A&O SCI 1 Lecture Notes - Lecture 8: Subtropics, Orbital Forcing, Jacob Bjerknes
2 Aug 2018
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Document Summary
External forcings : climate variations forced by phenomena outside the atmosphere / ocean / land system (include orbital forcing, human-induced changes in greenhouse gas concentrations. However, the atmosphere / ocean / land system varies a great deal on its own (without any external forcing) These variations occur on interannual to decadal time scales and longer, exactly the same time frame as anthropogenic climate change. Clearly, this internal variability will have an impact on interpretation of historical & future climate variations. Warming trend in global mean temperature record since 1880, but clearly a lot of wiggles too. Many of these wiggles = internal climate variability: background. Climate variations are often described in terms of their signatures in surface. Pressure = simply the weight of the air above a particular point (often related in a very atmospheric pressure straightforward way to temperature) If pressure is high then the weight of the air is relatively large.
