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Full-Text Articles in Physical and Environmental Geography
Distinguishing Land Change From Natural Variability And Uncertainty In Central Mexico With Modis Evi, Trmm Precipitation, And Modis Lst Data, Zachary Christman, John Rogan, J. Ronald Eastman, B. L. Turner Ii
Distinguishing Land Change From Natural Variability And Uncertainty In Central Mexico With Modis Evi, Trmm Precipitation, And Modis Lst Data, Zachary Christman, John Rogan, J. Ronald Eastman, B. L. Turner Ii
Zachary Christman
Precipitation and temperature enact variable influences on vegetation, impacting the type and condition of land cover, as well as the assessment of change over broad landscapes. Separating the influence of vegetative variability independent and discrete land cover change remains a major challenge to landscape change assessments. The heterogeneous Lerma-Chapala-Santiago watershed of central Mexico exemplifies both natural and anthropogenic forces enacting variability and change on the landscape. This study employed a time series of Enhanced Vegetation Index (EVI) composites from the Moderate Resolution Imaging Spectoradiometer (MODIS) for 2001–2007 and per-pixel multiple linear regressions in order to model changes in EVI as …
Evapotranspiration In The Nile Basin: Identifying Dynamics, Trends, And Drivers 2002-2011, H. Alemu, A. T. Kaptué, G. B. Senay, M. C. Wimberly, Geoffrey Henebry
Evapotranspiration In The Nile Basin: Identifying Dynamics, Trends, And Drivers 2002-2011, H. Alemu, A. T. Kaptué, G. B. Senay, M. C. Wimberly, Geoffrey Henebry
Geoffrey Henebry
Analysis of the relationship between evapotranspiration (ET) and its natural and anthropogenic drivers is critical in water-limited basins such as the Nile. The spatiotemporal relationships of ET with rainfall and vegetation dynamics in the Nile Basin during 2002–2011 were analyzed using satellite-derived data. Non-parametric statistics were used to quantify ET-rainfall interactions and trends across land cover types and subbasins. We found that 65% of the study area (2.5 million km2) showed significant (p < 0.05) positive correlations between monthly ET and rainfall, whereas 7% showed significant negative correlations. As expected, positive ET-rainfall correlations were observed over natural vegetation, mixed croplands/natural vegetation, and croplands, with a few subbasin-specific exceptions. In particular, irrigated croplands, wetlands and some forests exhibited negative correlations. Trend tests revealed spatial clusters of statistically significant trends in ET (6% of study area was negative; 12% positive), vegetation greenness (24% negative; 12% positive) and rainfall (11% negative; 1% positive) during 2002–2011. The Nile Delta, Ethiopian highlands and central Uganda regions showed decline in ET while central parts of Sudan, South Sudan, southwestern Ethiopia and northeastern Uganda showed increases. Except for a decline in ET in central Uganda, the detected changes in ET (both positive and negative) were not associated with corresponding changes in rainfall. Detected declines in ET in the Nile delta and Ethiopian highlands were found to be attributable to anthropogenic land degradation, while the ET decline in central Uganda is likely caused by rainfall reduction.
Remote Sensing And Gis Applications In Urban Expansion And Loss Of Vegetation Cover In Kaduna Town, Northern Nigeria, Olarewaju Oluseyi Ifatimehin
Remote Sensing And Gis Applications In Urban Expansion And Loss Of Vegetation Cover In Kaduna Town, Northern Nigeria, Olarewaju Oluseyi Ifatimehin
Olarewaju Oluseyi Ifatimehin
Anthropogenic drivers such as the urbanization and economic dependence have being a major force shaping various landscapes. Kaduna town is no exception of such landscapes. This study uses remote sensing and GIS techniques with survey to identify the various land uses, their various transformations over the a period of 11 years (1990-2000)and to measure the rate of urban expansion and loss of vegetation cover in the study area. The study revealed that built-up area is expanding at about 167.86 hectares annually vegetation covers declining at a faster rate of 297.5 hectares annually. It also revealed that bare land a component …
An Analysis Of Urban Expnasion And Loss Of Vegetation Cover In Lokoja, Using Gis Techniques, Olarewaju Oluseyi Ifatimehin
An Analysis Of Urban Expnasion And Loss Of Vegetation Cover In Lokoja, Using Gis Techniques, Olarewaju Oluseyi Ifatimehin
Olarewaju Oluseyi Ifatimehin
Since Lokoja became an administrative headquarters of Kogi State in 1991, it has been experiencing rapid expansion, urbanization and significant changes in its physical landscape – land use and land cover changes. This study uses remote sensing and GIS techniques combined with field checks and survey to map land use and land cover changes and to measure the rate of urban expansion and loss of vegetation in Lokoja between 1987 and 2005. There was a considerable change in land use types over the said period of the study. The built-up area, vacant land, cultivated land and other land use type …