A Refined Understanding of the Ice Cloud Longwave Scattering Effects in Climate Model
[1];
[2];
[1];
[4];
[1]
- Department of Climate and Space Sciences and Engineering the University of Michigan Ann Arbor MI USA
- Department of Climate and Space Sciences and Engineering the University of Michigan Ann Arbor MI USA, Now at Research Center for Environmental Changes Academia Sinica Taipei Taiwan
- Environmental &, Climate Sciences Department Brookhaven National Laboratory New York State NY USA
- Department of Atmospheric Sciences Texas A&,M University College Station TX USA
Abstract Because longwave (LW) absorption by greenhouse gases and clouds is more significant than the LW scattering effect by clouds, most climate models neglect cloud LW scattering to save computational costs. Ignoring cloud LW scattering directly overestimates outgoing longwave radiation (OLR). This study included ice‐cloud LW scattering treatment in the Exascale Energy Earth System Model (E3SM) version 2 and ran fully‐coupled simulations, prescribed sea surface temperature simulations, and offline radiative transfer calculations to comprehensively assess the impact of ice‐cloud LW scattering on global climate simulation. The instantaneous effect due to ice‐cloud LW scattering reduces the OLR by ∼1 W/m 2 on the global average and 2 W/m 2 on the tropical average. Tropospheric warming and high cloud amount reduction act to partially compensate for such instantaneous OLR reduction caused by the inclusion of LW scattering. When the simulation reaches the equilibrium, the surface warms by 0.66 K on average with respect to the simulation without LW scattering, with the Arctic surface temperature differences more than twice as large as that of the global mean. The impact of including LW scattering on the simulated climate change in response to 4 × CO 2 is also assessed. While including the cloud LW scattering does not significantly modify radiative forcing and total radiative feedback under such a scenario, it results in a 10% more positive cloud feedback.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- SC0019278; SC0022117
- OSTI ID:
- 2007440
- Journal Information:
- Journal of Advances in Modeling Earth Systems, Journal Name: Journal of Advances in Modeling Earth Systems Journal Issue: 10 Vol. 15; ISSN 1942-2466
- Publisher:
- American Geophysical Union (AGU)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Major improvements on the longwave radiative interactions between surface and clouds in the Polar Regions in atmospheric global circulation model (GCM). Final Project Report
Seasonal Dependent Impact of Ice Cloud Longwave Scattering on the Polar Climate