A clock-driven instrument mounting which automatically and continuously points in the direction of the sun. It is used with a pyrheliometera,hen continuous direct solar radiation measurements are required.

A wind blowing in a direction perpendicular to the course of a moving object.

February 2nd. In American folklore, a day that is popularly supposed to provide the key to the weather for the remainder of the winter. Specifically, if the ground-hog upon emerging from its hole casts a shadow, it will return underground, thereby forebod ...

The lowest value of a measured quality at which a sensor meets its accuracy specification.

A measure of the amount of "spin" (or rotation) in the atmosphere.

Of or pertaining to the air, atmosphere, or aviation. Also, same as antenna.