The Sun's average brightness varies over time, and the changes can affect global surface temperature. But long-term changes over the period of human-caused global warming are minimal.

The Oceanic Nino Index tracks the sea surface temperature in the east-central tropical Pacific Ocean. It is NOAA's primary indicator of the climate patterns known as El Niño and La Niña.

The Southern Oscillation Index tracks differences in air pressure between the eastern and western sides of the tropical Pacific.

The Arctic Oscillation (AO) refers to an atmospheric circulation pattern over the mid-to-high latitudes of the Northern Hemisphere. The most obvious reflection of the phase of this oscillation is the north-to-south location of the storm-steering, mid-latitude jet stream.

The North Atlantic Oscillation tracks a seesawing of surface pressure between two parts of the North Atlantic. Different phases often bring predictable changes in winds, temperature, and precipitation in the United States and Europe.

NOAA's Susan Solomon was awarded the 2009 Volvo Environment Prize for her pioneering contributions in atmospheric chemistry and physics.