Patterns of the seasonal response of tropical rainfall to global warming
TL;DR: In this paper, an analysis of climate model simulations shows that warm regions are projected to become wetter in annual mean, whereas seasonally high rainfall anomalies are expected in regions that are currently wet.
Abstract: The response of tropical precipitation to global warming varies spatially and the factors controlling the spatial patterns of precipitation changes are unclear. An analysis of climate model simulations shows that warm regions are projected to become wetter in annual mean, whereas seasonally high rainfall anomalies are expected in regions that are currently wet.
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Book Chapter•
01 Jan 2013
TL;DR: The authors assesses long-term projections of climate change for the end of the 21st century and beyond, where the forced signal depends on the scenario and is typically larger than the internal variability of the climate system.
Abstract: This chapter assesses long-term projections of climate change for the end of the 21st century and beyond, where the forced signal depends on the scenario and is typically larger than the internal variability of the climate system. Changes are expressed with respect to a baseline period of 1986-2005, unless otherwise stated.
2,253 citations
01 Dec 2010
TL;DR: In this paper, spatial variations in sea surface temperature (SST) and rainfall changes over the tropics are investigated based on ensemble simulations for the first half of the twenty-first century under the greenhouse gas emission scenario A1B with coupled ocean-atmosphere general circulation models of the Geophysical Fluid Dynamics Laboratory (GFDL) and National Center for Atmospheric Research (NCAR).
Abstract: Spatial variations in sea surface temperature (SST) and rainfall changes over the tropics are investigated based on ensemble simulations for the first half of the twenty-first century under the greenhouse gas (GHG) emission scenario A1B with coupled ocean–atmosphere general circulation models of the Geophysical Fluid Dynamics Laboratory (GFDL) and National Center for Atmospheric Research (NCAR). Despite a GHG increase that is nearly uniform in space, pronounced patterns emerge in both SST and precipitation. Regional differences in SST warming can be as large as the tropical-mean warming. Specifically, the tropical Pacific warming features a conspicuous maximum along the equator and a minimum in the southeast subtropics. The former is associated with westerly wind anomalies whereas the latter is linked to intensified southeast trade winds, suggestive of wind–evaporation–SST feedback. There is a tendency for a greater warming in the northern subtropics than in the southern subtropics in accordance ...
782 citations
TL;DR: This article investigated the origins of and feedback for tropical biases in the historical climate simulations of 18 coupled general circulation models (CGCMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5), together with the available Atmospheric Model International Journal of Meteorology (AMIP) simulations and concluded that the most prominent errors of the current generation of CGCMs stand out as the excessive equatorial Pacific cold tongue and double intertropical convergence zone (ITCZ).
Abstract: Errors of coupled general circulation models (CGCMs) limit their utility for climate prediction and projection. Origins of and feedback for tropical biases are investigated in the historical climate simulations of 18 CGCMs from phase 5 of the Coupled Model Intercomparison Project (CMIP5), together with the available Atmospheric Model Intercomparison Project (AMIP) simulations. Based on an intermodel empirical orthogonal function (EOF) analysis of tropical Pacific precipitation, the excessive equatorial Pacific cold tongue and double intertropical convergence zone (ITCZ) stand out as the most prominent errors of the current generation of CGCMs. The comparison of CMIP–AMIP pairs enables us to identify whether a given type of errors originates from atmospheric models. The equatorial Pacific cold tongue bias is associated with deficient precipitation and surface easterly wind biases in the western half of the basin in CGCMs, but these errors are absent in atmosphere-only models, indicating that the er...
440 citations
Cites background or result from "Patterns of the seasonal response o..."
...Figure 6 is consistent with a previous study (Hwang and Frierson 2013)....
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...Most of the state-of-the-art CGCMs suffer from the so-called double ITCZ problem (Lin 2007; Hirota et al. 2011; Hwang and Frierson 2013)....
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...The recent work of Hwang and Frierson (2013) argues that cloud biases outside the tropics contribute to the double ITCZ problem, consistent with the theoretical prediction that the tropical precipitation shifts toward the hemisphere receiving extra heat from ocean or sun (Kang et al. 2008, 2009)....
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...Thus, exploring the interhemispheric asymmetry biases of atmospheric energy terms at the surface and TOA helps understand the origins of the anomalous cross-equatorial energy and moisture transports as well as the double ITCZ problem in CGCMs (Hwang and Frierson 2013)....
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...As illustrated above, while the excessive heating in the SH midlatitudes is spread into the SH tropics by baroclinic eddies (Hwang and Frierson 2013), it forces anomalous southward cross-equatorial surface winds....
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University of California, San Diego1, National Center for Atmospheric Research2, Geophysical Fluid Dynamics Laboratory3, University of Exeter4, University of California, Los Angeles5, University of Reading6, University of Hawaii at Manoa7, Princeton University8, Centre national de la recherche scientifique9, Columbia University10, University of Tokyo11
TL;DR: In this paper, the authors consider recent advances in understanding of regional climate change, critically discuss outstanding issues, and recommend targets for future research, and conclude that the current priority is to understand and reduce uncertainties on scales greater than 100 km to aid assessments at finer scales.
Abstract: This Review considers recent advances in our understanding of regional climate change, critically discusses outstanding issues, and recommends targets for future research. Regional information on climate change is urgently needed but often deemed unreliable. To achieve credible regional climate projections, it is essential to understand underlying physical processes, reduce model biases and evaluate their impact on projections, and adequately account for internal variability. In the tropics, where atmospheric internal variability is small compared with the forced change, advancing our understanding of the coupling between long-term changes in upper-ocean temperature and the atmospheric circulation will help most to narrow the uncertainty. In the extratropics, relatively large internal variability introduces substantial uncertainty, while exacerbating risks associated with extreme events. Large ensemble simulations are essential to estimate the probabilistic distribution of climate change on regional scales. Regional models inherit atmospheric circulation uncertainty from global models and do not automatically solve the problem of regional climate change. We conclude that the current priority is to understand and reduce uncertainties on scales greater than 100 km to aid assessments at finer scales.
272 citations
TL;DR: In this paper, the authors present the Joint Program on the Science & Policy of Global Change (JSPG) and the Massachusetts Institute of Technology (MIT) for the task of climate change.
Abstract: Massachusetts Institute of Technology. Joint Program on the Science & Policy of Global Change
253 citations
References
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01 Jan 2007
TL;DR: The first volume of the IPCC's Fourth Assessment Report as mentioned in this paper was published in 2007 and covers several topics including the extensive range of observations now available for the atmosphere and surface, changes in sea level, assesses the paleoclimatic perspective, climate change causes both natural and anthropogenic, and climate models for projections of global climate.
Abstract: This report is the first volume of the IPCC's Fourth Assessment Report. It covers several topics including the extensive range of observations now available for the atmosphere and surface, changes in sea level, assesses the paleoclimatic perspective, climate change causes both natural and anthropogenic, and climate models for projections of global climate.
32,826 citations
TL;DR: The fifth phase of the Coupled Model Intercomparison Project (CMIP5) will produce a state-of-the- art multimodel dataset designed to advance the authors' knowledge of climate variability and climate change.
Abstract: The fifth phase of the Coupled Model Intercomparison Project (CMIP5) will produce a state-of-the- art multimodel dataset designed to advance our knowledge of climate variability and climate change. Researchers worldwide are analyzing the model output and will produce results likely to underlie the forthcoming Fifth Assessment Report by the Intergovernmental Panel on Climate Change. Unprecedented in scale and attracting interest from all major climate modeling groups, CMIP5 includes “long term” simulations of twentieth-century climate and projections for the twenty-first century and beyond. Conventional atmosphere–ocean global climate models and Earth system models of intermediate complexity are for the first time being joined by more recently developed Earth system models under an experiment design that allows both types of models to be compared to observations on an equal footing. Besides the longterm experiments, CMIP5 calls for an entirely new suite of “near term” simulations focusing on recent decades...
12,384 citations
TL;DR: In this paper, the authors examined some aspects of the hydrological cycle that are robust across the models, including the decrease in convective mass fluxes, the increase in horizontal moisture transport, the associated enhancement of the pattern of evaporation minus precipitation and its temporal variance, and decrease in the horizontal sensible heat transport in the extratropics.
Abstract: Using the climate change experiments generated for the Fourth Assessment of the Intergovernmental Panel on Climate Change, this study examines some aspects of the changes in the hydrological cycle that are robust across the models. These responses include the decrease in convective mass fluxes, the increase in horizontal moisture transport, the associated enhancement of the pattern of evaporation minus precipitation and its temporal variance, and the decrease in the horizontal sensible heat transport in the extratropics. A surprising finding is that a robust decrease in extratropical sensible heat transport is found only in the equilibrium climate response, as estimated in slab ocean responses to the doubling of CO2, and not in transient climate change scenarios. All of these robust responses are consequences of the increase in lower-tropospheric water vapor.
3,811 citations
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2,376 citations
TL;DR: The authors reviewed the connection between ocean basins via the "atmospheric bridge" through an examination of previous work augmented by analyses of 50 years of data from the National Centers for Environmental Prediction- National Center for Atmospheric Research (NCEP-NCAR) reanalysis project and coupled atmospheric general circulation (AGCM)-mixed layer ocean model experiments.
Abstract: During El Nino-Southern Oscillation (ENSO) events, the atmospheric response to sea surface temperature (SST) anomalies in the equatorial Pacific influences ocean conditions over the remainder of the globe. This connection between ocean basins via the ''atmospheric bridge'' is reviewed through an examination of previous work augmented by analyses of 50 years of data from the National Centers for Environmental Prediction- National Center for Atmospheric Research (NCEP-NCAR) reanalysis project and coupled atmospheric general circulation (AGCM)-mixed layer ocean model experiments. Observational and modeling studies have now established a clear link between SST anomalies in the equatorial Pacific with those in the North Pacific, north tropical Atlantic, and Indian Oceans in boreal winter and spring. ENSO-related SST anomalies also appear to be robust in the western North Pacific during summer and in the Indian Ocean during fall. While surface heat fluxes are the key component of the atmospheric bridge driving SST anomalies, Ekman transport also creates SST anomalies in the central North Pacific although the full extent of its impact requires further study. The atmospheric bridge not only influences SSTs on interannual timescales but also affects mixed layer depth (MLD), salinity, the seasonal evolution of upper-ocean temperatures, and North Pacific SST variability at lower fre- quencies. The model results indicate that a significant fraction of the dominant pattern of low-frequency (.10 yr) SST variability in the North Pacific is associated with tropical forcing. AGCM experiments suggest that the oceanic feedback on the extratropical response to ENSO is complex, but of modest amplitude. Atmosphere- ocean coupling outside of the tropical Pacific slightly modifies the atmospheric circulation anomalies in the Pacific-North America (PNA) region but these modifications appear to depend on the seasonal cycle and air- sea interactions both within and beyond the North Pacific Ocean.
1,668 citations