The Nile is one of the most vital, diverse and contentious river systems in the world. The people in the 11 nations that share the Nile's watershed must contend with droughts, floods and a variable unchanging climate.
NASA research is now bringing unprecedented measurement and monitoring capabilities to the Nile that help scientists, water managers, and policymakers understand changes in the river's water cycle.
Here we see the seasonal cycle of monthly precipitation in Africa, including the Nile Basin.
The annual migration of the rain-laden Intertropical Convergence Zone--from the Nile equatorial lakes region around Lake Victoria, northward into Sudan and the highlands of Ethiopia and back--is evident in the seasonal cycle of rainfall. This precipitation cycle drives water flow through the Nile River system.
But rainfall is only part of the picture since the region experiences high rates of evaporation, with more water leaving the basin through evaporation than by water flow.
This map of evapotranspiration, developed by USDA scientists, shows an unprecedented daily measurement of both evaporation from the soil and water released by plants, or transpiration.
The balance of rainfall and evapotranspiration can be seen in seasonal patterns of soil moisture as shown in this simulation, which merges satellite information with a physically-based land-surface model to simulate variability in soil moisture--a critical variable for rain-fed, agriculture and natural ecosystems.
How plant life responds to the water cycle can be seen in this measurement of vegetation.
The farmers and organizations like the Famine Early Warning Systems Network use these measurements to monitor croplands and predict food shortages.
Finally, NASA satellites use gravity to monitor the total water present in the system, including surface water, soil moisture and groundwater. The annual cycle estimates of water storage anomalies clearly show the seasonal movement of water storage due to precipitation patterns and the movement of surface waters from headwaters regions into the wetlands of South Sudan and the reservoirs of the lower Nile basin.
By providing a complimentary array of observations and models of Nile River flow, NASA research provides policy makers with objective, basin-wide information to inform collaborative water management.