Evapotranspiration variability and its association with vegetation dynamics in the Nile Basin, 2002–2011
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Abstract
Evapotranspiration (ET) is a vital component in land-atmosphere interactions. In drylands, over 90% of annual rainfall evaporates. The Nile Basin in Africa is about 42% dryland in a region experiencing rapid population growth and development. The relationship of ET with climate, vegetation and land cover in the basin during 2002–2011 is analyzed using thermal-based Simplified Surface Energy Balance Operational (SSEBop) ET, Normalized Difference Vegetation Index (NDVI)-based MODIS Terrestrial (MOD16) ET, MODIS-derived NDVI as a proxy for vegetation productivity and rainfall from Tropical Rainfall Measuring Mission (TRMM). Interannual variability and trends are analyzed using established statistical methods. Analysis based on thermal-based ET revealed that >50% of the study area exhibited negative ET anomalies for 7 years (2009, driest), while >60% exhibited positive ET anomalies for 3 years (2007, wettest). NDVI-based monthly ET correlated strongly (r > 0.77) with vegetation than thermal-based ET (0.52 < r < 0.73) at p < 0.001. Climate-zone averaged thermal-based ET anomalies positively correlated (r = 0.6, p < 0.05) with rainfall in 4 of the 9 investigated climate zones. Thermal-based and NDVI-based ET estimates revealed minor discrepancies over rainfed croplands (60 mm/yr higher for thermal-based ET), but a significant divergence over wetlands (440 mm/yr higher for thermal-based ET). Only 5% of the study area exhibited statistically significant trends in ET.
Suggested Citation
Alemu, H., Senay, G., Kaptue, A.T., Kovalskyy, V., 2014, Evapotranspiration variability and its association with vegetation dynamics in the Nile Basin, 2002–2011: Remote Sensing, v. 6, no. 7, p. 5885-5908, https://doi.org/10.3390/rs6075885.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Evapotranspiration variability and its association with vegetation dynamics in the Nile Basin, 2002–2011 |
| Series title | Remote Sensing |
| DOI | 10.3390/rs6075885 |
| Volume | 6 |
| Issue | 7 |
| Publication Date | June 25, 2014 |
| Year Published | 2014 |
| Language | English |
| Publisher | MDPI |
| Contributing office(s) | Earth Resources Observation and Science (EROS) Center |
| Description | 24 p. |
| First page | 5885 |
| Last page | 5908 |
| Other Geospatial | Nile Basin |