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751.
Future climate change scenarios over Korea using a multi-nested downscaling system: A pilot study 总被引:1,自引:0,他引:1
Song-You Hong Nan-Kyoung Moon Kyo-Sun Sunny Lim Jong-Won Kim 《Asia-Pacific Journal of Atmospheric Sciences》2010,46(4):425-435
This study examines a scenario of future summer climate change for the Korean peninsula using a multi-nested regional climate system. The global-scale scenario from the ECHAM5, which has a 200 km grid, was downscaled to a 50 km grid over Asia using the National Centers for Environmental Prediction (NCEP) Regional Spectral Model (RSM). This allowed us to obtain large-scale forcing information for a one-way, double-nested Weather and Research Forecasting (WRF) model that consists of a 12 km grid over Korea and a 3 km grid near Seoul. As a pilot study prior to the multi-year simulation work the years 1995 and 2055 were selected for the present and future summers. This RSM-WRF multi-nested downscaling system was evaluated by examining a downscaled climatology in 1995 with the largescale forcing from the NCEP/Department of Energy (DOE) reanalysis. The changes in monsoonal flows over East Asia and the associated precipitation change scenario over Korea are highlighted. It is found that the RSM-WRF system is capable of reproducing large-scale features associated with the East-Asian summer monsoon (EASM) and its associated hydro-climate when it is nested by the NCEP/DOE reanalysis. The ECHAM5-based downscaled climate for the present (1995) summer is found to suffer from a weakening of the low-level jet and sub-tropical high when compared the reanalysis-based climate. Predicted changes in summer monsoon circulations between 1995 and 2055 include a strengthened subtropical high and an intensified mid-level trough. The resulting projected summer precipitation is doubled over much of South Korea, accompanied by a pronounced surface warming with a maximum of about 2 K. It is suggested that downscaling strategy of this study, with its cloud-resolving scale, makes it suitable for providing high-resolution meteorological data with which to derive hydrology or air pollution models. 相似文献
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将模糊综合评价及马尔可夫链同时运用到空气质量的评价中,可克服大气环境系统所固有的模糊性及随机性。通过1994—1998年芜湖市大气环境监测数据计算表明:不仅预测结果准确,而且由于应用了模糊数学方法,使得结果较为可信,且整个过程计算简单,是一种较适合的方法。 相似文献
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主要介绍了利用NOAA和EOS卫星遥感监测莱州湾海冰的方法,简要分析了海冰对不同光谱的反应及海冰和水体在可见光、近红外通道反射率的差异等,对2008年莱州湾海面结冰状况进行了监测,利用国家卫星气象中心提供的海冰厚度计算经验模式,估算了海冰厚度分布及面积。为了使海冰分布更加清晰,对NOAA卫星监测海冰图像进行了彩色增强处理。 相似文献
756.
757.
根据最近发表的新编依巴谷星表数据,重新研究了经典造父变星周光关系零点问题.利用运动学模型对自行数据和视向速度分别拟合奥尔特常数及本地静止标准的旋转速度,得到太阳的银心距R0=8.0±0.8kpc.从太阳附近的旋转曲线,发现银河系盘的引力势具有弱椭圆分布的迹象.通过-个简单的非对称模型,得到太阳附近盘引力势的椭率e(R0)=0.067±0.036,其短轴指向φb=32°±15°. 相似文献
758.
该文研究了以星系作为透镜体产生的切向弧(即"爱因斯坦环")的强引力透镜现象,并对该领域近年来的观测和研究作了总结.对形成这些强引力透镜"环"的星系所进行的研究表明,其附近存在的质量所产生的会聚和剪切对透镜的质量分布模型非常敏感.在大视场巡天中找到的这种爱因斯坦环的数目相当多,大约是每平方度10个,其中"强引力透镜巡天"(Strong LensingLegacy Survey,SL2S)提供了大量处于星系团视场中的由椭圆星系产生的爱因斯坦环样本.系统地研究星系团外围存在的爱因斯坦环,一方面可以理解星系团环境对爱因斯坦环的影响,另一方面可以利用它们来探测星系团的物质分布,并进而对冷暗物质宇宙学提供新的探测方法. 相似文献
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760.
New insights into the origin of perylene in geological samples 总被引:1,自引:0,他引:1
Kliti Grice Hong Lu Pia Atahan Muhammad Asif Paul Greenwood Ercin Maslen Kenneth Williford 《Geochimica et cosmochimica acta》2009,73(21):6531-6543
The origin of the polycyclic aromatic hydrocarbon (PAH) perylene in sediments and petroleum has been a matter of continued debate. Reported to occur in Phanerozoic organic matter (OM), fossil crinoids and tropical termite mounds, its mechanism of formation remains unclear. While a combustion source can be excluded, structural similarities to perylene quinone-like components present in e.g. fungi, plants, crinoids and insects, potentially suggest a product-precursor relationship. Here, we report perylene concentrations, 13C/12C, and D/H ratios from a Holocene sediment profile from the Qingpu trench, Yangtze Delta region, China. Perylene concentrations differ from those of pyrogenic PAHs, and rise to prominence in a stratigraphic interval that was dominated by woody vegetation as determined by palynology including fungal spores. In this zone, perylene concentrations exhibit an inverse relationship to the lignin marker guaiacol, D/H ratios between −284‰ and −317‰, similar to the methoxy groups in lignin, as well as co-variation with spores from wood-degrading fungi. 13C/12C of perylene differs from that of land plant wax alkanes and falls in the fractionation range expected for saprophytic fungi that utilise lignin, which is isotopically lighter than cellulose and whole wood. During progressive lignin degradation, the relative carbon isotopic ratio of the perylene decreases. We therefore hypothesise a relationship of perylene to the activity of wood-degrading fungi. To support our hypothesis, we analysed a wide range of Phanerozoic sediments and oils, and found perylene to generally be present in subordinate amounts before the evolutionary rise of vascular plants, and to be generally absent from marine-sourced oils, few exceptions being attributed perhaps to a contribution of marine and/or terrestrial-derived fungi, anoxia (especially under marine conditions) and/or contamination of core material by fungi. A series of low-molecular-weight aromatic quinones bearing the perylene-backbone were detected in Devonian and Cretaceous sediments, potentially representing precursor components to perylene. 相似文献