Satellite evidence of hot lava flows from an Icelandic volcano

March 21st, 2010 |
NOAA-19 AVHRR 3.7 µm shortwave IR image

NOAA-19 AVHRR 3.7 µm shortwave IR image

The Eyjafjallajökull volcano in southern Iceland (which had last erupted in the 1820s) experienced a minor eruption on 21 March 2010. An AVHRR 3.7 µm shortwave IR image from the polar-orbiting NOAA-19 satellite (above) showed evidence of a “hot spot” (black to yellow pixels) due to the resulting lava flows.

According to the London VAAC, the volcanic eruption did not produce significant volcanic ash above the 5000 foot level:

FVXX01 EGRR 211458
VA ADVISORY
DTG: 20100321/1200Z
VAAC: LONDON
VOLCANO: EYJAFJOLL
PSN: N6339 W01926
AREA: ICELAND
SUMMIT ELEV: 1000M
ADVISORY NR: 2010/006
INFO SOURCE: ICELAND MET OFFICE
AVIATION COLOUR CODE: UNKNOWN
ERUPTION DETAILS: ERUPTION CONTINUES
OBS VA DTG: 21/1200Z
OBS VA CLD: SFC/FL050 N6331 W01923-N6559 W02252-N6559 W03252-N6047 W03823-N6017 W0342 -N6331 W01923
FCST VA CLD +6HR: 21/1800Z SFC/FL050 N6331 W01919-N6705 W02525-N6704 W03621-N5801 W04323-N5633 W03545-N6143 W03035-N6331 W01919
FCST VA CLD +12HR: 22/0000Z SFC/FL050 N6331 W01903-N6750 W02833-N6750 W03955-N6131 W04520-N5435 W04459-N5501 W03207-N5954 W03105-N6331 W01903
FCST VA CLD +18HR: 22/0600Z SFC/FL050 N6342 W01929-N6838 W03232-N6808 W04515-N5426 W04601-N5202 W03737-N5644 W02954-N6143 W03247-N6342 W01929
RMK: THIS ADVISORY SUPERCEDES ADVISORY 2010/005. VOLCANIC ASH NOT ABOVE FL050, ERUPTION MAINLY LAVA
NXT ADVISORY: 20100321/1800Z=

Icelandic Met Office.

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24 MARCH UPDATE

Aqua MODIS 3.7 µm shortwave IR image

Aqua MODIS 3.7 µm shortwave IR image

The minor volcanic eruptions continued for several days; meteorological clouds often obscured Iceland during that time, but on 24 March an overpass of NASA’s Aqua satellite allowed another view of the lava flow “hot spot” (red pixels) on a 1-km resolution MODIS 3.7 µm shortwave IR image (above). The maximum IR brightness temperatures within the red pixel area were 330 K. Additional photos and video have been posted by the Icelandic Met Office.

Aerosol plume moving offshore from the Northeast US

March 19th, 2010 |
GOES-12 0.65 µm visible images

GOES-12 0.65 µm visible images

McIDAS images of the GOES-12 0.65 µm visible channel data (above) revealed a large hazy aerosol plume that was moving off the Northeast US and drifting out over the adjacent waters of the Atlantic Ocean on 19 March 2010. This aerosol plume exhibited Aerosol Optical Depth (AOD) values of 0.6 and higher on the GOES Aerosol/Smoke Product (GASP) on the IDEA site. Real-time GASP images are also available from the NOAA/NESDIS/SSD/OSDPD site.

A MODIS true color Red/Green/Blue (RGB) image from the SSEC MODIS Direct Broadcast site (below) showed a better view of the varying structure and optical thickness of the aerosol plume.

MODIS true color Red/Green/Blue (RGB) image

MODIS true color Red/Green/Blue (RGB) image

An AWIPS image of the MODIS 0.65 µm visible channel data with an overlay of ECMWF 805-500 hPa layer winds (below) shows that the hazy aerosol plume was being advected eastward by a predominantly westerly flow within that layer.

MODIS 0.65 µm visible image + ECMWF 850-500 hPa layer winds

MODIS 0.65 µm visible image + ECMWF 850-500 hPa layer winds

Model output from the Realtime Air Quality Modeling System (RAQMS) shows the mixing ratio of surface sulfate or SO4 (below) — this demonstrates the increase in SO4 levels over the northeastern US during the 17-19 March period, with a forecast that then advects the high levels of SO4 eastward out over the Atlantic.

RAQMS surface sulfate (SO4) mixing ratio

RAQMS surface sulfate (SO4) mixing ratio

Clear Skies over the Great Lakes

March 19th, 2010 |

Saint Patrick’s Day over the Midwest was unusually clear, affording great images of the Great Lakes from the MODIS instrument aboard the Terra and Aqua satellites. The loop above includes the Visible imagery, the cirrus detection channel (1.38 micrometers), the snow-ice detection channel (2.1 micrometers), the derived lake-surface temperatures and the normalized difference vegetation index (NDVI).

Close-up views of the individual lake basins: Ontario, Erie, Michigan-Huron and Superior show mostly uniform surface temperatures in the upper 30s (Fahrenheit) as is normal in early Spring. There are warm thermal plumes in Lake Erie, however, emerging from Sandusky Bay and from the Maumee River at Toledo. MODIS-derived Lake surface temperatures in those regions are in the upper 40s. (True-color imagery for that time (here) show great turbidity over Lake Erie; perhaps the warm temperatures are a result of enhanced run-off from the Maumee and Sandusky Rivers) Temperatures over Lake Michigan are slightly warmer in the middle of the lake — near 40 F — than along the perimeter where lake temperatures are still in the mid-30s. This might be a signature of recently melted near-shore ice.

High-resolution imagery such as these will be routinely available when GOES-R is launched and becomes the operational GOES satellite over the United States.

Fires in Oklahoma and Arkansas

March 18th, 2010 |
GOES-13 (top) and GOES-12 (bottom) visible images

GOES-13 (top) and GOES-12 (bottom) visible images

McIDAS images comparing 1-km resolution GOES-12 and GOES-13 0.65 µm visible channel data (above) revealed several smoke plumes over parts of eastern Oklahoma and western Arkansas, while the corresponding 4-km resolution GOES-12 and GOES-13 3.9 µm shortwave IR images (below) showed numerous “hot spots” (black to yellow to red pixels) due to widespread fire activity that had flared up across that region on 18 March 2010. Even though there were a number of smoke plumes seen in eastern Oklahoma, the most obvious smoke plumes (in term of size and brightness on the visible imagery) were apparent in northwestern Arkansas.

GOES-13 (top) and GOES-12 (bottom) 3.9 µm shortwave IR images

GOES-13 (top) and GOES-12 (bottom) 3.9 µm shortwave IR images

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MODIS visible and 3.7 µm shortwave IR images

MODIS visible and 3.7 µm shortwave IR images

AWIPS comparisons of the 1-km resolution MODIS visible and 3.7 µm shortwave IR images at 19:31 UTC (above) and the 1-km resolution AVHRR visible and 3.7 µm shortwave IR images several hours later at 23:43 UTC (below) showed that many more fire hot spots could be detected with the use of higher spatial resolution shortwave IR images (GOES vs MODIS at 19:31 UTC | GOES vs AVHRR at 23:43 UTC). The spatial resolution of the shortwave IR channels on the ABI instrument of GOES-R satellite will be 2 km, which will be an improvement over the 4 km resolution on the current GOES satellites.

AVHRR visible and 3.7 µm shortwave IR images

AVHRR visible and 3.7 µm shortwave IR images

A closer view over northwestern Arkansas using the AVHRR visible channel, Cloud Type Product, Cloud Top Temperature, and Cloud Particle Effective Radius products at 22:03 UTC (below) showed the following: (1) the 3 large smoke plumes over northwestern Arkansas as well as the smaller cumulus clouds off the the east were composed primarily of water droplets (cyan color enhancement); (2) the Cloud Top Temperature values of the large smoke plumes were quite warm (+10 to +12º C, gray color enhancement), while some of the smaller cumulus clouds off to the east were beginning to exhibit CTT values several degrees below freezing (red to orange color enhancement); (3) the Cloud Particle Effective Radius values in the smoke plumes were significantly larger (30-40 µm, darker blue color enhancement) than those of the cumulus clouds off to the east (15-20 µm, cyan color enhancement).

AVHRR visible, Cloud Type, Cloud Top Temperature, and Cloud Particle Effective Radius

AVHRR visible, Cloud Type, Cloud Top Temperature, and Cloud Particle Effective Radius