It’s Dust (RGB) Season!

It’s Dust (RGB) Season!

A large dust plume occurred over the southwest CONUS on 23 March 2017 as high winds lofted surface materials from the Mexican plateau across the border toward Texas and New Mexico.  Blowing dust events are common in the Spring in this region given the frequency of strong cyclones passing over dry land with sparse vegetation at this time.  For this event the dust plume could be detected during the day in visible imagery and even infrared single channel imagery from the newly launched GOES-16 satellite; however, the high resolution visible imagery traditionally used to monitor dust is not valid after sunset and through the overnight period.  The nighttime impacts of the dust plume eventually extended to locations downstream in Colorado, Oklahoma, and Kansas. Fortunately, a combination of infrared channels from GOES-16 can be used within an red, green, and blue (i.e. RGB) imagery product to highlight the dust location (bright magenta coloring) both day and night.

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Dust RGB Imagery from GOES-16 at 0257 UTC (~9:57 PM Central) on 23 March 2017 centered on northwestern Texas of the U.S.  Dust plume is identified by magenta coloring while thick cloud features are mostly in tans to reds with other thin clouds in dark shades ranging from purples and blues to black.

 

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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Dust RGB Imagery from 0002 to 0357 UTC, 23 March 2017 centered over western Texas of the U.S.  Blowing dust is colored in magenta.

This “Dust RGB” was originally created by EUMETSAT nearly a decade ago during initial use of the MSG/SEVIRI instrument in order to more efficiently utilize the 3-fold increase of infrared channels available to forecasters. NASA/SPoRT transitioned this Dust RGB to U.S. forecasters via MODIS and VIIRS starting in 2011 in preparation for GOES-16, and this is the first look at geostationary Dust RGB imagery of a major blowing dust event over the southwest CONUS. This event continued into the night when visible imagery was no longer useful.  For this post note the Dust RGB and visible animations below and how the initial development of dust plumes in Mexico are more easily noticed in the Dust RGB around 1700 UTC in magenta while the plume is not readily evident in the visible imagery even at the end of the animation at 1842 UTC.  In addition, the visible imagery shows the thin clouds (orographically-induced) in northern Mexico as very similar in nature to the dust plumes themselves.  However, the Dust RGB shows the thin clouds in blue to black coloring and easily differentiates the dust from the clouds as well as land surface features.

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Dust RGB and visible 0.64 micron imagery from 1617 to 1842 UTC on 23 March 2017 centered over western Texas near the U.S./Mexico border (click on animation to enlarge)

Nighttime Microphysics RGB: Stratus and Fog Cover much of the Great Plains and South, March 2017

Nighttime Microphysics RGB: Stratus and Fog Cover much of the Great Plains and South, March 2017

The development of low clouds and fog over wide areas of the Gulf Coast states and the Great Plains began in the early morning around 0600 UTC on 22 March 2017.  Expansion of these features by 1200 UTC stretched from Texas to Florida in the South and from Oklahoma into the Dakotas along the Great Plains.  These features are easily distinguished in the Nighttime Microphysics (NtMicro) RGB imagery (Fig. 1) from the newly launched GOES-16 imager.  The low cloud/fog range from aqua coloring in the south and become more lime colored toward the colder portions of the Great Plains.  The Pueblo Colorado NWS Weather Forecast Office (PUB) commented on the use of GOES-16 to monitor these low cloud and fog features when considering possible impacts to the public and aviation users.

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Figure 1. Nighttime Microphysics RGB imagery from GOES-16 at 1207 UTC, 22 March 2017 over the CONUS.

For the above image and subsequent 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.

The forecast discussion from PUB included this paragraph in the aviation portion:

“GOES-R fog loop shows stratus deck expanding over the plains as of 10z, and expect at least patchy MVFR stratus along and east of I-25 until midday. Western fringe of the cloud deck will likely produce some IFR cigs/vis near the mountains and Palmer divide as clouds push up against higher terrain.”

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Figure 2. GOES-16 “Fog” product (i.e. 3.9 – 11 micron difference) and ceiling/visibility observations.   A default color enhancement is applied to the “Fog” product.  The animated GIF is from 0812 – 1207 UTC, 22 March 2017

The “fog” loop product mentioned above is the channel difference of 3.9-11 microns , and it is shown in the default AWIPS color curve (Fig 2.) where one can see the pink to nearly white features representing negative differences that correspond to low clouds and/or fog.  As anticipated, some MVFR conditions did occur due to ceilings below 3000 ft, and many parts of the Palmer Divide and the Raton Ridge became surrounded by these features.

While the “fog” product shows the various low cloud and fog features, this same capability is found in the “green” component of the Nighttime Microphysics RGB.  This event of low clouds and fog can also be seen in the NtMicro RGB below (Fig. 3) where the land surface and various mid/high clouds are more easily distinguished from the low clouds and fog. This differentiation of features occurs due to additional infrared channels/differences that help to classify cloud thickness and height.  While the event mostly involved low stratus, fog can be seen developing in the low lying areas of southeast Colorado and northeast New Mexico.  Given the improved resolution of GOES-16 in space and time and the availability of more channels compared to legacy GOES imagers, monitoring the fog between in situ observations becomes easier with the NtMicro RGB, and thus allows forecasters to better anticipate impacts to aviation sites and public roadways.

 

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Figure 3. Nighttime Microphysics RGB imagery from GOES-16 from 0812 – 1207 UTC, 22 March 2017 centered on west Kansas.

For more information regarding the Nighttime Microphysics RGB, including interpretation guides for the color features in the imagery:

SPoRT Quick Guide: Nighttime Microphysics RGB in the SPoRT Training Site

SPoRT Nighttime Microphysics RGB Fundamentals (Module) ~20 minutes

 

 

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

SPoRT-created training material now available via the new AIR Tool within AWIPS

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Training material now available for use by NWS forecasters via the new AIR tool within AWIPS. This example shows the SPoRT-created Nighttime Microphysics RGB Quick Guide.

NASA SPoRT has been working to get training materials available to NWS forecasters via the new AWIPS Integrated Reference (AIR) tool.  This Twitter post and attached video details how NWS forecasters can access the new training material.  This training is now available with the current POES RGB imagery, but will also be available once RGB imagery from GOES-16 is available in AWIPS. SPoRT will be working to add new training content within Vlab and accessible via the AIR tool in the coming months.

Dust RGB Imagery GOES Beyond Visible

The Dust RGB imagery product was originally developed by EUMETSAT for the MeteoSat Second Generation (MSG) SEVIRI imager and later applied to the JMA Himawari-8 (H8) imager (same as GOES-16). Now the same capabilities are seen with the GOES-16 Advanced Baseline Imager (ABI).  NASA/SPoRT has transitioned this product to operational users since 2011 as part of the NOAA Satellite Proving Ground efforts to prepare users for this new geostationary era in the U.S.  SPoRT has co-authored an NWA/JOM article about the impacts this Dust RGB Imagery has already had in operation procedures via use with MODIS and VIIRS instruments. The value of the Dust RGB is the ability the user has to analyze dust plumes when single channel imagery, such as visible channels, do not adequately depict the dust feature.  In addition, true color imagery will often “miss” seeing dust because the underlying surface has a similar color to the dust itself.  And lastly, the Dust RGB allows one to continue monitoring the dust event in both day and night scenes.  Below is an example from a blowing dust event today (March 6, 2017) in the Nebraska and Colorado areas.  Note in the comparison image that the dust (shown in magenta coloring) is readily apparent compared to using single channel visible (0.64 micron, channel 2) imagery alone.  Further below are loops of the imagery for comparison.  Also, note that dry vs. moist air is apparent and another utility of the imagery will be the analysis of drylines in the deep south of the U.S.

DustRGBcompare_Vis_20170306

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.

While the Dust RGB Imagery is not intuitive at first, one only has to look at the area over southern Nebraska  (see below) to see a streak of magenta that represents a dust plume.  The Dust RGB uses several infrared-based channels to differentiate various cloud characteristics and dust.  Particularly useful is the difference between channels 15 and 13 (i.e. 12.3 – 10.4 micron difference) that takes advantage of the low absorption by dust in channel 15, which results in a relatively large positive differnce.  This is the red component of the Dust RGB and it causes dust to have a greater amount of red compared to other cloud features.  The magenta color in the RGB results because the dust is relatively warm and the blue component of the RGB is the 10.4 micron channel which is sensitive to the thermal properties of the object.  In addition to the streak across Nebraska, the region of eastern Colorado also has a dust signature in the RGB.  At the time of this imagery, there were 40 kt wind gust and haze reported over this area, but the dewpoint temperatures were below zero degrees Celcius. While no dust was reported in the METAR observations at the time, it’s likely some type of blowing dust was causing the “haze” and some reduced visibility reports.

GOES16DustRGBExample

GOES16-VIS-Example

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.

Resources for the Dust RGB:

NASA/SPoRT Quick Guide: Dust RGB

SPoRT Application Library: Dust RGB Identifies Aviation Ceiling Hazard at KFMN (micro-lesson)

GOES-16 Air Mass RGB and NUCAPS Soundings

SPoRT has worked closely with the GOES-R and JPSS Proving Grounds to explore innovative applications for the Air Mass RGB and CrIS/ATMS NUCAPS Soundings.  Specific applications include identification of stratospheric air influence and tropopause folding to anticipate rapid cyclogenesis and hurricane tropical to extratropical transition.

When the Air Mass RGB was first introduced to NOAA NWS National Center forecasters in 2012, SPoRT developed a total column ozone product from the NASA AIRS instrument (a hyperspectral infrared sounder) as a way to help forecasters gain confidence in interpreting the qualitative RGB.  Since that time SPoRT has continued to develop quantitative ozone products such as the ozone anomaly and tropopause height products from additional hyperspectral infrared sensors such as CrIS/ATMS and IASI.

More recently, CrIS/ATMS NUCAPS Soundings were added to AWIPS-II for forecasters to utilize in operations.  SPoRT has specifically explored the utility of NUCAPS Soundings for hurricane tropical to extratropical transition (see link to training material).   With the availability of the GOES-16 Air Mass RGB and NUCAPS Soundings in AWIPS-II there is an opportunity to explore rapid cyclogenesis cases and extratropical transition events with next-generation satellite capabilities.  Since we have the capability to display the client-side generated Air Mass RGB here at SPoRT, here is a quick preview of how the NUCAPS Soundings can be used to compliment the Air Mass RGB.

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GOES-16 AWIPS-II client-side generated Air Mass RGB 3 March 1817 UTC

Please note, the GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

The Air Mass RGB is able to detect temperature and moisture characteristics in the mid- to upper levels of the atmosphere.  Warm, dry air upper level air appears in red/orange tones. Dry upper level air appears more red when associated with anomalous potential vorticity as warm, dry, ozone-rich air is pulled downward by the jet stream circulation.   Dry upper levels away from the jet stream appear orange. In contrast warm, moist tropical air appears in green tones, appearing more olive when less moisture is present.

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Air Mass RGB interpretation guide adapted from EUMETSAT (Zavodsky et al. 2013)

In the Air Mass RGB image above you can see a well-defined upper-level temperature and moisture boundary across the southern U.S. associated with yesterday’ s passing frontal system.  NUCAPS Soundings can provide additional information about the thermodynamic and stability characteristics of the lower-levels of the atmosphere which cannot be deciphered in the Air Mass RGB.  The Sounding at Location 1 shows a mostly dry atmospheric column, which is typical for the orange colored regions (i.e dry upper levels) in the RGB, note however there are moister conditions around 850 mb.    The Soundings at Location 2 and 3 in the green colored regions (i.e. moist upper levels)  confirm moist upper-level conditions.  What the NUCAPS Soundings reveal is a layer of much drier mid-level air between about 850-400 mb, which cannot be detected in the Air Mass RGB.  The ability to detect such a layer can be important in data sparse regions.  Although this is a benign weather situation where much of the Southeast enjoyed sunny, cool, and dry conditions today, this same technique can be applied to more intense, high impact events to assess the thermodynamic environment surrounding a developing low pressure system or weakening hurricane where moist or dry layers can have an impact on storm intensity.

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AWIPS-II CrIS/ATMS NUCAPS Sounding 3 March 2017 1817 UTC at Location 1

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AWIPS-II CrIS/ATMS NUCAPS Sounding 3 March 1817 UTC at Location 2

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AWIPS-II CrIS/ATMS NUCAPS Sounding 3 March 2017 1817 UTC at Location 3

 

For more information regarding the Air Mass RGB, including applications and interpretation guides for the color features in the imagery:

The Nighttime Microphysics RGB from GOES-16 ABI

The Nighttime Microphysics (NtMicro) RGB imagery provides multiple cloud characteristics of thickness, particle phase/size, and height within a single image in order to analyze cloud features. Below is an example of the NtMicro RGB from the full disk scans taken every 15 minutes.

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Nighttime Microphysics RGB from GOES-16 from 0610 UTC to 1225 UTC on 3 March 2017.

 

Please note, the GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

The NtMicro RGB imagery (below) over Florida in the early morning of 3 March 2017 show a variety of clouds in the scene.  In southern Florida, various shades of aqua represent low, water clouds where surface observations indicated ceilings of 1000-1500 ft (MVFR conditions).  Slightly further north in central Florida, cloud tops are represented by more tan/yellowish coloring with the RGB representing thicker, colder clouds with larger particles.  This suggests clouds that are a bit higher above the ground.  Continuing northward the cloud features are seen streaming to the east, northeast.  These clouds have mostly dark coloring suggesting little contribution from all the color components (red, green, blue).  The purple clouds are thin, mid-level clouds with ice.  One can tell that the clouds are thin because the underlying surface (land vs water) influences the resulting shade of color as the cloud passes over.  The dark blue is very thin, cold cirrus clouds while the dark red represents similar cirrus clouds but with slightly thicker characteristics.  Also note that some bright red clouds appear over the Gulf Stream (right side of image) representing very thick, cold ice tops of convection.   Overall, quite a number of cloud features can be seen in this IR-based RGB in a very efficient product.

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Nighttime Microphysics RGB over Florida from GOES-16 0701 UTC to 1156 UTC on 3 March 2017. Aqua colored clouds depicting impacts to TAF sites experiencing MVFR ceilings.

 

Please note, the GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

For more information regarding the Nighttime Microphysics RGB, including interpretation guides for the color features in the imagery:

SPoRT Quick Guide: Nighttime Microphysics RGB in the SPoRT Training Site

SPoRT Nighttime Microphysics RGB Fundamentals (Module) ~20 minutes

AGU EOS Project Update: Transforming Satellite Data to Weather Forecasts