Close to ice break-up at Barrow, Alaska?

June 14th, 2012 |
Suomi NPP VIIRS 0.64 µm visible and 1.61 µm near-IR images

Suomi NPP VIIRS 0.64 µm visible and 1.61 µm near-IR images

AWIPS images of Suomi NPP VIIRS 0.64 µm visible channel and 1.61 µm near-IR channel data (above) showed that there was a wide ice-free passage leading from the Bering Sea northward and northeastward through the Chukchi Sea toward Barrow, Alaska (station identifier PABR) on 14 June 2012. On the visible image, ice and optically thick clouds were brighter white, while on the near-IR image ice and water looked very dark (with supercooled water droplet clouds taking on a brighter appearance). Additional information on ice break-up at Barrow is available from the Sea Ice Group at the University of Alaska Fairbanks.

Great Lake Water Surface Temperatures

June 13th, 2012 |
MODIS and AVHRR Lake Surface Temperatures (click image to play animation)

MODIS and AVHRR Lake Surface Temperatures (click image to play animation)

Clear skies over the upper Midwest on the morning of 13 June 2012 allowed the MODIS instrument on board Aqua and the AVHRR instrument on board NOAA-19 to sense the surface temperature of Lakes Michigan and Superior. Which instrument yielded observations that were closer to those recorded in situ by the moored buoys maintained by the National Data Buoy Center? The loop above of MODIS Lake Surface Temperatures and AVHRR Lake Surface Temperatures suggests that the MODIS-derived values are 1-3 Fahrenheit degrees warmer. MODIS values are also closer to the observed values at the moored buoys (45002 and 45007 in Lake Michigan, 45003 in Lake Huron and 45004 in Lake Superior). The higher spectral resolution on MODIS leads to a more accurate depiction of the lake surface in this case.

The National Weather Service in Sullivan, WI, has noted that lake temperatures are running much warmer than normal this year, in part because of the record warmth in March.

Large wildfire in Labrador, Canada

June 13th, 2012 |
GOES-13 0.63 µm visible channel images (click image to play animation)

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 the development of a very broad and dense smoke plume emanating from a large wildfire that was burning just northwest of Goose Bay, Labrador (station identifier CYYR)  in far eastern Canada on 13 June 2012. Note the appearance of a number of bright “pyro-cumulus” clouds near the fire source region, as the very hot fires produced intense updrafts to form large towering cumulus clouds. As an aside, it is interesting to note that there were still a number of large ice floes (slow-moving brighter white features) not far off the Labrador coast, which were drifting slowly northward during the day.

McIDAS images of 375-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 0.64 µm visible channel data and 3.74 µm shortwave IR channel data (below) showed the large size of the fire “hot spot” (yellow to red to black pixels), in addition to the thick smoke plume.

Suomi NPP VIIRS 0.64 µm visible channel and 3.74 µm shortwave IR channel  images

Suomi NPP VIIRS 0.64 µm visible channel and 3.74 µm shortwave IR channel images

A comparison of Suomi NPP VIIRS 3.74 µm shortwave IR images from 12 June and 13 June (below) show how large the fire hot spot had grown in a day. Note that the surface air temperature at Goose Bay plotted on the 12 June image was 93 F (33.9 C) — the high temperature at Goose Bay on that day was actually 95 F (35 C), only 2.2 F (1.2 C) shy of their all-time record high temperature for the month of June.

Suomi NPP VIIRS 3.74 µm shortwave IR images (12 June and 13 June)

Suomi NPP VIIRS 3.74 µm shortwave IR images (12 June and 13 June)

Snow cover and cold temperatures in mid-June

June 12th, 2012 |
Suomi NPP VIIRS 0.64 µm visible channel images

Suomi NPP VIIRS 0.64 µm visible channel images

Parts of far northeastern Manitoba, Canada received significant snowfall on 11 June 2011, with 20 cm (7.9 inches) falling at Gillam (station identifier CYGX). On the following day (12 June 2012), Suomi NPP VIIRS 0.64 µm visible channel images (above) revealed that the remaining snow cover could be seen through the patches of clouds that were moving over that region.

A comparison of the 17:37 UTC (12:37 PM local time) Suomi NPP VIIRS 0.64 µm visible channel image with the corresponding 1.61 µm near-IR “snow/ice channel” image (below) confirmed that the brighter patch seen on the ground in the visible image was indeed snow cover (which shows up as a much darker shade of gray than the surrounding bare ground areas).

Suomi NPP VIIRS 0.64 µm visible image + 1.61 µm near-IR image

Suomi NPP VIIRS 0.64 µm visible image + 1.61 µm near-IR image

Farther to the south, a MODIS Land Surface Temperature (LST) product image at 09:06 UTC (4:06 AM local time) on 12 June (below) showed widespread areas from far southern Manitoba into parts of North Dakota, South Dakota, and Minnesota that exhibited LST values at or just below freezing (32º F or 0º C, darker blue color enhancement). The coldest overnight lows that morning were 32º F at Langdon, North Dakota and Warroad, Minnesota.

MODIS Land Surface Temperature product

MODIS Land Surface Temperature product