排序方式： 共有120条查询结果，搜索用时 15 毫秒
101.
Ocean Science Journal - Anatomical, histological, and histochemical investigations on the olfactory organ of the great blue spotted mudskipper Boleophthalmus pectinirostris were conducted using a... 相似文献
102.
Hyoun‐Tae Hwang Young‐Jin Park Edward A. Sudicky Steven J. Berg Robert McLaughlin Jon P. Jones 《水文研究》2018,32(6):729-746
This study demonstrates the importance of the including and appropriately parameterizing peatlands and forestlands for basin‐scale integrated surface–subsurface models in the northern boreal forest, with particular emphasis on the Athabasca River Basin (ARB). With a long‐term water balance approach to the ARB, we investigate reasons why downstream mean annual stream flow rates are consistently higher than upstream, despite the subhumid water deficit conditions in the downstream regimes. A high‐resolution 3D variably saturated subsurface and surface water flow and evapotranspiration model of the ARB is constructed based on the bedrock and surficial geology and the spatial distribution of peatlands and their corresponding eco‐regions. Historical climate data were used to drive the model for calibration against 40‐year long‐term average surface flow and groundwater observations during the historic instrumental period. The simulation results demonstrate that at the basin‐scale, peatlands and forestlands can have a strong influence on the surface–subsurface hydrologic systems. In particular, peatlands in the midstream and downstream regimes of the ARB increase the water availability to the surface–subsurface water systems by reducing water loss through evapotranspiration. Based on the comparison of forestland evapotranspiration between observation and simulation, the overall spatial average evapotranspiration in downstream forestlands is larger than that in peatlands and thus the water contribution to the stream flow in downstream areas is relatively minor. Therefore, appropriate representation of peatlands and forestlands within the basin‐scale hydrologic model is critical to reproduce the water balance of the ARB. 相似文献
103.
Kyu Rang KIM Tae Heon KWON Yeon-Hee KIM Hae-Jung KOO Byoung-Cheol CHOI Chee-Young CHOI 《大气科学进展》2009,26(2):283-292
Spatiotemporal changes in air temperature and humidity associated with the restoration of
an inner-city stream in Seoul, Korea, are investigated based on long-term monitoring data. The
Cheonggye stream, covered under a concrete structure for 46 years, was restored in 2005 and runs
5.8 km eastward through a central region of Seoul. Long-term monitoring of the air temperature and
relative humidity was made along the stream throughout the restoration and across the stream after
the restoration. The area along the stream had a higher air temperature than the entire metropolitan
area. The temperature anomaly between the monitoring area and the surrounding metropolitan area was
0.13oC lower on average at the center of the stream after the restoration. The stream's effect
on the air temperature was also evident in the temperature distribution along a street traversing the
stream. The relative and specific humidities were increased due to the restoration. The restored
stream modified the nearby urban climate in the opposite direction compared to urbanization. The
results could be used as a model case in mitigating urban climate by a stream in future urban planning
practices. 相似文献
104.
Keon Tae SOHN 《大气科学进展》2013,30(5):1343-1352
This study aimed to develop the seasonal forecast models of Korean dust days over South Korea in the springtime. Forecast mode was a ternary forecast (below normal, normal, above normal) which was classified based on the mean and the standard deviation of Korean dust days for a period of 30 years (1981-2010). In this study, we used three kinds of monthly data: the Korean dust days observed in South Korea, the National Center for Environmental Prediction in National Center for Atmospheric Research (NCEP/NCAR) reanalysis data for meteorological factors over source regions of Asian dust, and the large-scale climate indices offered from the Climate Diagnostic Center and Climate Prediction Center in NOAA. Forecast guidance consisted of two components; ordinal logistic regression model to generate trinomial distributions, and conversion algorithm to generate ternary forecast by two thresholds. Forecast guidance was proposed for each month separately and its predictability was evaluated based on skill scores. 相似文献
105.
An ENSO stability analysis. Part II: results from the twentieth and twenty-first century simulations of the CMIP3 models 总被引：2，自引：2，他引：0
In this study, a Bjerknes stability (BJ) index, proposed by Jin et al. (2006), is adopted to assess the overall stability of El Niño and Southern Oscillation (ENSO) in state-of-the-art coupled models. The twentieth and twenty-first century simulations of 12 coupled models among the coupled model intercomparison project phase 3 models used in the intergovernmental panel on climate change forth assessment report demonstrate a significant positive correlation between ENSO amplitude and ENSO stability as measured by the BJ index. The simulations also show a diversity of behavior regarding the ENSO stability among the coupled models, which can be attributed to different mean state and sensitivity of an oceanic and atmospheric response to wind and SST forcing from model to model. When respective components of the BJ index obtained from the coupled models are compared with those from observations, it is revealed that most coupled models underestimate the thermodynamic damping effect and the positive effect of the zonal advective and thermocline feedback. Under increased CO2 induced warm climate, changes, relative to the twentieth century simulations, in the damping and feedback terms responsible for the ENSO stability measured by the BJ index can be linked to mean state changes and associated atmospheric and oceanic response sensitivity changes. There is a clear multi-model trend in the damping terms and positive zonal advective feedback, thermocline feedback, and Ekman feedback terms under enhanced greenhouse gas conditions. However, the various behavior among the coupled models in competition between the positive feedback and negative damping terms in the BJ index formula prevent the formation of a definitive conclusion regarding future projections of ENSO stability using the current coupled models. 相似文献
106.
Magnolia obovata, a tree species native to Japan, is a traditional landscaping tree that has also been introduced to various countries. M. obovata individuals have recently emerged in non-planting areas in Korea, prompting us to investigate its distribution by establishing Dosolsan in an urban forest of Daejeon City as the target site. In order to determine its naturalization, the study explored the status of population growth by examining the diameter at breast height of the individuals, and diameter diminution quotient was calculated. Cores of the trees were collected, and the age distribution was estimated by regression analysis. Reproduction possibility was analyzed by verifying the flowerblooming and fruit-bearing. Spontaneous colonization was investigated in the other potential sites which have different location and environment, respectively.The diameter distribution showed a reverse J-shaped curve, and the diminution quotient was ≥ 1.8. The population was composed of different generations,thus confirming the growth of the population. The distributed M. obovata grew and flowered normally,and followed a normal life cycle. The same phenomenon was observed in other planting areas,residual forests in urban or rural areas, alluvial islands, and mountain forests. The continuous spread of M. obovata in new ecosystems may be attributable to its long-term distribution by birds, relatively fast growth, and maturity time. Investigations on the naturalization and spread of M. obovata in Korea, as well as in various countries, are warranted. 相似文献
107.
During the summer in the Yellow Sea and East China Sea, the resuspension of the bottom sediment is obstructed by strong stratification and, as a result, the concentration of total suspended sediment (TSS) can be used as an excellent tracer for Changjiang Diluted Water (CDW). To analyze the spatial and temporal variations of the CDW distribution, the monthly mean TSS from Moderate Resolution Imaging Spectroradiometer (MODIS) ocean color data are constructed and are converted to salinity using the relationship between salinity observed from AQUARIUS and TSS. The process produces the detailed horizontal distribution of salinity with very high resolution (1 km). From monthly mean salinity map from 2002 to 2012 in July and August, the expansion patterns of CDW are analyzed. The southerly wind in July and southeasterly wind in August transport the CDW eastward and northeastward, respectively. It is found that the yearly variation of the expansion of CDW toward the southern sea area of Korea is mostly due to the variation of southerly wind and the fluctuations of fresh water discharge into the Changjiang estuary show relatively little impact on the eastward extend of CDW. When 11-year mean (from 2002 to 2012) salinity map in August is compared with World Ocean Atlas 2013, it is revealed that wind in August strengthened six times from 1994 and it causes the expansion of CDW extended 150 km further eastward. 相似文献
108.
So Yun Park Eun Seok Choi Jinik Hwang Donggiun Kim Tae Kwon Ryu Taek-Kyun Lee 《Ocean Science Journal》2009,44(4):199-204
Prorocentrum minimum is a common bloomforming photosynthetic dinoflagellate found along the southern coast of Korea. To investigate the adaptive responses of P. minimum to high light stress, we measured growth rate, and generation of reactive oxidative species (ROS), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) in cultures exposed to normal (NL) and high light levels (HL). The results showed that HL (800 μmol m?2 s?1) inhibited growth of P. minimum, with maximal inhibition after 7–9 days. HL also increased the amount of ROS and MDA, suggesting that HL stress leads to oxidative damage and lipid peroxidation in this species. Under HL, we first detected superoxide on day 4 and H2O2 on day 5. We also detected SOD activity on day 5 and CAT activity on day 6. The level of lipid peroxidation, an indicator of cell death, was high on day 8. Addition of diphenyleneiodonium (DPI), an NAD(P)H inhibitor, decreased the levels of superoxide generation and lipid peroxidation. Our results indicate that the production of ROS which results from HL stress in P. minimum also induces antioxidative enzymes that counteract oxidative damage and allow P. minimum to survive. 相似文献
109.
Chang‐sik Cheong Keewook Yi Namhoon Kim Tae‐Ho Lee Seung Ryeol Lee Jian‐zhen Geng Huai‐kun Li 《地学学报》2013,25(3):228-235
Phanerozoic granitoids in South Korea are classified into four primary spatiotemporal groups showing geochemical and isotopic diversity. This study presents the first in situ Hf isotope data for zircons extracted from representative outcrops of each granitoid group. The core‐to‐rim variation in εHf values observed in some zircon grains provides evidence for open‐system processes influenced by the input of more primitive melts or interactions with pre‐existing crustal materials. A general core‐to‐rim decrease in Lu/Hf and Th/U ratios indicates a progressive compositional change in the melts during magmatic differentiation. Contrasting evolutionary paths demonstrated by zircon εHf values suggest that the Neoproterozoic to Palaeozoic crust including the Permian granitoids was recycled during the Cretaceous to Palaeogene magmatism in south‐eastern Korea, whereas the Palaeoarchaean to Palaeoproterozoic crust provided major source material for the Triassic to Jurassic granitoids in central Korea. 相似文献
110.
Young Keun Jin Robert D. Larter Yeadong Kim Sang Heon Nam Kyu Jung Kim 《Tectonophysics》2002,346(3-4)
The Pacific margin of the Antarctic Peninsula to the southwest of the Hero Fracture Zone (HFZ) is a former subducting margin which became inactive following the arrival of ridge crest segments of the Antarctic–Phoenix ridge at the margin during the Tertiary. In contrast, the part of the margin to the northeast of the HFZ remains active. Tertiary convergence was approximately perpendicular to the margin and ongoing motion is thought to have the same orientation. A new seismic reflection profile running along Boyd Strait, just northeast of the landward projection of the HFZ, shows major structural components similar to those typically observed along the margin to the southwest of the HFZ. In order of increasing proximity to the margin, these components are: the inner shelf, the shelf basin, the mid-shelf basement high (MSBH), and the outer shelf. The continuation of the post-subduction margin structures to the active margin suggests that the boundary between crust with passive and active margins characteristics is not sharply defined. Our postulated scenario for tectonic evolution along Boyd Strait is that: (1) before the arrival of the last ridge crest segment to the southwest of the HFZ, the inner shelf and the shelf basin were part of a Cretaceous–Tertiary arc and forearc area, (2) after the arrival, thermal effects resulting from interaction of the ridge crest with the margin just southwest of the HFZ lead to the formation of the MSBH to the northeast, but MSBH uplift in Boyd Strait did not prevent concurrent cross-shelf sediment transport contributing to development of an extensive outer shelf on the seaward flank of the MSBH, (3) Recent extension in Bransfield Strait, a marginal basin to the northeast of the landward projection of the HFZ, has caused about 10 km of seaward deflection in the strike of the part of the MSBH to the northeast of the projection of the HFZ. 相似文献