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www.atmos-chem-phys-discuss.net/8/20399/2008/
doi:10.5194/acpd-8-20399-2008
© Author(s) 2008. This work is distributed
under the Creative Commons Attribution 3.0 License.
Effects of model resolution on entrainment (inversion heights), cloud-radiation interactions, and cloud radiative forcing
1Atmospheric Science Division, Brookhaven National Laboratory, Upton, NY, USA
2Goddard Earth Sciences and Technology Center, University of Maryland at Baltimore County, Baltimore, Maryland, USA
3Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Abstract. We undertook three-dimensional numerical studies of a marine stratus deck under a strong inversion using an interactive shortwave- and longwave-radiation module. A suite of sensitivity tests were conducted to address the effects of model resolution on entrainment (inversion heights), cloud-radiation interactions, and cloud radiative-forcings by varying model horizontal resolution only, varying vertical resolution only, and varying horizontal- and vertical-resolution simultaneously but with a fixed aspect ratio of 2.5.
Our results showed that entrainment (inversion height) is more sensitive to vertical- than to horizontal-resolution. A vertical resolution finer than 40 m can simulate spatial- and temporal-variations in the inversion height well. The inversion height decreases with increasing vertical resolution, but tends to increase with increasing horizontal resolution. Cloud liquid water path doubles after refining both the vertical- and horizontal-resolution by a factor of four. This doubling is associated with a positive feedback between cloud water and cloud top radiative cooling, which amplifies small differences initiated by changes in the model resolution. The magnitude of the cloud radiative-forcing tends to increase with increasing model resolution, mainly attributable to the increase in the cloud liquid water path. Shortwave radiative forcing is dominant, and more sensitive to model resolution than the longwave counterpart.
Discussion Paper (PDF, 6151 KB) Interactive Discussion (Closed, 2 Comments) Publication in ACP not foreseen
Citation: Guo, H., Liu, Y., Daum, P. H., Zeng, X., Li, X., and Tao, W.-K.: Effects of model resolution on entrainment (inversion heights), cloud-radiation interactions, and cloud radiative forcing, Atmos. Chem. Phys. Discuss., 8, 20399-20425, doi:10.5194/acpd-8-20399-2008, 2008. Bibtex EndNote Reference Manager XML
