A5036700857- Oceanographic and Atmospheric Processes
- Climate variability and models
- Geology and Paleoclimatology Research
- Marine and coastal ecosystems
- Arctic and Antarctic ice dynamics
- Microplastics and Plastic Pollution
- Tropical and Extratropical Cyclones Research
- Coastal and Marine Dynamics
- Coastal wetland ecosystem dynamics
- Recycling and Waste Management Techniques
- Atmospheric aerosols and clouds
- Geological formations and processes
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Marine and fisheries research
- Geophysics and Gravity Measurements
- Seismic Waves and Analysis
- Ocean Waves and Remote Sensing
- Atmospheric and Environmental Gas Dynamics
- Underwater Acoustics Research
- Isotope Analysis in Ecology
- Marine Biology and Ecology Research
- Cryospheric studies and observations
- Seismic Imaging and Inversion Techniques
- Radio Astronomy Observations and Technology
University of Auckland
2013-2024
Royal Military College of Canada
2021
National Institute of Water and Atmospheric Research
2002-2017
CSIRO Oceans and Atmosphere
2017
GNS Science
2011
Victoria University of Wellington
2011
Heriot-Watt University
2007
University of Colorado Boulder
2000-2005
McGill University
2004
Woods Hole Oceanographic Institution
1999-2003
Abstract Dense water formed near Antarctica, known as Antarctic bottom (AABW), drives deep ocean circulation and supplies oxygen to the abyssal ocean. Observations show that AABW has freshened contracted since 1960s, yet drivers of these changes their impact remain uncertain. Here, using observations from Australian Basin, we transport reduced by 4.0 Sv between 1994 2009, during a period strong freshening on continental shelf. An increase in shelf salinity 2009 2018, previously linked...
Measurements of velocity, density, and pressure gradient in the lower Hudson River estuary were used to quantify dominant terms momentum equation characterize their variations at tidal spring–neap timescales. The vertical flux (assumed be due mainly turbulent shear stress) was estimated indirectly, based on residual from acceleration terms. indirect estimates stress compared favorably bottom using a quadratic drag law, supporting hypothesis that involves local balance between acceleration,...
The Southwest Pacific Ocean Circulation and Climate Experiment (SPICE) is an international research program under the auspices of CLIVAR.The key objectives are to understand circulation South Convergence Zone (SPCZ) dynamics, as well their influence on regional basin-scale climate patterns.South thermocline waters transported in westward flowing Equatorial Current (SEC) toward Australia Papua-New Guinea.On its way, SEC encounters numerous islands straits forms boundary currents jets that...
Abstract Accelerated warming of western boundary currents due to the strengthening subtropical gyres has had cascading effects on coastal ecosystems and is widely expected result in further tropicalization temperate regions. Predicting how species will respond requires a better understanding variability ocean complex current Using three ≥50 year temperature records we demonstrate high magnitude seasonality Southwest Pacific region. The greatest rate was evident off eastern Tasmania (0.20 °C...
We describe a method to infer total ozone abundance and effective cloud transmission from global (diffuse plus direct) spectral irradiance measurements taken at the Earth's surface. The derivation of relies on comparison measured ratios two wavelengths in UV part spectrum with synthetic chart this ratio computed for variety abundances. One these should be appreciably absorbed by (e.g., 305 nm) compared other one 340 nm). This (and therefore also inferred abundance) is insensitive value...
The transport of salt along the channel an estuary determines length saline intrusion and provides bounds on transfer other substances. Observations have been hampered by a lack long time series measurements complexities sampling situation (e.g., local topography simultaneous variations tides, freshwater, winds). Here we estimate at relatively uniform section Hudson Estuary over 70‐day period during drought conditions. balance is also assessed comparing with surveys total content in estuary....
Ocean temperature changes around New Zealand are estimated from satellite sea surface (SST) products since 1981, two high resolution expendable bathythermograph transects (HRXBT) 1986 and 1991, Argo data 2006. The datasets agree well where they overlap. Significant warming is found in subtropical waters. Greatest east of Australia the central Pacific. All NZ coastal waters warming, with strongest Wairarapa weakest between East Cape North Cape. Temperature intensified, extending to ∼200 m...
Dense, cold waters formed on Antarctic continental shelves descend along the margin, where they mix with other Southern Ocean to form Bottom Water (AABW). AABW then spreads into deepest parts of all major ocean basins, isolating heat and carbon from atmosphere for centuries. Despite AABW’s key role in regulating Earth’s climate long time scales recording conditions, remains poorly observed. This lack observational data is mostly due two factors. First, originates shelf slope situ...
As global oceans warm, long-term temperature records are critical in understanding and interpreting warming trends the significance of marine heatwaves (MHWs) coastal environments. Daily measurements sea surface (SST) have been taken since 1967 at Leigh Marine Laboratory, Hauraki Gulf, northern New Zealand. We analyse SST anomalies MHWs from to 2023. find a significant trend annual anomaly, with evident autumn winter, but not summer spring. has consistently anomalously warm over last decade,...
Abstract Consecutive Argo float profiles are used to observe upper ocean changes resulting from the passage of tropical cyclones (TCs) in South Pacific between 2001 and 2023. Cross‐sectional composites response produced by normalizing distance profile cyclone track 34‐knot wind radius (R 34 ) each TC better resolve average water properties. Surface cooling initial mixed layer (ML) extends center about twice R is stronger left track. Subsurface warming at base ML observed 0.4 2 on both sides...
Ocean surface circulation can be estimated by automated tracking of thermal infrared features in pairs sequential satellite imagery. A 7-yr time series velocity, extracted from imagery the East Australian Current using maximum cross-correlation (MCC) technique, provides enough measurements for a more statistical evaluation method than has previously been possible. Excluding 1 yr with extensive cloud cover, produces about 8000 velocity estimates per month some seasonal variation. Method...
A set of moored, bottom-mounted and shipboard measurements, obtained in a straight section the lower Hudson estuary during late summer early fall 1995, determine velocity, density, along-channel pressure gradient throughout 15-m water column, as well providing direct eddy-correlation estimates Reynolds stress indirect inertial-range dissipation within 3 m bottom. The analysis focuses on testing 1) simplified turbulent kinetic energy equation, which production balances dissipation; 2)...
The spatial and temporal variability of the East Australian Current (EAC) is investigated using 6 years (1993–1998) surface geostrophic stream function from an optimal interpolation altimeter sea heights velocities derived tracking thermal features in satellite imagery. Variability appears as a series cyclones anticyclones propagating southwestward westward with periods between 90 180 days. behavior changes over years. Energy mesoscale frequencies moves slowly south diminishes more...
Paleoceanographic archives derived from 17 marine sediment cores reconstruct the response of Southwest Pacific Ocean to peak interglacial, Marine Isotope Stage (MIS) 5e (ca. 125 ka). Paleo‐Sea Surface Temperature (SST) estimates were obtained Random Forest model—an ensemble decision tree tool—applied core‐top planktonic foraminiferal faunas calibrated modern SSTs. The reconstructed geographic pattern SST anomaly (maximum between 120 and 132 ka minus mean SST) seems indicate how MIS...
Abstract We present the first proxy record of sea‐ice area (SIA) in Ross Sea, Antarctica, from a 130 year coastal ice‐core record. High‐resolution deuterium excess data show prevailing stable SIA 1880s until 1950s, 2–5% reduction mid‐1950s to early‐1990s, and 5% increase after 1993. Additional support for this reconstruction is derived methanesulphonic acid concentrations whaling records. While has continued decline around much West Antarctic coastline since concurrent with increasing air...
Abstract Approximately 25% of Antarctic Bottom Water has its origin as dense water exiting the western Ross Sea, but little is known about what controls release plumes from Drygalski Trough. We deployed two moorings on slope to investigate properties bottom region at Cape Adare. Salinity increased in 2018 previous measurements 2008–2010, consistent with observed salinity increase Sea. find High Shelf Trough contributes pulses The timing and magnitude largely explained by an inverse...
Marine heatwaves (MHWs) are extreme ocean temperature events that can have wide-ranging and pervasive effects on marine species ecosystems. However, studies of MHW characteristics drivers primarily focus open-ocean environments, rather than the nearshore coastal (<10 km from coast, <50 m depth). This is despite waters sustaining significant commercial, recreational, customary fisheries aquaculture activities highly susceptible to impacts MHWs. The two longest (>50 year)...
The horizontal stirring properties of the flow in a region East Australian Current are calculated. A surface velocity field derived from remotely sensed data, using maximum cross correlation method, is integrated to derive distribution finite-time Lyapunov exponents. For studied (between latitudes 36 degrees S and 41 longitudes 150 E 156 E) mean exponent during 1997 estimated be lambda( infinity )=4x10(-7) s(-1). This close agreement with few other measurements rates ocean which available....
Abstract Stirring in the Tasman Sea is examined using surface geostrophic currents derived from satellite altimeter measurements. Calculations of distribution finite-time Lyapunov exponents (FTLEs) indicate that stirring this region not uniform and stretching rates over 15 days vary less than 0.02 day−1 to 0.3 day−1. These variations occur at both small (∼10 km) large (∼1000 scales cases are linked dynamical features flow. The small-scale related characteristics coherent vortex structures,...
Abstract The increased use of ambient seismic noise for imaging requires better understanding the wavefield and its source locations mechanisms. Although regions mechanisms Rayleigh waves have been studied extensively, characterization Love wave processes are sparse or absent. We present here first systematic comparison directions within primary (~10–20 s period) secondary (~5–10 microseism bands both in Southern Hemisphere using vertical‐ horizontal‐component recordings from a dense...
Marine plastic pollution, particularly microplastics, has been recognised as a global issue in the recent years, but research efforts Pacific are lagging. We carried out on microplastics contamination of surface waters Vava'u archipelago, Tonga. Since smaller than standard mesh size (333-335 μm) readily reported literature we used finer plankton net (100 to determine proportion captured 300 μm. Isolated were counted and measured using stereomicroscope with polymer identification performed by...
Ice shelf ocean cavities are among the least observed regions of oceans. While we know that eddying motions ubiquitous in oceans, there few observations such processes ice cavities. Here, describe multi-year hydrographic mooring from central Ross Shelf to understand baroclinic eddy properties and their potential effect on cavity circulation basal melting. As data limited, some assumptions need be made estimate motion separate it background circulation. Here resolve kinematic structures...
Abstract This paper investigates the mechanisms causing interannual variability of upper ocean heat content and sea surface temperature (SST) in southwest Pacific. Using ECCOv4 reanalysis it is shown that air–sea flux transport convergence due to dynamics both contribute temperatures around New Zealand. The responsible for are investigated. It SSTs significantly correlated with arrival barotropic Rossby waves estimated from South Pacific wind stress over latitudes Both Argo observations show...