Oct 3, 2016

Understanding why nights are getting warmer faster than days

by
Bjerknes Centre
"An improvement of the boundary-layer physics in climate models would very likely reduce our uncertainty in projections of temperture change", says Richard Davy, scientist at the Nansen Center and Bjerknes Centre for Climate Research. Photo: Bjerknes Centre
"An improvement of the boundary-layer physics in climate models would very likely reduce our uncertainty in projections of temperture change", says Richard Davy, scientist at the Nansen Center and Bjerknes Centre for Climate Research. Photo: Bjerknes Centre

A new publication led by Richard Davy, researcher at the Nansen Centre and the Bjerknes Centre has examined the causes of the more rapid warming at night compared to the day, which has been seen around the globe in recent decades. They have analysed the causes of these changes from observations and model reconstructions of the climate in the 20th century. By using model reconstructions they were able to determine how much of this asymmetrical warming could be explained by different processes.

Past efforts to understand the reason for this enhanced warming have focused on changes to climate processes that may have occurred at this time, such as increases in cloud cover, precipitation or soil moisture content. However, Davy and colleagues have shown that part of this more rapid warming at night is innate to the climate system, because the night-time temperatures are inherently more sensitive to climate forcing.