SPoRT LIS Shows Dry Soils During High Plains Blowing Dust Event…

Yesterday while working on some Dust RGB related training materials, I was looking at the RGB in AWIPS and noticed a dust event unfolding in real-time in the central High Plains.  The loop below shows Dust RGB imagery, generated by GOES-East, yesterday, 28 Jan 2019 during the late morning and early afternoon hours.  The loop is centered over NE Colorado and SW Nebraska where you’ll see the blowing dust develop and spread southeastward.  In case you’re not too familiar with this type of imagery, the dust is represented by the magenta colors.  It’s also possible to observe some of the individual dust streaks or plumes within the larger blowing dust event, which help to show their locations of origin.  (By the way, sorry about the loss of image fidelity when saving from AWIPS to an animated GIF).

Image 1.  GOES-East Dust RGB imagery, approx. 1737-2002 UTC, 28 Jan 2019. The blowing dust is defined by the magenta colors, near the center of the imagery.

Research has shown that it takes the right combination of factors to loft dust particles sufficiently to generate these larger scale blowing dust events, partly based on soil moisture and winds.  The SPoRT LIS 0-10 cm volumetric soil moisture (VSM) analysis at 18 UTC indicated very low values in the blowing dust source region, with VSM percentages generally around 12-16% (Image 2).  The METAR observations also indicate sustained winds were 35-40 knots with stronger gusts over 40 knots at one locations in the area.

Image 2. SPoRT LIS volumetric soil moisture (background colors) overlaid with surface METAR plots (yellow figures), valid at 18 UTC, 28 Jan 2019.

This last image is a snapshot of the Dust RGB taken at 1902 UTC, overlaid with surface visibility and ceiling observations.  Notice that at station KHEQ in far northeastern Colorado, a ceiling of 100 ft and visibility of 7 SM was reported, which was likely due to the blowing dust.

Image 3. GOES-East Dust RGB and ceiling and visibility observations from ground observation stations at approximately 19 UTC, 28 Jan 2019.

Some SPoRT collaborative NWS offices in the West CONUS have utilized LIS VSM values to locate areas where the probability of blowing dust events is heightened under the proper conditions.  However, SPoRT is looking into opportunities to better predict where these events will occur.

SPoRT LIS Shows Low Soil Moisture Conditions Near Large N. Cal Fire…

Just making a quick post here as I noticed there were relatively dry soil moisture conditions at the site of a rather large fire that developed quickly in Butte County, CA today.  The first image is the Fire Temperature RGB from the GOES-16 satellite (mesoscale domain sector 1) at 2018 UTC, today, 8 Nov 2018.  In this RGB, the fire can be observed by  colors ranging from near red to near white, just east of Chico, CA.  Notice there are a few white pixels, indicating relatively high emissions from shorter wavelengths (1.61 µm), and thus, relatively hot fire temperatures.

FireTempRGB_2018Z8Nov2018

Meanwhile, soil moisture data from SPoRT’s Land Information System show low soil moisture percentiles (from the 33-year climatology, next image below) at the fire’s location east of Chico.  In fact, these values are  below the 2nd percentile at the fire’s location.

SoilMoisturePercentile_12Z8Nov2018

Lastly, the one year change in deep layer soil moisture values (0-200 cm) also show significant decreases in soil moisture centered at the fire’s location and especially just east over the last year.

OneYearChange_12Z8Nov2018

SPoRT is conducting research and working closely with members of the wildfire community in the western U.S. to transfer these and other data sets for operational decision-makers.

-Kris W.

Fog at Sunrise with RGBs using Visible Imagery

Fog at Sunrise with RGBs using Visible Imagery

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Nighttime Microphysics RGB via GOES-16 at 1122 UTC, 13 August 2018 over the Southeast U.S.

During the early morning of 13 August 2018, clear skies resulted in wide spread low clouds and fog over the East/Southeast.  The image above is the Nighttime Microphysics (NtMicro) RGB via GOES-16 at 1122 UTC or 7:22 and 6:22 AM for Eastern and Central times respectively.  At this time the low clouds and fog in shades of cyan are still apparent, but soon this coloring will fade as solar reflectance at sunrise will influence the shortwave IR used in the RGB and therefore, the NtMicro will be rendered ineffective (see mp4 animation).  Typically, visible imagery is used at sunrise to continue to monitor fog in small-scale valleys, often with a lack of in situ observations.  The new capabilities of GOES-16 provide new RGBs for daytime use that include the 0.64 micron visible channel.  The Natural Color RGB, originally developed by EUMETSAT is available within AWIPS (as ‘Day Land Cloud’), and it uses the visible channel in it’s blue component.  Below is a slide show of the NtMicro, Natural Color and Visible RGBs just after sunrise (1222 UTC).  Note that the Natural Color RGB (also see mp4 animation) shows the fog and water clouds in gray while ice clouds are in cyan.  The Natural Color RGB can be used through the day to monitor the microphysics of cloud tops due to the use of the 1.61 micron channel, and it also provides qualitative land surface information via the 0.87 micron channel.   A legacy ‘Visible’ RGB (also see mp4 animation) that uses the visible in the red and green components (‘Day Land Convection’ within AWIPS), also provides value to monitor fog after sunrise as it depicts warm clouds in yellows and cold clouds in grays to white in daytime.

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Dust RGB Imagery and NASA’s CALIPSO/CALIOP

Dust RGB Imagery and NASA’s CALIPSO/CALIOP

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Dust RGB via GOES-16 from 1732-2232 UTC on 12 April 2018 over the U.S. Southwest

SPoRT used the MODIS and VIIRS imagers (on NASA’s Aqua & Terra satellites, and NOAA’s S-NPP satellite, respectively) within the NOAA’s Satellite Proving Ground to assess the value of a “Dust RGB Imagery” product for potential use with GOES-R (now GOES-16).  The Dust RGB proved useful on 13 April 2018 (animation above) where many dust plumes developed in the U.S. Southwest and Mexico.  Forecasters were able to monitor dust plume initiation and issue advisories and warnings.  In addition, several plumes continued to have impacts after sunset, and the Dust RGB, which uses only IR window channels (see Dust RGB Quick Guide), was able to continue monitoring the event at night while the visible imagery was no longer valuable.  Some advisories were extended beyond their original expiration time.  NASA SPoRT is using the NASA CALIPSO satellite and associated CALIOP lidar on board to validate and categorize dust signatures seen in the RGB and examine quantitative aspects like plume height and thickness.  The image below shows an event from 3 April 2018 where forecasters from the NWS Albuquerque WFO and CWSU evaluated the Dust RGB impact to operations as part of SPoRT’s assessment activities, and the CALIOP lidar backscatter captured the dust plume over west Texas.  From CALIOP the dust plume appears to be about 2 km thick in most locations, but the most concentrated region reached a height of about 3 km above ground.

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Dust RGB via GOES-16 (upper) over the CONUS and lidar backscatter via CALIOP (on NASA’s CALIPSO satellite) for 2007 UTC on 3 April 2018.  Annotations in yellow point out the dust plume and clouds along the path of CALIOP shown by white arrow/text.

Dust RGB analyzes “dryline” for 3/23/17

Dust RGB analyzes “dryline” for 3/23/17

 

The Dust RGB, originally from EUMETSAT and a capability of GOES-R/ABI, can be helpful in identifying features other than dust, including drylines. A dryline represents a sharp boundary at the surface between a dry air mass and moist air mass where there is a sudden change in dew point temperatures. In this event from 3/23/17, a dryline in eastern New Mexico and west Texas is distinguishable via the Dust RGB imagery animation from GOES-16 (Fig. 1), while a large dust plume (magenta) is impacting areas further west. Note that the visible imagery (Fig. 2) shows clouds forming along the dryline, but these clouds drift downwind toward the northeast as they mature, away from the dryline itself, making it difficult to monitor the dryline position.  However, the dryline position can easily be seen via the color difference of the Dust RGB across the boundary of dry and moist air, and in fact, the dryline appears fairly stationary or moves in a slight westward direction, opposite of the cloud motion.  In situ observations (Fig. 3) are a primary tool for monitoring the dryline location, but the advantage of satellite imagery is an increased spatial and temporal resolution for forecasters.

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Figure 1. GOES-16 Dust RGB valid from 2022 to 2322 UTC, on 23 March 2017 centered on extreme western Texas.  Dryline seen in color difference of cloud-free area in eastern New Mexico and west Texas while dust plume is in magenta shades.

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Figure 2. GOES-16 Visible (0.64u) channel valid from 2027 to 2322 UTC on 23 March 2017 as in Figure 1.

For the above and subsequent images/animations: NOAA’s GOES-16 satellite has not been declared operational and its data are preliminary and undergoing testing. Users receiving these data through any dissemination means  (including, but not limited to, PDA and GRB) assume all risk related to their use of GOES-16 data and NOAA disclaims any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose.

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Figure 3. METAR station plot of surface observations at 2143 UTC on 23 March 2017 centered over New Mexico.

The ability to identify drylines using the Dust RGB gives the forecaster the capability to analyze these boundaries in ways not seen before. In the Dust RGB (Fig. 4), the surface area on the dry side is seen as a purple color (i.e. increased red contribution), and the moist side appears more blue (i.e. less red). This dryline can be noted more easily than in visible imagery (Fig. 5) due to the sensitivity of the 12.3 micron channel used in the 12.3 – 10.35 micron difference within the Dust RGB red component.  The 12.3 micron channel goes from warmer to cooler brightness temperatures with changes in density from very dry to very moist air. The blue contribution is consistent on each side of the line because the surface temperature, and hence the 10.35 micron channel, does not change much from either side of the dryline. There is limited ability to identify drylines using high resolution visible imagery, as seen in the Midland WFO Graphicast (Fig. 6) where cumulus clouds are documented forming along the dryline. Unfortunately, visible imagery is only useable during daylight hours and a user is dependent on cloud features along the dryline in order to analyze its position. However, aside from the obvious value of the color difference in cloud free areas to depict the dryline, the Dust RGB, is viable both during daytime and nighttime hours.

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NtMicro RGB: Fog vs Stratus

NtMicro RGB: Fog vs Stratus

A veritable buffet of things to digest are occurring in this Nighttime Microphysics RGB animation from 0600 to 1000 UTC in the early morning of 3/28/17 where multi-state impacts of stratus and fog are seen (Fig 1). In blue/aqua to gray shades, the low cloud features are developing over the central CONUS while being sandwiched between Spring-time cyclones in the East and West.  The massive spreading of the stratus and fog can’t be missed and numerous METAR observations across the central CONUS verified the aviation hazards.

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Figure 1. Nighttime Microphysics RGB from GOES-16 at 0602 to 0957 UTC on 28 March 2017 over the U.S.

For the above and subsequent images/animations: NOAA’s GOES-16 satellite has not been declared operational and its data are preliminary and undergoing testing. Users receiving these data through any dissemination means  (including, but not limited to, PDA and GRB) assume all risk related to their use of GOES-16 data and NOAA disclaims any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose.

Focusing on the Tennessee and Lower Mississippi Valley regions, the fast motion of the animation from 0900 to 1130 UTC allows one to see the development of fog while other stratus clouds  pass to the east/northeast (Fig 2.).  Note that fog develops in the various low-lying areas, particularly eastern Tennessee valleys.  There is also a separate push of fog, noted by the black dotted oval of Figure 3, that moves southward along the back side of the eastern cyclone.  The METAR stations in the oval show the lowest visibility observations occurring in this area of southern and western Tennessee as well as northern Alabama.  A bit further upstream (north) from the push of fog there is a layer of very low stratus also moving southward and causing MFVR to IFR conditions.  With the large amount of precipitation from the previous day and relatively light winds overnight, a variety of fog and stratus developed over a wide area as the cyclone passed.  While not extremely common there are instances where fog develops even with  low stratus present overhead.  One can see this in central Missouri where fog is reported but the RGB shows stratus with large water droplets at their tops.  Fog below stratus was experienced at times in northern Alabama as well.

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Figure 2. Nighttime Microphysics RGB from GOES-16 at 0902 to 1122 UTC on 28 March 2017 centered over western Tennessee and covering the Tennessee and Upper Mississippi Valleys.

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Figure 3. METAR station plot from the Aviation Weather Center ADDS site (left) and the Nighttime Microphysics RGB.  Both from near 1100 UTC with annotations of fog and stratus locations and movement.  Blue arrow in METAR shows direction of movement and shared black dotted oval notes locations of lowest visibility reports.

A GOES-16 Multispectral View of the Late Season Nor’easter

A high impact late season Nor’easter is unfolding across the Mid-Atlantic and New England today.  An enhanced view of the impressive storm is possible with multispectral (i.e. RGB) imagery since GOES-16 ABI has 16 bands available compared to legacy GOES sensors. Both the Day Land Cloud RGB (Fig. 1) and Air Mass RGB (Fig. 2) were developed by EUMETSAT and provided to European forecasters with the launch of Meteosat-8 SEVIRI in the early 2000s. These RGBs are part of the set of EUMETSAT RGB best practices that was later adopted by the WMO and today are widely used by other countries such as Japan and Australia who have access to Himawari-8 AHI derived RGB products.  NASA SPoRT has worked closely with the GOES-R/JPSS Proving Grounds to provide RGB products derived from MODIS, VIIRS, AVHRR, and AHI to NWS offices, National Centers, and the Operations Proving Ground to prepare forecasters for multispectral capabilities with GOES-16.  More recently, NASA SPoRT has been working with the Total Operational Weather Readiness – Satellites (TOWR-S) and the Satellite Enhancement Team to provide client-side RGB imagery to the National Weather Service for use in operations.  These are just two examples of GOES-16 ABI RGB imagery that will be available to NWS forecasters in the near future.  A brief explanation of each product is found in the caption and links to training resources are below.

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Fig. 1 Day Land Cloud RGB 14 March 2017 15:52 UTC.  Provides the ability to distinguish snow from clouds.  Snow appears cyan, low water clouds appear gray to dull white, and high ice clouds appear cyan.  Although snow and high ice clouds both appear cyan, snow can be distinguished since it remains stationary.

NOAA’s GOES-16 satellite has not been declared operational and its data are preliminary and undergoing testing. Users receiving these data through any dissemination means  (including, but not limited to, PDA and GRB) assume all risk related to their use of GOES-16 data and NOAA disclaims any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose.

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Fig. 2 Air Mass RGB 14 March 2017 15:52 UTC.  The Air Mass RGB was designed to anticipate rapid cyclogenesis by enhancing regions of anomalous potential vorticity near the jet stream in orange/red tones.  These regions indicate where warm, dry, ozone-rich stratospheric air is being pull downward by the jet stream, which can be in indication of rapid cyclogenesis.  Low-, mid-, and high-clouds can also be identified in the RGB. Low clouds appear blue/green, mid clouds appear tan, and high clouds appear bright white.  Compare the clouds in the Air Mass RGB with the clouds in the Day Land Cloud RGB above to identify cloud height.

NOAA’s GOES-16 satellite has not been declared operational and its data are preliminary and undergoing testing. Users receiving these data through any dissemination means  (including, but not limited to, PDA and GRB) assume all risk related to their use of GOES-16 data and NOAA disclaims any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose.

For more information on the Day Land Cloud and Air Mass RGBs, including interpretation please see:

NASA SPoRT Natural Color RGB Quick Guide (PDF and Interactive)

EUMETSAT Natural Color RGB Interpretation Guide

NASA SPoRT Air Mass RGB Quick Guide (PDF and Interactive)

EUMETSAT Air Mass RGB Interpretation Guide