Oceanic Weather
The preliminary volcanic ash detection algorithm is shown in a) for the Soufriere Hills eruption on 20 May 2006 at 1445 UTC, approximately 3.5 hours after the initial eruption. For comparison, the corresponding visible satellite imagery is shown in b) and the infrared temperature imagery is shown in d). The cloud top height algorithm output (geopotential height in Kft) shown in c) is derived from the IR temperature through a mapping to the global model sounding.
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. Adverse headwinds, hazardous convection, turbulence, icing and lightning often necessitate aircraft rerouting while in-flight, leading to higher fuel costs and delays. 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, sponsored by the FAA, works to overcome these limitations through the use of a diverse range of satellite observations, global model results and satellite-based communications.
FY06 Accomplishments
A preliminary algorithm for volcanic ash detection has been devised using a scaled combination of several satellite-based volcanic ash detection algorithms. Figure 1 shows an example from the Soufriere Hills eruption on 20 May 2006. This preliminary algorithm shows good performance at detecting the ash cloud for the first few hours after the eruption. Future efforts will focus on improving detection performance as the ash cloud disperses. The “Weather in the Cockpit” operational demonstration of the cloud top height product was a significant milestone for the OWPDT. Each day four United Airlines flights have been given printouts of the cloud top height product when significant weather is expected to be encountered in the next two hours of flight. Pilot feedback shows a positive response to the product as they currently have little graphical inflight weather information.