Symposium on Ocean Circulation, Ecosystem, HypoxiA and CoNsequences (OCEAN)

Joint Workshop on Regional Oceanography Study

Seminar
Evidence of rising and poleward shift of storm surge in western North Pacific in recent decades

Speaker:

Prof. Leo OEY, Department of Oceanography, National Sun Yat-sen University

Abstract

Recently, there has been considerable interest in examining how sea-level extremes due to storm surge may be related to climate change. Evidence of how storm-surge extremes have evolved since the start of the most recent warming of mid-1970s to early 1980s has not been firmly established however. Here we use 64 years (1950-2013) of observations and model simulations, and find evidence of a significant rise in the intensity as well as poleward-shifting of location of typhoon surges in the western North Pacific after 1980s. The rising and poleward-shifting trends are caused by the weakening of the steering flow in the tropics, which is related to climate warming, resulting in slower-moving and longer-lasting typhoons which had shifted northward.

Date : 29 July 2016 (Friday)
Time : 3:30pm
Venue : Room 4472 (Lifts 25-26)
Seminar
Mixed-layer current and cyclonic eddy induced by global tropical cyclones

Speaker:

Prof. Ruo-Shan TSENG, Department of Oceanography, National Sun Yat-sen University

Abstract

Global velocity data from drifters of the Surface Velocity Program and the sea surface height and geostrophic velocity data from satellite altimetry observations under tropical cyclones (TCs) were analyzed to demonstrate strong ocean currents and their characteristics under various storm intensities in the Northern Hemisphere (NH) and in the Southern Hemisphere (SH). Mean TC’s translation speed (Uh) is faster in the NH (~4.7 m s-1) than in the SH (~4.0 m s-1), owing to the fact that TCs are more intense in the NH than in the SH. The rightward (leftward) bias of ocean mixed-layer (OML) velocity occurs in the NH (SH). As a result of this slower Uh and thus a smaller Froude number in the SH, the flow patterns in the SH under the same intensity levels of TCs are more symmetric relative to the TC center and the OML velocities are stronger than those in the NH. Several special cases were reported in this study showing the occurrence of prominent cyclonic eddies with a life span of several months which were induced by slow-moving (Uh ~ 1 m s-1) and intense (category 3, 4, and 5 of the Saffir-Simpson Scale) TCs, either in the NH and SH. This study provides the first characterization of the near-surface OML velocity response to all recorded TCs in the SH from direct velocity measurements.

Date : 29 July 2016 (Friday)
Time : 2:30pm
Venue : Room 4472 (Lifts 25-26)
Seminar
Various aspects of coastal dynamics embedded in high-frequency radar-derived surface currents

Speaker:

Prof. Sung Yong KIM, Korea Advanced Institute of Science and Technology (KAIST)

Abstract

The nearly completed U.S. West Coast (USWC) high-frequency radar (HFR) network provides an unprecedented capability to monitor and understand coastal ocean dynamics and phenomenology through hourly surface current measurements at up to 1 km resolution. The dynamics of the surface currents off the USWC are governed by tides, winds, Coriolis force, low-frequency pressure gradients (less than 0.4 cycles per day (cpd)), and nonlinear interactions of those forces. Alongshore surface currents show poleward propagating signals with phase speeds of O(10) and O(100 to 300) km/day and time scales of 2 to 3 weeks. The signals with slow phase speed are only observed in southern California. It is hypothesized that they are scattered and reflected by shoreline curvature and bathymetry change and do not penetrate north of Point Conception. The seasonal transition of alongshore surface circulation forced by upwelling-favorable winds and their relaxation is captured in fine detail. Submesoscale eddies, identified using flow geometry, have Rossby numbers of 0.1 to 3, diameters in the range of 10 to 60 km, and persistence for 2 to 12 days. The HFR surface currents resolve coastal surface ocean variability continuously across scales from submesoscale to mesoscale (O(1) km to O(1000) km). Their spectra decay with k-2 at high wave number (less than 100 km) in agreement with theoretical submesoscale spectra below the observational limits of present-day satellite altimeters.

Date : 2 Feb 2016 (Tuesday)
Time : 2:30pm
Venue : Room 1504 (Lifts 25-26), HKUST
Seminar
Satellite remote sensing of air-sea CO2 flux

About the speaker:

Dr. Yan Bai is professor with the SOED Second Institute of Oceanography, with research interests in ocean carbon cycling and Oceanography, ocean optics and bio-optics Models. The talk focuses on the estimation of air-sea CO2 flux with satellite data. Recent progresses on the ocean carbon research from space will be introduced, with the special attention to the sea surface partial pressure of carbon dioxide (pCO2), by using a mechanistic semi-analytic algorithm (MeSAA). Time series of satellite-derived air-sea CO2 flux in the China Sea and its variability are also presented.

Date : 11 Dec 2015
Time : 3:30 pm
Venue : Room 6573 (Lifts 29-30), HKUST
Seminar
Progress on marine satellite remote sensing applications in China

About the speaker:

Prof. Delu Pan is academician of the Chinese Academy of Engineering ( Expert of Marine Remote Sensing ) with the SOED Second Institute of Oceanography of the SOA of the People Republic China, has devoted himself to the study of ocean color remote sensing and simulation science. As one of the founders of Chinese marine remote sensing, and plays a key role in the development of Chinese ocean color remote sensing and simulation science, and has made great contribution to atmospheric correction algorithms, ocean color reverse models development and application, as well as to the development of Chinese ocean color satellites and sensors in spacecraft. More than 110 papers have been published in domestic and foreign journals, or delivered at conferences.

Date : 11 Dec 2015
Time : 2:30 pm
Venue : Room 6573 (Lifts 29-30), HKUST
Seminar
Autonomous Underwater Vehicles and Sensors Powered by Ocean Thermal Energy

Abstract:

This talk will describe a new stand-alone power system to harvest temperature differentials in the ocean.  This is a unique power source underwater in the absence of solar and wave energy.  The current state-of-the-art autonomous underwater vehicles and sensors are all powered by primary battery, and therefore have limited lifetime.  Harvesting the ocean thermal energy associated with vertical temperature differentials between the warm surface and cold deep water has the potential to power these autonomous underwater vehicles and sensors indefinitely.  Results from the development, deployment and recovery of a prototype thermal recharging underwater float (known as SOLO-TREC) in the ocean will be presented.  With eight hours energy harvesting and sampling interval, SOLO-TREC has made more than a thousand dives between the ocean surface and 500 meters water depth over a period of 1.5 years.  Recent progress to commercialize this thermal recharging technology in support of several climate and oceanographic initiatives will be presented.  Future applications of this thermal energy harvesting technology to power autonomous underwater vehicles such as gliders and propeller-driven AUVs will also be discussed.

Speaker : Prof. Yi Chao, Joint Institute for Regional Earth System Science and Engineering, University of California at Los Angeles
Date : 3 Nov 2015
Time : 2:30 pm
Venue : Room 1505 (Lifts 25-26), HKUST

HKUST ODMP – SCSIO joint workshop on ocean circulation and dynamics

A workshop on ocean circulation and dynamics was held in FYTRI, HKUST (Nansha) on 16th Oct. 2015. The workshop was jointly organized by Prof. Jianping Gan (ODMP HKUST) and Profs. Ping Shi, Ruixin Huang (SCSIO).buy used water slide             … Continue reading

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Seminar
Recent Advances in Turbidity Current Research

Abstract:

Turbidity currents hold the key to many fundamental questions in the fields of marine geology and sedimentology. Knowledge of turbidity currents’ cause and destructive nature has direct application in marine hazard mitigation, deep-water resource development, and hydrocarbon energy industry. Tremendous strides have been made through many researchers’ pioneering work in turbidity current theories, laboratory experiments, as well as numerical simulations. But because of its unpredictability and destructive nature, being able to continuously monitor field turbidity currents in-situ has yet been accomplished. This presentation first briefly reviews the history of turbidity currents research in the past century; highlights the milestone theoretical and technological advances; and discusses the major challenges in turbidity current research. Specifically, an initiative to conduct a full-scale field campaign to investigate large, destructive turbidity currents in Northeastern South China Sea is proposed.

Speaker : Prof. Jingping XU, College of Marine Geosciences, Ocean University of China
Date : 28 Aug 2015
Time : 11:00 a.m.
Venue : Room 1505 (Lifts 25-26), HKUST