Sand and Dust Weather Information - Forecast Air Trajectory
| A sandstorm or duststorm is a meteorological phenomenon usually caused by strong and turbulent winds blowing over loose soil or sand and sweeping up large quantities of sand or dust particles from the ground, clouding the air and reducing the visibility drastically. In general, sandstorm/duststorm can be defined as an ensemble of particles of sand and dust energetically lifted to great heights by a strong and turbulent wind bringing visibility down to less than 1,000 metres. If the visibility is observed to be 1,000 metres or greater it would be defined as sand or dust. |
| There are several tools for monitoring sand and dust weather, including (a) the latest reports on sand and dust weather, (b) satellite pictures enhanced to show delineated areas of sand and dust and (c) forecast trajectories of air. |
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Forecast trajectory of air mass which will reach |
| Go to text version of Sand and Dust Observation | This webpage shows the 72-hour trajectory of air forecast to reach Hong Kong at a height of 100 metres above ground level ending at 8 a.m. or 8 p.m. of the next 2 to 3 days. The product may be useful for tracing the origin of air reaching Hong Kong. From these trajectories, one can relate the local visibility to the possible origin of the air 72 hours ago. Relatively low visibility (excluding fog, mist and rain) is normally associated with air masses coming from the north and some others coming from the east. |