A Shallow Thermocline Bias in the Southern Tropical Pacific in CMIP5/6 Models Linked to Double‐ITCZ Bias

Samuels, Maya; Adam, Ori; Gildor, Hezi

doi:10.1029/2021gl093818

Cited by 5 publications

(6 citation statements)

References 61 publications

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“…The double-ITCZ bias widely exists in climate models (e.g., Li and Xie, 2014;Adam et al, 2018;Tian and Dong, 2020;Samuels et al, 2021) and boreal spring is the season that provides the largest contribution to the annual-mean double-ITCZ bias (e.g., Si et al, 2021). In the Coupled Model Intercomparison Project Phase 5 (CMIP5), CP-type El Niños are under-represented (e.g., Adam et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

“…Increased resolution in CMIP6 is able to reduce the positive precipitation bias over the tropical southern Atlantic Ocean, but it could not reduce the double-ITCZ bias over the Pacific Ocean (Ma et al, 2023). Reducing the double-ITCZ bias over the Pacific Ocean in the climate model remains a challenge (e.g., Fiedler et al, 2020;Tian and Dong, 2020;Samuels et al, 2021). ENSO diversity has increased in recent decades (e.g., Capotondi et al, 2015;Santoso et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

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Climate impacts of 2009/2010 mixed-type El Niño on double ITCZs over the eastern Pacific Ocean

Chen

et al. 2023

Front. Mar. Sci.

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A double intertropical convergence zone (ITCZ) pattern emerges over the eastern Pacific Ocean in March-April. Their inter-annual variabilities may exert major climatic and ecological effects. El Niño-Southern Oscillation (ENSO) can significantly regulate the inter-annual variability of double ITCZs. ENSO diversity has increased in recent years. A mixed-type El Niño occurred in 2009/2010. Our results reveal that the meridional SSTA pattern in mixed-type El Niño is a combination of “SST warming with a maximum at the equator” (i.e., EP-type delta SST) and “north-warm and south-cold” (i.e., CP-type delta SST) patterns. In a mixed-type El Niño, both meridional EP-type and CP-type delta SST played a role and had corresponding climate impacts. Under the coordinated modulation of EP-type and CP-type delta SST in a mixed-type El Niño, the climate effect of EP-type delta SST (increasing equatorial precipitation) is weakened; while the climate effect of CP-type delta SST (enhancing the northern ITCZ and weakening the southern ITCZ) is amplified. The climate effect of mixed-type El Niño finally resembles that of typical CP-type El Niños, intensifying the north-south asymmetry of the eastern Pacific double ITCZs. This study will contribute to a better understanding of the impacts of ENSO diversity on double ITCZs in the eastern Pacific region.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Climate impacts of 2009/2010 mixed-type El Niño on double ITCZs over the eastern Pacific Ocean

Chen

et al. 2023

Front. Mar. Sci.

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“…Dueri et al, 2014;Lehodey et al, 2015a;Bianucci et al, 2016;Gailbraith et al, 2017), we have used projections of physical and biogeochemical forcings derived from earth climate models such as those associated with the World Climate Research Programme's Coupled Model Intercomparison Project (Meehl, 1995;Meehl et al, 2000). However, the CMIP models have known biases when applied at local and regional scales (Li et al, 2019;Mckenna et al, 2020;Tian and Dong, 2020;Samuels et al, 2021;Tang et al, 2021;Zhu et al, 2021) and without corrections these biases can lead to spurious correlations when estimating habitat parameters over the historical period (Lehodey et al, 2013). Although we applied both bias-correction (as described in Bell et al, 2021) and ensemble simulations (Semenov and Stratonovitch, 2010;Tittensor et al, 2018;Eddy, 2019), there remains considerable uncertainty in our understanding of how the dynamics of the Western Pacific warm-pool will be altered due to climate change (Brown et al, 2014) and how dissolved oxygen availability within the Pacific will change (Ganachaud et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Ocean Futures for the World’s Largest Yellowfin Tuna Population Under the Combined Effects of Ocean Warming and Acidification

et al. 2022

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The impacts of climate change are expected to have profound effects on the fisheries of the Pacific Ocean, including its tuna fisheries, the largest globally. This study examined the combined effects of climate change on the yellowfin tuna population using the ecosystem model SEAPODYM. Yellowfin tuna fisheries in the Pacific contribute significantly to the economies and food security of Pacific Island Countries and Territories and Oceania. We use an ensemble of earth climate models to project yellowfin populations under a high greenhouse gas emissions (IPCC RCP8.5) scenario, which includes, the combined effects of a warming ocean, increasing acidification and changing ocean chemistry. Our results suggest that the acidification impact will be smaller in comparison to the ocean warming impact, even in the most extreme ensemble member scenario explored, but will have additional influences on yellowfin tuna population dynamics. An eastward shift in the distribution of yellowfin tuna was observed in the projections in the model ensemble in the absence of explicitly accounting for changes in acidification. The extent of this shift did not substantially differ when the three-acidification induced larval mortality scenarios were included in the ensemble; however, acidification was projected to weaken the magnitude of the increase in abundance in the eastern Pacific. Together with intensive fishing, these potential changes are likely to challenge the global fishing industry as well as the economies and food systems of many small Pacific Island Countries and Territories. The modelling framework applied in this study provides a tool for evaluating such effects and informing policy development.

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“…For each model we use monthly data from the first realization (ensemble members "r1i1p1" and "r1i1p1f1" for CMIP5 and CMIP6, respectively), linearly interpolated to a common 1° × 1° horizontal grid. The CMIP5 and CMIP6 ensemble-mean climatologies analyzed here are nearly indistinguishable and are therefore presented jointly (hereafter CMIP5/6; Adam et al, 2022;Fiedler et al, 2020;Samuels et al, 2021;Tian & Dong, 2020). We focus our analysis on the annual mean, which, for the case of systematic tropical P biases, is dominated by the January-June half year (Adam et al, 2018;Bellucci et al, 2010;Li & Xie, 2014).…”

Section: Datamentioning

confidence: 99%

Increased Uncertainty in Projections of Precipitation and Evaporation Due To Wet‐Get‐Wetter/Dry‐Get‐Drier Biases

Adam,

Shourky Wolff,

Garfinkel

et al. 2023

Geophysical Research Letters

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A key implication of the well known wet‐get‐wetter/dry‐get‐drier (WGW) scaling is that model biases in the representation of precipitation and evaporation in the present climate lead to spurious projected changes under global warming. Here we estimate the extent of such spurious changes in projections by 60 models participating in phases 5 and 6 of the Coupled Model Intercomparison Project. Utilizing known thermodynamic constraints on evaporation, we show that the WGW scaling can be applied to precipitation and evaporation separately (specific WGW scaling), which we use to correct for spurious projected changes in precipitation and evaporation over tropical oceans. The spurious changes in precipitation can be of comparable amplitude to projected changes, but are generally small for evaporation. The spurious changes may increase the uncertainty in projections of tropical precipitation and evaporation by up to 30% and 15% respectively.

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A Shallow Thermocline Bias in the Southern Tropical Pacific in CMIP5/6 Models Linked to Double‐ITCZ Bias

Cited by 5 publications

References 61 publications

Climate impacts of 2009/2010 mixed-type El Niño on double ITCZs over the eastern Pacific Ocean

Climate impacts of 2009/2010 mixed-type El Niño on double ITCZs over the eastern Pacific Ocean

Ocean Futures for the World’s Largest Yellowfin Tuna Population Under the Combined Effects of Ocean Warming and Acidification

Increased Uncertainty in Projections of Precipitation and Evaporation Due To Wet‐Get‐Wetter/Dry‐Get‐Drier Biases

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