Tuesday, February 17, 2009

Hazy sunrise over Sentosa

"The haze is back" is what many of my friends and also other Singaporeans will lament. Before we probably will start pointing our fingers at Indonesia again, reports have already stated that yes the haze is back, but blame it on fires on Singapore and that Singapore bush fires hit record high.


The sunrise yesterday was more orangey with the haze. This photo was taken with Tanjong Rimau, Sentosa.


Why is the sun more orangey or reddish when there is a haze?

This is because during a haze, the sunlight must travel further through the atmosphere before it gets to you as more of the light is reflected and scattered off by the particulate matter that causes the haze.

Shorter wavelengths like blue are more efficiently scattered by Rayleigh scattering. Only the longer wavelengths (orange and red) are left in the direct beam that reaches your eyes. Therefore, the sun looks more red and orangey when there are more particles in the air. But as the sun rises to a higher position in the sky, the distance for the sunlight to reach the earth's surface decreases. This decreases scattering and therefore during noon, the sun is not orange or red anymore.

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