The Surface Water Monitor

Map 030E040N

Satellite observation of the Earth's changing surface water

Citation: Brakenridge, G.R. and Kettner, A.J., date of access, The Surface Water Monitor: satellite observation of the Earth's changing surface water, TheUniversity of Colorado, Boulder, CO, USA (http://floodobservatory.colorado.edu/).

This map display provides current surface water conditions, and also the recent history of changes, beginning in January, 2000. Surface water expansion and contractions are both mapped.

This is Version 3 of a sustained effort by the Dartmouth Flood Observatory to preserve a global record of surface water variability, including the extremes caused by floods and by droughts. Some satellite data (e.g. Landsat, AVHRR, SPOT, ERS, Radarsat) were gathered commencing in 1993. With the launch of NASA's two MODIS sensors in late 1999 and 2002, that sensor's bands 1 and 2 (250 m spatial resolution) have been routinely used. At present, a daily MODIS water product derived from those two bands provides the current conditions information.

Symbology Key:

A special 4 partcolor scheme is usedBoth areas of expansion above a referIt shows areas of expanded surface water during current flooding. It also provides the observed history of flooding, commencing in the year 2000. See the Drought Display for areas of reduced surface water.

Red is most recent flooding mapped. Water areas are accumulated over 10 days to remove obscuration by cloud cover. See also NRT Global MODIS Flood Mapping for today's two-day composite, including areas of cloud cover. Very recent flooding (past several days) may not appear on this map if cloud cover is heavy.

Light red is previous flooding in the current year.

Light blue is previous flooding since January, 2000.

Dark blue is the reference water (February, 2000, from the Shuttle Radar Topography Mission Water Body data).

During flood events, and as the extent of lakes, reservoirs, and rivers expand, red areas appear and increase in size. As flooding wanes and floodplains dry, red transitions to light red and then (in the new year) to light blue.

Error notes: 1) In mountainous regions, terrain shadows mimic surface water and are mis-classified as water in our current algorithm. We are working to reduce such noise. 2) Reservoirs and impoundments constructed since yr 2000 appear permanently in red. 3)The observational record illustrated may not include all floods: prior to 2011 the records were obtained manually and focus was on major flood events.

Other information: See also the FAQ. Any clickable black dots on these displays link to the River Watch satellite discharge measurement sites. The shaded relief background is from topography provided by NASA SRTM data. Recent GIS data (daily surface water information, as .shp file water boundaries) from the automated MODIS-LANCE NRT Flood processor are located (find appropriate 10 degree folder) at http://csdms.colorado.edu/pub/flood_observatory/MODISlance/ . GIS data (MapInfo format) of the long term record of flooding are also available: at this location. Finally, see the technical description, and the time series of annual flooding via a powerpoint slide file.

Also obtain:

 

This display shows areas of reduced surface water during during times of drought and low tide. See the Flood Display for areas of expanded surface water during floods.

Blue is the extent of current surface water as imaged during the time interval shown by the two MODIS sensors aboard Terra and Aqua. Water areas are accumulated over 10+ days to remove obscuration by cloud cover.

Yellow indicates newly dry land, that was covered by surface water on a reference date (February, 2000, from the Shuttle Radar Topography Mission Water Body dataset). As lakes, reservoirs, and rivers shrink, yellow areas appear and increase in size.

Notes: 1) In mountainous regions, terrain shadows mimic surface water and are mis-classified as water in our current algorithm; we are working to reduce such noise. 2) The reference water is at much higher spatial resolution (90 m instead of 250 m). As a result, many small or narrow water bodies are shown in yellow, but are not necessarily locations of reduced surface water. Larger yellow areas, however, should have been classified as water during the current accumulation, and thus represent significant surface water contraction. The contraction of lakes and artificial impoundments (reservoirs) in particular is well documented.

Other information: See also the FAQ. Any clickable black dots on these displays link to the River Watch satellite discharge measurement sites. The shaded relief background is from topography provided by NASA SRTM data. Recent GIS data (daily surface water information, as .shp file water boundaries) from the automated MODIS-LANCE NRT Flood processor are located (find appropriate 10 degree folder) at http://csdms.colorado.edu/pub/flood_observatory/MODISlance/ . GIS data (MapInfo format) of the long term record of surface water are also available: at this location. Finally, see the technical description, and, when available, a powerpoint slide file of this display, or a time series of successive dates.

The display and any associated geotif and .kmz (Google Earth) files can be further distributed under the Creative Commons Attribution 3.0 Unported License.

Also obtain:

Geotif format

kmz format