November 22, 2014

Weekend Edition: As Supertyphoon Nuri moves off, it still has structure

Nearly two weeks ago, Supertyphoon Nuri underwent explosive cyclogenesis as it approached the Aleutians. The cold weather penetrating the US for the last week was a result of what is left of Nuri moving across North America. The Air Quality Problem in Buffalo has been unrelenting snow from Northwest and west winds blowing off Lake Erie and Lake Ontario. In the image today on the left, Nuri still looks like a big storm even though it has left the continent and is moving towards Europe. It is quite possible that this big dog is not done yet. The right image shows the streamers of snow and cloud out over the Atlantic off the New England Coast.

In another amazing image, Hudson's Bay also has many streamers but the open water in Hudson's Bay in the end of November is truly remarkable. It will freeze but it must have taken in a lot of heat over the summer.

In the final image, the US AQI image shows that there were areas in the northwest that still have high PM2.5 levels overnight Friday to Saturday. Wood burning and low PBL heights will cause these elevated pollution events to pop up throughout the winter.

November 21, 2014

Unhealthy AQI in Pacific Northwest; Fires in Southeast

The EPA AQI loop, below left, shows areas of Moderate AQI over most of the country, as well as areas of Unhealthy for Sensitive Groups and Unhealthy in the Pacific Northwest. The poor AQI in this region may be related to the lack of winds available to disperse anything in the air, seen in the RTMA wind image below right, as well as the inversion mentioned in previous posts, which has persisted through today's 0 UTC soundings in that region.

The elevated air quality in the Southeast may be related to the fires in that part of the country seen in the HMS fire and smoke product shown below left. The smoke from some of these fires is visible in the MODIS Aqua RGB image with MODIS fire detections shown below right.

November 19, 2014

Moderate to Unhealthy PM2.5 due to Air Stagnation in the Pacific Northwest

Code Yellow to Orange (Moderate to Unhealthy for Sensitive Groups) PM2.5 AQI levels were reported in the Pacific Northwest states due to air stagnation. Air stagnation is a phenomenon which occurs when an air mass remains over an area for an extended period. Due to light winds and lack of precipitation, pollutants cannot be cleared from the air, either gaseous (like ozone) or particulate (like soot/dust/aerosols). The top left image (courtesy of the Spokane Regional Clean Air Agency) shows hazy skies over Spokane, Washington, associated this air stagnation episode. The five air quality monitoring stations with the greatest PM2.5 concentrations are shown in the top right. Concentrations ranged from 17 to 63 ug/m3 (bottom left image, data courtesy of Airnowtech).

November 18, 2014

Code Red in Pacific Northwest due to PM 2.5

The NOAA HMS product, below left, shows the fire source locations for the United States. Most of these fires are concentrated in the Pacific Northwest location and in the Mississippi Valley region with light smoke. The KNMI OMI NRT NO2 product below right, shows increases in NO2 throughout the troposphere. There appears to be an increase in tropospheric NO2 along the western coastline of the United States and near the Rocky Mountain region. Most of this increased NO2 correlates well with a string of high pressure systems that are stretching across the western United States and are forecasted to move into the Great Lakes region tomorrow.

The surface PM 2.5 AQI loop, courtesy AIRNow below left, shows a code red for a portion of the day in Oregon for the center of the state and near Portland. The surface monitors near Bend, Oregon, courtesy AIRNowTech below right, show PM 2.5 values exceeding 90 ug/m3 and near Prineville, Oregon values reached nearly 110 ug/m3. The 12 UTC sounding from Medford, Oregon shows a large temperature inversion near the surface and several smaller temperature inversions in the first few kilometers which may have decreased ventilation of local pollutants (including residential wood burning) and increased AQI values.

November 17, 2014

NW and NE US Experiencing Moderate to Unhealthy AQIs

The Northwest and Northeastern US are experiencing elevated amounts of PM2.5 today, peaking around midday (EPA AirNow PM2.5 Loop, top left). The Northeast only sees a Moderate AQI (Code Yellow) whereas the AQI in the Northwest reaches Unhealthy (Code Red) in Wyoming, with USG (Code Orange) conditions in surrounding states like Idaho, Washington, and California. Fires in the Pacific Northwest as well as SW Canada, specifically British Columbia and Alberta, are producing light smoke (HMS, top right). This is presumably affecting air quality in the region. The MODIS Terra image (bottom) shows a band of elevated AOD over the Pacific, a little off from the coast of the Pacific Northwest. The rest of the nation, however, is covered by clouds, so it's harder to get a better picture of what's really going on.

November 15, 2014

Weekend Edition: Pavlof Volcano erupts in Alaska

Mark Ruminski pointed out today that Pavlof volcano has erupted and is putting out ash at 16kft. The plume can clearly be seen in Saturday's MODIS Terra and Aqua images.

We don't often use this product but the AIRS SO2 from Fred Prata's algorithm is superimposed on the plume here.

Here is the NOAA SO2 product from the same time.

In California there is evidence of dust in the high desert above LA (Twentynine Palms, Lancaster area). There are no monitor readings available, but Mojave hit 90 µg m-3 at noon today.

And finally on the air quality front in Hawaii, SO2 readings are high enough from the Kilauea Volcano in Pahoa Village that SO2 monitors are being added in the village. SO2 does not routinely show up in the AQI indices on AIRNOW. The State website does show SO2 levels.

Update: Sunday 11/16/2014

Pavlof volcano has settled down today and moderate AQI for PM is widespread across the US today. There are a couple of regions in Washington State that have code orange AQI today. However, it is nearly impossible to see anything from space as the entire country is covered by cloud and snow.

November 14, 2014

Fires in Pacific Northwest

The EPA AQI loop, below left, shows areas of Moderate AQI in the Southeast, the Pacific Northwest, and Pacific Southwest. The elevated AQI in the Pacific Northwest may be related to fires in the area, such as those seen in the MODIS Aqua image of the U.S.-Canada border northwest of Spokane, Washington, overlaid with MODIS fire detections, below right.

The lower air quality in these regions is reflected in webcam images from those areas: top left is the NPS image from North Cascades National Park, bottom left is that from Joshua Tree National Park. The images on the right are from the same locations, taken in clear and hazy conditions for comparison.