epict water use (in millimeters) for a given day or an entire growing season, and, when combined with crop data, can also reveal which crops are using the most, or least, water.
The two maps above show seasonal water use in the San Joaquin Valley in 1990 (left) and 2014 (right). Color coding indicates how irrigation patterns changed over time. Notice, for example, that water use intensified in many places (increase in blue areas) and some irrigated lands (green in 1990) transitioned out of agricultural production (reddish brown) by 2014.
Landsat data are free and easily accessible at http://earthexplorer.usgs.gov/. This research approach can be replicated to produce similar water use maps for other locations across the United States. These maps can help farmers, water management agencies, and rural development planners balance irrigation practices and crop choices with precious water resources.
Sometimes the destructive nature of wildland fires lies beyond the flames. It reveals itself in what is left behind—scorched mountainsides with no trees to stop rain-driven mudslides or dangerous debris flows. When such potential exists, the Shortwave Infrared (SWIR) bands on the sensors aboard the Landsat satellites help to identify those possibilities quickly.
The SWIR bands measure diminished moisture content in soil and vegetation. When SWIR band 7 is paired with Landsat’s Near-Infrared (NIR) band 5, which is highly sensitive to growing vegetation, the two produce vivid, accurate images of burn scars. That information is useful to post-fire responders who must act quickly to stabilize burn areas and address potential risks to people, property, and communities nearby.
Landsat 8 helped map destruction caused by the Cougar Creek fire 75 miles northeast of Portland, Oregon, in mid-August 2015. At left is a pre-fire image of Mount Adams in Washington. Snow appears cyan on its peak. In the middle is a post-fire image where the previous green vegetation south and east of the mountain is now charred and appears in shades of red. The burn severity map at right was produced with Landsat’s infrared imaging, including a SWIR band that is found on few other satellites. Within the fire perimeter, dark green is non-burned, light blue is low burn severity, yellow is moderate severity, and red is high.
Clouds can be a real headache when it comes to satellite imaging. Thin, almost transparent cirrus clouds are often difficult to spot, leaving scientists scratching their heads when data from pixels beneath them come out slightly skewed.
But Landsat 8 has an answer for that.
The newest spacecraft in the Landsat family – which has been acquiring data since February 2013 – contains a spectral band on its Operational Land Imager (OLI) that identifies the high-altitude clouds that are not otherwise apparent in other bands.
These images show that well. On the left, cirrus formations drift above the landscape. On the other hand, cirrus clouds are difficult to discern in the natural-color composite Landsat 8 image on the right, looking down on Columbia, S.C., and across the border north to Charlotte, N.C.
Scientists are using the cirrus band to flag images that are heavy with cirrus cloud contamination. Landsat’s newest band makes that easy to detect, thus allowing for the most accurate data possible.
Great Salt Lake North Arm Reaches Record Low February 19, 2016
The water level of the north arm of Great Salt Lake, Utah, has reached a record low elevation of 4,191.6 feet, 1 foot below the previous record. Lower snowpack in recent years has lessened the spring runoff flowing into the lake. These Landsat images show the change in water levels between 2011 and 2015.
Great Salt Lake is a closed lake, with no outlet. Since water leaves the lake only through evaporation, it leaves behind its dissolved minerals, making the lake up to 8 times as salty as seawater.
On the right side of these images are evaporation ponds. Water from the north arm is pumped to these ponds. The water evaporates and salt, potassium, and other minerals are extracted.
The lake’s north