| 英文摘要: | Nat. Geosci. http://doi.org/bstz (2016) Clouds strongly influence the amount of solar radiation absorbed into the Earth system and thermal radiation lost to space. Consequently changes in cloud cover and type, associated with the changing climate and the resultant balance of clouds' warming and cooling effects, are generally accepted to be the major source of uncertainty in our understanding of the Earth's climate sensitivity to a doubling of atmospheric CO2 — equilibrium climate sensitivity. Chen Zhou from the Lawrence Livermore National Laboratory, USA, and co-workers explore the relationship between cloud feedbacks and patterns of decadal climatic variability using climate model simulations. Their findings reveal that the global average cloud feedback effect has varied widely over time in association with patterns of sea surface temperature. In particular, increasing temperature gradients between the west and east Pacific facilitate an increase in the formation of low level clouds which then reflect a greater proportion of incoming solar radiation. These findings provide a mechanism that could explain why climate sensitivity estimates based on recently observed trends are likely too low and may also help to account for the reduced warming between 1998 and 2013. |