This lecture is a basic introduction to dust modelling and forecasting.
Published: 4 March 2010
When winds are strong, large amounts of sand and dust can be lifted from bare, dry soils into the atmosphere and transported downwind affecting regions hundreds to thousands of kilometres away. A dust storm or sandstorm is a meteorological phenomenon common in arid and semi-arid regions and arises when a gust front passes or when the wind force exceeds a threshold value where loose sand and dust are removed from the dry surface.
In desert areas, sand and dust storms are most commonly caused by either thunderstorm outflows, or by strong pressure gradients which cause an increase in wind velocity over a wide area. Drought and wind contribute to the emergence of dust storms, as do poor farming and grazing practices by exposing the dust and sand to the wind.
For countries in and downwind of arid regions, airborne sand and dust presents serious risks to the environment, property and human health. Impacts on health include respiratory and cardio-vascular problems, eye infections and in some regions, diseases such as meningitis and valley fever. Dust can carry irritating spores, bacteria, viruses and persistent organic pollutants. It can also transport nutrients to parts of the world oceans and affect marine biomass production. Other impacts include negative effects on the ground transport, aviation, agriculture and visibility.
The Inter-governmental Panel on Climate Change (IPCC) recognises dust as a major component of atmospheric aerosol that is an essential climate variable. More and more dust particles are considered by atmospheric researchers to have important effects on weather through feedback on atmospheric dynamics, clouds and precipitation formation. Thus, there is a need for international coordination of a diverse community dealing with the societal impacts of sand and dust storms. The World Meteorological Organization (WMO) has taken the lead with international partners to develop and implement a Sand and Dust Storm Warning Advisory and Assessment System (SDS-WAS).
The first part of this lecture briefly reviews some basic concepts about dust storms taking a close look to the global dust climatology and presents the WMO Sand and Dust Storm Warning and Assessment System program.
The second part focuses on how the atmospheric dust cycle is represented into models, including dust sources, emission, transport and deposition. Dust forecast skills and limitations are discussed.
After viewing the module, the user should be able to understand how models represent the atmospheric dust cycle and what are their skills and limitations. While dust models are very useful tools for dust forecasting, the lecture emphasises that dust storm forecasting needs to rely on the combination of satellites, surface observations, NWP models and dust models.
Pre-requisites: some knowledge about dust sources and dust climatology and basic knowledge on atmospheric/NWP models.
|Atmosphere||English||Basic||✓||60 min||Carlos Perez|
WMO SDS-WAS Programme presentation (PDF, 8 MB)
WMO SDS-WAS Programme recording (ZIP, 87 MB)