Using NWP to Assess the Influence of the Arctic Atmosphere on Midlatitude Weather and Climate     

Tido SEMMLER  Thomas JUNG  Marta A.KASPER  Soumia SERRAR 《大气科学进展》2018,35(1):5-13

The influence of the Arctic atmosphere on Northern Hemisphere midlatitude tropospheric weather and climate is explored by comparing the skill of two sets of 14-day weather forecast experiments using the ECMWF model with and without relaxation of the Arctic atmosphere towards ERA-Interim reanalysis data during the integration. Two pathways are identified along which the Arctic influences midlatitude weather: a pronounced one over Asia and Eastern Europe, and a secondary one over North America. In general, linkages are found to be strongest(weakest) during boreal winter(summer) when the amplitude of stationary planetary waves over the Northern Hemisphere is strongest(weakest). No discernible Arctic impact is found over the North Atlantic and North Pacific region, which is consistent with predominantly southwesterly flow. An analysis of the flow-dependence of the linkages shows that anomalous northerly flow conditions increase the Arctic influence on midlatitude weather over the continents. Specifically, an anomalous northerly flow from the Kara Sea towards West Asia leads to cold surface temperature anomalies not only over West Asia but also over Eastern and Central Europe. Finally, the results of this study are discussed in the light of potential midlatitude benefits of improved Arctic prediction capabilities.  相似文献   

Chemical weathering of granite under acid rainfall environment, Korea   总被引：1，自引：0，他引：1  

Seung Yeop Lee  Soo Jin Kim  Min Hoon Baik 《Environmental Geology》2008,55(4):853-862

Chemical weathering was investigated by collecting samples from five selected weathering profiles in a high elevation granitic environment located in Seoul, Korea. The overall changes of chemistry and mineralogical textures were examined reflecting weathering degrees of the samples, using polarization microscopy, X-ray diffraction (XRD), electron probe micro analysis (EPMA), X-ray fluorescence spectroscopy (XRF), and inductively coupled plasma–mass spectroscopy (ICP–MS). The chemical distribution in the weathering profiles shows that few trace elements are slightly immobile, whereas most major (particularly Ca and Na) and trace elements are mobile from the beginning of the granite weathering. On the other hand, there were mineralogical changes initiated from a plagioclase breakdown, which shows a characteristic circular dissolved pattern caused by a preferential leaching of Ca cation along grain boundaries and zoning. The biotite in that region is also supposed to be sensitive to exterior environmental condition and may be easily dissolved by acidic percolated water. As a result, it seems that some rock-forming minerals in the granitic rock located in Seoul are significantly unstable due to the environmental condition of acidic rainfall and steep slopes, where they are susceptible to be dissolved incongruently leading some elements to be highly depleted.  相似文献   

Snow depth estimation accuracy using a dual-interface GPS-IR model with experimental results     

Chen  Qiang  Won  Daehee  Akos  Dennis M. 《GPS Solutions》2017,21(1):211-223

GPS Solutions - Measuring snow depth using the GPS interferometric reflectometry is an active microwave remote sensing technique and an emerging approach because of its relatively large spatial...  相似文献   

Metagenomic characterization of viral communities in Goseong Bay,Korea     

Jinik Hwang  So Yun Park  Mirye Park  Sukchan Lee  Yeonhwa Jo  Won Kyong Cho  Taek-Kyun Lee 《Ocean Science Journal》2016,51(4):599-612

In this study, seawater samples were collected from Goseong Bay, Korea in March 2014 and viral populations were examined by metagenomics assembly. Enrichment of marine viral particles using FeCl₃ followed by next-generation sequencing produced numerous sequences. De novo assembly and BLAST search showed that most of the obtained contigs were unknown sequences and only 0.74% of sequences were associated with known viruses. As a result, 138 viruses, including bacteriophages (87%), viruses infecting algae and others (13%) were identified. The identified 138 viruses were divided into 11 orders, 14 families, 34 genera, and 133 species. The dominant viruses were Pelagibacter phage HTVC010P and Roseobacter phage SIO1. The viruses infecting algae, including the Ostreococcus species, accounted for 9.4% of total identified viruses. In addition, we identified pathogenic herpes viruses infecting fishes and giant viruses infecting parasitic acanthamoeba species. This is a comprehensive study to reveal the viral populations in the Goseong Bay using metagenomics. The information associated with the marine viral community in Goseong Bay, Korea will be useful for comparative analysis in other marine viral communities.  相似文献   

Boldness in a deep sea hermit crab to simulated tactile predator attacks is unaffected by ocean acidification     

Tae Won Kim  James P. Barry 《Ocean Science Journal》2016,51(3):381-386

Despite rapidly growing interest in the effects of ocean acidification on marine animals, the ability of deep-sea animals to acclimate or adapt to reduced pH conditions has received little attention. Deep-sea species are generally thought to be less tolerant of environmental variation than shallow-living species because they inhabit relatively stable conditions for nearly all environmental parameters. To explore whether deep-sea hermit crabs (Pagurus tanneri) can acclimate to ocean acidification over several weeks, we compared behavioral “boldness,” measured as time taken to re-emerge from shells after a simulated predatory attack by a toy octopus, under ambient (pH ～7.6) and expected future (pH ～7.1) conditions. The boldness measure for crab behavioral responses did not differ between different pH treatments, suggesting that future deep-sea acidification would not influence anti-predatory behavior. However, we did not examine the effects of olfactory cues released by predators that may affect hermit crab behavior and could be influenced by changes in the ocean carbonate system driven by increasing CO₂ levels.  相似文献   

Reproductive ecology of the dominant dinoflagellate, <Emphasis Type="Italic">Ceratium fusus</Emphasis>, in coastal area of Sagami Bay,Japan     

Seung Ho Baek  Shinji Shimode  Tomohiko Kikuchi 《Journal of Oceanography》2007,63(1):35-45

The seasonal abundance of the dominant dinoflagellate, Ceratium fusus, was investigated from January 2000 to December 2003 in a coastal region of Sagami Bay, Japan. The growth of this species was also examined under laboratory conditions. In Sagami Bay, C. fusus increased significantly from April to September, and decreased from November to February, though it was found at all times through out the observation period. C. fusus increased markedly in September 2001 and August 2003 after heavy rainfalls that produced pycnoclines. Rapid growth was observed over a salinity range of 24 to 30, with the highest specific rate of 0.59 d⁻¹ measured under the following conditions: salinity 27, temperature 24°C, photon irradiance 600 μmol m⁻²s⁻¹. The growth rate of C. fusus increased with increasing irradiance from 58 to 216 μmol m⁻²s⁻¹, plateauing between 216 and 796 μmol m⁻²s⁻¹ under all temperature and salinity treatments (except at a temperature of 12°C). Both field and laboratory experiments indicated that C. fusus has the ability to grow under wide ranges of water temperatures (14–28°C), salinities (20–34), and photon irradiance (50–800 μmol m⁻²s⁻¹); it is also able to grow at low nutrient concentrations. This physiological flexibility ensures that populations persist when bloom conditions come to an end.  相似文献   

Branching of the Tsushima Current by an Abrupt Increase of Bottom Depth     

Young Ho Seung 《Journal of Oceanography》2005,61(2):261-269

An analytical model of the branching of an inertial current partly afloat incident upon a step fall in bottom topography is considered to account for the branching of the Tsushima Current induced by an abrupt increase of the bottom depth near the northern end of the Korea-Tsushima Strait. The grounded portion of the incident current is constraint by bottom topography and eventually runs along the depth discontinuity over the shallow region. Due to the inertia of the incident current, however, the ungrounded portion crosses the depth discontinuity and forms a free inertial jet, giving rise to the branching. The deflection angle of this free inertial jet is determined through an integrated momentum balance. The branching is more restricted as the grounded portion of the incident current becomes relatively more important, in terms of the momentum transport, than the ungrounded portion. For typical values of the bottom depth, the transport of the Tsushima Current through the Korea-Tsushima Strait, and for acceptable values of other physical parameters, it appears that branching is possible. Hence, the abrupt increase of the bottom depth near the northern end of the Korea-Tsushima Strait, combined with the inertia of current, may indeed be an important factor in the branching of the Tsushima Current.  相似文献   

Significance of Shallow Bottom Friction in the Dynamics of the Tsushima Current   总被引：1，自引：0，他引：1  

Young Ho Seung 《Journal of Oceanography》2003,59(1):113-118

A simple analytical model is considered for the dynamics of volume transport of the Tsushima Current. This model is basically baroclinic but allows bottom friction over the shallow regions connecting the Pacific Ocean to the Japan Sea basin, and is thus different from previous models which are either purely barotropic with bottom friction predominating over the whole domain, or purely baroclinic with bottom friction completely ignored. Compared to the previous barotropic model, this model is not only more realistic but also gives much simpler results. It gives the observed downstream sea level slope, which is not seen in the previous baroclinic model. As a result, the estimated transport of the Tsushima Current is closer to the observational data than those of previous models. This model indicates that the localized bottom friction acting over the shallow regions not only controls the transport of the Tsushima Current but also moves the stagnation point of the western boundary current northward. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Wave-tide-surge coupled model simulation for Typhoon Maemi   总被引：2，自引：2，他引：2  

CHOI Byung Ho  KIM Dong Chule  KIM Young Bok  KIM Hyun Seung 《海洋学报(英文版)》2007,26(1):35-47

1 IntroductionThe main reason for coupling the tide and surgehydrodynamic model with a surface wave model canbe found in the physical interactions taking place inthe surface and bottom boundary layers. During thesevere storm conditions such interactions a…  相似文献   

Ecotoxicological evaluation of sewage sludge using bioluminescent marine bacteria and rotifer     

Gyung Soo Park  Sang Hee Lee  Soung Yun Park  Seong Jin Yoon  Seung Min Lee  Chang Soo Chung  Gi -Hoon Hong  Suk Hyun Kim 《Ocean Science Journal》2005,40(2):91-100

Bioassay using the marine bacteria,Vibrio fischeri and rotifer,Brachionus plicatilis, and chemical analyses were conducted to assess the toxicity of the various sewage sludges, one of the major ocean dumped materials in the Yellow Sea of Korea. Sludge elutriates extracted by filtered seawater were used to estimate the ecotoxicity of the sludge. Chemical characterization included the analyses of organic contents, heavy metals, and persistent organic pollutants in sludge. Bacterial bioluminescent inhibition (15 min), rotifer mortality (24 hr) and rotifer population growth inhibition (48 hr) assay were conducted to estimate the sludge toxicity. EC50 15 min (inhibition concentration of bioluminescence after 15 minutes exposed) values by Microtox® bioassay clearly revealed different toxicity levels depending on the sludge sources. Highest toxicity for the bacteria was found with the sludge extract from dyeing waste and followed by industrial waste, livestock waste, and leather processing waste. Clear toxic effects on the bacteria were not found in the sludge extract from filtration bed sludge and rural sewage sludge. Consistent with Microtox® results, rotifer neonate mortality and population growth inhibition test also showed highest toxicity in dyeing waste and low in filtration bed and rural sewage sludge. High concentrations of persistent organic pollutants (POPs) and heavy metals were measured in the samples from the industrial wastes, leather processing plant waste sludge, and urban sewage sludge. However, there was no significant correlation between pollutant concentration levels and the toxicity values of the sludge. This suggests that the ecotoxicity in addition to the chemical analyses of various sludge samples must be estimated before release of potential harmful waste in the natural environment as part of an ecological risk assessment.  相似文献