Atmosphere–ocean interactions in the Greenland Sea during solar cycles 23–24, 2002–2011
Summary: The recent period of exceptionally low solar activity has allowed a new approach to relating solar activity and climate. Analysis of daily sea surface temperature fields in the Greenland Sea from 2002-2011 shows that the day-to-day variability of the field during the solar low is significantly different, due to variability in the passage of weather systems. The influence of variations in the solar ultraviolet band acting in the stratosphere provides a credible mechanism for this difference.
Sea surface height and mixed layer depth responses to sea surface temperature in northwestern Pacific subtropical front zone from spring to summer
Summary: We made match-up datasets of satellite sea surface temperature(SST), sea level anomaly(SLA),and in situ mixed layer depth(MLD). Variations of SLA and MLD across subtropical front were examined. The steric component of SLA dominant the seasonal variations of SLA. Correlation betwwen SLA and SST is 0.76. Negative correlation between MLD and SST provide a feasibility to retrieval MLD using surface parameters.
Impact of currents on surface fluxes computation and their feedback on coastal dynamics
Summary: The paper studies the impact of the use of relative winds (i.e. winds minus ocean currents) to compute heat and momentum fluxes at sea surface. This was done in an area interested by mesoscale eddies and by a local coastal upwelling.
Impact is relevant both for heat and momentum fluxes, inferring respectively on surface temperature (improved) and on currents patterns and magnitude.
Currents in SW part shows a feedback on itself through momentum fluxes, also modyfing upwelling patterns.
In situ autonomous optical radiometry measurements for satellite ocean color validation in the Western Black Sea
Summary: The accuracy of primary satellite ocean color data products from MODIS on-board Aqua and the VIIRS, is investigated using in situ measurements from the Ocean Color component of the Aerosol Robotic Network (AERONET-OC). Results from the comparison of normalized-water leaving radiance LWN indicate biases of a few percent between satellite derived and in situ data at the center-wavelengths relevant for the determination of chlorophyll-a concentration.
Technical Note: A fully automated purge and trap-GC-MS system for quantification of volatile organic compound (VOC) fluxes between the ocean and atmosphere
Summary: The oceans are a key source of a number of atmospherically
important volatile gases. The accurate and robust
determination of trace gases in seawater is a significant
analytical challenge. Here we describe a gas chromatograph- mass spectrometer based purge and trap system that was developed for the fully automated analysis of dissolved very short-lived species (VSLS) in seawater sampled from a research ship.
Modelling origin and transport fate of waste materials on the south-eastern Adriatic coast (Croatia)
Summary: The south-eastern parts of the Adriatic Sea coastline were severely polluted by large amounts of accumulated waste material in the second half of November 2010. In the study we analysed meteorological and oceanographic conditions that lead to the waste deposition using available in situ measurements, remote sensing data as well numerical models of the ocean and the atmosphere.
Global representation of tropical cyclone-induced ocean thermal changes using Argo data – Part 2: Estimating air–sea heat fluxes and ocean heat content changes
Summary: 1. TCs are responsible for 1.87 PW (11.05 W/m2) of heat transfer annually from the global ocean to the atmosphere during storm passage (0-3 days) on a global scale. Of this total, 1.05±0.20 PW (4.80±0.85 W/m2) is caused by TS/TD and 0.82±0.21 PW (6.25±1.5 W/m2) is caused by hurricanes.
2.The net ocean heat uptake caused by all storms is 0.34 PW (4-20 days mean). Hurricanes induce 0.75±0.25 PW (5.98±2.1 W/m2) net heat gain, and TS/TD leads to 0.41±0.21 PW (1.90±0.96 W/m2) net heat loss.
Eddy characteristics in the South Indian Ocean as inferred from surface drifter
Summary: Eddies in the South Indian Ocean (SIO) have been statistically investigated based on 2082 surface drifters. 19252 eddies are identified with 60% anticyclonic eddies. Mesoscale and submesoscale eddies show different spatial distribution. Large Eddies mainly appear in regions with large eddy kinetic energy. The submesoscale anticyclonic eddies are densely distributed in the subtropical basin in the central SIO. The number of mesoscale eddies shows statistically significant seasonal variability.
Global representation of tropical cyclone-induced ocean thermal changes using Argo data – Part 1: Methods and results
Summary: 1. Argo floats were used to examine tropical cyclone (TC)-induced ocean thermal changes on the global scale by comparing temperature profiles before and after TC passage.
2. Global-average of the vertical structure of the average ocean thermal response for two different categories: tropical storms/depressions (TS/TD) and hurricanes were presented.
3. Significant differences between weak storm (TS/TD) and strong storm (Hurricane) were found.
A robust method for removal of glint effects from satellite ocean colour imagery
Summary: A novel glint correction algorithm is developed in this study which is capable of achieving meaningful retrievals of ocean radiances from the glint-contaminated pixels unless saturated by strong glint in any of the wavebands. When compared to the results of an existing model in the SeaDAS processing system, the new algorithm has the best performance in terms of yielding physically realistic water-leaving radiance spectra and improving the accuracy of the ocean colour products.
A Monte Carlo simulation of multivariate general Pareto distribution and its application
Summary: MPOT improves the efficiency of the extremes in raw data, and is superior to other methods (the annual maximum). But there are some difficulties (declustering, joint threshold, the resolution method of equation in high dimension) in application of MPOT. The paper shows all processes of analyzing the joint distribution of wind and wave in the South China Sea (SCS), and builds the solving method for MGPD by means of a Monte Carlo simulation.
Modelling of the anthropogenic tritium transient and its decay product helium-3 in the Mediterranean Sea using a high-resolution regional model
Summary: The anthropogenic tritium invasion and its decay product helium-3 was simulated for the first time in the Mediterranean Sea, using a high resolution regional model (NEMO-MED12). The simulation covers the entire tritium (3H) transient generated by the atmospheric nuclear-weapon tests performed in the 1950s and early 1960s and run till 2011. The model correctly simulates the main features of the thermohaline circulation of the Mediterranean Sea, with a realistic time compared to observations.
M. Ayache, J.-C. Dutay, P. Jean-Baptiste, K. Beranger, T. Arsouze, J. Beuvier, J. Palmieri, B. Le-vu, and W. Roether Ocean Sci. Discuss., 11, 2691-2732, 2014 AbstractDiscussion Paper (PDF, 6414 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for OS
05 Dec 2014
Assessment of an ensemble system that assimilates Jason-1/Envisat altimeter data in a probabilistic model of the North Atlantic ocean circulation
Summary: A realistic ocean circulation model is adapted to explicitly simulate model uncertainties and an ensemble data assimilation -stochastic perturbations, altimetric data and 4D observation operator- is developed in order to control the Gulf Stream dynamic. The performance of the ensemble system is measured through probabilistic approach: the update then adjusts the bias and the dispersion of the ensemble (reliability) and reduces the uncertainty by 30% (resolution) for the SSH variable.
Water level oscillations in Monterey Bay and Harbor
Summary: Seiches in coastal bays can produce significant water level oscillations that impact maritime operations and introduce ecological stress. Monterey Bay, California is found to have wave-driven short-period oscillations that can reinforce themselves resulting in water level amplification. At longer periods the oscillations are not wave-driven and several potential forcing mechanisms are examined. A gyre offshore the bay is suggested as the driver, while other potential drivers are discounted.
Exploring the isopycnal mixing and helium-heat paradoxes in a suite of Earth System Models
Summary: Many ocean circulation models use representations of lateral mixing based on instability theories that predict weak mixing in the ocean interior, much lower than observed. We show that using more realistic mixing improves the distribution of mantle helium-3. It does not, however, resolve the paradox that models reproduce the relationship between mantle helium and radiocarbon with flux of He-3 lower than is consistent with the heat leaving the mantle.
Reconstructing bottom water temperatures from measurements of temperature and thermal diffusivity in marine sediments
Summary: Temperature fields in marine sediments are mainly governed by the geothermal steady state heat flow and the bottom water temperature, which propagates into the sediment. Thus, the current sediments' temperature field stores the history of bottom water temperature variation. The aim of this work is the inverse modeling of the bottom water temperature variation from instantaneous measurements of the depth dependent temperature and the thermal diffusivity.