Background
Fig. 1. Cloud top height algorithm output (geopotential height in Kft) is shown for various domains that include a) the Pacific region, b) the north Pacific regions and c) the Gulf of Mexico. Black regions are missing data caused by the satellite scanning strategy. (click on image to enlarge).
A variety of hazards such as volcanic ash, convection, turbulence, icing and adverse headwinds affect the safety, efficiency and economic viability of aircraft operations over oceanic regions. Accident databases from national and international sources indicate that aircraft incursion into volcanic ash clouds, for example, is a safety concern that causes $10M/year in damage to engines, avionics and airframes and impacts efficiency costs by $1.4M/year. Hazardous convection produces turbulence, icing and lightning and necessitates aircraft rerouting while inflight, leading to higher fuel costs and delays. Turbulence, from convection and clear air, causes $5M/year in safety costs due to injuries and aircraft damage and $46.3M/year in efficiency costs.
Despite the significance of these hazards, few, if any, high-resolution aviation weather products are available to pilots, dispatchers, and air traffic managers. Development of improved tools for detecting and forecasting hazards has long been plagued by severely-limited data availability in remote oceanic regions, the long duration of transoceanic flights, and the difficulty of transmitting critical information into the cockpit. RAL’s Oceanic Weather Program works to overcome these limitations through the use of a diverse range of satellite observations, global model results and satellite-based communications.
The program, under the overall leadership of C. Kessinger, conducts research into a variety of hazard areas, develops new oceanic weather products, and creates in-flight displays for them. Aviation concerns addressed within the Oceanic Weather program include: Volcanic Ash (led by P. Herzegh and J. Cowie), Improved Inflight Winds (led by T. Tsui, Naval Research Laboratory-Monterey, and G. Blackburn), Product Dissemination to the Cockpit (led by G. Blackburn and C. Kessinger), Turbulence (led by R. Sharman and G. Wiener), Convection Diagnosis (led by C. Kessinger and G. Blackburn) and Convection Nowcasting/Forecasting (led by C. Kessinger, C. Mueller, and N. Rehak). Funding for the program comes primarily from the FAA’s Aviation Weather Research Program through the Oceanic Weather Product Development Team (OWPDT). Leveraged funding is provided by NASA’s Advanced Satellite Aviation-weather Products (ASAP) program. A new proposal in response to NASA’s Cooperative Agreement Notice (CAN) will be awarded in FY2006.
Results
Efforts within Volcanic Ash by P. Herzegh and B. Hendrickson have concentrated on case study analysis to refine satellite detection techniques. T. Tsui completed the quantification of error characteristics of global model winds and global satellite-tracked winds. Plans for incorporation of satellite-tracked winds into the ATOP Ocean 21 air traffic management system are underway. G. Blackburn, and K. Levesque have successfully uplinked a cloud top height product into the cockpit of an oceanic aircraft. B. Sharman,G. Wiener and K. Levesque have begun the technology transfer of the turbulence forecasting methodology to the Global Forecasting System (GFS) numerical model. C. Kessinger, C. Mueller, and N. Rehak have begun the technology transfer of convective nowcasting methodology to the GFS model. C. Kessinger devised a satellite-based convective diagnosis methodology that combines three algorithms in a fuzzy-logic sense. The convective diagnosis methodology has been tested and validated by E. Williams and M. Donovan of Massachusetts Institute of Technology Lincoln Laboratory. G. Blackburn and K. Levesque maintain the various computer systems within the OWPDT and keep the experimental web site functional.
Recent Accomplishments
Fig. 2. An example of the cockpit displays of the cloud top height (Kft) product is shown. The panel in a) shows the aircraft ground position (purple line) with the region contoured in b) and c) enclosed by the box. Aircraft positions are indicated by the purple “+”. The cockpit inflight displays are shown in b) graphical and c) textual formats with current and future aircraft position indicated by shaded arrows. For b) and c), the cloud top heights are contoured at 30-39Kft (green shading or ‘.’) and >40Kft (red shading or ‘C’). (click on image to enlarge).
As part of the National Weather Service's Aviation Weather Technology Transfer (AWTT) process, the cloud top height (CTOP) product (see Fig. 1) was thoroughly verified by the FAA’s Quality Assessment Group, which includes RAL’s B. Brown, L. Holland, and A. Takacs, prior to becoming an experimental product.This satellite-based product gives a depiction of the heights of cloud tops, in particular convective clouds, relative to flight-level altitudes, and is displayed on the OWPDT experimental web site. After Hurricane Katrina, a Houston dispatcher with Continental Airlines wrote to C. Kessinger to say that this product was invaluable when hurricanes and tropical storms were in the Gulf. The cloud top height product was uplinked for display (see Fig. 2) during one United Airlines flight by G. Blackburn and K. Levesque.J. Craig created a web-based comment page for pilot feedback on the utility of the product. This innovation will lead to the inflight display of other products such as turbulence.
Contact Information
Cathy Kessinger — ph: 303.497.8481| fx: 8401 | kessinge @ucar.edu