Preliminary Results of the Ground-Based Orographic Snow Enhancement Experiment for the Easterly Cold Fog （Cloud） at Daegwallyeong during the 2006 Winter     

Myoung-Joo LEE  Ki-Ho CHANG  Gyun-Myoung PARK  Jin-Yim JEONG  Ha-Young YANG  Ki-Deok JEONG  Joo-Wan CHA  Sung-Soo YUM  Jae-Cheol NAM  Kyungsik KIM  Byung-Chul CHOI 《大气科学进展》2009,26(2):222-228

The snow enhancement experiments, carried out by injecting AgI and water vapor into orographically enhanced clouds (fog), have been conducted to confirm Li and Pitter’s forced condensation process in a natural situation. Nine ground-based experiments have been conducted at Daegwallyeong in the Taebaek Mountains for the easterly foggy days from January–February 2006. We then obtained the optimized condi- tions for the Daegwallyeong region as follows: the small seeding rate (1.04 g min-1) of AgI for the easte...  相似文献   

Statistical Downscaling for Multi-Model Ensemble Prediction of Summer Monsoon Rainfall in the Asia-Pacific Region Using Geopotential Height Field   总被引：16，自引：1，他引：15  

ZHU Congwen  Chung-Kyu PARK  Woo-Sung LEE  Won-Tae YUN 《大气科学进展》2008,25(5):867-884

The 21-yr ensemble predictions of model precipitation and circulation in the East Asian and western North Pacific （Asia-Pacific） summer monsoon region （0°-50°N, 100° 150°E） were evaluated in nine different AGCM, used in the Asia-Pacific Economic Cooperation Climate Center （APCC） multi-model ensemble seasonal prediction system. The analysis indicates that the precipitation anomaly patterns of model ensemble predictions are substantially different from the observed counterparts in this region, but the summer monsoon circulations are reasonably predicted. For example, all models can well produce the interannual variability of the western North Pacific monsoon index （WNPMI） defined by 850 hPa winds, but they failed to predict the relationship between WNPMI and precipitation anomalies. The interannual variability of the 500 hPa geopotential height （GPH） can be well predicted by the models in contrast to precipitation anomalies. On the basis of such model performances and the relationship between the interannual variations of 500 hPa GPH and precipitation anomalies, we developed a statistical scheme used to downscale the summer monsoon precipitation anomaly on the basis of EOF and singular value decomposition （SVD）. In this scheme, the three leading EOF modes of 500 hPa GPH anomaly fields predicted by the models are firstly corrected by the linear regression between the principal components in each model and observation, respectively. Then, the corrected model GPH is chosen as the predictor to downscale the precipitation anomaly field, which is assembled by the forecasted expansion coefficients of model 500 hPa GPH and the three leading SVD modes of observed precipitation anomaly corresponding to the prediction of model 500 hPa GPH during a 19-year training period. The cross-validated forecasts suggest that this downscaling scheme may have a potential to improve the forecast skill of the precipitation anomaly in the South China Sea, western North Pacific and the East Asia Pacific regions, wh  相似文献   

Experiment on Dust Flux During Duststorm Periods over Desert Area          下载免费PDF全文

ZHANG Hongsheng  ZHU Hao  PENG Yan  KANG Ling  CHEN Jiayi  Soon-Ung PARK 《Acta Meteorologica Sinica》2008,22(2):239-247

The present study investigates the characteristics of turbulent transfer and the conditions for dust emission and transport using the dust concentration and micrometeorological data obtained during dust events occurring in the spring of 2004 over the Hunshandake desert area. The turbulent exchange coefficients and turbulent fluxes of momentum and heat are calculated. The relationships between dust flux, friction velocity, and wind speed are also explored. The results show that thermal turbulence is dominant during daytime of non-dusty days. The dynamic turbulence increases obviously and the sensible heat flux reduces by different degrees during dust events. There is an efficient downward transfer of momentum before duststorm occurrence, and both the dynamic turbulence and the thermal turbulence are important in the surface layer. The dynamic turbulence even exceeds the thermal turbulence during severe duststorm events. The values of dust flux vary in the range of -5 5, -30 30, and -200-300 μg m^-2 s^-1 during non-dusty days, blowing dust, and duststorm events, respectively. A slight upward transport of dust is observed during non-dusty days. The dust flux gradually varies from positive to negative during duststorm periods, which indicates the time evolution of dust events from dust rising to stably suspending and then deposition. The dust flux is found to be proportional to u＊^3. The threshold values of wind speed and friction velocity are about 6 and 0.4 m s^-1, respectively.  相似文献   

Conceptualizing a multi-layered shingle aquifer model based on volcanic stratigraphy and water inflow to lava caves in Jeju Island,Korea     

Ung San Ahn  Dong-Chan Koh  Joonghyeok Heo  Byong-Wook Cho  Taehee Kim  Byoung-Woo Yum 《水文研究》2021,35(8):e14316

Volcanic aquifers supply a substantial portion of water resources in many parts of the world, including islands, and their productivity depends strongly on volcanic stratigraphy, which exhibits considerable heterogeneity. We investigated water inflow to lava tube caves formed from numerous basaltic lava flows in the northeastern coastal area of Jeju Island after storm events and monitored relative inflow rates monthly over 1 year to characterize groundwater flow processes in the upper parts of volcanic aquifers, and to evaluate the applicability of the previous hydrogeological models proposed for the island. Considerable water inflow arose shortly after storms from exposed palaeosol layers on the walls of the caves. The monthly monitoring results showed that wall inflow associated with these palaeosol layers is substantial. In both cases, discharge from ceiling drips was much less and more temporally variable compared to wall inflow discharge. Water flowing into the caves was rapidly drained through the floor at all monitoring sites. The lateral extent of the palaeosol layers was identified using drill core logs near the cave and outcrops in the coastal area. Based on these results, we inferred that multiple perched aquifers are formed by low-permeability palaeosol layers between lava flows, which are connected by vertical flows at discontinuities in the palaeosol layer, eventually reaching the basal aquifer. This study revealed the water inflow processes observed in lava tube caves constrained by palaeosol layers, and established a hydrogeological conceptual model incorporating multiple perched aquifers in both coastal and mountainous areas associated with extensive palaeosol layers formed during volcanic hiatuses. This finding would help elucidate recharge, groundwater flow, and contaminant transport processes in many volcanic aquifers that are not adequately represented by the previous models, and contribute to better management of groundwater in those areas.  相似文献   

Orbital‐ and millennial‐scale climate and vegetation changes between 32.5 and 6.9k cal a BP from Hanon Maar paleolake on Jeju Island,South Korea          下载免费PDF全文

JUNGJAE PARK  HYOUN SOO LIM  JAESOO LIM  KEUN BAE YU  JINMU CHOI 《第四纪科学杂志》2014,29(6):570-580

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Geochemistry of peridotite xenoliths in alkali basalts from Jeju Island, Korea   总被引：1，自引：0，他引：1  

SEONG HEE  CHOI  JONG IK  LEE  CHUNG-HWA  PARK  JACQUES  MOUTTE 《Island Arc》2002,11(4):221-235

Abstract   Ultramafic xenoliths in alkali basalts from Jeju Island, Korea, are mostly spinel lherzolites with subordinate amounts of spinel harzburgites and pyroxenites. The compositions of major oxides and compatible to moderately incompatible elements of the Jeju peridotite xenoliths suggest that they are residues after various extents of melting. The estimated degrees of partial melting from compositionally homogeneous and unfractionated mantle to form the residual xenoliths reach 30%. However, their complex patterns of chondrite-normalized rare earth element, from light rare earth element (LREE)-depleted through spoon-shaped to LREE-enriched, reflect an additional process. Metasomatism by a small amount of melt/fluid enriched in LREE followed the former melt removal, which resulted in the enrichment of the incompatible trace elements. Sr and Nd isotopic ratios of the Jeju xenoliths display a wide scatter from depleted mid-oceanic ridge basalt (MORB)-like to near bulk-earth estimates along the MORB–oceanic island basalt (OIB) mantle array. The varieties in modal proportions of minerals, (La/Yb)_N ratio and Sr-Nd isotopes for the xenoliths demonstrate that the lithospheric mantle beneath Jeju Island is heterogeneous. The heterogeneity is a probable result of its long-term growth and enrichment history.  相似文献   

Recent Advancement in Modeling Seafloor Dissipative Mechanism in Shallow Water     

Philip L.-F.LIU  Yong Sung PARK 《中国海洋工程》2008,22(1):1-10

In this paper, the recent development in modeling seabed dissipative mechanisms in shallow water is reviewed. Specifically, laminar and turbulent boundary layer solutions as well as viscous mud flow solutions under transient waves are presented. These analytical solutions are compared with experimental data for both solitary waves and cnoidal waves. Very goed agreement is ohtained. The Boussinesq equations with boundary layer effects and the muddy seabed effects are also shown.  相似文献   

39Ar‐40Ar dating of the Zagami Martian shergottite and implications for magma origin of excess 40Ar     

Donald D. BOGARD  Jisun PARK 《Meteoritics & planetary science》2008,43(7):1113-1126

Abstract— The Zagami shergottite experienced a complex, petrogenetic formation history (McCoy et al. 1992, 1999). Like several shergottites, Zagami contains excess ⁴⁰Ar relative to its formation age. To understand the origin of this excess ⁴⁰Ar, we made ³⁹Ar‐⁴⁰Ar analyses on plagioclase and pyroxene minerals from two phases representing different stages in the magma evolution. Surprisingly, all these separates show similar concentrations of excess ⁴⁰Ar, ?1 × 10^?6 cm³/g. We present arguments against this excess ⁴⁰Ar having been introduced from the Martian atmosphere as impact glass. We also present evidence against excess ⁴⁰Ar being a partially degassed residue from a basalt that actually formed ?4 Gyr ago. We utilize our experimental data on Ar diffusion in Zagami and evidence that it was shock‐heated to only ?70 °C, and we assume this heating occurred during an ejection from Mars ?3 Myr ago. With these constraints, thermal considerations necessitates either that its ejected mass was impossibly large, or that its shock‐heating temperature was an order of magnitude higher than that measured. We suggest that this excess ⁴⁰Ar was inherited from the Zagami magma, and that it was introduced into the magma either by degassing of a larger volume of material or by early assimilation of old, K‐rich crustal material. Similar concentrations of excess ⁴⁰Ar in the analyzed separates imply that this magma maintained a relatively constant ⁴⁰Ar concentration throughout its crystallization. This likely occurred through volatile degassing as the magma rose toward the surface and lithostatic pressure was released. These concepts have implications for excess ⁴⁰Ar in other shergottites.  相似文献   

The duration of acute health problems in people involved with the cleanup operation of the Hebei Spirit oil spill     

Na JU  Sim MS  Jo IJ  Song HG 《Marine pollution bulletin》2012,64(6):1246-1251

The authors investigated the duration of health problems of people involved with cleanup efforts for the Hebei Spirit oil spill, which occurred in December 2007 in Taean County, South Korea. The study identified risk factors correlated with the continuation of symptoms. Approximately one year after the accident, 442 people who had participated in the cleanup operation were examined. Data regarding demographic information, risk factors, and the continuation and duration of any symptoms were obtained. Eye symptoms (9.7 months), headaches (8.4 months), skin symptoms (8.3 months), and neurovestibular symptoms (6.9 months) had a relatively longer duration than did back pain (1.8 months) or respiratory symptoms (2.1 months). In particular, the remission of headaches had a negative correlation with female gender (HR 0.57, 0.34-0.95, 95% CI), and remission of eye symptoms had a negative correlation with the total hours of daily participation in the cleanup operation (HR 0.24, 0.06-0.95, 95% CI).  相似文献   

Mineral Chemistry and Age Dating of W-skarn Deposit at Weondong mine,Taebak in Korea     

Chang-Yoon PARK  Yungoo SONG  Il-Mo KANG  Donghoon JUNG  Khulganakhuu CHULUUNBAATAR 《《地质学报》英文版》2013,87(Z1):676-677

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