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The dissolved nitrate is one of the major essential nutrients for primary production in the tropical ocean and it is brought to the surface though mixing. The depth of nitracline determines how much of nitrate enters to the upper ocean through mixing. The depth of nitracline is traditionally estimated using nitrate concentrations measured at standard depths that introduces significant error due to interpolation of data. Based nitrate profiles measured at 5 m interval using nitrate sensors onboard Argo, the exact depth of nitracline was derived in the Bay of Bengal that displayed a significant linear relationship with depth of 26°C isotherm (D26). Based on climatological D26, the temporal and spatial variations in the depth of nitracline was estimated for the entire Bay of Bengal. The depth of nitracline varied between 5 and 80 m with large spatial and temporal variability in the Bay of Bengal and it is 5–20 m deeper than simulations of numerical models. The relationship between the depth of nitracline and photic zone integrated primary production indicates that 7.5 ± 3 mgC m−2d−1of primary production increases due to shallowing of 1 m of depth of nitracline. Therefore, models seem to be over estimating the photic zone integrated primary production by 5%–25% in the Bay of Bengal. The numerical models may improve the simulation of primary production and carbon cycling by accounting the accurate estimation of depth of nitracline in the model initialization. In the tropical ocean, nitrate mainly controls the primary production and identifying the depth of nitracline, where nitrate concentration was 1 μM from that of surface, is important in simulating primary production by numerical models. All the numerical models are using nutrietns profiles collected at the standard depth and estimated depth of nitracline. Since the data collected at standard depth, and interpolation between depth may result in large error in the computation of nitracline depth. We used high depth resolution nitrate data collected by sensors and estimated nitracline depth and the same compared with modeled data. It was observed that models are estimating shallow nitracline than actual as a result higher biological response is simulated than reality. This exercise would be useful in improving model simulation in future. The depth of nitracline is strongly controlled by depth of 20°C isothermDeeper nitracline depth was noticed during spring and shallowers during summerModels estimate shallower nitracline depth by 5–20 m than measured The depth of nitracline is strongly controlled by depth of 20°C isotherm Deeper nitracline depth was noticed during spring and shallowers during summer Models estimate shallower nitracline depth by 5–20 m than measured

Let g1and g2be any two analytic functions defined in the unit disc which are normalized by the condition g1(0)=1=g2(0)and σnb-1,c(z)be the nthCesàro mean of type (b-1,c)for 1+b>c>0. Then g1is generalized Cesàro stable with respect to g2, whenever σnb-1,c(g1,z)g1(z)≺1g2(z)(z∈Δ,n∈N0),where σnb-1,c(g,z)=1Bn∑j=0nBn-jbjzj=σnb-1,c(z)∗g(z). The main aim of this article is to prove that (Az+1)/(Bz+1)ηis generalized Cesàro stable with respect to (1/(Bz+1)η)but not with respect to itself for -1≤B

ABSTRACTThe resolution of the model emerges to be an important factor in simulating the real oceanic features. In this paper, the performance of two coupled bio-physical models, having spatial resolutions 1/12° (∼9 km) and 1/4° (∼25 km) configured using Regional Ocean Modeling System (ROMS), have been evaluated in simulating upper ocean dynamics of the Arabian Sea. A comparison of the model simulated physical and biogeochemical fields with the observations from remote sensing, in-situship-borne, and Biogeochemical-Argo (BGC-Argo) floats showed that the high-resolution model reproduced the ocean physical and biogeochemical dynamics, and their seasonality more efficiently. The upper ocean dynamics associated with the variability of mixed layer depth, persistent occurrence of deep chlorophyll maxima, and seasonal phytoplankton blooms. as well as deep ocean characteristics of oxygen minimum zone were much effectively captured by the high-resolution model than by its counterpart. Similarly, the former model performed very well in reproducing the upwelling dynamics over the eastern continental shelf indicating that the open ocean-coastal coupling has been better established. Our analysis indicates that the realistic representation of the eddy fields by the high-resolution model leads to the better representation of the ocean fields in comparison to the coarse-resolution model.

With the exponential progression in communication technology, advanced mixed media content such as image, sound and video can be effectively duplicated and put away effortlessly without any loss in their original content. Therefore, it is distinctly critical to beat this and the need of a reasonable sort of copyright insurance framework inside the data. Reversible Data Hiding (RDH) keeps up the brilliant property that the first cover can be losslessly recouped after inserted information is separated while securing the picture substance's privacy. This may be liable to a few cause errors on information extraction and image reclamation. We propose to maintain the incredible property that the original cover has which can be losslessly recovered after embedded data is extracted while securing the image content's confidentiality. This strategy protects against different sorts of attacks on the computerized information and hence provides a robust answer for information theft cases.

Physical and biogeochemical observations from an autonomous profiling Argo float in the Bay of Bengal show significant changes in upper ocean structure during the passage of tropical cyclone (TC) Hudhud(7–14 October 2014). TC Hudhudmixed water from a depth of about 50 m into the surface layers through a combination of upwelling and turbulent mixing. Mixing was extended into the depth of nutricline, the oxycline, and the subsurface‐chlorophyll‐maximum and thus had a strong impact on the biogeochemistry of the upper ocean. Before the storm, the near‐surface layer was nutrient depleted and was thus oligotrophic with the chlorophyll‐aconcentration of less than 0.15 mg/m3. Storm mixing initially increased the chlorophyll by 1.4 mg/m3, increased the surface nitrate concentration to about 6.6 μM/kg, and decreased the subsurface dissolved oxygen (30–35 m) to 31% of saturation (140 μM). These conditions were favorable for phytoplankton growth resulting in an estimated increase in primary productivity averaging 1.5 g C·m−2·day−1over 15 days. During this bloom, chlorophyll‐aincreased by 3.6 mg/m3, and dissolved oxygen increased from 111% to 123% of saturation. Similar observations during TC Vardah(6–12 December 2016) showed much less mixing. Our analysis suggests that relatively small (high) translation speed and the presence of cold (warm) core eddy leads to strong (weak) oceanic response during TC Hudhud(TC Vardah). Thus, although cyclones can cause strong biogeochemical responses in the Bay of Bengal, the strength of response depends on the properties of the storm and the prevailing upper ocean structure such as the presence of mesoscale eddies. It is very difficult to quantify the upper ocean physical and biogeochemical response to extreme weather conditions like tropical cyclones (TCs). In situ vertical profiles of temperature, salinity, chlorophyll fluorescence, dissolved oxygen, nutrients, and optical backscatter from the biogeochemical‐Argo floats can provide unique opportunity to quantify the upper ocean biogeochemical response to tropical cyclone, if cyclones traverse over the floats. In this study, the proximity of a biogeochemical‐Argo float to TC Hudhud and TC Vardah tracks, having similar intensity when it was close to the float location, reveals that oceanic responses are quite higher in the former than the latter. Our results suggest that translation speed of the storm and background oceanic conditions such as the presence of mesoscale eddies determines the ocean biogeochemical evolution in response to TCs. Upper ocean biogeochemical response to the tropical cyclone Hudhud and Vardah using BGC‐Argo float in the Bay of BengalPreexisting oceanic conditions and TC translation speed on biogeochemical responses are examinedThe importance of profiling float on the calculation of primary productivity is examined

Intense oxygen minimum zone (OMZ) occurs in the middepth of the Eastern Tropical Pacific (ETP), Arabian Sea (AS), and Bay of Bengal (BoB). However, the occurrence of anammox/denitrification was reported only in the ETP and AS and its absence in the BoB is attributed to presence of traces of dissolved oxygen (DO). Anticyclonic eddies (ACEs) supply high‐nutrient, organic‐rich, and oxygen‐poor waters from the coastal upwelling regions leading to strengthening of OMZ in the offshore of AS and ETP. In the absence of western boundary upwelling, we hypothesize that the ACEs supply DO‐rich water leading to weakening of OMZ in the BoB. Six ACEs were sampled by bio‐argo floats and measured in situ hydrography and DO. All sampled eddies were formed in the eastern BoB, close to Andaman Sea, and moved toward west. Warm and DO‐rich waters were observed in the core of OMZ (150–300 m), influenced by ACEs, by 0.5–1.46°C and 3.2–6.5 μM, respectively, than no eddy region in the BoB. Based on the mean lifetime of ACE, the rate of ventilation in the 100–300 m was estimated to be 0.07 ± 0.02 μmol/L/day, which is 3 to 4 times higher than bacterial respiration rates (0.02 μmol/L/day). Concerns of OMZ intensification leading to denitrification/anammox conditions in the BoB have been expressed, but with several ACEs forming in time and space in the BoB the denitrification occurrence is unlikely. Anticyclonic eddies (ACE) supply oxygen and weakens OMZRate of ventilation of oxygen through ACE is 3–4 times higher than bacterial respiration

Global 2-day mean wind fields of Oceansat-2 scatterometer (OSCAT) were generated using variational data analysis method for the period 2010–2013. The resultant OSCAT gridded wind data with a resolution of 0.5° × 0.5° was validated using in situ observations from buoys and Advanced Scatterometer (ASCAT) for different global ocean basins and wind speed ranges. Globally, a bias of − 0.5 ms−1for uand 0.1 ms−1for vand root mean square difference (RMSD) of 1.95 ms−1for uand 1.7 ms−1for vwas observed. Inter-comparison in different oceanic basins revealed that the gridded OSCAT data is in concurrence with in situ measurements. Inter-comparison between OSCAT and ASCAT for different seasons showed a correlation greater than 0.75, bias in the range of − 1 to 1 ms−1and RMSD less than 2.5 ms−1; for both uand vwind components on a global scale. The resultant OSCAT gridded winds can be used to generate value added products like wind stress and curl for the global oceans.

Abstract: A new marine meteorological climatology named Marine Meteorological Atlas for Tropical Indian Ocean (MaMetAtTIO) is generated for tropical Indian Ocean (TIO). The climatology is derived from ship-based observations of International Comprehensive Ocean-Atmosphere Dataset (ICOADS) Release 3.0 and those obtained from the India Meteorological Department (IMD). The climatologies of several independent and derived variables are constructed and the framework is presented in detail. The enhancement in MaMetAtTIO is statistically evaluated with reference to ICOADS R3.0 climatology. ICOADS Release 3.0 dataset has been found to be self-robust, as there was no significant improvement in the monthly and annual climatology of independent variables in MaMetAtTIO even after adding new records to ICOADS Release 3.0. However, there are few filled grid points in the individual year–month summaries owing to the addition of unique data from IMD. An attempt to correct the systematic error in Beaufort estimated wind speed, has reduced the annual net heat flux for TIO by 14 W/m2. Furthermore, MaMetAtTIO is compared with in-situdata from moored buoys and Tropflux datasets. Two case studies (Madden–Julian oscillation (MJO) study, empirical orthogonal function (EOF) analysis) were undertaken to highlight the importance of adding individual observations to ICOADS R3.0 and the gridded fields of MaMetAtTIO. Better correlation (difference being significant) was observed between the time series derived from MaMetAtTIO and MJO index and the addition of new data resulted in filling of gaps in individual year–month summaries favourable to carry out statistical analyses such as EOF. Research highlights:

Marine meteorological atlas constructed exclusively from ship observations.

Gridded fields of annual, monthly climatologies and individual year–month summaries are available for all marine-meteorological parameters including fluxes.

A long climatology dataset showing well-defined features of most of the climate phenomenon and their influences across tropical Indian Ocean.

A 14 W/m2reduction in net annual heat flux for tropical Indian Ocean obtained through observational error correction.

Abstract.We obtain nontrivial solutions of some elliptic interface problems with nonhomogeneous jump conditions that arise in localized chemical reactions and nonlinear neutral inclusions. Our proofs in bounded domains use Morse theoretical arguments, in particular, critical group computations. An extension to the whole space is proved using concentration compactness arguments.

The most used temperature and salinity climatology for the world ocean, including the Indian Ocean, is the World Ocean Atlas (WOA) (Antonov et al 2006, 2010; Locarnini et al 2006, 2010) because of the vast amount of data used in its preparation. The WOA climatology does not, however, include all the available hydrographic data from the Indian Exclusive Economic Zone (EEZ), leading to the potential for improvement if the data from this region are included to prepare a new climatology. We use all the data that went into the preparation of the WOA (Antonov et al 2010; Locarnini et al 2010), but add considerable data from Indian sources, to prepare new annual, seasonal, and monthly climatologies of temperature and salinity for the Indian Ocean. The addition of data improves the climatology considerably in the Indian EEZ, the differences between the new North Indian Ocean Atlas (NIOA) and WOA being most significant in the Bay of Bengal, where the patchiness seen in WOA, an artifact of the sparsity of data, was eliminated in NIOA. The significance of the new climatology is that it presents a more stable climatological value for the temperature and salinity fields in the Indian EEZ.

We consider an initial value problem for a fractional differential equation of Caputo type. The convergence of the Picard successive approximations is established by first showing that the Caputo derivatives of these approximations converge. The method utilized, originally introduced in [O. Kooi, The method of successive approximations and a uniqueness theorem of Krasnoselskii–Krein in the theory of differential equations, Nederi. Akad. Wetensch, Proc. Ser. A61; Indag. Math. 20 (1958) 322–327], is interesting in itself.

The hybrid real number system consisting of terminating and nonterminating decimals, dark numbers, dual dark numbers, involving the notions of personal infinities and the impersonal infinity has been discussed. Some algebraic properties of dark numbers and dual dark numbers are discussed.

AbstractIt is known that a Fréchet space can be realized as a projective limit of a sequence of Banach spaces . The space Kc() of all compact, convex subsets of a Fréchet space, , is realized as a projective limit of the semilinear metric spaces . Using the notion of Hukuhara derivative for maps with values in Kc(), we prove the local and global existence theorems for an initial value problem associated with a set differential equation.

The seasonal and spatial variability of mixed layer depth (MLD) was examined in the Western Indian Ocean (WIO) (30E-80E and 10S-30N) for three consecutive years starting from June 2002-May 2005 using Argo temperature and salinity (T/S) profiles. These were compared with MLD estimates from World Ocean Atlas 2001 (WOA01) T/S data. Temporal and spatial variability of MLD estimated from Argo T/S profiles were found to correspond well with the MLD obtained from WOA01 T/S data. However, slight deviations in the form of months of occurrence of minima and maxima MLDs were observed. MLD from WOA01 climatology is underestimated compared to MLD from Argo for almost the entire three years of study. It is also observed that MLD variability features as brought Out by both the data sets followed the dynamics that govern the mixed layer variability in this region. [ABSTRACT FROM AUTHOR]

A series of molybdenum oxide catalysts with Mo loadings in the range 2.5−12.5 wt % Mo supported on La2O3-stabilized ZrO2 was prepared by impregnation. X-ray diffraction results of the catalysts showed the diffraction patterns of crystalline MoO3 from 10 wt % Mo. Dispersion of molybdena was determined by the oxygen chemisorption method, and it was found to decrease with an increase in Mo loading due to formation of MoO3 crystallites at higher Mo loadings. Temperature-programmed reduction results suggest that the reducibility is found to decrease with Mo loading as a result of the decrease in dispersion. The acidity of the catalysts was found to increase with Mo loading, and the activity of the catalysts also found to increase with the increase in Mo loading up to 7.5 wt % Mo loading. Laser Raman spectra of the catalysts show the Raman bands due to MoO3 from 7.5 wt % Mo at 819 and 997 cm^-1. At lower Mo loadings, highly dispersed species were observed. The catalytic properties were evaluated during the ammoxidation of toluene to benzonitrile and were related to the oxygen chemisorption sites on the support surface.

A series of MoO3/Nb2O5 catalysts with Mo loadings varying from 2.5 to 15 wt % were prepared and characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), temperature-programmed desorption (TPD) of ammonia, electron spin resonance (ESR), oxygen chemisorption, and pore size distribution measurements. X-ray diffraction patterns indicate the presence of a crystalline molybdenum phase at higher Mo loadings on niobia. Dispersion of molybdenum was determined by the oxygen chemisorption at 623 K by a static method on the samples prereduced at the same temperature. At low Mo loadings, i.e., <10.0%, molybdenum oxide is found to be present in a highly dispersed state. Pore size distribution studies indicate a decrease in average pore diameter and pore volume with increased Mo loading. ESR results suggest the presence of Mo⁵⁺ in the reduced catalysts. TPR results suggest that the reducibility of MoO3 increases with increased Mo loading. The reduction peaks due to niobia in TPR appeared at high temperatures (>1173 K) and their intensity decreases with Mo loading. TPD of ammonia results suggest that acidity of the catalysts was found to increase with increased molybdenum loading. The catalytic properties were evaluated for the vapor-phase ammoxidation of 3-picoline to nicotinonitrile and related to oxygen chemisorption sites.

Determining an oceanographic parameter on regular grid positions, using a set of data at random locations both in space and time, is the most sought after typical problem since long in the field of oceanography. This is usually called the gridding problem, and the outcome is useful for many applications such as data analysis, graphical display, forcing or initialization of models, etc. In the present study temperature and salinity profiles data obtained from Argo profiling floats were used, and data on regular grids were generated. Data-interpolating variational analysis (DIVA) method was chosen for generating the gridded product. Extensive analysis was done to obtain correct choices of correlation length (L) and signal-to-noise ratio (λ), which results in an optimal gridded product. The gridded data obtained for different choices of Land λwere later validated with datasets deliberately set aside before performing the analyses. For each combination of Land λ, the resultant gridded data was also validated with subsurface data from OMNI buoys. Based on the statistics of comparison with OMNI, the best-fit choice for Land λwas concluded. Later, a comparative analysis was performed with the obtained gridded products from DIVA against the gridded product obtained from objective analysis (OA) to demonstrate the method's reliability. The resultant optimal combination of Land λwill be used for generating Argo gridded data, which will be subsequently used for generating value-added products like mixed layer depth, ocean heat content, D20, etc., and will be made available on INCOIS Live Access Server.

Spatial variability in boundaries and thickness of oxygen minimum zone (OMZ) is derived based on measured dissolved oxygen data obtained from sensors on board biogeochemical (BGC) Argo floats between 2013 and 2019 in the Bay of Bengal (BoB). Upper and lower boundaries of the OMZ varied from 60 to 200 m and 100 to 800 m respectively with the thickness of 80–650 m in the BoB. Relatively thicker OMZ is noticed in the northern than southern BoB associated with stratification. The oxygen concentrations in the OMZ in the NW was low (<1.5 μM) than NE BoB (2.5 μM) indicating that thick and intense OMZ occurs in the NW region associating with stratification and high primary production. Significant decrease in particle‐back‐scatter signal was observed toward offshore from shelf indicating organic matter from the shelf sediments may be supporting bacterial carbon demand in the OMZ. The particle backscatter signal peaked in the OMZ region with a higher signal in the north than southern BoB and it is consistent with the low oxygen concentration in the former indicating that organic matter from shelf sediments may be supporting carbon needs in the OMZ. In addition to this, the occurrence of eddies significantly controls the intensity of the OMZ in the BoB through mixing at the upper boundary of OMZ. Therefore, this study suggests that spatial variations in intensity of OMZ in the BoB are governed by stratification, primary and export productions, organic matter decomposition, and eddy‐driven mixing. Based on the dissolved oxygen data collected by Biogeochemical (BGC) Argo floats, we have shown for the first time the boundaries and thickness of the OMZ in the BoB. The occurrence of OMZ in the BoB is mainly caused by freshwater discharge from the majors rivers, that do inhibit mixing of atmospheric oxygen, primary production, export of dead organic matter to OMZ, and subsequent decomposition by bacteria, that consumes oxygen in the water, and mixing of oxygen by eddies. We noticed that the thick and intense OMZ exists in the northwestern BoB associating with stratification, high primary production, and slower rate of dead organic matter sinking to OMZ and weaker eddy activity. The thick oxygen minimum zone (OMZ) occurred in the northern Bay of Bengal (BoB) associated with strong salinity stratificationParticle back‐scatter signal suggests cross‐shelf transport of organic matter may support heterotrophic carbon demand in the OMZIntense OMZ in the northwestern BoB associated with high primary production, and sinking carbon fluxes The thick oxygen minimum zone (OMZ) occurred in the northern Bay of Bengal (BoB) associated with strong salinity stratification Particle back‐scatter signal suggests cross‐shelf transport of organic matter may support heterotrophic carbon demand in the OMZ Intense OMZ in the northwestern BoB associated with high primary production, and sinking carbon fluxes

A series of molybdena catalysts supported on anatase titania with Mo loadings ranging from 2 to 12 wt % were investigated by ¹H MAS NMR, XRD, ESR, and oxygen chemisorption. ¹H MAS NMR spectra reveals the presence of two types of OH groups (acidic and basic) on TiO2. Dispersion of molybdena was determined by the oxygen chemisorption at 623 K through a static method on the samples prereduced at the same temperature. At low Mo loadings, i.e., below 6% Mo, molybdenum oxide is found to be present in a highly dispersed state. A comparison of the dispersion of molybdena determined by low-temperature oxygen chemisorption (samples reduced at 773 K for 6 h and subsequent oxygen chemisorption at 195 K) with that determined at 623 K shows that the latter method provides a better measure of the dispersion of molybdena. ESR results suggest the presence of Mo⁵⁺ in the reduced catalysts.

AbstractTwo different ordinary differential operators L1and L2(not of the same order) defined on two adjacent intervals I1and I2, respectively, with certain mixed conditions at the interface are considered. These problems are encountered in the study of ?acoustic waveguides in ocean?, ?transverse vibrations in nonhomogeneous strings?, etc. A complete set of physical conditions on the system give rise to three types of (selfadjoint) boundary value problems associated with the pair (L1, L2). In a series of papers, a systematic study of these new classes of problems is being developed. In the present paper, we construct the fundamental systems and exhibit the forms of solutions of nonhomogeneous problems associated with the pair (L1, L2).

A series of TiO2 (anatase) supported vanadia catalysts with V2O5 loadings ranging from 2 to 12% were characterized by temperature-programmed reduction (TPR), X-ray diffraction, electron spin resonance (ESR), and oxygen chemisorption studies. TPR profiles indicate the presence of a single peak for the reduction and suggest that the reducibility of vanadia depends on its loading on TiO2. Dispersion of vanadia was determined by the static oxygen chemisorption method at 640 K on the samples prereduced at the same temperature. At low vanadia loadings, i.e., below 6%, vanadium oxide is found to be present in a highly dispersed state. A comparison of dispersion of vanadia determined by low-temperature oxygen chemisorption (samples reduced at 773 K for 6 h and subsequent oxygen chemisorption at 195 K) with that determined at 640 K shows that the latter method provides a better measure of dispersion of vanadia. ESR spectra obtained under ambient conditions for the catalysts reduced at 640 K show the presence of V⁴⁺ ions in axial symmetry. The results are discussed with the possible surface vanadia species present on TiO2. The catalytic properties were evaluated for the vapor-phase ammoxidation of 3-picoline to nicotinonitrile and related to the oxygen chemisorption sites.

We shall develop, in this paper, the hybrid set theory extending some notions of the hybrid real number system considered in [V. Lakshmikantham, D. Kovach, Hybrid real number system, Nonlinear Analysis: Hybrid Systems (2006), doi:10.1016/nahs.2006.07.001], so as to shed some light on the existing set theory and strengthen it. We shall also list some ideas of set theory that existed long before Cantor’s discovery [G. Cantor, Contributions to the Founding of the Theory of Transfinite Numbers (P.E.B., Trans.), The Open Court Publishing Co., la Salle, Illinois, 1952].

Vapour phase ammoxidation of 3-picoline to nicotinonitrile was carried out on highly dispersed vanadia catalysts supported on zirconia, the results suggest that vanadia/zirconia possesses high activity and selectivity for nicotinonitrile formation.

We introduce a generalized notion of invariance for differential inclusions, using a proximal aiming condition in terms of proximal normals. A set of sufficient conditions for the weak and strong invariance in the generalized sense are presented.

An algorithm for the computation of Green's matrices for boundary value problems associated with a pair of mixed linear regular ordinary differential operators is presented and two examples from the studies of acoustic waveguides in ocean and transverse vibrations in nonhomogeneous strings are discussed.