That portion of the atmosphere which is above the lower troposphere. Generally applied to levels above 850 mb.

A measurement of atmospheric conditions aloft, above the effective range of a surface weather observation. Elements evaluated include temperature, humidity, pressure, wind speed, and wind direction.

The highest continuous deck which runs the full length of the ship without a fall or interruption.

Unearned Passenger Revenue

Uninterrupted Power Supply

Solar and terrestrial radiation directed upward (away From the earth's surface); outgoing radiation.

The rising of cold water from the deeper areas of the ocean to the surface. This phenomena often occurs along the California coast during the spring and summer.

In the direction from which the wind is blowing.

To windward, in the direction of the eye of the wind; toward the wind; in the direction from which the wind is coming

Ukrainian Register

Uruguay Round

Universal Resource Locator

United States Agency for International Development

United States Code

Unless Sooner Commenced

United States Coast Guard

United States Dollar

United States Department of Agriculture

Heat stored above room temperature (in a solar heating system).

United States Environmental Protection Agency.