The expanding tropics: a critical assessment of the observational and modeling studies
Citations Over TimeTop 10% of 2013 papers
Abstract
This review provides comprehensive coverage of the tropical expansion literature to date. The primary focus is on the annual‐ and zonal‐mean behavior of the phenomenon. An idealized model that identifies the mean meridional circulation as a hemisphere‐wide structure with significant tropical–extratropical interaction is introduced as background for the understanding of the expansion and the methodologies used for detection. A variety of metrics from different data sources have been used to identify an expansion of the global tropics since 1979 by 1°–3° latitude in each hemisphere, an average trend of approximately 0.5°–1.0° decade −1 . The symmetry of this expansion—whether Northern and Southern hemispheres are expanding at the same rate—is unclear. Limitations of observational datasets, including reanalyses, prevent a more precise determination at this time. General circulation models are able to qualitatively reproduce this expansion, but generally underestimate its magnitude. Multiple factors have been identified as potential drivers of the expansion, including increasing greenhouses gases, stratospheric ozone depletion, and anthropogenic aerosols. No single factor by itself appears to explain the full expansion, perhaps a shortcoming of the models or experiment design. It may be that some combination of these forcings is producing the change, but the relative contribution of each forcing to the expansion is currently unknown. The key issues remaining to be resolved are briefly summarized at the end. WIREs Clim Change 2014, 5:89–112. doi: 10.1002/wcc.251 This article is categorized under: Paleoclimates and Current Trends > Modern Climate Change Climate Models and Modeling > Knowledge Generation with Models
Related Papers
- → Improved Skill of Northern Hemisphere Winter Surface Temperature Predictions Based on Land–Atmosphere Fall Anomalies(2007)97 cited
- → Objective determination of the extratropical transition of tropical cyclones in the Northern Hemisphere(2015)26 cited
- → Climate prediction for the extratropical northern hemisphere for the next 500 years based on periodic natural processes(2016)6 cited
- → A description of low‐frequency atmospheric oscillations over the extratropical Northern Hemisphere using singular spectrum analysis(1992)5 cited
- → Analysing and combining atmospheric general circulation model simulations forced by prescribed SST: northern extratropical response(2009)3 cited