Maritime Continent seasonal climate biases in AMIP experiments of the CMIP5 multimodel ensemble

Toh, Ying Ying; Turner, Andrew G.; Johnson, Stephanie J.; Holloway, Christopher E.

doi:10.1007/s00382-017-3641-x

Cited by 24 publications

(23 citation statements)

References 75 publications

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“…Di Nezio et al () used the CESM model, whose convection scheme relies on Richter and Rasch () for the deep convection and Park and Bretherton () for the shallow convection. These two schemes have been shown to produce lower precipitation rates in the convective area of the Maritime Continent when compared to Emanuel's (Toh et al, ). In the light of our sensitivity tests, we suggest that discrepancies among previous studies and our results regarding the shelf influence on rainfall patterns likely arise from differing parameterizations as well.…”

Section: Discussionmentioning

confidence: 99%

Impact of the Sunda Shelf on the Climate of the Maritime Continent

2019

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Drastic paleogeography changes in the Indonesian archipelago over the Plio‐Pleistocene, either in response to sea level oscillations or vertical land motion, enabled the periodic emergence of the Sunda shelf. When emerged, this wide continental platform in the heart of the Maritime Continent may have modified regional and global climate systems. We investigate the effect of the exposure of the Sunda shelf on climate dynamics using a set of numerical simulations with (i) atmosphere‐land surface and (ii) fully coupled general circulation models. We first explore the impact of convection schemes on the rainfall regime simulated over the Maritime Continent and show how they could explain the discrepancies among previous studies. We further depict a robust and common mechanism that prevails. We show that diurnal heating of the surface of the continental platform enhances low‐level convergence and local convection, and fosters local precipitations. This effect, to a second order, is modulated by the radiative effect and increased turbulent heat flux driven by vegetated surface properties such as albedo or roughness. Increasing precipitations over the exposed platform also impacts freshwater export into seawater, making salinity of the Indian Ocean and Indonesian Throughflow highly dependent on the routing scheme over the exposed shelf.

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Section: Discussionmentioning

confidence: 99%

Impact of the Sunda Shelf on the Climate of the Maritime Continent

2019

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“…Figure shows that models overpredict precipitation over the western Indian Ocean as well as western Pacific with well‐known double Intertropical Convergence Zone biases (Lin, ). Over the southern MC, weak negative biases are shown in nearly all the models, which are linked to the biases of the local Hadley circulation (Toh et al, ). In summary, models tend to predict excess surface precipitation (except in the southern MC) and have a lower‐tropospheric dry bias over the Indo‐Pacific region.…”

Section: Mjo Processes and Mean Statementioning

confidence: 99%

MJO Propagation Processes and Mean Biases in the SubX and S2S Reforecasts

Kim

Janiga²,

Pegion

2019

JGR Atmospheres

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The Madden‐Julian oscillation (MJO) is the leading source of global subseasonal predictability; however, many dynamical forecasting systems struggle to predict MJO propagation through the Maritime Continent. Better understanding the biases in simulated physical processes associated with MJO propagation is the key to improve MJO prediction. In this study, MJO prediction skill, propagation processes, and mean state biases are evaluated in reforecasts from models participating in the Subseasonal Experiment (SubX) and Subseasonal to Seasonal (S2S) prediction projects. SubX and S2S reforecasts show MJO prediction skill out to 4.5 weeks based on the Real‐time Multivariate MJO index consistent with previous studies. However, a closer examination of these models' representation of MJO propagation through the Maritime Continent reveals that they fail to predict the MJO convection, associated circulations, and moisture advection processes beyond 10 days with most of models underestimating MJO amplitude. The biases in the MJO propagation can be partly associated with the following mean biases across the Indo‐Pacific: a drier low troposphere, excess surface precipitation, more frequent occurrence of light precipitation rates, and a transition to stronger precipitation rates at lower humidity than in observations. This indicates that deep convection occurs too frequently in models and is not sufficiently inhibited when tropospheric moisture is low, which is likely due to the representation of entrainment.

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“…This is also reflected in the 850-hPa humidity in WRF and ERA-I (Figures 4 and S5). Despite these processes being related to representation of land and sea areas, the AMIP runs at higher resolution do not appear to have additional skill relative to the coarser models-the lack of sensitivity to model resolution was previously reported with respect to mean rainfall biases in the region (Toh et al, 2017). Thus, the accurate simulation of Maritime Continent rainfall goes well beyond the area averages considered here.…”

Section: Discussionmentioning

confidence: 62%

“…The atmosphere-only (AMIP) model simulations also show large spread and there are consistent biases among some models including underestimates in ACCESS1-0 and MPI-ESM-MR, both of which have negative rainfall biases in the western MC (Toh et al, 2017), and overestimates in MRI-CGCM3. The 11-year WRF simulation-series (Vincent & Lane, 2017a) is more similar to GPCP especially in the first five and last three summers.…”

Section: Resultsmentioning

confidence: 80%

Using Global and Regional Model Simulations to Understand Maritime Continent Wet‐Season Rainfall Variability

King

Vincent

2018

Geophysical Research Letters

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The Maritime Continent is a densely populated area of complex topography located between the Pacific and Indian Oceans. It is an area where model skill is particularly important but also difficult to obtain. In this study we examine interannual austral summer rainfall variability in the region and the teleconnection to the El Niño–Southern Oscillation (ENSO) in observation‐based data, reanalyses, and global and regional atmosphere‐only model simulations. We show that model ability to capture interannual rainfall variability is strongly related to model skill in reproducing the ENSO teleconnection to the region, despite strong spatial variability in the ENSO‐rainfall response in coastal areas. Model ability in capturing the spatial pattern of both the midtropospheric moisture and circulation response to ENSO is a strong predictor for model performance in capturing the ENSO‐Maritime Continent rainfall teleconnection. High‐resolution regional simulations and better performing models have opposing ENSO‐rainfall teleconnections between land and sea areas.

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Maritime Continent seasonal climate biases in AMIP experiments of the CMIP5 multimodel ensemble

Cited by 24 publications

References 75 publications

Impact of the Sunda Shelf on the Climate of the Maritime Continent

Impact of the Sunda Shelf on the Climate of the Maritime Continent

MJO Propagation Processes and Mean Biases in the SubX and S2S Reforecasts

Using Global and Regional Model Simulations to Understand Maritime Continent Wet‐Season Rainfall Variability

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