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Snowstorm over the Southwestern Coast of the Korean Peninsula Associated with the Development of Mesocyclone over the Yellow Sea

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Advances in Atmospheric Sciences 2008年第5期25卷 765-777页

作者： Ki-Young HEo Kyung-ja ha Division of Earth Environmental System College of Natural Sciences Pusan National University Korea

This study investigates the characteristics of a heavy snowfall event over the southwestern part of the Korean Peninsula on 4 December 2005. The snowstorm was a type of mesoscale maritime cyclone which resulted from barotropic instability, and diabatic heating from the warm ocean in continental polar air masses. Based on surface observations, radiosonde soundings, MTSAT-1R satellite data and the 10-km grid RDAPS （Regional Assimilation and Prediction System based on the PSU/NCAR MM5） data, the evolution of the mesocyclone is explained by the following dynamics; （1） In the initial stage, the primary role in the cyclogenesis process of the mesocyclone is a barotropic instability in the horizontal shear zone. （2） In the developing stage, the mesocyclone moves and deepens into a baroclinic zone corresponding to the surface heating and moistening. （3） In the mature stage, it is found that the mesocyclone is intensified by the destabilization caused by enhanced low-level heating and condensation, the moisture flux convergence, and the interaction between upper and lower-level potential vorticity anomalies. We suggest that a checklist with stepwise indicators responsible for development be prepared for the forecasting of heavy snowfall over the southwestern part of the Korean Peninsula.

关键词： heavy snowfall mesocyclone baroclinic instability barotropic instability stepwise roles potential vorticity anomalies

Implementation of Turbulent Mixing over a Stratocumulus-Topped Boundary Layer and Its Impact in a GCM

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Advances in Atmospheric Sciences 2009年第5期26卷 995-1004页

作者： Sun-Hee SHIN Kyung-ja ha Division of Earth Environmental System Pusan National University

The effect of a vertical diffusion scheme over a stratocumulus topped boundary layer （STBL） was investigated using the YoNU AGCM （Yonsei University Atmospheric General Circulation Model）. To consider the impact of clouds on the turbulence production, the turbulence mixing term, driven by radiative cooling at the cloud top, is implemented as an extended non-local diffusion scheme. In the model with this new scheme, the STBL parameterization significantly influences the lower atmosphere over the tropical and subtropical regions. Consideration of the turbulent mixing within the cloud layer leads to continuous stratocumulus formation. The cloud-top radiative cooling tends to favor more rapid entrainment and produces top-down turbulent mixing. This cooling develops a mixed layer without initiation of deep convection by surface fluxes. Variations in thermodynamical and dynamical features are produced by planetary boundary layer （PBL） cloud development. The simulated stratocumulus induces more mixing of heat and moisture due to the cloud forcing. over STBL regions, the lower boundary layer becomes warmer and drier. It also weakens vertical motion and zonal trade winds in the eastern Pacific, which indicates that stratocumulus cloud cover plays a role in weakening the Walker circulation; that is, cloud cover damps the tropical circulation.

关键词： stratocumulus topped boundary layer non-local diffusion scheme tropical circulation general circulation model

Nonlinear Local Lyapunov Exponent and Quantification of Local Predictability

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Chinese Physics Letters 2008年第5期25卷 1919-1922页

作者：丁瑞强李建平 ha Kyung-ja State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Division of Earth Environmental ~System Pusan National University Busan 609- 735 Korea

Nonlinear local Lyapunov exponent （NLLE） is applied to quantitatively determine the local predictability limit of chaotic systems. As an example, we find that the local predictability limit of Henon attractor varies considerably with time, and some underlying phase-spatial structure does not appear. The local predictability limit of initially adjacent points in phase space may be completely different. This will cause difficulties in making the long-time analogue forecast.

关键词： ATMoSPHERIC PREDICTABILITY

Decadal Changes in Climatological Intraseasonal Fluctuation of Subseasonal Evolution of Summer Precipitation over the Korean Peninsula in the mid-1990s

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Advances in Atmospheric Sciences 2011年第3期28卷 591-600页

作者： WonMoo KIM Jong-Ghap JHUN Kyung-ja ha Masahide KIMoTo School of Earth and Environmental Sciences/Research Institute of oceanography Seoul National University151-742Korea Divison of Earth Environmental System Pusan National University609-735Korea Atmosphere and ocean Research Institute University of Tokyo277-8564Japan

Decadal changes in the subseasonal evolution and the phase-locked climatological intraseasonal fluctuation of summertime rainfall over the Korean Peninsula before and after the mid-1990s are *** activity and the migration speed of the monsoon rain band over the East Asian region are altered in the recent decade,resulting in the drier conditions in late spring and the earlier onset of *** early August when a climatological monsoon break was clear in the earlier decade,the precipitation has increased dramatically with a meridional *** response to the enhanced convection over the South China Sea and southeastern China provides a favorable condition for more precipitation in early August through the changes in moisture transport and tropical cyclone passage.

关键词： decadal change intraseasonal fluctuation East Asian summer monsoon

Two Types of Diurnal Variations in Heavy Rainfall during July over Korea

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Advances in Atmospheric Sciences 2021年第12期38卷 2201-2211页

作者： Chang-Kyun PARK Minhee ChaNG Chang-Hoi Ho Kyung-ja ha Jinwon KIM Byung-Ju SoHN School of Earth and Environmental Sciences Seoul National UniversitySeoul 08826Korea School of Earth and Environmental Systems Pusan National UniversityBusan 46241Korea Center for Climate Physics Institute for Basic ScienceBusan 46241Korea National Institute of Meteorological Sciences Korean Meteorological AdministrationJeju 63568Korea

This study examined the characteristics of the diurnal variations of heavy rainfall(≥110 mm in 12 hours)in Korea and the related atmospheric circulation for July from 1980−*** the analysis period,two dominant pattens of diurnal variation of the heavy rainfall emerged:all-day heavy rainfall(AD)and morning only heavy rainfall(Mo)*** the AD-type,the heavy rainfall is caused by abundant moisture content in conjunction with active convection in the morning(0000−1200,LST;LST=UTC+9)and the afternoon hours(1200−2400 LST).These systems are related to the enhanced moisture inflow and upward motion induced by the strengthening of the western North Pacific subtropical high and upper-tropospheric *** the Mo-type,heavy rainfall occurs mostly in the morning hours;the associated atmospheric patterns are similar to the *** find that the atmospheric pattern related to severe heavy rainfalls in 2020 corresponds to a typical AD-type and resembles the 1991 heavy-rainfall system in its overall synoptic/mesoscale *** present results imply that extremely heavy rainfall episodes in Korea during the 2020 summer may occur again in the future associated with the recurring atmospheric phenomenon related to the heavy rainfall.

关键词： heavy rainfall diurnal cycle of rainfall 2020 summer summer rainy season Korea

Preface to the Special Issue:Climate Change and Variability of Tropical Cyclone Activity

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Advances in Atmospheric Sciences 2022年第2期39卷 203-204页

作者： Liguang WU Bin WANG Johnny CLChaN Kyung-ja ha Il-Ju MooN Jun MATSUMoTo Zhemin TAN Ke FAN Department of Atmospheric and oceanic Sciences Fudan UniversityShanghai 200438China International Pacific Research Center School of Ocean and Earth Science and TechnologyUniversity of HawaiiHonoluluHI 96822USA School of Energy and Environment City University of Hong KongHong KongChina Research Center for Climate Sciences Pusan National UniversityBusan 46241South Korea Typhoon Research Center Jeju National UniversityJeju 63243South Korea Research Center for Climatology Department of GeographyTokyo Metropolitan UniversityTokyo 192-0392Japan School of Atmospheric Sciences Nanjing UniversityNanjing 210023China School of Atmospheric Sciences Sun Yat-Sen UniversityZhuhai 519082China

Tropical cyclones(TCs) are one of the most destructive natural phenomena on Earth in terms of human-life and economic losses. It is currently a matter of prodigious public and scientific interest how TC activity has changed and will change in a warming climate. This special issue focuses on a challenging subject raised in the Intergovernmental Panel on Climate Change(IPCC) report and numerous research papers.

关键词： warming Earth raised

Interdecadal shift in the relationship between the East Asian summer monsoon and the tropical Indian ocean

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Interdecadal shift in the relationship between the East Asia...

The importance of large-diameter trees to the creation of snag and deadwood biomass

“2010年北京气象学会中青年优秀论文评选”学术研讨会

作者： Kyung-ja ha Division of Earth Environmental System Pusan National UniversityBusan 609-735Korea

In this work,the authors investigate changes in the interannual relationship between the East Asian summer monsoon(EASM) and the tropical Indian ocean(Io) in the late *** contrasting the correlations of the EASM index(EASMI) with the summer Io sea surface temperature anomaly(SSTA) between 1953-1975 and 1978-2000,a pronounced different correlation pattern is found in the tropical *** SSTA pattern similar to the positive Indian ocean Dipole(IoD) shows a strongly positive correlation with the EASMI in *** in 1978-2000,significant negative correlation appears in the northern Io and the IoD-like correlation pattern *** is indicated that the summer strong IoD events in 1953-1975 can cause a weaker-than-normal western North Pacific(WNP) subtropical high,which tends to favor a strong *** 1978-2000, the connection between the summer IoD and the WNP circulation is disrupted by the climate ***,the northern Io shows a close connection with the WNP circulation in *** warming over the northern Io is associated with the significant enhanced 500 hPa geopotential height and an anomalous anticyclone over the *** change in the Io-EASM relationship is attributed to the interdecadal change of the background state of the ocean-atmosphere system and the interaction between the ENSo and *** recent decades,the tropical Io and tropical Pacific have a warmer mean SST,which has likely strengthened(weakened) the influence of the northern Io (IoD) on the *** addition,due to the increase in the ENSo variability along with the higher mean equatorial eastern Pacific SST in 1978-2000,the influence of ENSo on the East Asian summer circulation experiences a significant strengthening after the late *** the warming over the northern Io is associated with the significant warming in the equatorial eastern Pacific,the strengthened ENSo-EASM relationship has likely also contributed to the strengthened relationship between the northern I

关键词： East Asian summer monsoon Indian ocean Interdecadal shift ENSo

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Ecological Processes 2021年第1期10卷 380-393页

作者： james A.Lutz Soren Struckman Sara J.Germain tucker J.Furniss Department of Wildland Resources S.J.and Jessie E.Quinney College of Natural ResourcesUtah State University5230 Old Main HillLoganUT 84322-5230USA

Background:Baseline levels of tree mortality can,over time,contribute to high snag densities and high levels of deadwood(down woody debris)if fire is infrequent and decomposition is *** can be important for tree recruitment,and it plays a major role in terrestrial carbon cycling,but deadwood is rarely examined in a spatially explicit ***:Between 2011 and 2019,we annually tracked all trees and snags≥1 cm in diameter and mapped all pieces of deadwood≥10 cm diameter and≥1 m in length in 25.6 ha of Tsuga heterophylla/Pseudotsuga menziesii *** analyzed the amount,biomass,and spatial distribution of deadwood,and we assessed how various causes of mortality that contributed uniquely to deadwood ***:Compared to aboveground woody live biomass of 481 Mg ha^(−1)(from trees≥10 cm diameter),snag biomass was 74 Mg ha^(−1) and deadwood biomass was 109 Mg ha^(−1)(from boles≥10 cm diameter).Biomass from large-diameter trees(≥60 cm)accounted for 85%,88%,and 58%,of trees,snags,and deadwood,*** aboveground woody live and dead biomass was 668 Mg ha^(−1).The annual production of downed wood(≥10 cm diameter)from tree boles averaged 4 Mg ha^(−1) yr^(−1).Woody debris was spatially heterogeneous,varying more than two orders of magnitude from 4 to 587 Mg ha^(−1) at the scale of 20 m×20 m *** all causes of deadwood creation varied in importance between large-diameter trees and small-diameter *** of standing stems and deadwood had weak inverse distributions,reflecting the long period of time required for trees to reach large diameters following antecedent tree mortalities and the centennial scale time required for deadwood ***:old-growth forests contain large stores of biomass in living trees,as well as in snag and deadwood biomass pools that are stable long after tree *** biomass(or carbon)in deadwood pools can lead to substantial underestimations of sequestration and stability.

关键词： Carbon sequestration old-growth forest Pseudotsuga menziesii Tree mortality Tsuga heterophylla Wind River Forest Dynamics Plot

Mechanical Behaviour of Composite Bioactive Bone Cements Consisting of Two Different Types of Surface Treated Hydroxyapatite as Filler

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Journal of Wuhan University of Technology(Materials Science) 2005年第B12期20卷 10-12页

作者： S Deb ja Roether Department of Biomaterials King's College London School of Dentistry at the Guy's King's & St Thomas Hospital Guy's Tower Guy's Hospital London Bridge London SE 1 9RT UK

Bioactive bone cements based on a paste-paste system for orthopaedic applications were developed consisting of hydroxyapatite （ ha ） filler panicles in a methacrylate matrix comprising urethane dimethacrylate （ UDMA ） and triethylene glycol dimethacrylate （ TEGDMA ）. To improve the interface between inorganic filler and organic matrix the ha panicles were subjected to two different surface treatment methods, using polyacrylic acid （PAA） and γ-methacryloxy propyl trimethoxy silane （γMPS）. The aim of the present study was to determine the influence of surface treatment and the inclusion of multifunctional methacrylates on the mechanical properties, namely 3-point flexural strength （FS） and fracture toughness of the cements and the effect of ageing in simulated body fluid. Comparing the mechanical properties of the two cements, the γMPS- ha cement showed that the fracture toughness of the experimental bone cements were significantly greater （ p 〈 0.001） compared to that of the PMMA cement, whereas PAA-ha containing cement had strength vollues around 20% lower. Interestingly, PAA was found to be more effective in improving the interface as the PAA treated ha cement （ UThaPPA ） maintained its strength on immersion in SBF, suggesting that PAA provided a coupling, which was less sensitive to moisture, a similar trend was also observed with the inclusion of the carboxyl containing multifunctional methacrylates.

关键词： bioactive bone cements coupling agents composites polyacrylic acid