SPoRT’s Role in the SWOT Early Adopter Program

By Ben Houser

Between May 26 and June 1, 2020, a virtual hackathon was hosted by the University of Washington for SWOT early adopters. SWOT, or Surface Water and Ocean Topography, is a joint mission between NASA’s Jet Propulsion Laboratory (JPL) and the French space agency, The National Centre for Space Studies (CNES), with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. The SWOT satellite observatory will survey surface and ocean water around the globe, collecting data with groundbreaking resolution. SWOT is the first satellite mission to ever survey water level on a global scale, and its data will have a major impact on a number of applications.

Along with fifteen other groups, NASA SPoRT is a member of the SWOT Early Adopter Program; these early adopters are preparing to integrate SWOT data into their projects. When the SWOT satellite observatory is launched by a SpaceX Falcon 9 rocket in 2022 and begins collecting data, SWOT early adopters will be prepared to use this data in a variety of applications. The SWOT Hackathon was designed to engage early adopters and help them overcome technical issues they may have experienced. SPoRT scientist Dr. Nicholas Elmer participated in the hackathon as a presenter and “hacker helper,” assisting early adopters in the use of the CNES SWOT hydrology data simulator.

The SWOT satellite observatory will carry a number of instruments to facilitate data collection. A JPL-developed Ka-Band Radar Interferometer, or KaRIn, will be the primary instrument used to collect water level data. KaRIn, which utilizes two antennas, will work by transmitting a signal from one antenna, and then receiving the same signal back with both antennas after it bounces off of the earth’s surface. The phase difference between these two signals will be used to calculate water level with extreme precision; over the ocean, SWOT’s data will be accurate down to about a centimeter, over an area of 125 km at any given time. SWOT will collect data in 21-day cycles, during which the entirety of the globe, excluding the poles, will be observed. The satellite observatory will also carry an altimeter, a DORIS antenna to receive signals from Earth, a radiometer to measure water vapor between SWOT and the surface, an X-band antenna for data downlink, and a GPS receiver.

As a SWOT early adopter, SPoRT is preparing to integrate SWOT data into the NOAA National Water Model and the SPoRT Land Information System (or LIS) product. For his PhD dissertation, Dr. Nicholas Elmer developed a method to assimilate SWOT data into the WRF-Hydro modeling system, which is the backbone of the NOAA National Water Model. As a SPoRT scientist, Dr. Elmer is taking the next step to include SWOT data in the SPoRT LIS product. Dr. Elmer plays a key role in the SWOT early adopter process, as he contributed to the CNES-developed SWOT data simulator, which early adopters use to ensure their applications will function correctly with SWOT data. Dr. Elmer was one of the first early adopters to make use of the simulator, and wrote the tutorial used by early-adopters at the hackathon. During the hackathon, Dr. Elmer assisted international researchers who were working on integrating SWOT data into local hydrological models. Dr. Elmer also contributed code to the simulator that allowed it to create a time series of simulated SWOT data with varying water surface elevations, which CNES adopted into the official simulator distribution.

Example of CNES SWOT simulator pixel cloud (point-based water surface elevations; small circles, no outline) and spatially-averaged water surface elevations (large circles with black outline) along the Nenana River in Alaska. Figure adapted from Elmer et al. (2020).

Throughout the early adopter process, SPoRT has been providing valuable feedback to NASA and CNES. Due to its focus on research to operations and research to applications, SPoRT has provided a unique perspective, communicating the need for low-latency SWOT products for use in operational and near-real-time systems. When SWOT launches, it will bring major improvements to a wide array of applications: SWOT will vastly improve our understanding of Earth’s bodies of water, and will benefit forecasters, scientists, oceanographers, hydrologists, and many others. SWOT will also improve understanding of changing lake, reservoir, and river volumes, which will allow scientists to understand fresh water availability. SWOT’s observations of the ocean will improve scientists’ understanding of global climate change, pollution, and environment stability. SWOT is a major breakthrough in water observation, and SPoRT is playing a small but important role in its development.

References:

Elmer, N. J., C. R. Hain, F. Hossain, D. Desroches, C. Pottier (2020), Generating proxy SWOT water surface elevations using WRF-Hydro and the CNES SWOT Hydrology Simulator, Water Resources Research, American Geophysical Union, Early Online Release, https://doi.org/10.1002/essoar.10502399.1.

High-resolution Satellite Imagery Assists in NWS Damage Surveys…

The NASA Earth Science Disasters Program and NASA SPoRT has been working with the National Weather Service and the Damage Assessment Toolkit (DAT) team for a number of years on the production of hi-resolution satellite imagery for inclusion in the DAT, and training on the usage of the imagery.  Imagery from the Landsat satellite at 30 m resolution is available regularly in the DAT as swaths become available, but higher resolution imagery from sources such as Sentinel (~10 m) and Worldview (<1 m) are available upon request through the USGS Hazards Data Distribution System.  These images are then processed by members of SPoRT and the Disasters Program for inclusion in the DAT.

Several tornado events earlier this year have helped to illustrate the effectiveness of the imagery for post-storm analysis and damage assessment.  This is especially true when damage is of sufficient magnitude and spatial extent to be resolved by the particular satellite instrument and cloud-free (or near cloud-free) conditions exist at the time of the satellite pass.  On April 12-13, a number of tornadoes developed and moved across the Southeast region of the U.S., some of which produced damage up to EF-4 scale in parts of southeastern Mississippi.  Meanwhile, closer to the Tennessee Valley, EF-2 tornado damage occurred in portions of the Huntsville and Birmingham, AL County Warning and Forecast Areas (CWFAs), with a tornado up to EF-3 strength damaging portions of Chattanooga in the Morristown, TN NWS CWFA.

This first image of damage is along a small portion of Interstate-65 in Cullman County, AL, and just south of the city of Cullman (Image 1 below).  Notice the area of damaged vegetation, which consisted of downed trees to the north of the preliminary tornado path and just east of Interstate 65 (red circle).  Although some of this area was shaded by clouds, damaged trees were clearly evident.  The location of damaged vegetation allowed for a relocation of the damage indicator (green triangle) farther north, which was originally closer to the green line.

Image 1.  Worldview imagery at approx. 1631 UTC 3 May 2020 of areas near tornado damage in Cullman County, AL.  The green line indicates the preliminary tornado track path, and the red circle indicates the swath of downed trees, while colored triangles represent the degree of tornado damage.

A zoomed-in look at the damage also shows that trees were not just downed or uprooted, but snapped.  Imagery from sources such as Worldview is of sufficiently high resolution to see snapped tree trunks, which will often be indicated by small, bright dots against the darker green/brown background, due to the higher reflectivity of wood on the inside of the tree.

Image 2.  Zoomed in from Image 1.  Some of the snapped trees in the image are annotated.  Snapped trees were also verified by visual ground inspection.

 

Farther to the east, along the same damage path in Cullman County,  a damage swath was previously undetected due to its distance from the road network that made visual ground inspection impossible (without a trek through the woods!).  However, the advantage of satellite imagery allowed for assessment of the tree damage (Image 3 below).  In Image 3, the blue triangle denotes the damage point that was added thanks to the presence of tree damage indicated by the satellite image.  Notice the lack of small bright dots as in Images 1 and 2 (in the red circle), suggesting that most if not all of these trees in this area were uprooted rather than snapped.

Image 3.  Worldview image at approx. 1631 UTC 3 May 2020.  The swath of downed trees can be clearly observed from SW to NE extending from near a small church and cemetery near the bottom of the image.  This damage could not be observed from the road seen in the bottom to left portions of the image.  The blue triangle (at the upper left part of image) indicates the tornado damage point added to the survey.

Another advantage of the DAT is the ability to underlay maps or other baseline imagery below the near real-time hi-res imagery.  Not only does this allow for proper geographic referencing, but the ability to assess vegetation type and state at a previous time.  Image 4 (below) is one such representative image in the DAT taken from the cold season.  Notice the lack of leaves and long shadows extending from the hardwood trees in the image.  However, the softwood trees, likely consisting of cedar and pine species, remain green.  Notice that the blue triangle was located within a patch of softwood trees, allowing for a better identification of tree types and thus the proper Damage Indicator to assess the wind rating for the uprooted trees.

Image 4.  Background image of the same area shown in Image 3 above.  Notice the area of damage (around the blue triangle) was within a patch of softwood trees.

Lastly for this post, we’ll take a look at another area of damage in Cullman County, just downstream and farther east along the same damage path.  This was also an area of previously unknown damage due to the lack of a specific report and the inability to view the damage from a nearby roadway.  The tree damage in this location was similar to the damage shown in images 1 and 2, with numerous bright dots indicating trees were likely snapped.

Image 5.  Worldview image at approx. 1631 UTC 3 May 2020.  A swath of tree damage can be extending southeastward just south of County Road 616 in east central Cullman County.  The green triangle indicates the added damage point due to the indication of damage in the satellite imagery.

The background reference image (Image 6 below, same imagery type as used in Image 4) from the same location however, showed that much of this scene was dominated by hardwood trees.

Image 6.  Background image of the same area shown in Image 5 above.  Notice the area of tree damage (around the green triangle) was within an area of mixed forest, but primarily consisted of hardwood trees.

This allowed for the proper Damage Indicator again to be used suggesting a higher wind speed rating than the damage from the previous scene (Image 3).  Due to the presence of many snapped hardwood trees, the damage here was rated EF1.

So, in these cases, we demonstrated several uses of the high-resolution imagery for damage assessment:  the ability to better affix damage points, locate damage otherwise hidden from typical roadway viewing, detect uprooted versus snapped trees, and identify primary tree types that were damaged in a location and assign proper damage indicators.

We would like to thank members of NASA MSFC, and the USGS who helped make this post possible, along with Digital Globe for permission to use and distribute the imagery in these examples.

-Kris and Lori

 

 

Undergraduate Student Highlight: Nicholas Johnson

Written by Ben Houser

Nicholas Johnson has just graduated from the University of Alabama in Huntsville, earning a bachelor’s degree in Earth System Science with a concentration in Atmospheric Science. To earn this degree, Nicholas was required to complete an undergraduate capstone project in his field of study, which he accomplished with the help of SPoRT. Nicholas’s project was the creation of a wind speed adjustment factor that would allow scientists to estimate the surface wind speed in tropical cyclones based on wind speed at higher altitudes. Once its accuracy is tested, this adjustment factor may prove useful to hurricane researchers and forecasters, as it will allow scientists who fly aircraft through storms to predict wind speeds near the surface.

Since he was young, Nicholas has been interested in studying the weather. He chose UAH due to his interest in atmospheric science; the UAH Atmospheric and Earth Science Department provides students with a wide array of unique opportunities. While at UAH, Nicholas took advantage of these opportunities, working on research projects concerning severe weather, meteorology and aviation, and remote sensing technology. Through the UAH Honors College, Nicholas collaborated with the National Weather Service in Memphis, TN, in 2018 to investigate abrupt changes in wind speed at the Memphis International Airport. During the summer of 2019, Nicholas interned at NOAA’s Atlantic Oceanographic and Meteorological Laboratory, where he worked with Hurricane Research Division scientists. The project consisted of finding new ways of organizing data collected by NOAA Hurricane Hunter aircraft and developing new visualizations of aircraft data from tropical cyclones. Nicholas spent his time coding for the project and meeting with scientists to discuss the project, while also attending regular science meetings which included scientists from NOAA and the University of Miami. During the internship, Nicholas had the opportunity to fly with NOAA scientists on a Hurricane Hunter aircraft; Nicholas said watching the sunrise while flying above the storm was one of the most breathtaking experiences of his life. Nicholas’s work with NOAA resulted in a consolidated dataset that combined measurements from various instruments, making it significantly easier for researchers to work with data gathered from Hurricane Hunter aircraft. The project also involved exploring the relationship between aircraft-measured wind speeds and surface wind speeds; this aspect of the NOAA project evolved into Nicholas’s undergraduate capstone project.

Nicholas standing beside one of the NOAA Hurricane Hunter aircraft after a flight into Tropical Storm Barry in July 2019.

In his work with SPoRT, Nicholas relied on NOAA Hurricane Research Division data that included the temperature, pressure, storm structure, high-altitude wind speed, and surface wind speed of tropical cyclones. Nicholas’s goal was to produce an adjustment factor that would allow researchers to convert aircraft-measured wind speed to surface wind speed. Through the analysis of hurricane data, Nicholas produced multiple tables of this adjustment factor based on elements such as storm intensity and the research aircraft’s altitude. Once they are tested for their accuracy, these tables would be used by forecasters, such as those at the National Hurricane Center, to assist in forecasting hurricanes. These tables would allow the National Hurricane Center to make more detailed forecasts, and allow them to more accurately determine a hurricane’s category. More detailed hurricane forecasts result in more thorough emergency-preparedness, and Nicholas’s work could allow authorities more time and information to ensure public safety.

Vertical profile of Nicholas’s wind speed adjustment factor from 0-18 km in altitude. This is from one center pass during a flight in Hurricane Irma on September 5, 2017. The empty space in the middle of the figure at 0 km radial distance is the eye of the storm. The warmer colors indicate surface wind speed is greater than flight level wind speed while the cooler colors indicate surface wind speed is less than the flight level wind speed.

SPoRT has been helpful in Nicholas’s project, as it has provided a community in which Nicholas was able to receive valuable feedback on ideas and interact with scientists who are working on similar projects. At SPoRT, Nicholas spent his time working on code to analyze data, drawing conclusions from analysis, and generating visualizations of his conclusions. Nicholas frequently met with other SPoRT scientists to discuss projects and compare research.

            In the fall, Nicholas will continue to research tropical cyclones as a graduate student at the University of Albany in Albany, New York.

The Rumble Heard ‘Round the Valley

Written by Chris Schultz and Brian Carcione

Hear a long rumble and several loud bangs around 06:22 pm CT last night?  You weren’t alone if you were in the Tennessee Valley.  While severe storms were ongoing in Southern Mississippi and Alabama, a large shield of moderate stratiform rain was parked over Northern Alabama. Most of the time things were quiet, but at 06:22 pm CT, thunder shook the entire Tennessee Valley.

Looking at the lightning data available from the Geostationary Lightning Mapper (GLM), National Lightning Detection Network (NLDN), and NASA Marshall’s Lightning Mapping Array (NALMA), we can pinpoint the extent, the origin, and the number of contributing lightning flashes to this loud rumble that lasted 7-10 seconds.

From the GLM perspective, a large swath of lightning was observed extending northward from South Central Alabama at 06:22 pm CT (Figure 1a). Using information from a real-time long flash detection algorithm from Peterson (2019), there was a series of 2 flashes that occurred within 1 second of each other. One was approximately 267 km long and propagated along the AL/MS border, while the second occupied much of Central Alabama and was approximately 253 km long.  The NALMA also indicates this dual propagation path structure over West Central and Central Alabama (Figure 1b).

Figure 1 – (top, a.) GLM Flash Extent Density between 2320 and 2325 UTC on 19 April 2020.  Underlaid is GOES-16 10.35 µm brightness temperature.  (bottom, b.) NASA Marshall’s North Alabama Lightning Mapping Array data from 2320-2330 UTC. Blue dots indicate the path of lightning flashes during this period, with two paths going northward from the strong storms in South Alabama.

105 lightning flashes were observed in the state of Alabama between 06:22:35 pm and 06:22:39 pm CT (Figure 2a).  Zooming in on the Tennessee Valley (Figure 2b), 11 NLDN points were observed in the National Weather Service County Warning area. Nine of these were positive cloud-to-ground strokes, or strokes typically characterized by strong electric fields, with peak amplitudes between 46 and 202 kA. Positive strokes make up less than 5% of all lightning strikes (NWS), but are well known to occur in vast stratiform regions (e.g., Makowski et al. 2013 and references therein).

Figure 2 – NLDN data between 23:22:35 UTC and 23:22:39 UTC on 19 April 2020.  Left shows flashes in all of Alabama during this time, right shows a zoomed in version of the Tennessee Valley. 

Indicators of electrification visible in the radar data for nearly the previous hour across West Central Alabama. In Figure 3, horizontal reflectivity is mostly uniform; however, examination of differential reflectivity (ZDR) at 1.3 degrees suggests the formation of depolarization streaks. The orientation of snow crystals in thunderstorm clouds is often altered in the presence of strong electric fields and this can produce noticeable cross-coupling between radar signals at the horizontal and vertical polarizations, when both signals are present (Ryzhkov and Zrnić 2007, Kumjian 2013). This leads to the presence of “streaks” in the ice crystals, which are visible in ZDR. Such streaks were present to the southwest and southeast of the KHTX radar at Hytop, AL, and are located above the melting layer (Fig 3b).

Figure 3 – Radar data at 2319 UTC from the NWS radar at Hytop, Alabama (KHTX).  Left is horizontal reflectivity, and right is differential reflectivity at 1.3 degrees elevation.  Depolarization streaks are denoted in red ovals, and the melting layer is identified by orange arrows.

At this point, it’s unclear what percentage of depolarization streaks are followed by lightning occurrence, but the depolarization streak does indicate the potential for lightning. With additional work and operational testing, the depolarization streak could be a useful for Integrated Decision Support Services such as airport weather warnings. Thus, there are potentially additional fusion techniques to develop between the radar and lightning data to anticipate and confirm lightning presence in these low flash rate situations.

References

Kumjian, M. R., 2013: Principles and applications of dual-polarization weather radar. Part III: Artifacts. J. Operational Meteor., 1 (21), 265-274, doi: http://dx.doi.org/10.15191/nwajom.2013.0121.

Makowski, J. A., D. R. MacGorman, M. I. Biggerstaff, and W. H. Beasley, 2013: Total lightning characteristics relative to radar and satellite observations in Oklahoma Mesoscale Convective Systems. Mon. Wea. Rev., 141, DOI: 10.1175/MWR-D-11-00268.1

Peterson, M., (2019), Research applications for the Geostationary Lightning Mapper Operational Lightning Flash Product, J. Geophs. Res., 17-18, https://doi.org/10.1029/2019JD031054

Ryzhkov, A.V. and D.S. Zrnić, 2007: Depolarization in Ice Crystals and Its Effect on Radar Polarimetric Measurements. J. Atmos. Oceanic Technol., 24, 1256–1267, https://doi.org/10.1175/JTECH2034.1

New-generation satellite observations monitor air pollution during COVID-19 lockdown measures in California

Written by Dr. Aaron Naeger

Preventative measures recently adopted to prevent further spread of COVID-19 in the U.S. have prompted an overall slowdown in economic activity and fewer vehicles on the roadways.  Since combustion engine powered vehicles can represent a major source of nitrogen dioxide (NO₂) emissions, less traffic on the roadways may lead to a significant reduction in NO₂ concentrations and, as a result, fine particulate matter (Particulate Matter less than 2.5 microns in diameter or PM2.5) as NO₂ emissions are a known precursor to PM formation.

The Tropospheric Monitoring Instrument (TROPOMI), launched in 2017 as part of the polar-orbiting European Space Agency’s (ESA) Sentinel-5 precursor (Sentinel-5P) satellite, has advanced our capability to monitor fine-scale emission sources, including vehicular emissions along traffic corridors, with unprecedented spatial resolution of 5.6 x 3.5 km².  Daily midday scans of TROPOMI over the densely populated cities and heavily trafficked corridors in California during March 2020 show how the adoption of stricter COVID-19 measures have impacted air quality in the state.  To effectively examine the changes in air quality in California, we constructed weekday averaged NO₂ maps for March at 0.05° grid spacing from high-quality, cloud-free retrievals provided by TROPOMI level 2 data.  It is also important to note the role of natural weather variability on air pollutants during this seasonal transitional period, as warmer temperatures and higher mid-day solar angles lead to shorter NO₂ lifetimes and generally lower NO₂ column concentrations.

Figure 1. a) Gridded 0.05 x 0.05° NO₂ map from TROPOMI Offline (OFFL) L2 retrievals during 2-6 March 2020 (pre-shutdown) over California.  b-d) Same as a), except valid for b) 9-13 March during soft shutdown measures, c) 16-20 March when “shelter in place” orders were announced, d) full period of “shelter in place” orders during 23-27 March. Panel d) generated using near real-time (NRT) product due to 7-10 day lag of OFFL product.

For the first weekday period of March (2-6 March) when COVID-19 measures were yet to be implemented, the largest tropospheric NO₂ concentrations were observed in Los Angeles and bordering counties with a less prominent peak in NO₂ around San Francisco (Fig. 1a).  The TROPOMI scans also resolved areas of enhanced NO₂ along the heavily trafficked corridor of State Route 99 (SR-99) in the Central Valley, particularly around the cities of Bakersfield and Fresno.  As initial, soft COVID-19 measures were adopted by businesses in California during the second weekday period in March (9-13 March), TROPOMI observed strong reductions in tropospheric column NO₂ around the large cities of Los Angeles and San Francisco along with noticeable decreases along SR-99 (Fig. 1b).  As California announced statewide “shelter in place” orders during the third weekday period of March (16-20 March), further decreases in NO₂ were apparent throughout all populated areas in the state and along SR-99 (Fig. 1c).  Noticeable decreases in NO₂ continued throughout much of the state during the fourth weekday period of March (23-27 March), especially around San Francisco (Fig. 1d).  Overall, these observed reductions in TROPOMI NO₂ throughout March are the result of decreased emissions on top of the seasonal changes in meteorological conditions.

SPoRT Graduate Student Spotlight: Holley Kenward

Written by Ben Houser

SPoRT is home to several graduate researchers, who are each working on completing the research required to earn their master’s degrees. Previously, we have featured the work of Sebastian Harkema, Angela Burke, and Abby Whiteside. Now, we are featuring Holley Kenward and her research into tropical cyclones. Holley has completed her undergraduate degree in Earth System Science with a concentration in Atmospheric Science at the University of Alabama in Huntsville.

Holley presenting her research at the Marshall Space Flight Center Jamboree in February of 2020

Holley is researching the diurnal cycles of tropical cyclones, or the daily patterns of tropical cyclones’ intensity and structure. By studying these daily changes in tropical cyclones, Holley is discovering how they impact changes in tropical cyclones’ moisture content. Along with data from a numerically simulated cyclone, Holley uses observations of Hurricane Dorian, which struck the Bahamas with extreme intensity in 2019, to conduct her research. Using imagery from the GOES-16 satellite series and NUCAPS weather soundings, Holley has discovered a distinct diurnal cycle in Hurricane Dorian. In other words, the hurricane exhibited a daily pattern of increase in size and water vapor content that occurred on multiple days. The same diurnal cycle was found in Holley’s numerically simulated hurricane, indicating the great potential of her research. As NASA prepares to launch the TROPICS satellites series, which will provide groundbreaking observation of tropical storms, Holley is working with TROPICS proxy data in her research to determine the data’s potential for understanding hurricanes.

GOES-16 Low-level Water Vapor in Hurricane Dorian at 3 and 16 Local Time on August 28, 2019. The black rings are every 100km from storm center. There is a very clear increase in overall storm size and water vapor content in the afternoon denoting the diurnal cycle change within Hurricane Dorian.

Holley learned about SPoRT as a freshman at UAH, when she played for the atmospheric science department softball team with a few SPoRT graduate students. As a senior about to graduate, Holley reached out to SPoRT to ask about graduate research positions. When she found about the TROPICS mission and the research associated with it, she was sold!

Holley’s favorite part of working for SPoRT has been the opportunities it has provided her. With the help of SPoRT, Holley has presented her research at the Marshall Space Flight Center Jamboree in February, and has attended the 2^nd TROPICS Applications Workshop in Miami, FL. Holley appreciates SPoRT’s help with meeting and learning from other scientists, and the amount of learning she finds within the department itself. She also enjoys doing research that will go into a useful product for operational meteorologists.

In the future, Holley plans on finishing up her masters. When she graduates, Holley would love to continue working with SPoRT, but will be happy as long as she can keep studying tropical cyclones!

2nd NASA TROPICS Applications Workshop in Miami, FL

By Ben Houser

            On February 19 and 20, 2020, the second TROPICS (Time-Resolved Observations of Precipitation Structure and Storm Intensity with a Constellation of Smallsats) Applications Workshop occurred in Miami, FL. The workshop’s purpose was to both connect scientists with TROPICS early adopters, or scientists who are performing pre-launch research to determine the mission’s capabilities, and potential end-users, and to discuss the mission’s status and direction. The workshop was organized by SPoRT scientist and TROPICS Deputy Program Applications Lead Dr. Emily Berndt, and University of Miami and NOAA/Hurricane Research Division scientist Dr. Jason Dunion. Along with Dr. Berndt, SPoRT scientists Dr. Erika Duran, Dr. Patrick Duran, and graduate student Holley Kenward attended the conference to engage with early adopters. Attendees included algorithm developers, applied researchers, forecasters, and international representatives from Brazil’s National Institute for Space Research, Météo France, and the European Centre for Medium-Range Weather Forecasts.

TROPICS is a series of small satellites launching no earlier than 2021 that will measure the temperature, humidity, and precipitation of tropical regions with state-of-the-art accuracy and unprecedented frequency. TROPICS’s primary mission objective is to provide a means for end-users to observe hurricanes, and the satellite series will be able to provide high-resolution data of both a hurricane’s eye and the surrounding environment. Using TROPICS, scientists will be able to understand the relationship between temperature, humidity, and precipitation as a hurricane evolves. In 2018, the SPoRT team began the TROPICS Early Adopter program in order to connect potential end-users with TROPICS researchers.

The workshop’s primary purpose was to connect early adopters and potential end-users to TROPICS’s Science Team. Early adopters shared their results and expressed successes, challenges, and future needs. Furthermore, early adopters helped identify technical and visualization enhancements which would make TROPICS data easy to use in a broad range of applications and enable users to quickly adopt the data after launch. During breakout sessions, attendees discussed mission latency, needs for tools and visualizations, and the strengths/limitations of using small satellites in applied research and operations (Fig. 1).

Fig 1: Attendees at the 2nd TROPICS Applications Workshop discuss the value of TROPICS products to support research and applications related to tropical cyclone analysis and forecasting during a breakout session on community needs for products, tools, and visualizations. Right to Left: Holley Kenward (Univ of Alabama in Huntsville-NASA SPoRT), Jason Dunion (Univ of Miami/CIMAS- NOAA/HRD), Derrick Herndon (Univ of Wisconsin-Madison/CIMSS), Stephanie Stevenson (CIRA/NHC), Erika Duran (Univ of Alabama in Huntsville-NASA SPoRT) and Patrick Duran (NASA MSFC SPoRT).

            During the workshop, presentations were given by SPoRT scientists Dr. Emily Berndt and Dr. Erika Duran. Dr. Berndt, who organized the event with Dr. Jason Dunion, presented on the workshop’s plan and expectations and introduced the objectives of each breakout session. Dr. Duran presented on her research analyzing hurricanes using TROPICS proxy data, which is data that mimics what TROPICS data will look like once launched (Fig. 2). Further presentations were given by other scientists on applied research, modeling, and applications relating to precipitation, disasters, and severe weather.

Fig 1. Comparison of temperature between a simulation of a hurricane (blue line) and TROPICS proxy data (green line). Snapshots of temperature are taken at midnight (0:00 local time) just outside the core region of the hurricane. The general similarity of the shape and sign of both temperature profiles suggest a good agreement between the two datasets.

New NUCAPS Training & Resources

SPoRT has been part of a multi-organizational collaboration within the JPSS Sounding Initiative to develop products from Hyperspectral Infrared Sounders and assess the utility of the new observations in the operational environment.  Many of the products and capabilities start out as a “proof of concept” and are then introduced to end users to incorporate end user feedback into the design and implementation process, one example of this is Gridded NUCAPS.   The team has focused on satellite soundings processed through the NOAA Unique Combined Atmospheric Processing System (NUCAPS) which is the NOAA operational satellite sounding retrieval algorithm for hyperspectral infrared sounders on S-NPP and NOAA-20.  Currently NOAA-20 NUCAPS Soundings and Gridded Products are available to all National Weather Forecast Offices.   A recent article “Adapting Satellite Soundings for Operational Forecasting within the Hazardous Weather Testbed” highlights the applied research, assessment of satellite soundings in a quasi-operational setting, and the role of end-user feedback in adapting products/capabilities to meet end users’ needs.  The team comprised of algorithm developers, product developers, and end users has found ways to interact, translate science to operations/operations back to science, leveraging the cross-benefit of science and applications to guide applied research to improve satellite sounding algorithms and products.

The success of NUCAPS for the Cold Air Aloft aviation hazard and diagnosing the pre-convective environment along with the accessibility of NUCAPS products to end users has led to applied research to assess the utility of products for additional applications (Berndt et al. 2020).  NASA’s 2017 Decadal Survey points out “The final missing piece of applications research in the agencies is the very initial phase of creating applications—supporting studies that have an idea about how an application might work, and then attempting to create a community for it, and demonstrate its utility”.  There are complex barriers that exist when identifying end users and transitioning relevant data to meet their needs.  As pointed out by NASA’s 2017 Decadal Survey  “… the applications field is becoming associated with a science of its own…”  Recently, SPoRT has investigated the utility of NUCAPS products for fire weather applications as a “proof of concept”.  As SPoRT engages with users on application of NUCAPS observations, a new interactive training  was developed to communicate the value and utility of these data.  SPoRT has found that creating short, focused, applications-based training can remove some barriers to end users integrating new data and capabilities in operations.   Last SPoRT has created a NUCAPS webpage where scientist and users can find information relevant to NUCAPS products, resources such as training, blogs, peer-reviewed literature, and data access.

New Interactive training on application of NUCAPS products to assess fire weather conditions –> Go to training

NUCAPS resource webpage for scientists and end users –> Go to webpage

 

 

SPoRT Graduate Student Spotlight: Abby Whiteside

Written by Ben Houser

SPoRT is home to several graduate researchers, who are each working on completing the research required to earn their master’s degrees. Last week, we featured Angela Burke’s research into “false alarms” in SPoRT’s imaging software. In this article, we are spotlighting the work of SPoRT graduate researcher Abby Whiteside. Like Angela, Abby has completed a bachelor’s degree in Earth System Science with a concentration in Atmospheric Science at the University of Alabama in Huntsville. Abby is now researching the impact and nature of hail damage.

Abby Whiteside presenting her research at the annual American Meteorological Society conference.

When a thunderstorm produces a significant amount of hail damage, it creates a hail scar, which is an observable area of large hail damage to the environment, such as a long streak of dead vegetation. Abby is working to better understand storms that create these hail scars. She utilizes data from the GOES-R satellite series’ Advanced Baseline Imager (ABI) and Geostationary Lightning Mapper (GLM) in conjunction with radar data to understand the characteristics and inner-workings of hail scar producing storms. In order to find out why specific storms cause hail damage, Abby compares the storm structures of hail scar producing storms and non-damaging storms. By combining different data sources, Abby can get a more thorough understanding of the way hail producing thunderstorms work. Abby said that she really enjoys working with satellite data, so this project was a unique opportunity that she couldn’t pass up. 

Abby’s thesis is a part of a larger collaboration between SPoRT, NASA’s Langley Research Center, and the Marshall Space Flight Center. Abby started working at SPoRT in 2019, after she crossed paths with SPoRT scientists Dr. Chris Hain and Dr. Chris Shultz during an internship with NASA Develop, where SPoRT was a partner. 

An Above Anvil Cirrus Plume that manifested from an Overshooting Top producing storm. This storm produced large amounts of hail damage in Nebraska and Wyoming

Abby’s favorite part of working with SPoRT has been the opportunity to work on solving a problem that has never been thoroughly examined by the meteorology community. She also enjoys finding trends in the GOES-16 satellite’s GLM data. Since the GLM is a newer product, Abby was excited about the opportunity to use its data to support the satellite community. Abby also appreciates working with experts from different areas of meteorology, and attending meteorology conferences is a highlight of her job.

In the future, Abby plans to finish her master’s degree with SPoRT. After completing her masters, Abby hopes to use her expertise in meteorology in support of NASA’s future exploration missions.

A first look at GLM observations of the supercell thunderstorm responsible for tornadoes in Tennessee on March 2-3 2020

Written by Chris Schultz

Overnight on March 2-3, 2020, several severe thunderstorms affected parts of Missouri, Arkansas, Kentucky, and Tennessee, with the most notable damage occurring around the Nashville metropolitan area.  At the time of this blog post, storm surveys continue in Tennessee by National Weather Forecast Offices in Nashville and Memphis TN (https://www.weather.gov/ohx/  ,  https://www.weather.gov/meg/).  This post takes a preliminary look at the electrical characteristics of the thunderstorms responsible for this damage from the lens of the newer instruments on the GOES-R series of satellites, the Geostationary Lightning Mapper (GLM).  GLM measures optical lightning signatures in thunderstorms to determine the spatial extent and frequency of lightning as it propagates through the cloud.

Figure 1 – Flash Extent Density information from the Geostationary Lightning Mapper between 0445 UTC and 0835 UTC.

Figure 1 shows an animation of flash extent density within the NWS primary warning dissemination tool, AWIPS2 between 0445 UTC and 0835 UTC.  Note that there are 3-4 distinct pulses in lightning activity as the storm traverses Central Tennessee.  If we look at a time series of this flash data, there are five distinct rapid increases in the flash rate, known as lightning jumps, were observed (0445 UTC, 0509 UTC, 0545 UTC, 0730 UTC, and 0802 UTC; below, Fig. 2).  Rapid increases in flash rate depicted in Figure 2 are associated to strengthening updrafts in the mid-levels of thunderstorms, where the strengthening updraft facilitates charge separation and an increase in the lightning frequency.

Figure 2 – Time trend information of the maximum flash extent density value aggregated over a five minute period, updated every one minute between 0445 UTC and 0840 UTC.

Examining the initial lightning jump, there are notable differences in storm structure when the pre-jump and post-jump radar images are compared (Figure 3).  The first main difference is the notable bounded weak echo region (BWER) in the horizontal reflectivity data (Panels A vs F).  Cross section of reflectivity also show an increased depth of the BWER in Panels E and J.  The second notable difference is the increase in low-level rotation in radial velocity between Panels B and G. Research completed at UAH indicates that 77% of the time a lightning jump was observed in a sample of 19 supercell events, low and mid-level rotation increased, similar to what is observed in this time period.  The first severe weather reported with this storm was at 0507 UTC with 1.50 inch hail falling near Camden, Tennessee.

Figure 3 – 10 panel image of radar information from the National Weather Service Radar at Ft. Campbell, Kentucky at 0445 UTC and 0456 UTC. Panels A and F are horizontal reflectivity at 0.5 degrees elevation, B and G are radial velocity, C and H are differential reflectivity, D and I are correlation coefficient, and E and J are vertical cross sections of the storm through the center of the mesocyclone region.

Another observation is the relative lull in lightning activity around 0620 UTC through 0730 UTC. It is unclear at this point in time of the specific start time of the tornado that tracked from Nashville to Mt. Juliet due to ongoing surveys; however, radar data indicates lofted debris from the tornado as early as 0636 UTC (Figure 4A), lasting all the way to at least 0733 UTC (not shown). Previous work on lightning lulls near the time of tornadogenesis theorize that the lack of lightning is due to weakening vertical motion in the mixed phase region as downdraft processes in the thunderstorm taking over.

Figure 4  – Two panel radar image from KOHX in Old Hickory, Tennessee at 0636 UTC, when the first instances of a tornadic debris signature was present, confirming the tornado’s presence at the surface.

It must be emphasized that the low and mid-level rotation increases do not directly correspond to the development of tornadoes because the processes that are responsible for tornadogenesis are found within the lowest 1 km of the atmosphere, while those related to lightning generation are generally above 4 km. However, forecasters within the NWS have been able to combine the lightning, radar, and local environmental data to anticipate potential strengthening of a thunderstorm in specific severe weather environments (e.g., https://nasasport.wordpress.com/2020/01/31/the-utilization-of-glm-during-the-january-11th-tornado-event/ ).

Additional details on storm evolution will unfold as the NWS offices complete their surveys. We will be looking into the resurgence in flash rates around 0730 UTC as the storm moved eastward from Nashville and Mt. Juliet. Additional damage was reported near Cookeville, Tennessee, but radar data at this time do not allow us to confirm any details on this portion of the storm’s lifecycle.