Enhanced equatorial warming causes deep-tropical contraction and subtropical monsoon shift

Zhou, Wenyu; Xie, Shang‐Ping; Yang, Da

doi:10.1038/s41558-019-0603-9

Cited by 59 publications

(59 citation statements)

References 36 publications

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“…12f), reducing water availability and affecting its use for hydroelectricity, mining, agribusiness and human consumption (MMA 2015). Under global warming, the subtropical descent is predicted to expand towards the poles, which is referred to as the Hadley expansion (Johanson and Fu 2009;Zhou et al 2019). In turn, this expansion displaces the subtropical anticyclone of the South Pacific towards the south, where greater atmospheric stability is achieved due to the storm repelling effect of the anticyclone (Johanson and Fu 2009).…”

Section: Discussionmentioning

confidence: 99%

Climate change projections of temperature and precipitation in Chile based on statistical downscaling

et al. 2020

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General circulation models (GCMs) allow the analysis of potential changes in the climate system under different emissions scenarios. However, their spatial resolution is too coarse to produce useful climate information for impact/adaptation assessments. This is especially relevant for regions with complex orography and coastlines, such as in Chile. Downscaling techniques attempt to reduce the gap between global and regional/local scales; for instance, statistical downscaling methods establish empirical relationships between large-scale predictors and local predictands. Here, statistical downscaling was employed to generate climate change projections of daily maximum/minimum temperatures and precipitation in more than 400 locations in Chile using the analog method, which identifies the most similar or analog day based on similarities of largescale patterns from a pool of historical records. A cross-validation framework was applied using different sets of potential predictors from the NCEP/NCAR reanalysis following the perfect prognosis approach. The best-performing set was used to downscale six different CMIP5 GCMs (forced by three representative concentration pathways, RCPs). As a result, minimum and maximum temperatures are projected to increase in the entire Chilean territory throughout all seasons. Specifically, the minimum (maximum) temperature is projected to increase by more than 2 °C (6 °C) under the RCP8.5 scenario in the austral winter by the end of the twenty-first century. Precipitation changes exhibit a larger spatial variability. By the end of the twenty-first century, a winter precipitation decrease exceeding 40% is projected under RCP8.5 in the central-southern zone, while an increase of over 60% is projected in the northern Andes.

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Section: Discussionmentioning

confidence: 99%

Climate change projections of temperature and precipitation in Chile based on statistical downscaling

et al. 2020

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“…Because the SST warming is larger in CMIP6 models on average (due to their higher climate sensitivity), the SST-driven component of the circulation response would be expected to be larger in CMIP6 models, resulting in a larger net equatorward contraction of the NH Hadley circulation during JJA than in CMIP5 models. However, as pointed out by Zhou et al (2019), the exact pattern of SST warming is critical for capturing the equatorward contraction of the NH JJA Hadley cell edge seen in the abrupt 4×CO 2 runs. A uniform 4 K SST warming would instead result in a poleward expansion of the NH JJA Hadley circulation (Fig.…”

Section: Dynamical Sensitivity Of Cmip6 Modelsmentioning

confidence: 99%

Hadley cell expansion in CMIP6 models

2020

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Abstract. In response to increasing greenhouse gases, the subtropical edges of Earth's Hadley circulation shift poleward in global climate models. Recent studies have found that reanalysis trends in the Hadley cell edge over the past 30–40 years are within the range of trends simulated by Coupled Model Intercomparison Project Phase 5 (CMIP5) models and have documented seasonal and hemispheric asymmetries in these trends. In this study, we evaluate whether these conclusions hold for the newest generation of models (CMIP6). Overall, we find similar characteristics of Hadley cell expansion in CMIP5 and CMIP6 models. In both CMIP5 and CMIP6 models, the poleward shift of the Hadley cell edge in response to increasing greenhouse gases is 2–3 times larger in the Southern Hemisphere (SH), except during September–November. The trends from CMIP5 and CMIP6 models agree well with reanalyses, although prescribing observed coupled atmosphere–ocean variability allows the models to better capture reanalysis trends in the Northern Hemisphere (NH). We find two notable differences between CMIP5 and CMIP6 models. First, while both CMIP5 and CMIP6 models contract the NH summertime Hadley circulation equatorward (particularly over the Pacific sector), this contraction is larger in CMIP6 models due to their higher average climate sensitivity. Second, in recent decades, the poleward shift of the NH annual-mean Hadley cell edge is slightly larger in CMIP6 models. Increasing greenhouse gases drive similar trends in CMIP5 and CMIP6 models, so the larger recent NH trends in CMIP6 models point to the role of other forcings, such as aerosols.

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“…99,160,190 Thermodynamic intensification of moisture transport increases the intensity and area of monsoon rainfall, but this is offset by a weakening tropical circulation. 191,192 Monsoon systems are sensitive to spatially varying radiative forcing relating to anthropogenic aerosol 168,171,193,194 but also greenhouse gases 183 and changes in SST patterns 195,196 that play a strong role by altering cross-equatorial energy transports and land-ocean temperature contrasts. Aerosols affect the monsoon by altering hemispheric temperature gradients and cross-equatorial energy transports but also drive more local changes through altering land-ocean contrasts and changing moisture flux that depend on whether absorbing or scattering aerosol dominate.…”

Section: Large-scale Responses In Atmospheric Circulation Patternsmentioning

confidence: 99%

Advances in understanding large‐scale responses of the water cycle to climate change

Allan

Barlow

Byrne

et al. 2020

Annals of the New York Academy of Sciences

366

153

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Globally, thermodynamics explains an increase in atmospheric water vapor with warming of around 7%/°C near to the surface. In contrast, global precipitation and evaporation are constrained by the Earth's energy balance to increase at ∼2-3%/°C. However, this rate of increase is suppressed by rapid atmospheric adjustments in response to greenhouse gases and absorbing aerosols that directly alter the atmospheric energy budget. Rapid adjustments to forcings, cooling effects from scattering aerosol, and observational uncertainty can explain why observed global precipitation responses are currently difficult to detect but are expected to emerge and accelerate as warming increases and aerosol forcing diminishes. Precipitation increases with warming are expected to be smaller over land than ocean due to limitations on moisture convergence, exacerbated by feedbacks and affected by rapid adjustments. Thermodynamic increases in atmospheric moisture fluxes amplify wet and dry events, driving an intensification of precipitation extremes. The rate of intensification can deviate from a simple thermodynamic response due to in-storm and larger-scale feedback processes, while changes in large-scale dynamics and catchment characteristics further modulate the frequency of flooding in response to precipitation increases. Changes in atmospheric circulation in response to radiative forcing and evolving surface temperature patterns are capable of dominating water cycle changes in some regions. Moreover, the direct impact of human activities on the water cycle through water abstraction, irrigation, and land use change is already a significant component of regional water cycle change and is expected to further increase in importance as water demand grows with global population.

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Enhanced equatorial warming causes deep-tropical contraction and subtropical monsoon shift

Cited by 59 publications

References 36 publications

Climate change projections of temperature and precipitation in Chile based on statistical downscaling

Climate change projections of temperature and precipitation in Chile based on statistical downscaling

Hadley cell expansion in CMIP6 models

Advances in understanding large‐scale responses of the water cycle to climate change

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