Atmosphere‐ocean coupled processes in the Madden‐Julian oscillation

DeMott, Charlotte A.; Klingaman, Nicholas P.; Woolnough, Steven J.

doi:10.1002/2014rg000478

Cited by 215 publications

(216 citation statements)

References 407 publications

(760 reference statements)

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“…This is an important question, given that air-sea feedbacks have been shown to affect the fidelity of model representations of key phenomena that control weather and climate extremes (e.g. the Madden-Julian oscillation; DeMott et al, 2015). These Tier 2 experiments use atmospheric GCMs coupled to either one-dimensional mixed-layer oceans (i.e.…”

Section: Tier 2 Experimentsmentioning

confidence: 99%

Half a degree additional warming, prognosis and projected impacts (HAPPI): background and experimental design

et al. 2017

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Abstract. The Intergovernmental Panel on Climate Change (IPCC) has accepted the invitation from the UNFCCC to provide a special report on the impacts of global warming of 1.5 • C above pre-industrial levels and on related global greenhouse-gas emission pathways. Many current experiments in, for example, the Coupled Model Inter-comparison Project (CMIP), are not specifically designed for informing this report. Here, we document the design of the half a degree additional warming, projections, prognosis and impacts (HAPPI) experiment. HAPPI provides a framework for the generation of climate data describing how the climate, and in particular extreme weather, might differ from the present day in worlds that are 1.5 and 2.0 • C warmer than pre-industrial conditions. Output from participating climate models includes variables frequently used by a range of impact models. The key challenge is to separate the impact of an additional approximately half degree of warming from uncertainty in climate model responses and internal climatePublished by Copernicus Publications on behalf of the European Geosciences Union. Large ensembles of simulations (> 50 members) of atmosphere-only models for three time slices are proposed, each a decade in length: the first being the most recent observed 10-year period (2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015), the second two being estimates of a similar decade but under 1.5 and 2 • C conditions a century in the future. We use the representative concentration pathway 2.6 (RCP2.6) to provide the model boundary conditions for the 1.5 • C scenario, and a weighted combination of RCP2.6 and RCP4.5 for the 2 • C scenario.

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Section: Tier 2 Experimentsmentioning

confidence: 99%

Half a degree additional warming, prognosis and projected impacts (HAPPI): background and experimental design

et al. 2017

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“…DeMott et al 2015), observational work is needed to explore the interactions between organized tropical convective systems and SST or sea surface salinity across scales. Specifically, this analysis could look at processes important for aggregation in idealized models.…”

Section: Ocean Interaction and Feedbackmentioning

confidence: 99%

Observing Convective Aggregation

et al. 2017

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Convective self-aggregation, the spontaneous organization of initially scattered convection into isolated convective clusters despite spatially homogeneous boundary conditions and forcing, was first recognized and studied in idealized numerical simulations. While there is a rich history of observational work on convective clustering and organization, there have been only a few studies that have analyzed observations to look specifically for processes related to self-aggregation in models. Here we review observational work in both of these categories and motivate the need for more of this work. We acknowledge that self-aggregation may appear to be far-removed from observed convective organization in terms of time scales, initial conditions, initiation processes, and mean state extremes, but we argue that these differences vary greatly across the diverse range of 123Surv Geophys (2017) 38:1199-1236 https://doi.org/10.1007/s10712-017-9419-1 model simulations in the literature and that these comparisons are already offering important insights into real tropical phenomena. Some preliminary new findings are presented, including results showing that a self-aggregation simulation with square geometry has too broad distribution of humidity and is too dry in the driest regions when compared with radiosonde records from Nauru, while an elongated channel simulation has realistic representations of atmospheric humidity and its variability. We discuss recent work increasing our understanding of how organized convection and climate change may interact, and how model discrepancies related to this question are prompting interest in observational comparisons. We also propose possible future directions for observational work related to convective aggregation, including novel satellite approaches and a groundbased observational network.

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“…The formation mechanisms and seasonal variations of the BLs differ from region to region (Sato et al 2004(Sato et al , 2006, and they are deeply involved in the Indian Ocean Dipole (IOD; Saji et al 1999) (Masson et al 2004;Qiu et al 2012) and ENSO (Ando and McPhaden 1997;Maes et al 2002Maes et al , 2005Maes et al 2006). Previous studies have noted that the BL shows various responses to atmospheric forcing associated with westerly wind bursts and the continuous precipitation of the Madden-Julian oscillation (MJO; Madden and Julian 1971) (Cronin and McPhaden 2002;DeMott et al 2015;Drushka et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Drastic thickening of the barrier layer off the western coast of Sumatra due to the Madden-Julian oscillation passage during the Pre-Years of the Maritime Continent campaign

Moteki

Katsumata

Yoneyama

et al. 2018

Prog Earth Planet Sci

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The drastic thickening of the barrier layer in the marginal sea off the western coast of Sumatra during the passage of the Madden-Julian oscillation (MJO) observed during December 2015 is investigated. Before the MJO arrival, the halocline above a depth of 20 m was very strong, and the barrier layer thickness was 5-10 m based on R/V Mirai observations. During the MJO forcing of 13-16 December, the isothermal layer drastically deepened from 20 to 100 m. Meanwhile, the mixed layer deepening lagged behind the isothermal layer deepening by 1 day, and the barrier layer underwent dramatic thickening to 60 m within 24 h. An evaluation of the vertical salinity gradient tendency showed that the dramatic thickening of the barrier layer was due to the vertical oceanic mixing by the atmospheric MJO forcing and the vertical stretching by the oceanic downwelling coastal Kelvin wave intruding from the open ocean. In addition, an evaluation of the vertical temperature gradient tendency showed that the temperature inversion in the barrier layer formed by losing heat to the atmosphere due to the MJO forcing and downward advection of the temperature gradient due to the downwelling Kelvin wave resulting in the dramatic isothermal layer deepening. One of the important factors in the drastic barrier layer thickening was the atmospheric external forcing and the oceanic internal wave being in phase. The downwelling oceanic Kelvin wave continuously lowered the thermocline from the middle of November to the end of December, and the salinity stratification in the vicinity of the thermocline was continuously mitigated by the vertical stretching. Under such conditions, the MJO forcing caused vertical mixing of the freshwater with strong salinity stratification and temperature stratification near the surface. The combination of the two distinct processes caused the drastic thickening of the barrier layer, and the barrier layer thickness reached a maximum of 85 m 5 days after the MJO arrival.

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Atmosphere‐ocean coupled processes in the Madden‐Julian oscillation

Cited by 215 publications

References 407 publications

Half a degree additional warming, prognosis and projected impacts (HAPPI): background and experimental design

Half a degree additional warming, prognosis and projected impacts (HAPPI): background and experimental design

Observing Convective Aggregation

Drastic thickening of the barrier layer off the western coast of Sumatra due to the Madden-Julian oscillation passage during the Pre-Years of the Maritime Continent campaign

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