Yes, I’m just having one of those interesting moments, but cannot help from seeing the face in this picture. The Pacific is looking at us! This is a SPoRT-generated Airmass RGB from the Advanced Himawari Imager (AHI) aboard the recently launched Himawari satellite. SPoRT is generating some test imagery from the AHI, including several RGBs such as this Airmass RGB. By the way, that is Typhoon Goni on the left, approaching Taiwan, while Typhoon Atsani is farther to the east (on the right) and is currently forecast to track north of the Marianas Islands over the next few days.
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Intense fires in Canada began releasing large amounts of smoke into the atmosphere on June 6th. Since the initial fires, winds have transported the smoke towards the Upper Midwest. The smoke advancing over the Upper Midwest is evident on the VIIRS True Color image from June 8th (shown below).
Last year, NASA SPoRT developed a near-real time aerosol optical depth (AOD) product that combines observations from polar-orbiting (S-NPP VIIRS and MODIS Aqua and Terra) and geostationary (GOES-15 and MTSAT-2) satellites in an effort to generate a product capable of providing a more complete spatial distribution of AOD across the Pacific Ocean. Although this SPoRT AOD product was originally developed to help support the NOAA-led CalWater 2 field campaign (January-March 2015) with monitoring and tracking long-range transported aerosols across the Pacific Ocean, it can also detect aerosols over the United States. AOD products using observations from only a single satellite sensor often provide a very incomplete picture of AOD since high reflectance from clouds generally mask the aerosol signal. The use of multiple satellite sensors in the SPoRT AOD product helps increase the likelihood of observing a cloud-free region where aerosols are present. Our product has been successfully monitoring and tracking the smoke from the Canadian fires since the initial outbreak on June 6th. A snapshot of the AOD product on June 8th is shown below which is zoomed-in to highlight the very high AOD (red colors indicate AOD >1.0) associated with the smoke plume identified in the VIIRS True Color image. Moderate values of AOD (~0.5) are shown in green while low values (<0.2) are shown in blue and magenta.
The smoke plume has propagated further eastward today to over the Mid-Atlantic region, but is lofted in the atmosphere and has not impacted visibility at the surface.
The MODIS RGB image below captured the dust event in portions of the Intermountain West today, April 14th, as strong winds lifted dust across the drought-stricken region. NWS offices in the region issued high wind warnings and dust storm warnings due to the conditions. Visibilities below one quarter mile in some instances were reported with portions of I 80 closed near Tooele, Utah. The dust is indicated by pinkish colored steaks across portions of Utah and Nevada in the Dust RGB below.
This pic was tweeted by Jed Boal of KSL5 TV in Salt Lake City.
Addendum… I just wanted to update with another image a little later on the 14th to show the evolution of the blowing dust. The area of dust ahead of the frontal boundary was diminishing by about 2030 UTC in Utah, while the large area of dust continued to impact portions of southern Nevada in strong northwesterly flow in the post-frontal airmass (image below).
A quick-moving upper-level trough and associated cold front moved across the TN and lower OH valleys this morning, producing snow showers around the region. The Nighttime Microphysics RGB image below from the VIIRS instrument (Image 1), from around 0805 UTC, shows low/mid clouds associated with the trough. Notice most of the clouds appear light green/yellow and or green/red, indicating predominantly low/mid cloud types. A synthesis of radar and sounding data indicates these clouds were dominated by snow/ice crystals and perhaps some super-cooled liquid droplets. Reports of only light snow have been received at surface stations in the region this morning.
Notice the narrow swath of darker green colors stretching from NE Mississippi northeastward into northern middle Tennessee. Although it may not be apparent, the green color contribution (green represents the 10.8-3.9 µm channel difference in the RGB recipe) in this swath was actually lower than in adjacent clouds. In addition to lower contributions of green, red and blue color contributions were also lower in this narrow swath. The resulting interpretation is that this area was composed of lower, warmer clouds. Due to the variations in green color contribution across the cloud deck, it was immediately unclear whether there was a mix of super-cooled liquid water and ice/snow crystals. Radar imagery from the Nashville, TN and Columbus, MS radars from about the same time indicate mostly uniformity in falling hydrometeors. The image below (Image 2) shows Correlation Coefficient values from the KOHX and KGWX radars at ~0806 UTC.
A small area of slightly lower CC values can be seen to the northwest of Nashville and an inspection of ZDR values (not shown) indicated slight/moderate wet snowflakes. Although, standard reflectivity imagery from the same time shows little in the way of precipitation in that area (Image 3). It should be noted that precipitation echoes were somewhat absent from the darker green swath. However, since these clouds and any resulting precipitation (if present) was relatively low, echoes were below the lowest scans of the regional radars.
Incidentally, the KHTX radar was down for a needed repair and thus not available during this time. One advantage of this type of satellite imagery is that it is safer to make inferences about the presence of precipitation, and in some cases, perhaps even precipitation intensity and type, given similar RGB cloud characteristics. During an event such as this where standard radar data may not be available at a given location, the value of the imagery becomes even more apparent.
The prospect for additional snow and mixed precipitation events over the upcoming week or so will offer more interesting observations of the Nighttime Microphysics RGB. More posts to follow soon!
It is the time of the year when deep plumes of tropical moisture known as atmospheric rivers tend to bring heavy precipitation to the west coast. A particularly strong atmospheric river impacted the west coast this weekend (6-8 February) bringing over 10 inches of rainfall to parts of northern California and nearly 20 inches of snowfall across portions of the Sierra Nevada. The CIRA total layered precipitable water product clearly shows the large amount of moisture streaming into California from the tropics.
However, there is another component to this atmospheric river event that does not get much attention but they can significantly impact precipitation from these storms. They are dust aerosols originating from the deserts in Asia, the Middle East, and Africa, and pollution aerosols from the megacities of eastern Asia. These aerosols are transported across the Pacific most frequently during the late winter and early spring when the wind pattern is ideal. In fact, a currently ongoing NOAA-led field investigation (i.e. CalWater 2) is focused on investigating the interaction between aerosols and atmospheric rivers to better understand how they modify precipitation. SPoRT is supporting this effort by disseminating a near-real time product that combines aerosol optical depth (AOD) retrievals from geostationary and polar-orbiting satellites to monitor and track the long-range transport of aerosols. Extensive cloud cover over the Pacific can often make it difficult to track the aerosols via satellites, therefore, the SPoRT product takes advantage of MODIS, VIIRS, MTSAT, and GOES AOD retrievals in order to provide a more comprehensive look at aerosol activity across the Pacific. SPoRT is disseminating 6-hourly and daily AOD composites throughout the extent of CalWater 2 field campaign set to end mid-March with the overall goal of supporting their aerosol forecasting and flight planning activities. Shortly before the atmospheric river made landfall on 7 February, the SPoRT daily AOD composite shows unusually high AOD of 0.3 to 0.5 (Image 2) in the vicinity of the atmospheric river in Image 1. Higher values of AOD indicate an increasing amount or loading of aerosols in the atmosphere. AOD is typically minimal (< 0.2) over the eastern Pacific when long-range transported aerosols are not present.
The CalWater 2 field investigators flew an aircraft equipped with advanced instruments directly through this atmospheric river on 7 February, which sampled an abundance of long-range transported dust according to CalWater investigator Dr. Jessie Creamean. Further investigation is warranted to determine the source region of the dust. With weeks to go still in the CalWater 2 campaign, field investigators are hoping for more opportunities to fly through aerosol laden atmospheric rivers. If the trend from the past week continues, the CalWater 2 team should be able to gather a wealth of unique measurements that will ultimately lead to improved forecasting of these atmospheric river events.
Aerosol activity over the Pacific was relatively calm during January, but February kicked off with a bang. The SPoRT daily AOD composite on 3 February shows a very thick, extensive aerosol plume propagating from eastern Asia to the western Pacific (Image 3). Closer analysis suggested this plume was a mixture of dust and pollution aerosols.
SPoRT AOD composites can be found at http://weather.msfc.nasa.gov/sport/aod/aodCalendarView.html
We’re near full-moon phase now so I thought I’d take a moment to show some recent VIIRS Day-Night Band (DNB) observations from the Suomi-NPP satellite. This first DNB image from the early morning of Feb 2nd, shows a broad swath of snow on the ground across portions of the Midwest, in addition to a variety of clouds across the Tennessee and Ohio Valleys and further east. The snow field in the DNB image (Image 1) is fairly easily distinguishable from the clouds due to presence of the river valleys cutting across the snow field in the image. Notice the edge of the snowpack extends about as far south as Kansas City, but is mainly on the northern half of the metro area. In this case, having the city lights as a reference can be operationally beneficial…for help in determining surface snow impacts.
This VIIRS Nighttime Microphysics RGB can further help to distinguish snow from clouds (Image 2). Notice that the snow doesn’t really show up well in this RGB (although it encompasses the slightly more orange hues against the surface pink colors). Toggling these two images in AWIPS II would allow a forecast to more readily distinguish snow from clouds .
Following are a couple of DNB images from the past couple of mornings. Notice that the snowpack remains but has been shrinking slightly at its edges over the past couple of days.
SPoRT and NESDIS are currently collaborating on an assessment of a snowfall rate (SFR) product that includes data from the Suomi-NPP Advanced Technology Microwave Sounder (ATMS) instrument. ATMS provides more channels, better resolution, and a wider swath than previous operational microwave sounders, like the Advanced Microwave Sounding Unit (AMSU) and Microwave Humidity Sounder (MHS). The SFR product uses information in microwave channels to estimate liquid-equivalent snowfall rates that forecasters can use for pinpointing the locations of the heaviest snowfall during winter weather events. These observations are being provided in near-real-time (less than 30 minutes latency) through access to data from direct broadcast provided by the University of Wisconsin/CIMSS.
The northeast is currently experiencing a historic blizzard with areas of New England recording more than a foot of snow with more snow to come later today. Below is an example of the output from the ATMS SFR product depicting heavy snow over most of New England. This image indicates that the heaviest snowfall at this time was centered over southeastern Connecticut with rates anywhere from 1-1.5 inches of solid snow per hour.
Coupled with other microwave sensors on board other NOAA and European satellites, up to 10 swaths of observations are available to provide observations of where the heaviest snowfall is falling and allows forecasters to track these features when used in conjunction with GOES imagery and radar.