Tuning of a new parameterization of ice supersaturation in LMDZ
| Autor: | Sanogo, S., Boucher, O., Borella, A., Hourdin, F., Bellouin, N., Vignon, E., Musat, I., Coulon-Decorzens, M. |
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| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| DOI: | 10.57757/iugg23-3276 |
| Popis: | Ice supersaturation is a feature of the upper troposphere and is a necessary condition for cirrus cloud formation. Aircraft flying in these ice-supersaturated regions (ISSR) can produce contrails that can persist and grow for several hours, with important radiative effects. These radiative effects have an uncertain magnitude both in observations and in climate models and represent a significant fraction of the non-CO2 effects of aviation’s impact on climate.A parameterization of ISSR has been implemented in the atmospheric component (LMDZ) of the IPSL climate model known as IPSL-CM. Its main shortcoming is an underestimation of ISSR in the northern hemisphere, limiting its use to study the formation mechanisms of contrails and their radiative effects. These deficiencies come partly from an insufficient calibration.In this study, we have applied statistical methods based on Gaussian process and history matching to tune 16 free parameters of the ISSR, large-scale condensation and convection parameterizations in LMDZ. It allowed us to efficiently explore the space of these 16 parameters to identify LMDZ configurations satisfactorily matching global (top-of-atmosphere radiative budget) and regional (ISSR frequency of occurrence, cloud fraction and the ice water path) constraints, thus presenting smaller biases on the clouds and contrails radiative effects.These tuned configurations will be used in our future work to study the mechanisms of contrail and induced cirrus formation and to investigate their radiative effects while better characterizing the parametric uncertainties attached to these effects. Our tuning method could be applied to other climate models. The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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