This means the seasonal variation of the aerosol spectral optical depth is mainly determined by the variation of surface visibility.

而不分级的光学厚度季节起伏主要由各季节的几率能见度决定。

youdao

A thick cloud of water droplets suspended in the atmosphere at or near the earth's surface that obscures or restricts visibility (strictly, reducing visibility to below 1 km).

云层中的水滴悬浮在空气中或者接近地表，使能见度变低（严格地说，使能见度变得不足1千米）。

youdao

There is no simple one-to-one correspondence between optical depth and surface horizontal visibility.

光学厚度与地面水平能见度不呈简单的对应关系。

youdao

"The warmth of the water and the visibility is incredible, so you can see the whole ship from the surface, " says Easterbrook.

CNN: A worthy wreck for divers: USS Kittiwake

Even when the sharks are found closer to the ocean surface, they spend their time in the cool-temperature, plankton-rich waters that limit underwater visibility and make diving difficult.

CNN: Scientists discover winter home of world's second-biggest fish

And we have rope tenders that control us on the surface and give us particular signals and tell us where to turn and things of that nature, because with no visibility you normally will lose your sense of direction and everything else.

NPR: River Poses Hazard for Dive Teams