Coupled Warm Pool Dynamics in the Indo-Pacific

CSHOR

Ming Feng, Susan Wijffels, Andy Hsu, Anna Maggiorano, Gang Yang, Chris Chapman

July 2020

Warm pool project | Ming Feng

Background: warm pool and its influences on global climate

2 |

ENSO, IOD, MJO

Asian monsoon

Australian monsoon

• To advance our knowledge of high-frequency air-sea coupling in the eastern Indian Ocean warm pool

• To better understand roles of the Indonesian Throughflow and associated ocean circulation in influencing the heat and freshwater balance of the Indian Ocean

• To work with international community on the design and implementation of the Indian Ocean observing system

Warm pool project | Ming Feng

Goals of the project

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1. Successful meteorology and ocean profiling buoy operation off northwest Australia – BAMS publication

2. R/V Investigator voyage delivered valuable air-sea exchange datasets

3. Hemispheric asymmetry mode of global ocean heat content variability identified to better attribute greenhouse gas induced warming – paper in Nature Communications

4. (UNSW) Anna Maggiorano has finalised the 2013 northwest shelf marine heatwave manuscript; new progress from Gang Yang – PhD student working on Darwin Harbour

WP Project | Ming Feng

Highlights during 2019-2020

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Bailong Buoy deployment and retrieval

November 2018 January 2020

Ian Darby Ryan Crossing

YongliangDuan

CSHOR Field Measurement(2018-2019)

2 m wind

Feng, Duan, Wijffels, Hsu … Yu 2020 BAMS

Warm pool project | Ming Feng

R/V Investigator voyage Oct-Nov 2019

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CSHOR participants:Susan WijffelsJe-Yuan HsuAnna Maggiorano

Triaxus

Wire walker

Robust hemispheric asymmetry in global OHC changeObserved ocean heat content (1018 J/m) during 2005-2015 for (a) Northern Hemisphere and (b) Southern Hemisphere

0-700 m 700-2000 mSouthern

Hemisphere 5.12 ± 0.45 2.66 ± 0.19Northern

Hemisphere -0.74 ± 0.29 1.35 ± 0.14

Ocean Heat Content trend (1022

J/decade)

Northern Hemisphere

Southern Hemisphere

Saurabh Rathore

Distribution of the decadal trend of the ocean heat content (OHC) (1022 J/decade) for the depth of 0-2000 m

Rathore, Bindoff, Phillips, Feng 2020 Nature Communications

Transport (Sv) ITF AC (32S) Windstress curl (32S)

Historical run -15.3 -50.2 -35.0

RCP8.5 run -10.7 -43.5 -32.8

Change 4.6 6.7 2.2

Weakening of Indian Ocean southward heat transport: contribution of Agulhas Current

The weakened ITF heat transport is overcompensated by the Indian Ocean meridional heat transport reduction

Ma, Feng, Lan, Hu, 2020 GRL

Publications• Ming Feng; Yongliang Duan; Susan Wijffels; Je-Yuan Hsu; Chao Li; Huiwu Wang; Yang Yang; Hong Shen;

Jianjun Liu; Chunlin Ning; Weidong Yu (2020), Tracking air-sea exchange and upper ocean variability in the Indonesian-Australian Basin during the onset of the 2018-19 Australian summer monsoon, Bulletin of the American Meteorology Society, in press.

• Rathore, S., N. L. Bindoff, H. E. Phillips, M. Feng (2020), Recent hemispheric asymmetry in global ocean warming induced by climate change and internal variability. Nature Communications, 11, 2383.

• Ma, J., Feng, M., Lan, J. and Hu, D., 2020. Projected future changes of meridional heat transport and heat balance of the Indian Ocean. Geophysical Research Letters. 47.

• Yuhong ZHANG; Yan Du; W.N.D.S JAYARATHNA; Qiwei SUN; Ying ZHANG; Fengchao YAO; Ming FENG, (2020). A prolonged high-salinity event in the Northern Arabian Sea during 2014-2017, Journal of Physical Oceanography, 50, 849-865.

• Hu, S. Y. Zhang, M. Feng, Y. Du, J. Sprintall, F. Wang, D. Hu, Q. Xie, F. Chai (2019). Interanual to decadal variability of upper ocean salinity in the southern Indian Ocean and the role of the Indonesian Throughflow. Journal of Climate, 32(19), 6403-6421.

• Cyriac, A., McPhaden, M. J., Phillips, H. E., Bindoff, N. L., & Feng, M. (2019). Seasonal evolution of the surface layer heat balance in the eastern subtropical Indian Ocean. Journal of Geophysical Research: Oceans, 124, 6459–6477. https://doi.org/10.1029/2018JC014559.

• Hsu, J.Y. Hendon H., Feng M., Zhou, X. (2019) Magnitude and Phase of Diurnal SST Variations in the ACCESS-S1 model during the Suppressed Phase of the MJOs. Journal of Geophysical Research: Oceans, 124(12), 9553-9571.

Salinity variations in the Indo-Pacific warm pool

2011–2017 minus 2004–2010 (contour: temperature)Hu et al. 2019 J. Climate

Zhang et al. 2020 JPO

Ying Zhang

Mixed layer processes

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Hsu et al. 2019 JGRCyriac et al. 2019 JGR

1m resolution model is necessary to capture the strong diurnal warmingCollaboration with U. Tas and NOAA to better

understand air-sea heat flux in the SE IO

RAMA

Confirmed with BoM ACCESS coupled model

Modelling the 2013 marine heatwave

Maggiorano et al. submitted

Wave effects on sediment dynamics in Darwin Harbour during monsoon season

Yang and Wang 2020 ECSS, acceptedGang Wang

• Beal, L. M., Vialard, J., Roxy, M. K. and lead authors (including Feng, M, Sloyan B) 2019: Executive Summary. IndOOS-2: A roadmap to sustained observations of the Indian Ocean for 2020-2030. CLIVAR-4/2019, GOOS-237, 8 pp. https://doi.org/10.36071/clivar.rp.4-1.2019.

• Beal, L. M., Vialard, J., Roxy, M. K. and lead authors (including Feng, M., Sloyan, B) 2019: Full Report. IndOOS-2: A roadmap to sustained observations of the Indian Ocean for 2020-2030. CLIVAR-4/2019, GOOS-237, 206 pp. https://doi.org/10.36071/clivar.rp.4.2019.

• Beal, L.M., Vialard, J., Roxy, M.K., Li, J., Andres, M., Annamalai, H., Feng, M., Han, W., Hood, R., Lee, T., Lengaigne, M., Lumpkin, R., Masumoto, Y., McPhaden, M.J., Ravichandran, M., Shinoda, T., Sloyan, B.M., Strutton, P.G., Subramanian, A.C., Tozuka, T., Ummenhofer, C.C., Unnikrishnan, A.S., Wiggert, J., Yu, L., Cheng, L., Desbruyères, D.G., Parvathi, V. (2020). A roadmap to IndOOS-2: Better observations of the rapidly warming Indian Ocean. Bulletin of the American Meteorological Society. DOI: 10.1175/BAMS-D-19-0209.1.

Warm pool project | Ming Feng

Publications

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Beal et al. 2020

• Continue to analyse 2018-19 profiling float data and Bailong buoy time series, and improve understanding of the large-scale climate drivers of coupled ocean-atmosphere dynamics in the Indonesian-Australian Basin

• Quality control of the R/V Investigator cruise data for the Years of Maritime Continent program (collaboration with WHOI)

• Contribute to International Indian Ocean Expedition-2 (IIOE-2) research and review publications

• Improved assessment on the influences of the Indo-Pacific warm pool on Australian rainfall variability and predictability (U. Tas PhD student)

• Finalise publication on the 2013 northwest shelf marine heatwave event

Warm pool project | Ming Feng

Year 4 plan

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Bailong buoy observations over the whole year

Monsoon Onset Tropical Cyclones

Severe TC Riley

Severe TC Veronica

Severe TC Wallace

Yongliang Duan

Weidong Yu

• Develop composites of MJO events from oceanography and meteorology data and model output (iHESP or ACCESS)

• Identify links between the "deep" oceanography and the onset/breakdown/detouring of the MJO• Is MJO onset favored by deep thermocline anomalies?• What’s the influence of the Pacific coming through the ITF?

Warm pool project | Ming Feng

Coupled process in the Indonesian-Australian Basin

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Chris Chapman

Rapid foundation SST Warming Captured by ALAMO Floats during the Suppressed Phase of the MJO

Je-Yuan Hsu, National Taiwan University

Ming Feng and Susan Wijffels Centre for Southern Hemisphere Oceans Research (CSHOR)

Temperature and Salinity on ALAMO Floats

• Vertical resolution ≤ 1 m in the upper 50 m• Temperature measurements at ~ 0.1-0.2 m-depth used as SST

Barrier LayerSalinity-driven Barrier Layer:• Lukas and Lindstrom (1991) first report the barrier layer due to the

salinity stratification• The salinity-driven barrier layer can inhibit turbulent mixing

Temperature-driven Barrier Layer:• Thick DWL should be regarded as a barrier

layer, because high stratification in DWL also prevents nighttime mixing for eroding restratified upper ocean

• However, the 1-D ROMS model with KPP or other turbulent closure mixing scheme cannot simulate the thick DWL (not shown)

BL

CSHORMing FengSenior Principal Research Scientistt +61 8 9333 6512e ming.feng@csiro.auw https://cshor.csiro.au/

Thank you