Role of Atmosphere-ocean-ice Interaction in the Linkage between December Bering Sea Ice and Subsequent February Surface Air Temperature Over North America

Under embargo until 2023-08-16This study revealed that the interannual variations of December Bering Sea ice and subsequent February surface air temperature (SAT) over North America are significantly correlated during 2000/01-2020/21, which is not the case during 1966/67-1999/2000. During 2000/01-2020/21, reduced December Bering Sea ice is generally followed by a February meridional dipole pattern in the atmospheric circulation over North America, which provides favorable conditions for colder temperatures. Further analysis elucidates that the intensified persistence of December Bering Sea ice anomaly might be responsible for the identified change in such a lead-lag sea ice-SAT linkage. During 2000/01-2020/21, the Bering Sea ice anomaly in December can persist into the subsequent February during which the Bering Sea ice anomaly can stimulate an eastward-propagating Rossby wave train propagating to North America and causing the meridional dipole pattern. The longer persistence of December Bering Sea ice anomaly during 2000/01-2020/21 is attributed to the interdecadal intensified atmosphere-ocean-ice interaction over the Bering Sea - a positive feedback loop that favors the persistence of Bering Sea ice anomaly. A negative sea-ice concentration anomaly with more open water in the Bering Sea would allow the ocean to release more heat and warm more the air aloft. This will lead to more downward longwave radiation, preventing the winter sea ice growth and helping maintain the Bering Sea ice anomaly. Results of this study indicates that the intensity of atmosphere-ocean-ice interaction in the Bering Sea may modulate the linkage between the February SAT over North America and the preceding December Bering Sea ice.publishedVersio

Fabrication of a NiFe Alloy Oxide Catalyst via Surface Reconstruction for Selective Hydrodeoxygenation of Fatty Acid to Fatty Alcohol

Traditional NiFe alloy catalyst (NiFe AC) possesses low alcohol selectivity for the hydrodeoxygenation (HDO) of fatty acid due to its excessive deoxygenation into alkane. Herein, we innovatively provide the NiFe alloy oxide catalyst (NiFe AOC) to suppress the adsorption of aldehyde, which is the crucial intermediate of objective product alcohol converting into a side product, via the steric hindrance of lattice oxygen to inhibit the further conversion of alcohol. NiFe AOC reaches 100% conversion of lauric acid with 90% selectivity to lauryl alcohol. Kinetic analysis indicated that the apparent activation energy of side reaction increases by 71.1 kJ/mol for NiFe AOC relative to NiFe AC, evidencing the inhibition for the conversion of objective product alcohol into alkane for NiFe AOC. Furthermore, DFT calculation also suggests that the activation energy of the side reaction increases by 0.33 eV on NiFe AOC compared to NiFe AC. In addition, used NiFe AOC can be totally regenerated via surface reconstruction during the reduction-reoxidation treatment. However, overoxidation inducing NiFe surface phase separation weakened the synergistic interaction of Ni-Fe bimetallic sites and further decreased the catalytic activity

Precise Tide-independent Bathymetric Survey and Application to the Inshore Monitoring of Seabed Evolution

Due to the influences of tidal water level, vessel attitude and wave motion, the traditional bathymetric method of reducing depths by the tidal level makes it difficult to meet precise engineering requirements in the vertical direction. Therefore a precise method, termed a tide-independent bathymetric survey, is presented in this paper. In this method, the quality of the sounding and positioning solution, the influences of time offset and vessel attitude as well as height transformation are considered by taking a series of measurements. The tide-independent method has been used for inshore monitoring of the seabed sediments. The statistical parameters acquired by comparing the traditional method with the tide-independent method used in the monitoring show that the latter is accurate and credible.Debido a las influencias del nivel del agua de las mareas, la actitud de los buques y el movimiento de las alas, el metoda batimetrico tradicional de reduccion de profundidades mediante los niveles de las mareas dificulta el cumplimiento de los requerimientos precisos de ingenieroa en la direccion vertical. Asf pues, en este articulo se presenta un metoda preciso, denominado levantamiento batimetrico independiente de las mareas. En este metoda, la calidad de los sondeos y la solucion del posicionamiento, las influencias del desfase horario y de la actitud de la nave, asl como la transformacion de las altura son consideradas mediante la toma de una serie de mediciones. El metoda independiente de las mareas ha sido utilizado para el control costero de los sedimentos del fonda del mar. Los parametres estadisticos adquiridos comparando el metoda tradicional con el metoda independiente de las mareas utilizado en el control muestran que este ultimo es exacto y creible.En raison de l'influence du niveau de la maree, de l'attitude du navire et du mouvement de l'eau, la methode bathymetrique traditionnelle de reduction des profondeurs par le niveau de l'eau rend difficile la satisfaction d'exigences precises d'ingenierie dans la direction verticale. Cet article presente done une methode precise, appelee leve bathymetrique independant des marees. Dans cette methode, la qualite du systeme de sondages et de determination de la position, les influences des decalages temporels et l'attitude du navire ainsi que la transformation de la hauteur sont pris en compte dans une serie de mesures. La methode independante des marees a ete utilisee pour le controle cotier des sediments du fond de la mer. Les parametres statistiques obtenus en comparant la methode traditionnelle a la methode independante des marees utilisee montre que cette derniere est exacte et credible