CHARACTERISTICS OF ANTICYCLONIC EDDY FORMED AT THE PACIFIC COAST OF THE SOUTHERN KURIL ISLANDS IN THE SPRING 1999

Based on the analysis of oceanographic survey materials and sea surface temperature satellite observations, the conditions of formation and characteristics of the anticyclonic eddy located in the region of the South Kuril Islands in the spring of 1999 were studied. It was shown that it separated from the subarctic front as result of its interaction with the Oyashio current stream in the second half of March and ceased to exist in mid-June, which is also confirmed by observations of the concentration of chlorophyll-a. In contrast the eddies formed as a result of meandering of the warm Kuroshio and Tsugaru currents, the eddy core, located at depths of 150–300 m, was characterized by lower values of temperature and salinity (4°–4.6°С and 33.55–33.65 е.п.с.) and low current velocities ( about 10 cm/s). The eddy was rather weakly distinguished in the density field both on horizontal and vertical distributions, as well as according to satellite altimetry data.

Sensitivity of spatial aerosol particle distributions to the boundary conditions in the PALM model system 6.0

High-resolution modelling is needed to understand urban air quality and pollutant dispersion in detail. Recently, the PALM model system 6.0, which is based on the large-eddy simulation (LES), was extended with a detailed aerosol module SALSA2.0 to enable studying the complex interactions between the turbulent flow field and aerosol dynamic processes. This study represents an extensive evaluation of the modelling system against the horizontal and vertical distributions of aerosol particles measured using a mobile laboratory and a drone in an urban neighbourhood in Helsinki, Finland. Specific emphasis is on the model sensitivity of aerosol particle concentrations, size distributions and chemical compositions to boundary conditions of meteorological variables and aerosol background concentrations. The meteorological boundary conditions are drawn from both a numerical weather prediction model and observations, which occasionally differ strongly. Yet, the model shows good agreement with measurements (fractional bias

Horizontal and Vertical Distributions of Heartwood for Teak Plantation

Tectona grandis is a valuable timber species with heartwood that is used worldwide. Most of the previous studies on its heartwood and sapwood have focused on dominant or mean trees, while trees with different social status might show different vertical and horizontal distributions of heartwood and sapwood. Studies on their heartwood and sapwood properties could be conducive to increasing heartwood yield at stand level. In 31-year-old plantations of T. grandis in southwest Guangxi, China, the trees were divided into three groups including dominant, mean and suppressed trees. Stem analysis was conducted for sampled trees in each of these groups to explore the differences in the horizontal and vertical distribution of their heartwood and sapwood. The results indicated that the heartwood radius, heartwood and sapwood areas of T. grandis showed significant differences in horizontal and vertical directions among trees of different social status. Heartwood began to form when xylem radius was 2–3 cm, and the heartwood radius ratio tended to be stable when the xylem radius reached about 8 cm. Heartwood radius and area, sapwood area and section heartwood volume all decreased with increasing tree height. The ratios of heartwood radius and area were relatively stable for sections under 50% of tree height. The sapwood width did not vary largely in horizontal and vertical directions among the three social status tree groups, which mainly fluctuated in the range of 1–4 cm. The heartwood volume proportions for dominant, mean and suppressed trees were 60%, 55% and 51%, respectively. There was a significant exponential relationship between heartwood volume and diameter at breast height (DBH) regardless of social status. The model HV = 0.000011 × DBH2.9787 (R2 = 0.8601) could accurately estimate heartwood volume for all T. grandis with different social statuses at this age. These findings could provide evidence for stand management and high-quality and large-sized timber production of T. grandis.

KEANEKARAGAMAN DAN SEBARAN EKOLOGIS AMFIBI DI AIR TERJUN BARAMBAISAMARINDA, KALIMANTAN TIMUR

Diversity and ecological distributions of amphibians in Berambai Waterfall area, East Kalimantan have never been known. The purposes of this study were to determine the diversity of amphibian species in relation to environmental conditions and the vertical-horizontal distribution. A total of 109 amphibians were captured using methods of the transect and the visual encounter survey for 20 days on two type observation habitats. The results of this study found 18 species from six amphibian families. Based on the number of species, the diversity amphibian index and dominance index have a stable of communities, with the high value of Shannon-wiener diversity index (H'), the evenness index (E), and the low value of dominance index (D) were 2.26, 0.78, and 0.16, respectively. Horizontal distribution of amphibians in their habitat showed that aquatic amphibian groups were found to be less than 5 m from the river bank, while terrestrial and semi-aquatic amphibians have a distribution of 5–15 m from the river bank. Vertical distribution of Polypedates leucomystax, Polypedates otilophus and Odorrana hosii in vegetation were found from 1.5–2.5 m above ground level, while Ansonia spinulifer, Chalcorana chalconota, Chalcorana raniceps were at a height of 0.5–<1.5 m from ground level. Diversity of amphibian in Berambai Waterfall area related to habitat conditions, while horizontal and vertical distributions are influenced by species, habits and food resources.

Inverting the East Asian Dust Emission Fluxes Using the Ensemble Kalman Smoother and Himawari-8 AODs: A Case Study with WRF-Chem v3.5.1

We present the inversions (back-calculations or optimizations) of dust emissions for a severe winter dust event over East Asia in November 2016. The inversion system based on a fixed-lag ensemble Kalman smoother is newly implemented in the Weather Research and Forecasting model and is coupled with Chemistry (WRF-Chem). The assimilated observations are the hourly aerosol optical depths (AODs) from the next-generation geostationary satellite Himawari-8. The posterior total dust emissions (2.59 Tg) for this event are 3.8 times higher than the priori total dust emissions (0.68 Tg) during 25–27 November 2016. The net result is that the simulated aerosol horizontal and vertical distributions are both in better agreement with the assimilated Himawari-8 observations and independent observations from the ground-based AErosol RObotic NETwork (AERONET), the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). The developed emission inversion approach, combined with the geostationary satellite observations, can be very helpful for properly estimating the Asian dust emissions.

Analysis of Hydrodynamic Performance of L-Type Podded Propulsion with Oblique Flow Angle

In this study, the Reynolds-averaged Navier–Stokes (RANS) method and a model experimental test in a towing tank are used to investigate the unsteady hydrodynamic performance of L-type podded propulsion under different oblique flow angles and advance coefficients. The results show that the load of the operative propeller increases with oblique flow angle and the bracket adds resistance to the pod due to the impact of water flow, leading to a reduced propeller thrust coefficient with increased oblique flow angle. Under a high advance coefficient, the speed of increase of the pressure effect is higher than that of the viscosity effect, and the propeller efficiency increases with the oblique flow angle. The nonuniformity of the inflow results in varying degrees of asymmetry in the horizontal and vertical distributions of the propeller blade pressure. Under high oblique flow angle, relatively strong interference effects are seen between venting vortexes and the cabin after blades, leading to a disorderly venting vortex system after the blade. The numerical simulation results are in good agreement with the experimental values. The study findings provide a foundation for further research on L-type podded propulsors.

A STUDY ON INTENSITY DISTRIBUTION OF CONCRETE IN STRUCTURE WITH DIFFERENT BUILDING AGES

Recently, seismic diagnosis and earthquake resistant reinforcement works of buildings built before the new earthquake resistant standards are conducted in various places. However, there is no uniformity in sampling methods, and it seems that there are occasional extreme variations in the determination of representative intensity of the building. In addition, the physical properties of structure concrete which factor of the above-mentioned variations are considered to reflect the horizontal and vertical distribution at the time of concrete placing. Therefore, this study, the core of the existing buildings to be disassembled was collected, and the distribution of physical properties of structure concrete was examined. All target buildings were reinforced concrete constructions, and cores were collected from pillars and waist walls. In addition, there are parts that were built at the time without the ready-mixed concrete plant (from 1960) and pump truck (from 1964). Experimental results of horizontal and vertical distributions of compressive intensity at the pillars and waist walls revealed that there was no greatest decrease in strength and there was not much difference between the maximum strength of the pillar and 300 mm from the vicinity of the pillar and about 300 mm from F. L. Therefore, from this study, it seems that the position of 300 mm from the pillar and F. L. is suitable for the measurement position which develops the representative intensity of the building.

Soil mesostigmatid mites as a potential tool for bioindication concerning ecological status of forest

Free-living predatory mesostigmatid soil mites from five different forests from the Danube Delta Biosphere Reserve (DDBR) were analyzed in order to get information for defining the conservation status of the investigated sites. On the whole, in the five studied sites 32 species of Mesostigmata belonging to 22 genera and 11 families were recorded. The analyzed material includes new species of Romanian fauna as well as rare and less cited species from Romania. A quarter of the identified species were formerly found in the Danube Delta, two species being identified only within DDBR territory. The particular conditions of each stand (vegetation, type of soil etc.) as well as climatic conditions influence both the quantitative and qualitative aspects of the structure of the mesostigmatid mites communities. Horizontal and vertical distributions and the aspects of demographic structure are discussed and the degree of similarity of the gamasid mite communities from the five sites were analyzed on the basis of specific composition and quantitative parameters.