Location of this Satellite Gauging Reach
Medium blue: DFO Maximum Observed Flooding, all sensors, 1993 to present
Light blue: Landsat maximum extent (J-F Pekel and others, 2016, Nature) and DFO "Mean Annual Flood" water extent. Much of this land floods nearly every year.
Dark blue: NASA Shuttle Water Boundary Data (winter, 2000).
Red: NASA SWOT River Reaches.
Black rectangle: the measurement reach.
The River Watch passive microwave radiometry (PMR) signal records changing water surface area within this SGR (black square): the "M" pixel.
The SGR is .09 x .09 degrees latitude and longitude in size or (at low and middle latitudes) approximately 10 x 10 km.
Each day, the GFDS at the European Commission's Joint Research Center automatically chooses driest pixel comparison values from a 22 x 22 pixel array surrounding this measurement pixel (the "C" values). The resulting M/C ratio is the water area monitoring signal used in the River Watch time series.
Notes for this SGR: 1) Side tributaries to the Nam Ngum River may cause some of the surface water changes shown within this SGR. 2) River flooding does, however, cause significant changes in the southern portion of the SGR. 3) A better SGR location could be one pixel to the south. 4) Flow data for the river from a nearby ground gauging station (yellow triangle) is available from the Global Runoff Data Center.
Information on River Watch observation method
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