The Experts below are selected from a list of 51 Experts worldwide ranked by ideXlab platform
P. N. Sen - One of the best experts on this subject based on the ideXlab platform.
-
Estimation of sonic layer depth from surface Parameters
Geophysical Research Letters, 2007Co-Authors: Sarika Jain, M. M. Ali, P. N. SenAbstract:Mixed layer depth (MLD) is an important Oceanographic Parameter. However, the lack of direct observations of MLD hampers both specification and investigation of its spatial and temporal variability. An important alternative to direct observation would be the ability to estimate MLD from surface Parameters easily available from satellites. In this study, we demonstrate estimation of MLD using Artificial Neural Network methods and surface meteorology from a surface mooring in the Arabian Sea. The estimated MLD had a root mean square error of 7.36 m and a coefficient of determination (R 2 ) of 0.94. About 67% (91%) of the estimates lie within 5m( 10 m) of the MLD determined from temperature sensors on the mooring.
Tim M Conway - One of the best experts on this subject based on the ideXlab platform.
-
the biogeochemical cycling of zinc and zinc isotopes in the north atlantic ocean
Global Biogeochemical Cycles, 2014Co-Authors: Tim M Conway, Seth G JohnAbstract:Zinc (Zn) is a marine micronutrient, with an overall oceanic distribution mirroring the major macronutrients, especially silicate. Seawater Zn isotope ratios (δ66Zn) are a relatively new Oceanographic Parameter which may offer insights into the biogeochemical cycling of Zn. To date, the handful of published studies of seawater δ66Zn show the global deep ocean to be both remarkably homogeneous (approximately +0.5‰) and isotopically heavier than the marine sources of Zn (+0.1 to +0.3‰). Here we present the first high-resolution oceanic section of δ66Zn, from the U.S. GEOTRACES GA03 North Atlantic Transect, from Lisbon to Woods Hole. Throughout the surface ocean, biological uptake and release of isotopically light Zn, together with scavenging of heavier Zn, leads to large variability in δ66Zn. In the ocean below 1000 m, δ66Zn is generally homogeneous (+0.50 ± 0.14‰; 2 SD), though deviations from +0.5‰ allow us to identify specific sources of Zn. The Mediterranean Outflow is characterized by δ66Zn of +0.1 to +0.3‰, while margin sediments are a source of isotopically light Zn (−0.5 to −0.8‰), which we attribute to release of nonregenerated biogenic Zn. Mid-Atlantic Ridge hydrothermal vents are also a source of light Zn (close to −0.5‰), though Zn is not transported far from the vents. Understanding the biogeochemical cycling of Zn in the modern ocean begins to address the imbalance between the light δ66Zn signature of marine sources and the globally homogeneous deep oceans (δ66Zn of +0.5‰) on long timescales, with overall patterns pointing to sediments as an important sink for isotopically light Zn throughout the oceans.
Sarika Jain - One of the best experts on this subject based on the ideXlab platform.
-
Estimation of sonic layer depth from surface Parameters
Geophysical Research Letters, 2007Co-Authors: Sarika Jain, M. M. Ali, P. N. SenAbstract:Mixed layer depth (MLD) is an important Oceanographic Parameter. However, the lack of direct observations of MLD hampers both specification and investigation of its spatial and temporal variability. An important alternative to direct observation would be the ability to estimate MLD from surface Parameters easily available from satellites. In this study, we demonstrate estimation of MLD using Artificial Neural Network methods and surface meteorology from a surface mooring in the Arabian Sea. The estimated MLD had a root mean square error of 7.36 m and a coefficient of determination (R 2 ) of 0.94. About 67% (91%) of the estimates lie within 5m( 10 m) of the MLD determined from temperature sensors on the mooring.
Seth G John - One of the best experts on this subject based on the ideXlab platform.
-
the biogeochemical cycling of zinc and zinc isotopes in the north atlantic ocean
Global Biogeochemical Cycles, 2014Co-Authors: Tim M Conway, Seth G JohnAbstract:Zinc (Zn) is a marine micronutrient, with an overall oceanic distribution mirroring the major macronutrients, especially silicate. Seawater Zn isotope ratios (δ66Zn) are a relatively new Oceanographic Parameter which may offer insights into the biogeochemical cycling of Zn. To date, the handful of published studies of seawater δ66Zn show the global deep ocean to be both remarkably homogeneous (approximately +0.5‰) and isotopically heavier than the marine sources of Zn (+0.1 to +0.3‰). Here we present the first high-resolution oceanic section of δ66Zn, from the U.S. GEOTRACES GA03 North Atlantic Transect, from Lisbon to Woods Hole. Throughout the surface ocean, biological uptake and release of isotopically light Zn, together with scavenging of heavier Zn, leads to large variability in δ66Zn. In the ocean below 1000 m, δ66Zn is generally homogeneous (+0.50 ± 0.14‰; 2 SD), though deviations from +0.5‰ allow us to identify specific sources of Zn. The Mediterranean Outflow is characterized by δ66Zn of +0.1 to +0.3‰, while margin sediments are a source of isotopically light Zn (−0.5 to −0.8‰), which we attribute to release of nonregenerated biogenic Zn. Mid-Atlantic Ridge hydrothermal vents are also a source of light Zn (close to −0.5‰), though Zn is not transported far from the vents. Understanding the biogeochemical cycling of Zn in the modern ocean begins to address the imbalance between the light δ66Zn signature of marine sources and the globally homogeneous deep oceans (δ66Zn of +0.5‰) on long timescales, with overall patterns pointing to sediments as an important sink for isotopically light Zn throughout the oceans.
Javier Marcello - One of the best experts on this subject based on the ideXlab platform.
-
on the use of gnss r data to correct l band brightness temperatures for sea state effects results of the albatross field experiments
IEEE Transactions on Geoscience and Remote Sensing, 2011Co-Authors: E Valencia, Adriano Camps, X Boschlluis, N Rodriguezalvarez, I Ramosperez, F Eugenio, Javier MarcelloAbstract:Sea surface salinity is a key Oceanographic Parameter that can be measured by means of L-band microwave radiometry. The measured brightness temperatures over the ocean are influenced by the sea state, which can entirely mask the salinity signature. Sea-state corrections Parameterized in terms of wind speed and/or significant wave height have proven not to be fully satisfactory. In 2003, it was proposed to use reflectometry using navigation opportunity signals [Global Navigation Satellite System Reflectometer (GNSS-R)] for sea-state determination and correction of the measured L-band brightness temperature changes associated to the sea state. The novelty of the approach relies in the measurement of the whole Delay-Doppler Map that captures the scattering of the GNSS signals in the whole glistening zone. In this framework, the “Advanced L-BAnd emissiviTy and Reflectivity Observations of the Sea Surface” (ALBATROSS) field experiments were undertaken in 2008 and 2009, collecting an extensive data set of collocated radiometric and reflectometric measurements over the Atlantic Ocean, as well as Oceanographic and meteorological data. In this paper, the experimental results and conclusions of the ALBATROSS 2009 field experiment are compiled and presented, showing the great potential of this technique to perform the necessary corrections in future salinity missions. Empirical relationships are derived among measured brightness temperature variations due to the sea-state effect and direct GNSS-R observables, and the sea surface correlation time at L1 band, a key Parameter for GNSS-R data processing since it determines the maximum coherent integration time, was experimentally determined.