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Articles 1 - 5 of 5
Full-Text Articles in Physical and Environmental Geography
Reconstruction Of Daily 30 M Data From Hj Ccd, Gf-1 Wfv, Landsat, And Modis Data For Crop Monitoring, Mingquan Wu, Xiaoyang Zhang, Wenjiang Huang, Zheng Niu, Changyao Wang, Wang Li, Pengyu Hao
Reconstruction Of Daily 30 M Data From Hj Ccd, Gf-1 Wfv, Landsat, And Modis Data For Crop Monitoring, Mingquan Wu, Xiaoyang Zhang, Wenjiang Huang, Zheng Niu, Changyao Wang, Wang Li, Pengyu Hao
GSCE Faculty Publications
With the recent launch of new satellites and the developments of spatiotemporal data fusion methods, we are entering an era of high spatiotemporal resolution remote-sensing analysis. This study proposed a method to reconstruct daily 30 m remote-sensing data for monitoring crop types and phenology in two study areas located in Xinjiang Province, China. First, the Spatial and Temporal Data Fusion Approach (STDFA) was used to reconstruct the time series high spatiotemporal resolution data from the Huanjing satellite charge coupled device (HJ CCD), Gaofen satellite no. 1 wide field-of-view camera (GF-1 WFV), Landsat, and Moderate Resolution Imaging Spectroradiometer (MODIS) data. Then, …
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
Natural Resource Management Faculty Publications
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.
A Contemporary Decennial Examination Of Changing Agricultural Field Sizes Using Landsat Time Series Data, Emma V. White, David P. Roy
A Contemporary Decennial Examination Of Changing Agricultural Field Sizes Using Landsat Time Series Data, Emma V. White, David P. Roy
GSCE Faculty Publications
Field size distributions and their changes have not been studied over large areas as field size change datasets are not available. This study quantifies agricultural field size changes in a consistent manner using Landsat satellite data that also provide geographic context for the observed decadal scale changes. Growing season cloud-free Landsat 30 m resolution images acquired from 9 to 25 years apart were used to extract field object classifications at seven sites located by examination of a global agricultural yield map, agricultural production statistics, literature review, and analysis of the imagery in the US Landsat archive. High spatial resolution data …
Spatial And Seasonal Responses Of Precipitation In The Ganges And Brahmaputra River Basins To Enso And Indian Ocean Dipole Modes: Implications For Flooding And Drought, M. S. Pervez, G. M. Henebry
Spatial And Seasonal Responses Of Precipitation In The Ganges And Brahmaputra River Basins To Enso And Indian Ocean Dipole Modes: Implications For Flooding And Drought, M. S. Pervez, G. M. Henebry
Natural Resource Management Faculty Publications
We evaluated the spatial and seasonal responses of precipitation in the Ganges and Brahmaputra basins as modulated by the El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) modes using Global Precipitation Climatology Centre (GPCC) full data reanalysis of monthly global land-surface precipitation data from 1901 to 2010 with a spatial resolution of 0.5° × 0.5°. The GPCC monthly total precipitation climatology targeting the period 1951–2000 was used to compute gridded monthly anomalies for the entire time period. The gridded monthly anomalies were averaged for the years influenced by combinations of climate modes. Occurrences of El Niño alone significantly …
A One Year Landsat 8 Conterminous United States Study Of Cirrus And Non-Cirrus Clouds, Valeriy Kovalskyy, David P. Roy
A One Year Landsat 8 Conterminous United States Study Of Cirrus And Non-Cirrus Clouds, Valeriy Kovalskyy, David P. Roy
GSCE Faculty Publications
The first year of available Landsat 8 data over the conterminous United States (CONUS), composed of 11,296 acquisitions sensed over more than 11 thousand million 30 m pixel locations, was analyzed comparing the spatial and temporal incidence of 30 m cloud and cirrus states available in the standard Landsat 8 Level 1 product suite. This comprehensive data analysis revealed that on average over a year of CONUS observations (i) 35.9% were detected with high confidence cloud, with spatio-temporal patterns similar to those observed by previous Landsat 5 and 7 cloud analyses; (ii) 28.2% were high confidence cirrus; (iii) 20.1% were …