Satellite Algorithm Development, Training and Education Research

Satellite information improves our ability to observe current environmental conditions (relevant, e.g., to increase warning lead times) and advance the representation of physics in numerical weather and climate prediction models. NOAA geostationary and polar orbiting satellites are an integral part of the international global space-based observing system, providing a 'global spectral shell' of information with varying spatial, spectral, and temporal characteristics.

Satellite Algorithm Development, Training and Education is a core thematic area of research for CIRA, and we hold over 30 years of experience in developing, demonstrating, transitioning, and training operational users on satellite meteorological products. This expertise spans both national and international operational satellite systems and extends to operational risk-reduction and research-grade systems. We apply this expertise to the development of new satellite algorithms, anticipating future system capabilities, and training forecasters on the capabilities and limitations of satellite-derived information.

Meeting the mission-critical needs of NOAA in satellite research and development requires close working partnerships and full immersion within NOAA's program planning, budget and execution cycle. This level of involvement is best facilitated by regular, face-to-face interactions. The Cooperative Institute program accomplishes this interaction in a unique way - allowing Federal scientists to physically sit at academic institutions and vice versa.

For example, CIRA hosts the Regional and Mesoscale Meteorology Branch (RAMMB) of NOAA/NESDIS/STAR, who interact closely with CIRA scientists at Colorado State University in Fort Collins. Our co-location with CSU's Department of Atmospheric Science enables direct linkages to faculty and their students in the discipline areas of Satellite Meteorology, Radiative Transfer and Remote Sensing Theory, Thermodynamics and Cloud Physics, Atmospheric Chemistry and Air Quality, and Tropical Meteorology and Dynamics. In addition, the NOAA Weather and Climate Center in College Park, MD serves as host to a group of CIRA scientists who are fully entrained within the research activities of Satellite Oceans Sensors Branch as well as the Marine Ecosystems & Climate Branch as part of the NESDIS Environmental Applications Team (NEAT).

In both on-site and remote arrangements, Federal scientists serve as technical advisors to ensure that our research follows in lock-step with NOAA mission needs.

RELATED PROJECTS

CIRA's palette of research in the Satellite Algorithm Development, Training and Education theme includes multiple sub-thrusts which span the needs for current and future observing systems. Provided below is a cross section of current projects falling under this theme:

  1. Algorithm Development for Current Satellite Observing Systems:  Developing practical applications of satellite remote sensing for the analysis of current environmental conditions through physically-based and statistically-based, multi-spectral, multi-sensor, and model-fusion techniques.
  2. Algorithm Development for Future Satellite Observing Systems:  Improving environmental data records and conducting pre-launch research based on simulated/heritage observing systems to increase 'first light' operational utility.
  3. Bridging the Gap Between Research and Operations:  Participating in NOAA programs to transfer the results of research and algorithm development into the hands of end-users and demonstrate these capabilities in an operational setting.
  4. Satellite Education and Training for the Operational Community:  Realizing the potential of satellite observations through an integrated program of education and training for operational users based on interactive, distance learning tools.

RESEARCH HIGHLIGHTS

When it comes to new satellite measurements, we have become accustomed to expecting the unexpected. This is particularly true when the measurements push the limits of technology. The Suomi-NPP VIIRS Day/Night Band detects extremely faint levels of light, down to the noise floor of 7e-11 W cm^-2 sr^-1. During normal cal/val, while attempting to characterize instrument noise over dark-night Pacific scenes, a team of CIRA, NOAA, Northrop Grumman, and Navy scientists discovered the presence of reflecting cloud structures. IR signal and cross talk were ruled out, and the nature of the illumination was not local.

Above:  Low-light imagery from a series of adjacent Suomi NPP VIIRS/DNB nighttime passes over the Pacific Ocean on the night of 22 February, 2012. The coverage domain spans 20,000 km east-to-west and 12,500 km north-to-south, with geopolitical boundaries drawn in green. The data were collected during new moon conditions (no sunlight or moonlight present). In addition to city light emissions (e.g., L), the observations capture clouds (e.g., C) illuminated by reflected airglow, starlight and zodiacal light. Also apparent are broad, diffuse regions of primary airglow emission (e.g., A).

Discussions with astronomers led to the conclusion that principal sources were 1) nightglow from 85-95 km layer near mesopause, and 2) the integrated starlight. The first results of this ground breaking remote sensing discovery are detailed in the Proceedings of the National Academy of Sciences. There are several important implications of this discovery:

  • The Day/Night Band has revealed a new kind of measurement capability, based on a source that has never been exploited for meteorological sensing and heretofore has represented 'noise' to the astronomy community.
  • When we are without the sun or the moon, Earth's upper atmosphere can serve as our illumination source.
  • Some beneficial aspects of visible light imaging (lower atmos/surface feature detection improvements over conventional IR, the ability to peer through optically thin cirrus which is opaque in the thermal IR) are possible at night with and *without* the lunar illumination. Moonlight is available only ½ (2 weeks) of the 29.5 day lunar cycle.
  • We are seeing some cases of direct emission from the nightglow where it is strong enough (the emission layer is non-uniform, varies over space/time both with season and over the course of an evening; a strong function of temperature and oxygen availability among other factors). The structures occur at multiple spatial scales including waves forced by various mechanisms.
  • We have surface-based validation of Day/Night Band-viewed concentric gravity waves atop a Texas thunderstorm.
  • There are challenges related to the space/time variability and diffuse source nature of nightglow when considering applications of the capability, and the current Day/Night Band is not optimized to this kind of imagery. It would be better to have a geostationary measurement and additional low-light bands that could isolate the nightglow component and thereby allow for correction of the integrated scene and possibly quantitative applications.

We look forward to working closely with the broad research community, including our Cooperative Institute partners and NOAA, to explore the Day/Night Band's remarkable abilities to shed new light on nighttime environmental parameters.