Aviation Weather

• Introduction
• Thunderstorm nowcasting
• Wind shifts and wind shear
• Ceiling and visibility
• Volcanic ash

Introduction

The Bureau of Meteorology Research Centre undertakes research and development to advance the science of meteorology, develop a better understanding of Australia's weather and climate, and improve the operations and services of the Bureau. Much of this activity is directed at further development of numerical weather prediction models and specialized observing systems which underpin many of the Bureau's services, including the aviation weather service. There is also a more focussed program of applied research and development directed at improving the aviation weather service. The main objectives of this program are improvements in the detection and forecasting of hazardous and significant weather in the vicinity of major airports (thunderstorms, fog and low cloud, wind shifts and wind shear) and improvements in the volcanic ash warning service.

Thunderstorm Nowcasting

Thunderstorms pose a safety hazard to aviation and the objective of this project is to provide better short-term guidance on thunderstorms in the terminal area including storm initiation and movement and associated phenomena such as lightning and hail. The main focus has been improving the way weather radar data is utilised in the Bureau, taking better advantage of new data processing systems and enabling automated forecast and warning products to be more easily generated.

• TITAN applications

Wind shifts and wind shear

Wind shifts and wind shear have a significant impact on airport operations. Wind shifts may require a change of airport configuration with resultant delays and economic impacts, particularly if such wind shifts occur at peak times with little warning. Low altitude wind shear, including vertical and horizontal wind shear, presents a significant safety hazard to aircraft on arrival and departure. The objective of this project is to improve the detection and forecasting of wind shifts and the detection of wind shear in the vicinity of airports.

Ceiling and Visibility

The objective of this work is to develop real-time fog analyses based on improved remote sensing techniques and to investigate the utility of modern numerical modelling and statistical techniques for improving fog forecasting. Sydney and Perth have been identified as locations where there is a priority for improved fog forecasts.

Applications that automatically process night-time NOAA AVHRR and GOES-9 multispectral satellite data and generate products showing areas of fog or low cloud are now operating routinely. The products are available to operational forecasters for the early morning issue of terminal forecasts. Work to improve the applications and validate the results is continuing.

Studies on the utility of the Bureau's high resolution numerical weather prediction model for fog forecasting are exploring details of the model physics and associated biases, and also the skill of the model in forecasting mesoscale circulations that might indicate the likely occurence of fog. The model is run twice per day with a base time of 0001 UTC and 1200 UTC. Output from the 0001 UTC run provides a lead time of 14-19 hours while output from the 1200 UTC run provides a forecast lead time of 3-8 hours. Each is being evaluated with the main focus being Sydney and Perth.

Volcanic Ash

The hazard presented by volcanic ash to modern jet aircraft operations was highlighted in 1982 when two aircraft encountered ash from the Gallungung volcano in Indonesia and suffered total engine failure. Since that time there have been a number of encounters with ash around the globe with damage to aircraft ranging from minor skin abrasion to engine failure. Volcanic ash may be carried great distances from an erupting volcano by upper level winds and present a hazard to aircraft well away from the volcano. The ash cannot been seen on weather radar and, after moving away from the initial eruption column, looks similar to water/ice clouds.

In recent years a number of Volcanic Ash Advisory Centres have been established around the world, including the Darwin VAAC, to provide advice on volcanic ash for the aviation industry. This advice is based on an initial report or detection of a volcanic eruption or ash cloud, an analysis of satellite data to identify and track the ash cloud, and a forecast of its movement derived from upper level winds and a numerical dispersion model. Research and development activities in BMRC are directed at:

• Development of a user interface that will streamline preparation of the Volcanic Ash Advisory and provide a stable framework for implementation of improved analysis and forecast methodologies;
• Improved detection of volcanic ash in satellite imagery; and
• Better utilisation of the volcanic ash dispersion model used in the Bureau of Meteorology.

• The Darwin VAAC Volcanic Ash Warning Preparation System (pdf file - 285KB)


• Darwin VAAC - Home page
• Darwin VAAC - Volcanic Ash Advisories