MODIS 0.65 µm visible channel and 2.1 µm near-IR "snow/ice channel" images

AWIPS images of 1-km resolution MODIS 0.65 µm visible channel and MODIS 2.1 µm near-IR “snow/ice channel” data on 23 June 2011 (above) demonstrated the utility of the snow/ice channel to help highlight areas of potential flooding — because water is a strong absorber at the 2.1 µm wavelength, it appears very dark in the snow.ice images. The Souris River located in north-central North Dakota stands out in the images, along with the Missouri River to the southwest.

A comparison of 250-meter resolution MODIS true color and false color images (below) showed greater detail of the flooded areas on the false color image, as well as the fact that a great deal of sediment was flowing into the Missouri River and even into the western portion of Lake Sakakawea.

MODIS true color and false color Red/Green/Blue (RGB) images

A comparison between MODIS false color images on 29 June 2010 and 23 June 2011 (below) showed the dramatic change in the Souris River, as well as in the Missouri River southwest of Williston, North Dakota. In June 2011 historic flooding was occurring in the city of Minot along the Souris River.

MODIS false color RGB image comparison: 29 June 2010 vs 23 June 2011

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MARCI Imagery of the Martian North Pole

The Mars Reconnaissance Orbiter was launched in August of 2005 and began orbiting Mars in March 2006. Its mission is to seek evidence that water persisted on Mars long enough to allow life to develop. One of the instruments on board the MRO is MARCI, the Mars Color Imager, which monitors the clouds and dust storms of the planet. The sensor detects radiation in 5 visible light bands as well as 2 ultraviolet bands. The image loop above shows two days’ of data from the Red Band from the Polar orbiter. The Red Band shows very little distortion and therefore the surface ice (a mix of water and frozen carbon dioxide) remains largely stationary. The images show thin clouds associated with an anticyclonic gyre oscillating around the North Pole in synch with a semi-diurnal tide. Dust and ice comprise the clouds in this scene.

SSEC has a long history of investigating the meteorology of other planets (Examples here and here) using satellite data. For more information on MARCI and MRO from NASA, click here.

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GOES-13 0.63 µm visible channel images (click image to play animation)

McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) revealed numerous pyrocumulus clouds and large areas of very dense smoke associated with the “Honey Prairie Fire” in the Okefenokee Swamp area of southeastern Georgia on 20 June 2011. The shadows cast by the pyrocumulus towers almost resembled those cast by overshooting tops which are often seen on the anvil tops of severe thunderstorms.

A sequence of 3 AWIPS images of POES AVHRR 0.63 µm visible channel data (below) offered a larger-scale view of the smoke as it drifted eastward across the adjacent offshore waters of the Atlantic Ocean. The shadow cast by a pyrocumulus tower could be seen on the final 21:22 UTC image. As expected, this dense smoke plume exhibited very high Aerosol Optical Depth (AOD) values (see the US Air Quality “Smog Blog” and the NOAA IDEA sites for AOD imagery).

POES AVHRR 0.63 µm visible channel images

The 21:22 UTC POES AVHRR 10.8 µm IR image (below) showed that the coldest cloud top IR brightness temperatures at that time were -18º C, which corresponded to an altitude of nearly 24,000 feet using the interactive Skew-T diagram with data from the rawinsonde report from Charleston, South Carolina.

POES AVHRR 10.8 µm IR image + interactive Skew-T for Charleston SC rawinsonde

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On the following day (21 June 2011) the winds were much lighter across the region, so the smoke was not being transported as far eastward over the Atlantic Ocean. In fact, GOES-13 0.63 µm visible channel images (below; click image to play animation) showed that significant amounts of the smoke remained just offshore — so when a sea breeze front began to move inland during the afternoon hours, much of this smoke was brought back inland. For example, at St. Augustine, Florida (surface identifier KSGJ), the surface visibility dropped from 10 miles to 0.75 mile after the surface winds shifted to easterly behind the sea breeze front.

GOES-13 0.63 µm visible channel images (click image to play animation)

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A sequence of 250-meter resolution MODIS true color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (below; displayed using Google Earth) showed varying regimes of transport of the thick smoke on 19 June, 20 June, 21 June, and 22 June 2011.

MODIS true color RGB images (displayed using Google Earth)

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POES AVHRR 10.8 µm IR images

AWIPS images of POES AVHRR 10.8 µm IR data (above) showed a thunderstorm that was moving off the Georgia/Florida coast during the pre-dawn hours on 17 June 2011. Rapidly-warming cloud top IR brightness temperatures indicated that this thunderstorm was quickly dying.

A POES AVHRR false color Red/Green/Blue (RGB) image at 12:36 UTC (below) depicted a well-defined outflow boundary resulting from the downdrafts of the collapsing thunderstorm — and to the east of the storm, the hazy signature of residual smoke from wildfires that had been burning across the region during previous days.

POES AVHRR false color Red/Green/Blue (RGB) image

McIDAS images of GOES-13 0.63 µm visible channel data (below) showed that a great deal of the smoke east of the storm was apparently dissipated by cleaner downdraft air from the dying convection.

GOES-13 0.63 µm visible channel images

This clearing of the smoke was also apparent on a MODIS true color image from the SSEC MODIS Today site (below).

MODIS true color image

For additional images and information, see the US Air Quality “Smog Blog”.

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