Observation Techniques
[Index] |
![]() Observing pollution, dust, smoke or moisture haze [Back to introduction of more advanced techniques] |
Haze refers to a light cloud of fine particles that consequently reduces visibility. The extent of the visibility loss depends on the amount of particles in the air and the thickness of the haze.There are four main types of hazes: pollution, dust, smoke and moisture hazes. Each of the hazes Besides the fact that these hazes reduce visibility, they also make the surroundings such as the landscape and clouds appear different than the would normally look in clear conditions. Observing pollution haze
Observing dust haze
Visibility from dust hazes can vary from a light dusty haze to heavy brown haze that can cover the sun and make it very dark. This dark haze situation is known as a dust storm. In 1983, Melbourne (Australia) experienced a dust storm in which street lights were switched on automatically due to the dark conditions. Dust may settle on the ground as the weather conditions responsible for the thick dust haze (namely the wind) eases. Back to topObserving smoke haze
Observing moisture haze
The synoptic conditions associated with moisture hazes are developing troughs of low pressure, cold fronts and trough lines. In the case of trough lines, the clear air can be seen at the rear of the haze region. The haze region lies ahead of the trough line boundary as it passes through.The large cumulus and thunderstorms develop in the region with the moisture haze. Generally, with all cases of hazes, clearing edges of normally indicate changes in weather conditions such as a change in wind direction and/or speed. In the case of pollution hazes, an approaching sea breeze is sufficient to disperse the pollution. A cold front will clear the pollution. In bush fire weather conditions, wind changes associated with cold fronts can clear or change the paths of bush fires. The important points to note from these observations is the reverse of these observations. For instance, if there is a change in direction of the smoke plumes, there is a change in wind direction. If there is moisture haze, the air may be unstable and thunderstorms may develop. Using these techniques are sometimes very important ways of determining what the weather is doing nearby. |
Document: hazes.htm
Updated: 20th March 2008 |
[Australian Severe Weather index] [Copyright Notice] [Email Contacts] [Search This Site] |