Characterizing the Hadley Circulation Response through Regional Climate Feedbacks
نویسندگان
چکیده
The robust weakening of the tropical atmospheric circulation in projections of anthropogenic warming is associated with substantial changes in regional and global climate. The present study focuses on understanding the response of the annual-mean Hadley circulation from a perspective of interactions between climate feedbacks and tropical circulation. Simulations from an ensemble of coupled ocean–atmosphere models are used to quantify changes in Hadley cell strength in terms of feedbacks, radiative forcing, ocean heat uptake, atmospheric eddies, and gross moist stability. Climate feedbacks are calculated for the model integrations from phase 5 of CMIP (CMIP5) using radiative kernels. Tropical mean circulation is found to be reduced by up to 2.6%K for an abrupt quadrupling of carbon dioxide concentration. The weakening is characterized by an increase in gross moist stability, by an increase in eddy heat flux, and by positive extratropical feedbacks, such as those associated with lapse rate and sea ice response. Understanding the impact of radiative feedbacks on the large-scale circulation provides a framework for constraining uncertainty in the dynamic climate response, including the hydrological cycle.
منابع مشابه
Modeled sensitivity of upper thermocline properties to tropical cyclone winds and possible feedbacks on the Hadley circulation
sensitivity of upper thermocline properties to tropical cyclone winds and possible feedbacks on the Hadley circulation" (2010). [1] The sensitivity of upper thermocline properties, and global climate, to tropical cyclone (TC) winds is examined using global ocean and atmosphere general circulation models. We combine seven years of global, satellite‐based TC wind records with a standard surface w...
متن کاملCoupled High-Latitude Climate Feedbacks and Their Impact on Atmospheric Heat Transport
The response of atmospheric heat transport to anthropogenic warming is determined by the anomalous meridional energy gradient. Feedback analysis offers a characterization of that gradient and hence reveals how uncertainty in physical processes may translate into uncertainty in the circulation response. However, individual feedbacks do not act in isolation. Anomalies associated with one feedback...
متن کاملThe influence of regional feedbacks on circulation sensitivity
Weakening of the tropical overturning circulation in a warmer world is a robust feature in climate models. Here an idealized representation of ocean heat flux drives a Walker cell in an aquaplanet simulation. A goal of the study is to assess the influence of the Walker circulation on the magnitude and structure of climate feedbacks, as well as to global sensitivity. We compare two CO2 perturbat...
متن کاملEffects of large-scale Amazon forest degradation on climate and air quality through fluxes of carbon dioxide, water, energy, mineral dust and isoprene
Loss of large areas of Amazonian forest, through either direct human impact or climate change, could exert a number of influences on the regional and global climates. In the Met Office Hadley Centre coupled climate-carbon cycle model, a severe drying of this region initiates forest loss that exerts a number of feedbacks on global and regional climates, which magnify the drying and the forest de...
متن کاملOn the link between Hadley circulation changes and radiative feedback processes
[1] Previous studies have demonstrated that meridional displacements of precipitation in the tropics and changes in the Hadley circulation accompany interhemispherically asymmetric surface temperature changes. In this study, an attempt is made to provide a different perspective by linking this dynamical response to radiative feedback processes. An idealized experiment is conducted in which sola...
متن کامل