Clear Skies over the Great Lakes

October 6th, 2011 |
06 October MODIS Visible Image

06 October MODIS Visible Image

High pressure over the eastern United States on October 6th allowed a rare view of the (almost) cloud-free Great Lakes, above, from the MODIS instrument on board Terra. The clear skies also allowed observations of lake surface temperatures over the entire Lake system, shown below. (Click here for an animation between the Visible and Lake Surface Temperatures). Note that the region of turbulent, sediment-laden waters over southern Lake Michigan — (link for blog post) — are warmer than adjacent waters. The default AWIPS Lake-surface temperature enhancement shows little variations in temperature, when in fact the temperature ranges from 46 F in Lake Superior to 74 F in Lake Erie (near the mouth of Sandusky Harbor). An image with a stretched enhancement that more clearly shows the temperature variability is here. Lakes Michigan, Huron and Ontario continue to show the effects of persistent easterly winds associated with a series of cut-off lows that have passed south of the Great Lakes in the past weeks: cold near-shore temperatures associated with upwelling in the eastern part of the basins.

06 October MODIS Sea Surface Temperature Image

06 October MODIS Sea Surface Temperature Image

Screenshot of AWIPS including MODIS True-color image, 06 October

Screenshot of AWIPS including MODIS True-color image, 06 October

MODIS multi-channel data can be combined to produce a true-color image in the AWIPS environment. In this case, above, the sediment-laden lake waters over southern Lake Michigan jump out. Fall colors over northern Wisconsin and the southern Upper Peninsula of Michigan are also evident. More true-color imagery is available at the MODIS today site: Link.

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