Abstract
AbstractThe precipitation response to radiative forcing (RF) can be decomposed into a fast precipitation response (FPR), which depends on the atmospheric component of RF, and a slow response, which depends on surface temperature change. We present the first detailed climate model study of the FPR due to tropospheric and stratospheric ozone changes. The FPR depends strongly on the altitude of ozone change. Increases below about 3 km cause a positive FPR; increases above cause a negative FPR. The FPR due to stratospheric ozone change is, per unit RF, about 3 times larger than that due to tropospheric ozone. As historical ozone trends in the troposphere and stratosphere are opposite in sign, so too are the FPRs. Simple climate model calculations of the time‐dependent total (fast and slow) precipitation change, indicate that ozone's contribution to precipitation change in 2011, compared to 1765, could exceed 50% of that due to CO2 change.
Highlights
Recent research [e.g., Allen and Ingram, 2002; Ming et al, 2010; O’Gorman et al, 2012] has created a framework, based on energetic constraints, for understanding the global precipitation response to climate perturbations
This almost constant proportion contrasts with the absorbing aerosol case of Ming et al [2010] where ΔSH became the dominant term in balancing RFatm when aerosol was located in the boundary layer
The contrasting behavior may be because our ozone perturbations are rather deep or it may be related to the differences in the impact of ozone and aerosol on RFatm
Summary
Recent research [e.g., Allen and Ingram, 2002; Ming et al, 2010; O’Gorman et al, 2012] has created a framework, based on energetic constraints, for understanding the global precipitation response to climate perturbations. A simple model has been developed [e.g., Allan et al, 2014; Ming et al, 2010; Thorpe and Andrews, 2014] that relates the component of top-of-atmosphere radiative forcing (RF) that directly affects the atmosphere (RFatm), surface temperature change (ΔT) and global-mean precipitation change (ΔP). We first use radiation-only calculations to illustrate how RFatm depends on the height of the ozone perturbation These provide a platform for interpreting the response of an atmospheric general circulation model (GCM) which explicitly simulates the FPR. The second set uses more realistic ozone perturbations to quantify the FPR in response to historical ozone changes and to derive representative values for f We use these values in a simple global-mean model of historical precipitation change which includes both the FPR and SPR (equation (1)) to contrast the roles of tropospheric and stratospheric ozone change and compare them with CO2. The increased SW absorption results in a tropospheric energy gain; whether the atmosphere as a whole gains or loses LW energy depends on the altitude of the ozone change
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
