Thermodynamic Control of Anvil Cloud Amount. Bony, S.; Stevens, B.; Coppin, D.; Becker, T.; Reed, K. A.; Voigt, A.; and Medeiros, B. 113(32):8927–8932.
Thermodynamic Control of Anvil Cloud Amount [link]Paper  doi  abstract   bibtex   
[Significance] Assessing the response of clouds to global warming remains a challenge of climate science. Past research has elucidated what controls the height and temperature of high-level anvil clouds, but the factors that control their horizontal extent remained uncertain. We show that the anvil cloud amount is expected to shrink as the climate warms or when convection becomes more clustered, due to a mechanism rooted in basic energetic and thermodynamic properties of the atmosphere. It is supported by three climate models and consistent with results from a cloud-resolving model and observations. We thus believe that this mechanism is robust and that it adds a new piece to understanding how clouds respond to climate warming. [Abstract] General circulation models show that as the surface temperature increases, the convective anvil clouds shrink. By analyzing radiative-convective equilibrium simulations, we show that this behavior is rooted in basic energetic and thermodynamic properties of the atmosphere: As the climate warms, the clouds rise and remain at nearly the same temperature, but find themselves in a more stable atmosphere; this enhanced stability reduces the convective outflow in the upper troposphere and decreases the anvil cloud fraction. By warming the troposphere and increasing the upper-tropospheric stability, the clustering of deep convection also reduces the convective outflow and the anvil cloud fraction. When clouds are radiatively active, this robust coupling between temperature, high clouds, and circulation exerts a positive feedback on convective aggregation and favors the maintenance of strongly aggregated atmospheric states at high temperatures. This stability iris mechanism likely contributes to the narrowing of rainy areas as the climate warms. Whether or not it influences climate sensitivity requires further investigation.
@article{bonyThermodynamicControlAnvil2016,
  title = {Thermodynamic Control of Anvil Cloud Amount},
  author = {Bony, Sandrine and Stevens, Bjorn and Coppin, David and Becker, Tobias and Reed, Kevin A. and Voigt, Aiko and Medeiros, Brian},
  date = {2016-08},
  journaltitle = {Proceedings of the National Academy of Sciences},
  volume = {113},
  pages = {8927--8932},
  issn = {1091-6490},
  doi = {10.1073/pnas.1601472113},
  url = {http://mfkp.org/INRMM/article/14110598},
  abstract = {[Significance]

Assessing the response of clouds to global warming remains a challenge of climate science. Past research has elucidated what controls the height and temperature of high-level anvil clouds, but the factors that control their horizontal extent remained uncertain. We show that the anvil cloud amount is expected to shrink as the climate warms or when convection becomes more clustered, due to a mechanism rooted in basic energetic and thermodynamic properties of the atmosphere. It is supported by three climate models and consistent with results from a cloud-resolving model and observations. We thus believe that this mechanism is robust and that it adds a new piece to understanding how clouds respond to climate warming.

[Abstract]

General circulation models show that as the surface temperature increases, the convective anvil clouds shrink. By analyzing radiative-convective equilibrium simulations, we show that this behavior is rooted in basic energetic and thermodynamic properties of the atmosphere: As the climate warms, the clouds rise and remain at nearly the same temperature, but find themselves in a more stable atmosphere; this enhanced stability reduces the convective outflow in the upper troposphere and decreases the anvil cloud fraction. By warming the troposphere and increasing the upper-tropospheric stability, the clustering of deep convection also reduces the convective outflow and the anvil cloud fraction. When clouds are radiatively active, this robust coupling between temperature, high clouds, and circulation exerts a positive feedback on convective aggregation and favors the maintenance of strongly aggregated atmospheric states at high temperatures. This stability iris mechanism likely contributes to the narrowing of rainy areas as the climate warms. Whether or not it influences climate sensitivity requires further investigation.},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-14110598,~to-add-doi-URL,climate,cloudiness,feedback,non-linearity,thermodynamics,uncertainty},
  number = {32}
}
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