  Whether natural factors could interpret the rise of the Earth's surface
temperature is still controversial. Though numerous recent researches have
reported apparent correlations between solar activity and the Earth's climate,
solar activity has encountered a big problem when describing the rapid global
warming after 1970s. Our investigation shows the good positive correlations
between the Earth's surface Ultraviolet irradiance (280-400 nm) and the Earth's
surface temperature both in temporal and spatial variations by analyzing the
global surface Ultraviolet irradiance (280-400 nm) and global surface
temperature data from 1980-1999. The rise of CO$_2$ cannot interpret the good
positive correlations, and we could even get an opposite result to the good
correlations when employing the rise of CO$_2$ to describe the relation between
them. Based on the good positive correlations, we suggest a new effect, named
"Highly Excited Water Vapor" (HEWV) effect, which can interpret how the Sun
influences the Earth's surface temperature reasonably, including the rapid
warming after 1970s.
