Observing & Predicting

Rainfall was measured by the foot in South Carolina in an event that statistically would happen, on average, once every thousand years.

September 2009

  •  The Sun is the main source of power for the Earth's climate machine. Space-based measurements, begun in 1978, indicate Earth receives an average of 1,361 W/m<sup>2</sup> of incoming sunlight, and the amount varies by about one-tenth of a percent over the course of the 11-year solar cycle.