Joint Seminar: Humidity–dependence of Climate Sensitivity

In this talk I will be presenting the paper published with L. Kluft and B. Stevens in GRL, entitled 'Dependence of Climate Sensitivity on the Given Distribution of Relative Humidity'. We study how the vertical distribution of relative humidity (RH) affects climate sensitivity, even if it remains unchanged with warming. Using a radiative‐convective equilibrium model, we show that the climate sensitivity depends on the shape of a fixed vertical distribution of humidity, tending to be higher for atmospheres with higher humidity. We interpret these effects in terms of the effective emission height of water vapor. Differences in the vertical distribution of RH are shown to explain a large part of the 10%–30% differences in clear‐sky sensitivity seen in climate and storm‐resolving models. The results imply that convective aggregation reduces climate sensitivity, even when the degree of aggregation does not change with warming. Combining our findings with RH trends in reanalysis data shows a tendency toward Earth becoming more sensitive to forcing over time.

Date

12.05.2021

Time

13:30 h

Place

Virtual Seminar
Hamburg

Speaker

Stella Bourdin

Organizers

Diego Jiménez-de-la-Cuesta Otero

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