GLM observes a long flash in Minnesota

One of the unique, new features of the Geostationary Lightning Mapper, or GLM, is the instrument’s ability to observe the spatial extent of lightning flashes.  This capability had been previously demonstrated with the ground-based lightning mapping arrays (LMAs).  The LMAs, however, only have a range of 200 km versus the GLM’s near hemispheric field of view.

The figure below shows the 1 min, 8 km GLM group density plot in AWIPS.  The GLM data have been intentionally made all yellow to highlight spatial extent only.  The GLM data are overlaid on the Advanced Baseline Imager (ABI) daytime convection red-green-blue (RGB) composite.  Here, the brighter, more yellow cloud tops indicate newer, more vigorous convection give large numbers of small, ice particles.  The redder cloud types are more mature/dissipating convection due to warmer cloud tops and amount of larger ice particles.  The GLM observes a flash that extends well behind the main convection (observed by the radar mosaic) and spans over 100 miles.  The extent is roughly between Duluth, Minnesota and International Falls, Minnesota.  This example shows the importance that the spatial extent of GLM observations can play in lightning safety as the threat of lightning is non-zero, even after the main convective line has passed.  This case will be analyzed further to compare with the National Lightning Detection Network and Earth Networks observations.

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Figure:  AWIPS screen capture of 1 min, 8 km GLM group densities (yellow, filled) overlaid on the ABI daytime convection RGB, along with the corresponding radar mosaic from NOAA (inset).  Annotations highlight the main features, particularly a long flash observed by the GLM (black dashed oval) that extended around 100 miles in the stratiform region across Minnesota on June 13, 2017.

NOTE:  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. 

NASA SPoRT Helps Prepare for GOES-R

November 19th has been eagerly anticipated by the meteorological community as it is the launch of the next-generation GOES-R satellite.  The satellite will carry a suite of space weather instruments as well as two Earth observing sensors.  The Advanced Baseline Imager (ABI) will provide three times more channels to view the Earth, four times greater spatial resolution, and 5 times faster coverage.  The ABI will provide new means to monitor atmospheric phenomena.  Additionally, GOES-R will carry the first ever lightning observation sensor on a geostationary platform; the Geostationary Lightning Mapper (GLM).  Numerous organizations, including NASA SPoRT, have been supporting the GOES-R Proving Ground for many years to aid the operational community in preparing for the new capabilities of GOES-R.

Specifically, NASA SPoRT has been formally involved with the Proving Ground since 2009, although much of our work prior to this point has provided relevant information with respect to GOES-R.  SPoRT has been primarily involved in two activities.  The first has been the assessment of and training for multi-spectral imagery, often called red-green-blue (RGB) composites.  The RGB composites are used to combine multiple single channels into a single image in order to help emphasize phenomena that forecasters wish to monitor.  This can range from air mass microphysics to atmospheric dust.  This work has leveraged work by Europe’s EUMETSAT organization who first developed several of these RGB composites for their Meteosat Second Generation satellite.  SPoRT has worked with NASA’s MODIS instruments from Aqua and Terra as well as the JPSS VIIRS instrument to create the respective RGBs from polar orbiting instruments.  These snapshot demonstrations provided forecasters local examples of RGB composites to allow them to investigate these products prior to GOES-R’s launch.  SPoRT has also coordinated with other product developers to help transition their early development work to National Weather Service forecasters.  This included the University of Alabama in Huntsville’s GOES-R convective initiation product and the NESDIS quantitative precipitation product.

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MODIS Dust RGB demonstrating a future capability of the GOES-R ABI. Dust (magenta) can be seen approaching Las Vegas, Nevada.

In additional to the ABI work, SPoRT has been integral to supporting total lightning (intra-cloud and cloud-to-ground) observations in operational applications.  This dates back to 2003 with the first transition of experimental ground-based lightning mapping arrays that evolved into the pseudo-geostationary lightning mapper (PGLM) product in 2009 to provide operational training for the GLM.  Since then, SPoRT has developed the GLM plug-in for the National Weather Service’s AWIPS system, has personnel serving as the National Weather Service liaison for the GLM, and have developed foundational training that is being provided to every forecaster in the National Weather Service.

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Sample of the pseudo-geostationary lightning mapper demonstration product in AWIPS being used for training on the Geostationary Lightning Mapper.

SPoRT will continue to be actively engaged in GOES-R applications post launch.  This will take the form of developing an applications library, or short 3-5 focused case examples, for both the ABI RGBs and the GLM.  SPoRT will also participate in the formal applications training for RGBs and GLM that will be released to the National Weather Service.  Lastly, SPoRT will be leading an operational assessment of the GLM with National Weather Service forecasters and associated emergency managers.

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GOES-R launching on November 19, 2016!

Limb and Bias Correction Applied to MODIS Air Mass RGB Imagery

MODIS Air Mass RGB Imagery with limb correction applied to the water vapor and ozone channels.  1859 UTC, 13 May 2014

MODIS Air Mass RGB Imagery with limb correction applied to the water vapor and ozone channels. 1859 UTC, 13 May 2014

The Air Mass RGB imagery product via MODIS has often appeared to lack “green” coloring near the edge of the swath and there have been noticeable differences between the channels from Aqua and Terra used within the RGB.  Forecasters from the Great Falls, MT and Albuquerque, NM WFOs applying this experimental data noted these issues.  The above image is a limb and bias corrected version of the Air Mass RGB.  The water vapor and ozone channels tend to “cool” near the swath edge as they pass through more atmosphere and the differences in satellite instrument quality result in physical characteristics between the images having different coloring.  SPoRT has worked to develop a non-linear function to correct much of the limb cooling as well as a bias correction, both through comparison of the MODIS instruments to the EUMETSAT SEVIRI instrument.  Annotations to the image attempt to classify the various features indicated by the resulting composite color during a MODIS pass from 1859 UTC on 13 May 2014 when a cold air mass was moving into the upper Midwest.  Simple interpretation guides can be found via SPoRT’s Training page or EUMETSAT. For comparison, additional plots of GOES Water Vapor,  and NAM 500mb Temperature, Humidity, and Height 0-hour analysis and 6-hour forecasts are provided below for reference. There is also a single image of the Hybrid GEO/LEO Water Vapor / Air Mass RGB product that loops GOES Water Vapor imagery and inserts the MODIS Air Mass RGB swath as it is available because the RGB is largely made up of water vapor channels.  Both the Hybrid and single-swath MODIS files are available in netCDF format for use in AWIPS I or II as well as KML format.

This new limb/bias corrected Air Mass RGB product is credited in large part to graduate student work being done at the University of Alabama Huntsville in conjunction with NASA/SPoRT. Primary contributors are:
Nicolas Elmer (UAH graduate student)
Dr. Emily Berndt (NASA/SPoRT Post-Doctoral Scientist)
Dr. Gary Jedlovec (NASA/SPoRT PI)

Additional contributors include:
Frank LaFontaine (Raytheon, Data processing and analysis)
Kevin McGrath (Jacobs, Product code development and real-time processing)
Matthew Smith (UAH, Data processing and product code development)
Dr. Andrew Molthan (NASA/SPoRT, RGB code development and research science)

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GOES Water Vapor Imagery at 1845 UTC, for 13 May 2014

 

 

 

 

NAM 500mb, 0-hour forecast valid 1200 UTC, 12 May 2014 of Temperature, Humidity, and Height via

NAM 500mb, 0-hour forecast valid 1200 UTC, 13 May 2014 of Temperature, Humidity, and Height via NCAR RAL website

NAM 500mb, 0-hour forecast valid 1200 UTC, 13 May 2014 of Temperature, Humidity, and Height via NCAR RAL website

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NAM 500mb, 6-hour forecast valid 1800 UTC, 13 May 2014 of Temperature, Humidity, and Height via NCAR RAL website

NAM 500mb, 6-hour forecast valid 1800 UTC, 13 May 2014 of Temperature, Humidity, and Height via NCAR RAL website

CAR RAL website

Example: SPoRT Hybrid GEO/LEO Water Vapor and Air Mass RGBimagery

Example: SPoRT Hybrid GEO/LEO Water Vapor and Air Mass RGBimagery

VIIRS RGB Night-Time Microphysics Makes the Most of Limited Darkness in Alaska

Despite the hours of darkness becoming rare over Alaska as the northern hemisphere approaches its summer solstice, the RGB Night-Time Microphysics product still has some utility in Alaska south of the Arctic Circle right around midnight. Just before midnight Alaska Time on May 6, 2014 (0743 UTC, May 7) an RGB NT Micro image derived from the SNPP VIIRS instrument depicted a deck of moderately low marine stratus clouds over the northeastern Bering Sea, as outlined in the black box in Figure 1.

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Figure 1: RGB NT Micro product derived from VIIRS data, 1143pm Alaska Daylight Time May 6, 2014. Area of interest noted in the black box.

A closer view of this area is shown in Figure 2, along with the ceiling and visibility data from surface observing sites. In this scenario, ceilings, rather than visibility, are the problematic weather element, with the exception of Nome where the imagery shows a localized area of higher conditions. It can be challenging to discern ceilings and visibilities from satellite imagery, and in this respect the RGB NT Micro product has an advantage over conventional satellite imagery. Per the Quick Guide available at http://weather.msfc.nasa.gov/sport/training/rgb_ntmicro/RGB%20Night-time%20Microphysics%20Reference%20Guide%20AK%20by%20SPoRT.pdf and as demonstrated in the Alaskan training module http://weather.msfc.nasa.gov/sport/training/aviationForecasting_Alaska/launcher.html a tan to light green appearance indicates low clouds, but not necessarily fog, in colder climate regions such as Alaska. Surface observations on Saint Lawrence Island and in the Yukon Delta area indicate MVFR ceilings of between one and three thousand feet, but no reduction to visibility due to fog.

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Figure2 : the same RGB NT Micro product as in Figure 1, zoomed into the northeastern Bering Sea. Ceiling and visibility data from surface observation sites are also shown in green.

Dust Storm Shown by VIIRS and MODIS in Southwest 2014

VIIRS True Color RGB imagery produced by NASA/SPoRT.  Southwest region domain at 1836UTC, 11 March 2014.

VIIRS True Color RGB imagery produced by NASA/SPoRT. Southwest region domain at 1836UTC, 11 March 2014.

In the southwest CONUS region, severe to extreme drought conditions exist in many areas.  In particular southwest Colorado, northeast New Mexico and the Texas and Oklahoma panhandle areas are very dry according to the U.S. Drought Monitor.  A building high pressure area developed a strong pressure gradient across these areas during the afternoon of 11 March 2014, resulting in 20-30 kt sustained northerly winds with gusts over 40 kt. Combined with the dry conditions, WFOs in the southwest have been anticipating blow dust events to be large and more frequent with strong Spring cyclones. VIIRS True Color RGB imagery (above) shows the blowing dust in Colorado and Texas, but the clouds in Colorado and Kansas have a similar color and the dry ground characteristics in Texas also look similar in color to the dust.  To provide a more efficient analysis of the blowing dust, VIIRS and MODIS can be used to create an RGB imagery product that shows blowing dust in shades of magenta to differentiate it from clouds and ground features.  This is done using the EUMETSAT recipe for the “Dust RGB” per their “Best Practices” after years of experience with the MeteoSat Second Generation SEVIRI instrument.  This geostationary instrument has similar capabilities to that of the future GOES-R ABI instrument.  Hence VIIRS and MODIS provide operational utility now and demonstrate future capabilities that all U.S. forecasters can use to be ready for the next generation of satellite products.  The VIIRS and MODIS passes show three times from this afternoon to aid forecasters with tracking the dust event.

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MODIS Dust RGB Imagery for 1941UTC 11 March 2014

MODIS Dust RGB Imagery for 1941UTC 11 March 2014

VIIRS Dust RGB Imagery for 2019UTC 11 March 2014

VIIRS Dust RGB Imagery for 2019UTC 11 March 2014

WFO Juneau assessment of Nighttime Microphysics for 1/24/14

SPoRT is conducting an assessment of RGB imagery for Aviation and Cloud Analysis with Alaska WFO partners.  A 17 minute training module for high-latitude application of nighttime RGBs with an Alaska example was created by SPoRT to support this assessment (see SPoRT training page to download or launch module). The Juneau WFO provided feedback for 1/24/14.  Here is a part of their feedback regarding the value of the Nighttime Microphysics RGB imagery from MODIS and VIIRS and an example image from AWIPS/D2d.

WFO Juneau feedback:
“… the microphysics image was very helpful in picking out where the fog and low clouds were in the complex terrain that is the SE panhandle. most of the fog this morning was confined to the narrower valleys and channels while the wider channels were mostly clear. This is possibly due to higher winds still present in the wider channels limiting fog formation there. It also showed little or no fog and low clouds out in the gulf. The microphysics image was very helpful with figuring out fog for zone and marine forecasts. It also helped out with the TAFs with seeing if there were any higher clouds layers above the fog layer.”

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An area to watch: Sensebaugh Fire, near Casper, WY

The Sensebaugh Fire was reported to have started on 7/11/13 and have a high growth potential (inciweb.org).  This could be an area to watch with the VIIRS Day-Night Band (DNB) Radiance RGB Composite (below) in the coming days.  No bright fire (would be yellow, like the cities) is seen in the image, and there is a large amount of cloud cover (blue shades).  SPoRT and CIRA are partnering with NWS users to evaluate this type of product in night-time operations.

To monitor VIIRS DNB products in the Front Range of CO and WY see SPoRT’s Real-Time Data page.

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