February 8, 2009
Haze in midwest; fires in the southeast (and southeast Australia)
We have elevated moderate PM concentrations in the southern Great Lakes today. The Aqua image shows snow and clouds in the area but there is an indication of haze. In the Southeast, we still have fires in GA right image.
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The GASP 15:15 AOD readings look elevated compared to the MODIS AOD values. GASP is still tuning up after having been down for almost a month when GOES-12 had control issues. GASP is left and MODIS is right.
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I will take tonight to post up some California valley comparisons from the last two months and you can see some of the issues with MODIS and GASP in the west. The panels go from Chico in the north (upper left) to Fresno in the south. Interestingly Bakersfield has "not enough clear days" to get a correlation.
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Finally, it is a horror story in Australia. Over 100 people have died in the fires near Melbourne. The MODIS Aqua image from Rapidfire's subsetter were overlain on the fire locations from Geoscience Australia's Sentinel site. These data are provisional and used without permission. They are for general guidance of where MODIS fires have been seen.
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Conditions across Ohio were hazy on Sunday, Feb. 8. Visibility never exceeded 7 miles at CAK, and was hovering around 4-5 miles at Findlay and Wilmington.
What in the world is causing it? I was thinking it might be smoke being drawn into the system coming out of the plains, but on Sunday, the winds across Ohio were coming out of the north.
Posted by: Phil Creed at February 9, 2009 8:29 AMThere are a number of reasons for wintertime haze.
Salt. Road salt gets abraded from roads and launched as small particles.
Nitrate. In the wintertime, nitrate is more stable against photochemistry and temperature. Peroxyacetyl Nitrate - PAN (yes, the PAN which was eye scorching in the 1950's in LA is much more stable at low temperature. Springtime nitrate tends to bring the white hazes in the early spring.
But we will have to look at the speciation data from the STN network for these cases to be sure.
Thanks for the question and good viewing at night!
Posted by: Ray Hoff at February 9, 2009 7:23 PM