View : 82 Download: 0
A Positive Iris Feedback: Insights from Climate Simulations with Temperature-Sensitive Cloud-Rain Conversion
- A Positive Iris Feedback: Insights from Climate Simulations with Temperature-Sensitive Cloud-Rain Conversion
- Li, R. L.; Storelvmo, T.; Fedorov, A., V; Choi, Y-S
- Ewha Authors
- SCOPUS Author ID
- Issue Date
- Journal Title
- JOURNAL OF CLIMATE
- JOURNAL OF CLIMATE vol. 32, no. 16, pp. 5305 - 5324
- Cirrus clouds; Climate sensitivity; Cloud radiative effects
- AMER METEOROLOGICAL SOC
- SCIE; SCOPUS
- Document Type
- Estimates for equilibrium climate sensitivity from current climate models continue to exhibit a large spread, from 2.1 to 4.7 K per carbon dioxide doubling. Recent studies have found that the treatment of precipitation efficiency in deep convective clouds-specifically the conversion rate from cloud condensate to rain C-p-may contribute to the large intermodel spread. It is common for convective parameterization in climate models to carry a constant C-p, although its values are model and resolution dependent. In this study, we investigate how introducing a potential iris feedback, the cloud-climate feedback introduced by parameterizing C-p to increase with surface temperature, affects future climate simulations within a slab ocean configuration of the Community Earth System Model. Progressively stronger dependencies of C-p on temperature unexpectedly increase the equilibrium climate sensitivity monotonically from 3.8 to up to 4.6 K. This positive iris feedback puzzle, in which a reduction in cirrus clouds increases surface temperature, is attributed to changes in the opacity of convectively detrained cirrus. Cirrus clouds reduced largely in ice content and marginally in horizontal coverage, and thus the positive shortwave cloud radiative feedback dominates. The sign of the iris feedback is robust across different cloud macrophysics schemes, which control horizontal cloud cover associated with detrained ice. These results suggest a potentially strong but highly uncertain connection among convective precipitation, detrained anvil cirrus, and the high cloud feedback in a climate forced by increased atmospheric carbon dioxide concentrations.
- Appears in Collections:
- 엘텍공과대학 > 기후·에너지시스템공학전공 > Journal papers
- Files in This Item:
There are no files associated with this item.
- RIS (EndNote)
- XLS (Excel)
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.