Conceptual deconstruction of the simulated precipitation response to climate change
Stassen, C; Dommenget, D; Chadwick, R
Date: 25 May 2020
Journal
Climate Dynamics
Publisher
Springer
Publisher DOI
Abstract
State-of-the-art climate change projections of the CMIP5 simulations suggest a fairly
complex pattern of global precipitation changes, with regions of reduced and
enhanced precipitation. Conceptual understanding of these projected precipitation
changes is difficult if only based on coupled general circulation model (CGCM)
...
State-of-the-art climate change projections of the CMIP5 simulations suggest a fairly
complex pattern of global precipitation changes, with regions of reduced and
enhanced precipitation. Conceptual understanding of these projected precipitation
changes is difficult if only based on coupled general circulation model (CGCM)
simulations, due to the complexity of these models. In this study we describe a simple
deconstruction of the ensemble mean CMIP5 projections based on sensitivity
simulations with the globally resolved energy balance (GREB) model. In a series of
sensitivity experiments we force the GREB model with four different CMIP5 ensemble
mean changes in: surface temperature, evaporation and the vertical atmospheric
velocities mean and its standard deviation. The resulting response in the precipitation
of the GREB model is very close to the CMIP5 ensemble mean response, suggesting
that the precipitation changes can be well represented by a linear combination of these
four forcings. The results further provide good insights into the drivers of precipitation
change. The GREB model suggests that not one forcing alone can be seen as the
main driver, but only the combination of all four changes results in the complex
response pattern. However, the dominant forcings are the changes in the large-scale
circulation, rather than the pure thermodynamic warming effect. Here, it is interesting
to note that changes in high-frequency atmospheric variability of vertical air motion
(weather), that are partly independent of the changes in the mean circulation, have a
control on the pattern of the time-mean global precipitation changes. The approach presented here provides a powerful basis on which the hydrological cycles of CGCM
simulations can be analysed.
Mathematics and Statistics
Faculty of Environment, Science and Economy
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