The four classes of extremes -- high heat, heavy precipitation and floods, duration and intensity of droughts and extremes related to higher sea levels -- have changed in the last 50 years, Field said.

CNN: Extreme weather: Get ready to see more of it, scientists say

Each component of the energy balance net radiation, turbulent heat fluxes, heat transfer into the ice and heat supplied by precipitation is derived separately from the measurements, and the variability throughout the year is evaluated.

UNESCO: Dublin Core