Wave height forecasting by the transfer function model

Three completing methods were introduced in this paper. The data were completed from 1983 to 1988 at the KL and PTC stations. The completed data were called original data. The completing methods were the transfer function with fixed-parameters then built the Transfer Function (TF) model between the two stations. The TF model was used to estimate the wave data of the future. The difference of the estimated data and the original data were conferred in this paper. Two types of forecasting differences were discussed here: (1) the input data year increases from 1 to 6 years, and the difference of the estimated data and the original data were then compared. (2) Use one-year data as the input series to forecast the data of the next five years, and then compare the differences of the estimated data and the original data. After comparing the differences we can know the results. The mean value and the standard deviation of the differences decrease and go more stable as the quantity of the input data year increases. The mean value and the standard deviation of the differences increase and go more unstable as the quantity of the forecasted data year increases. This model can be used to forecast the wave data.     

Chemical Composition Based Aerosol Optical Properties According to Size Distribution and Mixture Types during Smog and Asian Dust Events in Seoul,Korea

This study investigated the optical properties of aerosols involved in different meteorological events, including smog and Asian dust days. Carbonaceous components and inorganic species were measured in Seoul, Korea between 25 and 31 March 2012. Based on the measurements, the optical properties of aerosols were calculated by considering composition, size distribution, and mixing state of aerosols. To represent polydisperse size distributions of aerosols, a lognormal size distribution with a wide range of geometric mean diameters and geometric standard deviations was used. For the optical property calculations, the Mie theory was used to compute single-scattering properties of aerosol particles with varying size and composition. Analysis of the sampled data showed that the water-soluble components of organic matter increased on smog days, whereas crustal elements increased on dust days. The water content significantly influenced the optical properties of aerosols during the smog days as a result of high relative humidity and an increase in the water-soluble component. The absorption coefficients depended on the aerosol mixture type and the aerosol size distributions. Therefore, to improve our knowledge on radiative impacts of aerosols, especially the regional impacts of aerosols in East Asia, accurate measurements of aerosols, such as size distribution, composition, and mixture type, under different meteorological conditions are required.     

<Emphasis Type="Italic">In-situ</Emphasis> measured primary productivity of ice algae in Arctic sea ice floes using a new incubation method

Recent changes in climate and environmental conditions have had great negative effects such as decreasing sea ice thickness and the extent of Arctic sea ice floes that support ice-related organisms. However, limited field observations hinder the understanding of the impacts of the current changes in the previously ice-covered regions on sea ice algae and other ice-related ecosystems. Our main objective in this study was to measure recent primary production of ice algae and their relative contribution to total primary production (ice plus pelagic primary production). In-situ primary productivity experiments with a new incubation system for ice algae were conducted in 3 sea ice cores at 2 different ice camps in the northern Chukchi Sea, 2014, using a ¹³C and ¹⁵N isotope tracer technique. A new incubation system was tested for conducting primary productivity experiments on ice algae that has several advantages over previous incubation methods, enabling stable carbon and nitrogen uptake experiments on ice algae under more natural environmental conditions. The vertical C-shaped distributions of the ice algal chl-a, with elevated concentrations at the top and bottom of the sea ice were observed in all cores, which is unusual for Arctic sea ice. The mean chl-a concentration (0.05 ± 0.03 mg chl-a m^?3) and the daily carbon uptake rates (ranging from 0.55 to 2.23 mg C m^?2 d^?1) for the ice algae were much lower in this study than in previous studies in the Arctic Ocean. This is likely because of the late sampling periods and thus the substantial melting occurring. Ice algae contributed 1.5–5.7% of the total particulate organic carbon (POC) contents of the combined euphotic water columns and sea ice floes. In comparison, ice algae contributed 4.8–8.6% to the total primary production which is greater than previously reported in the Arctic Ocean. If all of the ice-associated productions were included, the contributions of the sea ice floes to the total primary production would be greater in the Arctic Ocean and their importance would be greater in the arctic marine ecosystems.     

Flow of a double-diffusive stratified fluid in a differentially-rotating cylinder

Abstract

A study has been made of a basic state of axisymmetric flow, at large rotational Reynolds numbers, in a double-diffusive stratified fluid contained in a vertically-mounted, differentially-rotating cylindrical cavity. The aim is to describe the qualitative characteristics of the flow of a fluid, the density of which is stratified by two diffusive effects, i.e., temperature and salinity gradients. Attention is confined to situations in which the temperature and salinity gradients make opposing contributions to the overall density profile, the undisturbed stratification being gravitationally stable. Finite difference numerical solutions of the governing Navier-Stokes equations have been obtained using the Boussinesq approximation. The results are presented in a way that illustrates the explicit effects of double-diffusivity when the cavity aspect ratio, height/radius, is O(1). The principal non-dimensional parameters characterizing the flow field are identified. In the interior core, the primary dynamic balance is between the horizontal density gradient and the vertical shear of the prevailing azimuthal velocity. The effective stratification is seen to decrease as the double-diffusivity increases, even if the overall stratification parameter, St, is held constant. The solute field contains a very thin boundary layer structure at large Lewis numbers. The effective stratification increases with the Prandtl number. Results have been derived for extreme values of the cavity aspect ratio. For small cavity aspect ratios, the dominant dynamic ingredients are viscous diffusion and rotation. For large aspect ratios, the bulk of the flow field is determined by the rotating sidewall. In this case, the direct influence of the double-diffusivity is minor.     

Differential calibration of seismometers for measurement of rotation and strain

A method of correcting the seismometers’ responses discrepancy for differential measurements of strains and rotations in the seismic far field is proposed. The method concerns differential calibration of the whole seismometers’ array by electric current. A model of corrective filtering of the obtained differential signals in the Z domain is given. Two methods of the filter parameters’ estimation are introduced; they are based on the seismometers response to the calibration. A practical test of the methods — an analysis of a recorded seismic event — is added. Significant reduction of differences between simultaneous seismic recordings was obtained, which is interpreted as cleaning of differential signal from spurious elements.     

Late Quaternary glacial–interglacial variations in sediment supply in the southern Drake Passage

Geochemical characteristics of marine sediment from the southern Drake Passage were analyzed to reconstruct variations in sediment provenance and transport paths during the late Quaternary. The 5.95 m gravity core used in this study records paleoenvironmental changes during the last approximately 600 ka. Down-core variations in trace element, rare earth element, and Nd and Sr isotopic compositions reveal that sediment provenance varied according to glacial cycles. During glacial periods, detrital sediments in the southern Drake Passage were mostly derived from the nearby South Shetland Islands and shelf sediments. In contrast, interglacial sediments are composed of mixed sediments, derived from both West Antarctica and East Antarctica. The East Antarctic provenance of the interglacial sediments was inferred to be the Weddell Sea region. Sediment input from the Weddell Sea was reduced during glacial periods by extensive ice sheets and weakened current from the Weddell Sea. Sediment supply from the Weddell Sea increased during interglacial periods, especially those with higher warmth such as MIS 5, 9, and 11. This suggests that the influence of deep water from the Weddell Sea increases during interglacial periods and decreases during glacial periods, with the degree of influence increasing as interglacial intensity increases.     

Ecological effects of soil antimony on the crop plant growth and earthworm activity

High levels of antimony have been frequently detected in some industrial sites. This study evaluated the adverse effects of antimony (Sb) on the surface-casting activity of earthworm and the early growths of some important crop plants. Asian earthworm (Perionyx excavates) and four crop plant species (Chinese cabbage, Brassica campestris; wheat, Triticum aestivum; cucumber, Cucumis sativus; and mung bean, Phaseolus radiatus) were exposed to soil antimony in laboratory. Survival, abnormality and the surface-casting activity of earthworm were monitored. Negative effects of the survival and the morphological abnormalities were observed in the P. excavates exposed to Sb. The earthworm activity, expressed as surface cast production, was significantly inhibited with elevated Sb levels. In terms of plant assay, the growth of all test plants was adversely affected in Sb-contaminated soils, and the content of Sb in plant tissues increased with increasing Sb concentration in soil. The results demonstrate that elevated Sb concentrations in soil would inhibit the early growth of crop plants, and the earthworm casting activity that is a key function of earthworm to increase soil fertility. This is the first report on the negative effect of Sb on the casting activity of earthworm as well as the growth of test plant species selected.