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Centurioni, LR, Hormann V, Talley LD, Arzeno I, Beal L, Caruso M, Conry P, Echols R, Fernando HJS, Giddings SN, Gordon A, Graber H, Harcourt RR, Jayne SR, Jensen TG, Lee CM, Lermusiaux PFJ, L'Hegaret P, Lucas AJ, Mahadevan A, McClean JL, Pawlak G, Rainville L, Riser SC, Seo H, Shcherbina AY, Skyllingstad E, Sprintall J, Subrahmanyam B, Terrill E, Todd RE, Trott C, Ulloa HN, Wang H.  2017.  Northern Arabian Sea Circulation Autonomous Research (NASCar): A research initiative based on autonomous sensors. Oceanography. 30:74-87.   10.5670/oceanog.2017.224   AbstractWebsite

The Arabian Sea circulation is forced by strong monsoonal winds and is characterized by vigorous seasonally reversing currents, extreme differences in sea surface salinity, localized substantial upwelling, and widespread submesoscale thermohaline structures. Its complicated sea surface temperature patterns are important for the onset and evolution of the Asian monsoon. This article describes a program that aims to elucidate the role of upper-ocean processes and atmospheric feedbacks in setting the sea surface temperature properties of the region. The wide range of spatial and temporal scales and the difficulty of accessing much of the region with ships due to piracy motivated a novel approach based on state-of-the-art autonomous ocean sensors and platforms. The extensive data set that is being collected, combined with numerical models and remote sensing data, confirms the role of planetary waves in the reversal of the Somali Current system. These data also document the fast response of the upper equatorial ocean to monsoon winds through changes in temperature and salinity and the connectivity of the surface currents across the northern Indian Ocean. New observations of thermohaline interleaving structures and mixing in setting the surface temperature properties of the northern Arabian Sea are also discussed.

Williams, NL, Juranek LW, Feely RA, Johnson KS, Sarmiento JL, Talley LD, Dickson AG, Gray AR, Wanninkhof R, Russell JL, Riser SC, Takeshita Y.  2017.  Calculating surface ocean pCO(2) from biogeochemical Argo floats equipped with pH: An uncertainty analysis. Global Biogeochemical Cycles. 31:591-604.   10.1002/2016gb005541   AbstractWebsite

More than 74 biogeochemical profiling floats that measure water column pH, oxygen, nitrate, fluorescence, and backscattering at 10 day intervals have been deployed throughout the Southern Ocean. Calculating the surface ocean partial pressure of carbon dioxide (pCO(2sw)) from float pH has uncertainty contributions from the pH sensor, the alkalinity estimate, and carbonate system equilibrium constants, resulting in a relative standard uncertainty in pCO(2sw) of 2.7% (or 11 mu atm at pCO(2sw) of 400 mu atm). The calculated pCO(2sw) from several floats spanning a range of oceanographic regimes are compared to existing climatologies. In some locations, such as the subantarctic zone, the float data closely match the climatologies, but in the polar Antarctic zone significantly higher pCO(2sw) are calculated in the wintertime implying a greater air-sea CO2 efflux estimate. Our results based on four representative floats suggest that despite their uncertainty relative to direct measurements, the float data can be used to improve estimates for air-sea carbon flux, as well as to increase knowledge of spatial, seasonal, and interannual variability in this flux. Plain Language Summary The Southern Ocean is a key player in the global flow of carbon, yet it is hard to reach, and there are relatively few measurements there, especially in winter. Measuring the amount of carbon dioxide gas in seawater is key to advancing our understanding of the Southern Ocean. More than 74 robotic floats that use sensors to measure seawater properties have been deployed throughout the Southern Ocean, and each has a lifetime of around 5 years. It is currently not possible to directly measure carbon dioxide gas from these floats; however, it is possible to estimate carbon dioxide from things that the float can measure, like pH, a measure of ocean acidity. Here surface ocean carbon dioxide is estimated from several floats and compared to two ship-based estimates. In some locations, the floats closely match the existing estimates, but in other locations the floats see significantly higher surface ocean carbon dioxide in the wintertime, reinforcing the idea that the Southern Ocean's role in the global carbon cycle needs a closer look. Our results show that despite not measuring carbon dioxide directly, these floats will help scientists learn a lot about the Southern Ocean's part in the global flow of carbon.

Tishchenko, PY, Talley LD, Lobanov VB, Zhabin IA, Luchm VA, Nedashkovskii AP, Sagalaev SG, Chichkin RV, Shkirnikova EM, Ponomarev VI, Masten D, Kang DJ, Kim KR.  2003.  Seasonal variability of the hydrochemical conditions in the sea of Japan. Oceanology. 43:643-655. AbstractWebsite

In the summer of 1999 and the winter of 2000, during international expeditions of R/Vs Professor Khromov and Roger Revelle, hydrological and hydrochemical studies of the Sea of Japan were performed. Comparing the hydrochemical characteristics of the Sea of Japan in the summer and winter seasons, we have found that the seasonal variability affects not only the upper quasihomogeneous layer but also the deeper layers. This variability is caused by the intensification of vertical mixing during the winter season. It was shown that the mixing intensification in the deep layers of the sea in the winter might be caused both by the slope convection and by the deep convection in the open part of the sea, penetrating deeper than 1000 in. It was found that the area of positive values of the biological constituent of the apparent oxygen consumption coincides with the area of deep convection. The climatic zoning in the distribution of partial pressure of carbon dioxide was revealed for both seasons. In the northwestern part of the sea, carbon dioxide is released into the atmosphere due to the deep convection in the winter and the heating process in the summer. The southern part of the sea absorbs the atmospheric carbon dioxide because of the process of photosynthesis and cooling of the waters supplied from the Korea Strait.

Tishchenko, PY, Talley LD, Nedashkovskii AP, Sagalaev SG, Zvalinskii VI.  2002.  Temporal variability of the hydrochemical properties of the waters of the Sea of Japan. Oceanology. 42:795-803. AbstractWebsite

Hydrochemical studies were performed in the Sea of Japan from onboard R/V Akademik Vinogradov in 1992 and R/Vs Roger Revelle and Professor Khromov in 1999. A comparison of the hydrochemical properties (concentrations of dissolved oxygen and nutrients and proteins of the carbonate system) of the waters of the Sea of Japan with those of the adjacent basins (the Sea of Okhotsk, Pacific Ocean, and East China Sea) demonstrates significant differences between them. In addition, a significant temporal variability of the hydrochemical properties of the intermediate and abyssal waters of the Sea of Japan was revealed. A general increase in the contents of inorganic forms of phosphorus, nitrogen, and normalized organic matter along with a general decrease in the oxygen concentration and normalized alkalinity with time was established. We suggest a model for an open basin, in which the principal reason for the observed features and temporal variability of the hydrochemical properties is related to the water exchange between the Sea of Japan and adjacent basins. A supposition is posed on the strong dependence of the water exchange on the variability of the intensity analysis direction of the major currents of the northwestern Pacific Ocean, especially the Kuroshio Current.