Hawaiian “vog” plume

January 1st, 2010 |
GOES-11 and GOES-14 visible channel images

GOES-11 and GOES-14 visible channel images

McIDAS images of GOES-11 and GOES-14 visible channel data (above) revealed a large hazy plume streaming northeastward from the Hawaiian Islands on 31 December 2009 – 01 January 2010. The primary source of this plume was ongoing emissions from the Kilauea volcano on “The Big Island” of Hawaii — the resulting “vog” (volcanic smog) is air pollution that forms when sulfur dioxide and other gases/particles emitted by an erupting volcano react with oxygen and moisture in the presence of sunlight. On 31 December the haze was reducing visibility to 5 miles at Lahaina on Maui island.

This GOES-11 vs GOES-14 visible image comparison helps to highlight two important points: (1) due to a more favorable “forward scattering” geometry with GOES-14 positioned at 105º West longitude, the extent of the “vog” plume shows up with greater clarity on GOES-14 images later in the day compared to GOES-11 (positioned at 135º West longitude), and (2) the performance of the GOES visible channel detectors degrades over time, so the much older GOES-11 (launched in 2000) visible imagery appears significantly darker (the enhancement of the images is the same). GOES-14 (launched in 2009) was emulating GOES-West during the final days of its NOAA Science Test.

Under typical conditions, the dominant northeasterly trade winds act to advect the plume of “vog” toward the southwest — but in this case, an AWIPS image of the GOES-11 IR channel with an overlay of ASCAT scatterometer winds (below) showed that there was a southwesterly flow in advance of an approaching cold front.

GOES-11 IR image + ASCAT scatterometer winds

GOES-11 IR image + ASCAT scatterometer winds

An image of the Aura satellite Ozone Measuring Instrument (OMI) Total Column Sulphur Dioxide (SO2) product (below; courtesy of NOAA/NESDIS) confirms that elevated levels of SO2 were present within the “vog” plume seen on GOES visible imagery.

OMI SO2 product (courtesy of NOAA/NESDIS)

OMI SO2 product (courtesy of NOAA/NESDIS)

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