51.4 km², from 10,285.9 km² to 10,234.5 km². The greatest changes to Little Lagoon were found on its southern shoreline and near inlets, human development, and hurricane overwash fans. A correlation analysis conducted on the Gulf shoreline and Little Lagoon' s southern shoreline indicated that although weak overall correlation values exist when the entire 12.7 km study area is compared, strong correlation values are obtained in some areas when compared over one kilometer sections. The strongest correlations were found in the same locations as the greatest changes.
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    War and Agriculture: Three Decades of Agricultural Land Use and Land Cover Change in Iraq
    Gibson, Glen R. (Virginia Tech, 2012-05-09)
    The main objective of this dissertation was to assess whether cultivated area in Iraq, as estimated using satellite remote sensing, changed during and as a result of war and sanctions. The first study used MODIS NDVI data during OIF and the end of UN sanctions to study changes in cultivated area for Iraq as a whole and to identify spatial patterns. The results revealed significant changes in cultivated area for Iraq as a whole, with cultivated area decreasing over 35,000 ha per year. Regionally, there was little change in cultivated area in northern governorates in the Kurdish Autonomous Region, significant decreases in governorates in central Iraq, and initial increases in governorates containing the southern marshlands followed by decreases related to drought. The second study used Landsat images converted to NDVI to study changes in cultivated area in central Iraq for four periods of conflict, and relates those changes to effects on food security. The results indicated that cultivated area changed little between the Iran-Iraq War (1980 to 1988) and the Gulf War (1990 to 1991), increased by 20 percent (from 1.72 to 2.04 Mha) during the period of United Nations sanctions (1990 to 2003), and dropped to below pre-sanction levels (1.40 Mha) during Operation Iraqi Freedom (2003 to 2011). Finally, the third study builds on findings from the second study to address patterns of agricultural land abandonment in central Iraq. The largest areas of abandoned land were those cultivated during the Late Sanctions period (2000-2003). Further, the results indicate that proximity to surface water and roads are strong indicators of continuity of agricultural land use, and that abandoned lands are positioned in peripheral regions more distant from surface water and the transportation grid. We also found that surface soil salinity is increasing in the cultivated lands of central Iraq, regardless of whether it was cultivated during every period or during only a single period. The overall findings indicate that the UN sanctions had the greatest impact on cultivated area, which increased during sanctions, when food imports all but ceased, and then decreased after sanctions ended and food imports resumed.
  • War and Agriculture: Three Decades of Agricultural Land Use and Land Cover Change in Iraq Dataset
    Gibson, Glen R. (2012-05-09)
    War and geopolitical forces are important drivers of land use and land cover change, and agricultural regions are the most susceptible to those types of changes. Iraq has suffered more than three decades of near-continuous war and instability, including the Iran-Iraq War (1980 to 1988), the Gulf War (1990 to 1991), comprehensive economic sanctions (1990 to 2003), and Operation Iraqi Freedom (OIF) (2003 to 2011). During these conflicts, Iraq’s landscapes were observed by civil satellite remote sensing systems. However, I found little published research applying remote sensing to assess the long-term effects of war on Iraq’s agricultural land cover. The main objective of this dissertation is to assess whether cultivated area in Iraq, as estimated using satellite remote sensing, changed during and as a result of war and sanctions, and to determine where and when changes occurred. The dissertation is composed of three studies. The first study uses MODIS NDVI data during the OIF and the end of UN sanctions to study changes in cultivated area for Iraq as a whole and to identify spatial patterns and temporal differences related to crop type. The second study uses Landsat images converted to NDVI to study changes in cultivated area in central Iraq for all four periods of conflict listed above, and relates those changes to effects on food security. Finally, the third study builds on findings from the second study to address patterns of agricultural land abandonment in central Iraq as related to three drivers: ecological, socio-economic, and land mismanagement. The overall findings indicate that the UN sanctions had the greatest impact on cultivated area, increasing during sanctions when food imports all but ceased and decreasing after the sanctions had ended and food imports resumed, significantly affecting land use and food security. README ======= When all files are downloaded and extracted, the file structure is as shown in contents.txt These contents are archived in multi-volume tar files using the following command: printf 'n Gibson_Iraq-%03d.tar\n' {2..1000} | tar -ML 200000 -cf Gibson_Iraq-001.tar Gibson_Iraq/ Note, only GNU tar version 1.23 or newer (e.g., Red Hat/CentOS Linux version 6.x contains tar version 1.23) may be used to create and extract the tar files. Older versions contain a bug and cannot properly extract files across volumes when long file paths/names are present. Contents in each tar file are shown in contents_tar.txt You may only download the tar volume containing the files you need, then extract this single tar volume. If a file spans across multiple volumes, you'll need to download all related volumes and extract them together. For example, if you download Gibson_Iraq-480.tar to Gibson_Iraq-486.tar and want to extract all the contents in these volumes, run this command: printf 'n Gibson_Iraq-%03d.tar\n' {481..486} | tar --extract --multi-volume --file=Gibson_Iraq-480.tar