韩国济州岛柑橘园景观与空间分布演变（1526—2019年）     

黄普基  吴俊范 《热带地理》2022,42(5):834-842

韩国济州岛的柑橘园景观具有重要的文化遗产价值,是当地人利用济州岛特殊的气候、水文、植被环境所塑造的独特农业景观。16世纪朝鲜王朝建立柑橘进贡制度,济州官府设置柑橘园,此后至今,济州岛柑橘园区域分布与地理景观都呈现较大变迁。文章结合气候、水资源等自然因素与韩国柑橘产业政策、市场、社会变化与技术进步等人文因素,分析16世纪以来济州岛柑橘园景观与空间分布变化,探讨济州岛柑橘生产空间变迁原因与驱动力。结果显示：16世纪至2019年,济州岛柑橘生产经历了发展、没落、强力复兴的大起大落发展历史,呈现从北到南的生产空间大迁移,柑橘生产空间逐渐扩大。济州岛的柑橘园生产经历从朝鲜时期的官府果园到现代观光体验农场的转变。柑橘生产空间变迁与地理景观变化的原因与驱动力较复杂,水资源是影响朝鲜时期柑橘园分布的主要自然因素。社会制度、交通与市场是16世纪以来影响柑橘园生产空间扩展的主要人文因素,在近500年的柑橘生产空间发展变迁的过程中,人文因素不断加强,影响柑橘空间与地理景观的优化调整。20世纪70年代以来,水资源开发技术的进步改变了现代柑橘园生产空间分布格局。对济州岛柑橘园长时段的生产空间与地理景观变化及其作用机制的研究,可以为中国传统柑橘栽培地区打造具有地方特色柑橘园文化景观与民俗、文化产品,以及中国柑橘产业的升级发展提供参考。  相似文献   

Flows within the Ekman layer during spin-up of a thermally stratified fluid     

Jae Min Hyun 《地球物理与天体物理流体动力学》2013,107(1-4):65-79

Abstract

Finite-difference numerical solutions were obtained to present the flow and temperature field details within the transient Ekman layer during spin-up of a thermally stratified fluid in a cylinder. This complements the earlier studies on stratified spin-up which examined the flows in the interior core region. As the stratification increases, the following changes in the flow field are noticeable. The radial velocity in the Ekman layer decreases in magnitude. The azimuthal flows adjust smoothly from the interior region to the endwall boundary, and the Ekman layer in the azimuthal flow field fades. Vertical motions are inhibited, resulting in a weakened Ekman pumping. The axial vorticity field behaves similarly to the azimuthal flows. The temperature deviation from the equilibrium profile decreases, and the heat transfer flux from the endwall to the fluid decreases. The thickness of the thermal layer is larger than the velocity layer thickness. Illustrative comparisons of the relative sizes of the terms in the governing equations are conducted in order to assess the stratification effect in the adjustment process of the fluid.  相似文献   

Contrast in life histories of exploited fishes and ecosystem structures in coastal waters off west Canada and east Korea     

Gordon A. McFarlane  Chang Ik Zhang  Jacquelynne R. King  Suam Kim  Richard J. Beamish  Jae Ho Oh 《Ocean Science Journal》2009,44(1):43-60

By reviewing the history of fishery exploitation in the coastal waters of west Canada and east Korea, related with contrasting life history strategies of the dominant species, the fishery management challenges that each country would face in the upcoming decades were outlined. In the ecosystem of the Canadian western coastal waters, the dominant oceanographic feature is the coastal upwelling domain off the west coast of Vancouver Island, the northernmost extent of the California Current System in the eastern North Pacific. In the marine ecosystem of the eastern coasts of Korea (the Japan/East Sea), a major oceanographic feature is the Tsushima Warm Current, a branch of the Kuroshio Current in the western North Pacific. Fishes in the Canadian ecosystem are dominated by demersal, long-lived species such as flatfish, rockfish, sablefish, and halibut. During summer, migratory pelagic species such as Pacific hake, Pacific salmon, and recently Pacific sardine, move into this area to feed. In the late 1970s, Canada declared jurisdiction for 200 miles from their coastline, and major fisheries species in Canadian waters have been managed with a quota system. The overall fishing intensity off the west coast of Vancouver Island has been relatively moderate compared to Korean waters. Fishes in the ecosystem of the eastern Korean waters are dominated by short-lived pelagic and demersal fish. Historically, Korea has shared marine resources in this area with neighbouring countries, but stock assessments and quotas have only recently (since the late-1990s) been implemented for some major species. In the Korean ecosystem, fisheries can be described as intensive, and many stocks have been rated as overfished. The two ecosystems responded differently to climate impacts such as regime shifts under different exploitation histories. In the future, both countries will face the challenge of global warming and subsequent impacts on ecosystems, necessitating developing adaptive fisheries management plans. The challenges will be contrasting for the two countries: Canada will need to conserve fish populations, while Korea will need to focus on rebuilding depleted fish populations.  相似文献   

Lateral bearing performance and mechanism of piles in the transition zone due to pit-in-pit excavation     

Tong  Liyuan  Li  Hongjiang  Ha  Si  Liu  Songyu 《Acta Geotechnica》2022,17(5):1935-1948

Acta Geotechnica - Excavation types of foundation pits for large-scale or special-purpose urban construction have been more and more complex, and the environmental safety issues caused by pit...  相似文献   

Numerical simulation and evaluation of Asian dust events observed in Mongolia in spring 2011     

Eun-Hee Lee  Erdenebayar Munkhtsetseg  Seung-Bum Kim  Jong-Chul Ha  Sang-Sam Lee  Youngsin Chun 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(1):111-120

The Asian dust forecasting model, Mongolian Asian Dust Aerosol Model (MGLADAM), has been operated by the National Agency for Meteorology and Environmental Monitoring of Mongolia since 2010, for the forecast of Asian dust storms. In order to evaluate the performance of the dust prediction model, we simulated Asian dust events for the period of spring 2011. Simulated features were compared with observations from two sites in the dust source region of the Gobi desert in Mongolia, and in the downstream region in Korea. It was found that the simulated wind speed and friction velocity showed a good correlation with observations at the Erdene site (one of the sites in the Gobi desert). The results show that the model is proficient in the simulation of dust concentrations that are within the same order of magnitude and have similar start and end times, compared with PM₁₀ observed at two monitoring sites in the Gobi regions. Root Mean Square Error (RMSE) of the dust simulation ranges up to 200 μg m^?3 because of the high concentrations in source regions, which is three times higher than that in the downstream region. However, the spatial pattern of dust concentration matches well with dust reports from synoptic observation. In the downwind regions, it was found that the model simluated all reported dust cases successfully. It was also found that the RMSE in the downwind region increased when the model integration time increased, but that in the source regions did not show consistent change. It suggests that MGLADAM has the potential to be used as an operational dust forecasting model for predicting major dust events over the dust source regions as well as predicting transported dust concentrations over the downstream region. However, it is thought that further improvement in the emission estimation is necessary, including accurate predictions in surface and boundary layer meteorology. In the downwind regions, background PM₁₀ concentration is considerably affected by other aerosol species, suggesting that a consideration of anthropogenic pollutants will be required for accurate dust forecasting.  相似文献   

PM10 data assimilation over south Korea to Asian dust forecasting model with the optimal interpolation method     

Eun-Hee Lee  Jong-Chul Ha  Sang-Sam Lee  Youngsin Chun 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(1):73-85

A data assimilation (DA) system using ground PM₁₀ observation for Asian Dust Aerosol Model version 2 (ADAM2), which is the operational dust forecasting model of Korea Meteorological Administration (KMA), has been developed with the optimal interpolation (OI) method. The observations are provided by the PM₁₀ network operated by KMA. Three DA experiments are performed to simulate a dust event observed in Korea from 1 March to 31 May 2009 with different assimilation cycles of 24 (DA24), 12 (DA12), and 06 hours (DA06). 48-hour forecasts from the adjusted Initial Condition (IC) of dust concentration are compared with control simulation (CTL) and observation from independent stations. It is found that CTL simulates spatial patterns of dust emitted and transported associated with a developing low pressure system over the dust source regions quite well, compared with satellite measurement. However, it appears that there is considerable uncertainty in estimating the concentration of dust. With IC adjustment, the model simulates improved dust concentration, showing considerably reduced RMSE, particularly for the prediction within 12 hours of forecast. At the same time, it is shown that the time interval of DA affects the predictability of ADAM2, so that DA06 appears to have better predictability within a 12-hour simulation, reducing RMSE by 50% compared with CTL. This suggests that assimilating PM₁₀ to the dust prediction model using OI has the potential to predict air quality in Korea when the cycle of assimilation is sufficiently short.  相似文献   

Implications of simultaneously mitigating and adapting to climate change: initial experiments using GCAM     

Katherine Calvin  Marshall Wise  Leon Clarke  Jae Edmonds  Page Kyle  Patrick Luckow  Allison Thomson 《Climatic change》2013,117(3):545-560

Most research on future climate change discusses mitigation and impacts/adaptation separately. However, mitigation will have implications for impacts and adaptation. Similarly, impacts and adaptation will affect mitigation. This paper begins to explore these two veins of research simultaneously using an integrated assessment model. We begin by discussing the types of interactions one might expect by impact sector. Then, we develop a numerical experiment in the agriculture sector to illustrate the importance of considering mitigation, impacts, and adaptation at the same time. In our experiment, we find that climate change can reduce crop yields, resulting in an expansion of cropland to feed a growing population and a reduction in bioenergy production. These two effects, in combination, result in an increase in the cost of mitigation.  相似文献   

Sensitivity of multi-gas climate policy to emission metrics     

Steven J. Smith  Joseph Karas  Jae Edmonds  Jiyong Eom  Andrew Mizrahi 《Climatic change》2013,117(4):663-675

The Global Warming Potential (GWP) index is currently used to create CO₂-equivalent emission totals for multi-gas greenhouse targets. While many alternatives have been proposed, it is not possible to uniquely define a metric that captures the different impacts of emissions of substances with widely disparate atmospheric lifetimes, which leads to a wide range of possible index values. We examine the sensitivity of emissions and climate outcomes to the value of the index used to aggregate methane emissions using a technologically detailed integrated assessment model. The methane index is varied between 4 and 70, with a central value of 21, which is the 100-year GWP value currently used in policy contexts. We find that the sensitivity to index value is, at most, 10–18 % in terms of methane emissions but only 2–3 % in terms of the maximum total radiative forcing change, with larger regional emissions differences in some cases. The choice of index also affects estimates of the cost of meeting a given end of century forcing target, with total two-gas mitigation cost increasing by 7–9 % if the index is increased, and increasing in most scenarios from 4 to 23 % if the index is lowered, with a slight (1 %) decrease in total cost in one case. We find that much of the methane abatement occurs as the induced effect of CO₂ abatement rather than explicit abatement, which is one reason why climate outcomes are relatively insensitive to the index value. We also find that the near-term climate benefit of increasing the methane index is small.  相似文献   

Revisiting Solar and Heliospheric 1.3-Year Signals during 1970 – 2007     

I.-H. Cho  J. Hwang  Y.-D. Park 《Solar physics》2014,289(3):707-719

We revisit the 1.3-year (yr) signals observed on the Sun, in the interplanetary space, and in the Earth’s magnetosphere to study the coupling among signals from the three regions for about 40 years (1970?–?2007) covering the three solar cycles 21, 22, and 23. For this, we make dynamic spectra of datasets including three different regions. From this, we estimate the peak frequency around 1.3 yr for each region and the corresponding band power. We found that coherent power only appears during 1987?–?1995 and the coherent behavior is found only in the interplanetary space and Earth, not in the Sun. Although the solar surface magnetic field shows significant power around 1.3 yr, their peak frequencies are statistically different from those of the outer regions, which make us dismiss the existence of coherence among the three regions. But it is notable that the peaks in band power corresponding to the 1.3-yr period are clearly simultaneous in the interplanetary space and Earth.  相似文献   

Trace metals in seawater and copepods in the ocean outfall area off the northern Taiwan coast   总被引：3，自引：0，他引：3  

Fang TH  Hwang JS  Hsiao SH  Chen HY 《Marine environmental research》2006,61(2):224-243

The distribution, partitioning and concentrations of trace metals (Cd, Cr, Cu, Fe, Mn, Pb and Zn) in seawater, including dissolved and particulate phases, and in copepods in the ocean outfall area off the northern coast of Taiwan were investigated. Normalization of metal concentrations to the background metal concentration to yield relative enrichment factors (EF), which were used to evaluate the contamination of dissolved and particulate trace metals in seawater around the ocean outfall. The EF results indicated that the outfall area was significantly contaminated by dissolved Fe and Zn, and by particulate Fe, Cr, Cu, Pb and Zn. In addition, most trace metals were chiefly in the particulate phase. The average percentage of total metal concentrations (dissolved plus particulate phases) bound by suspended particulate matter followed the sequence Al(95%) = Mn(95%) > Pb(88%) > Cu(86%) > Fe(72%) > Zn(32%) > Cr(17.5%) > Cd(3.4%). Therefore, metal contamination is better evaluated in solid phase than in the dissolved phase. The concentration ranges of trace metals in the copepods, Temora turbinata, Oncaea venusta and Euchaeta rimana, near the outfall were: Cd, 0.23-1.81 microg g(-1); Cr, 16.5-195 microg g(-1); Cu, 14-160 microg g(-1); Fe, 256-7255 microg g(-1); Mn, 5.5-80.8 microg g(-1); Pb, 2.6-56.2 microg g(-1); Zn, 132-3891 microg g(-1); and Al, 0.21-1.13%. Aluminum, and probably Fe, seemed to be the major elements in copepods. The concentrations of trace metals in copepods, especially Temora turbinata, near the outfall were generally higher than those obtained in the background station. The mean increase in bioconcentration factor of metals in copepods ranged from 4 to 7 and followed the sequence Al(6.4) > Cu(6.2) > Fe(6.0) > Zn(5.7) > Pb(5.6) > Cr(5.5) > Cd(5.1) > Mn(4.7). Therefore, marine copepods in the waters of northern Taiwan can accumulate trace metals over background concentrations and act as contamination indicators.  相似文献