利用EP/TOMS气溶胶指数分析中国和韩国的沙尘天气过程   总被引：5，自引：1，他引：4  

金正润  牛生杰  河惠卿  王振会 《中国沙漠》2009,29(4):750-756

利用 EP/TOMS卫星反演气溶胶指数、卫星云图和天气形势,研究了沙尘天气对大气气溶胶的贡献以及中国和韩国沙尘天气过程的强度及其演变。结果表明,TOMS气溶胶指数高值对应着沙尘天气的出现地区,可以判别和监测大规模沙尘天气,而且TOMS气溶胶指数能结合卫星云图、大气环流分析,对沙尘天气的影响范围和传输路径进行有效地预报。另外气溶胶指数能排除云的影响并准确地检测到云覆盖的地区。  相似文献   

Rate of late Quaternary ice-cap thinning on King George Island, South Shetland Islands, West Antarctica defined by cosmogenic ³⁶Cl surface exposure dating     

YEONG BAE SEONG  LEWIS A. OWEN  HYOUN SOO LIM  HO IL YOON  YEADONG KIM  YONG IL LEE  MARC W. CAFFEE 《Boreas: An International Journal of Quaternary Research》2009,38(2):207-213

Glacial landforms on the Barton and Weaver peninsulas of King George Island in the South Shetland Islands, West Antarctica were mapped and dated using terrestrial cosmogenic ³⁶Cl methods to provide the first quantitative terrestrial record for late Quaternary deglaciation in the South Shetland Islands. ³⁶Cl ages on glacially eroded and striated bedrock surfaces range from 15.5±2.5 kyr to 1.0±0.7 kyr. The ³⁶Cl ages are younger with decreasing altitude, indicating progressive downwasting of the southwestern part of the Collins Ice Cap at a rate of ∼12 mm yr⁻¹ since 15.5±2.5 kyr ago, supporting the previously published marine records for the timing and estimate of the rate of deglaciation in this region.  相似文献   

Two-stage growth of porphyroblastic biotite and garnet in the Barrovian metapelites of the Imjingang belt, central Korea     

Y. KIM  M. CHO 《Journal of Metamorphic Geology》2008,26(3):385-399

Porphyroblastic biotite and garnet in the Barrovian metapelites of the Imjingang belt, Korea, were investigated to unravel the sequence and mechanism of mineral growth. Poikiloblastic biotite contains straight inclusion trails (S_i) discontinuous to the major foliation, and develops clear zones at the grain margin. These microstructures suggest an initial growth of biotite between two contractional deformations (D_n−1 and D_n) followed by an overgrowth during D_n. Although garnet poikiloblasts contain variable S_i patterns, their major growth is likely to have occurred during D_n on the basis of compositional relationships among variable garnet types. Early poikiloblasts of both minerals were formed by chemical replacement of the matrix that consisted mainly of chlorite, muscovite and quartz. Subsequent growth of biotite was governed by a crack-filling mechanism, and was accompanied by the production of extensional cracks inside or around biotite, providing fluid pathways. The overgrowth of garnet was favoured at the biotite–garnet interface, and the consequence was a partial replacement of inclusion-poor garnet after biotite subsequent to D_n. In addition, clear zones and pressure shadows as well as the matrix around biotite porphyroblasts were replaced by garnet, suggesting an inheritance of various pre-existing microstructures in the S_i pattern of garnet. Further attention is thus required for any attempt to delineate the microstructural interaction between deformation and metamorphism, particularly in a sample containing early-grown porphyroblasts. Microstructural evidence for the two-stage growth of biotite and garnet is present up to the kyanite zone, indicating that this growth mechanism is prevalent during progressive metamorphism of Barrovian metapelites.  相似文献   

A New Video and Digital Camera System for Studies of the Dynamics of Microtopographic Features on Tidal Flats     

LARS CHRESTEN LUND-HANSEN  EINER LARSEN  KURT THOMAS JENSEN  KIM N. MOURITSEN  CHRISTIAN CHRISTIANSEN  THORBJØRN JOEST ANDERSEN 《Marine Georesources & Geotechnology》2013,31(1-2):115-122

A newly developed video and camera system for tidal flat microtopographic studies is presented. It consists of a SONY handy cam placed in an underwater housing mounted on a frame about 70?cm above the sediment surface. A rectangular surface area of 30?×40?cm is imaged by the camera. The camera records video sequences and/or digital images at predetermined time lapses. The total number of images is about 540, and a similar number of 10-second long video sequences can be recorded. The camera is programmed with a PC before deployment, and the total deployment time depends on the time lapse between recordings. The camera is connected to an external power supply (12?volt), and a halogen projector pointing towards the sediment surface ensures that the system is operable on a 24-hours scale. The system has been tested in the Danish Wadden Sea. It has proved to be a very useful tool in studies of topographic effects of erosion and deposition sequences, and for studies of benthic organisms-sediment interactions. The test site was further equipped with sensors for water and seabed measurements, which proved to be indispensable regarding the interpretation of recorded image time-series.  相似文献   

三种云导风资料及其对台风数值预报影响试验的比较分析   总被引：4，自引：0，他引：4  

河惠卿  王振会  金正润  李峰  徐爱淑 《热带气象学报》2009,25(1):82-88

由于在海面上缺乏重要的常规观测资料,因而云导风成为研究西太平洋台风一种不可缺少的重要资料。为了对“南京信息工程大学”开发的云导风系统(CWIS)进行质量评价及其对台风研究的贡献,选取了三种云导风资料进行综合对比。通过对比CWIS导出FY2C云迹风数据、中国气象局国家卫星中心(NSMC)导出FY2C云迹风数据和日本气象卫星中心（JMSC）的MTSAT云导风数据,采用逐点比较法分析了不同资料的精度与误差。所得结果发现：CWIS的风速与JMSC风速、NSMC的风向与JMSC风向分别均有较好的一致性。使用三重制约法获得了三种云导风资料的误差信息,风速误差标准差以JMSC最小、NSMC最大;风向误差标准差以JMSC最小、CWIS最大。云导风资料在中尺度对流云带和高空急流云带上,NSMC云导风风速大于CWIS、JMSC;而在台风云系上三种云导风资料没有特别的差异。根据以上比较的三种云导风资料的结果,进行了云导风资料对台风路径数值预报的影响的初步试验。结果表明：加入云导风资料模拟后得到的台风移动路径与实况总体上比较接近,不同的资料导出不同的结果,台风中心位置误差减小到23%~74%。  相似文献   

Characteristics and Nonlinear Growth of the Singular Vector Related to a Heavy Rainfall Case over the Korean Peninsula     

Yonghan CHOI  Joowan KIM  Dong-Kyou LEE 《大气科学进展》2012,29(1):10-28

In this study,singular vectors related to a heavy rainfall case over the Korean Peninsula were calculated using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) adjoint modeling system.Tangent linear and adjoint models include moist physical processes,and a moist basic state and a moist total energy norm were used for the singular-vector calculations.The characteristics and nonlinear growth of the first singular vector were analyzed,focusing on the relationship between the basic state and the singular vector.The horizontal distribution of the initial singular vector was closely related to the baroclinicity index and the moisture availability of the basic state.The temperature-component energy at a lower level was dominant at the initial time,and the kinetic energy at upper levels became dominant at the final time in the energy profile of the singular vector.The nonlinear growth of the singular vector appropriately reflects the temporal variations in the basic state.The moisture-component energy at lower levels was dominant at earlier times,indicating continuous moisture transport in the basic state.There were a large amount of precipitation and corresponding latent heat release after that period because the continuous moisture transport created favorable conditions for both convective and nonconvective precipitation.The vertical propagation of the singular-vector energy was caused by precipitation and the corresponding latent heating in the basic state.  相似文献   

Seasonal Prediction of Monthly Precipitation in China Using Large-Scale Climate Indices     

Maeng-Ki KIM  Yeon-Hee KIM 《大气科学进展》2010,27(1):47-59

In this study, seasonal predictions were applied to precipitation in China on a monthly basis based on a multivariate linear regression with an adaptive choice of predictors drawn from regularly updated climate indices with a two to twelve month lead time.A leave-one-out cross validation was applied to obtain hindcast skill at a 1% significance level.The skill of forecast models at a monthly scale and their significance levels were evaluated using Anomaly Correlation Coefficients(ACC) and Coefficients Of De...  相似文献   

Influence of Tropical Cyclone Landfalls on Spatiotemporal Variations in Typhoon Season Rainfall over South China     

Min-Hee LEE  Chang-Hoi HO  Joo-Hong KIM 《大气科学进展》2010,27(2):443-454

This study examined the impact of tropical cyclone (TC) landfalls on the spatiotemporal variations in the rainfall over South China for the period 1957–2005. The target region was selected to show the noteworthy contribution of TC landfalls to the total rainfall during the typhoon season (July–October). Two prevailing spatial variations in the rainfall were obtained from an EOF analysis. The first EOF mode displays singlesign variability over South China with an explained variance of 23.4%. The associated t...  相似文献   

2002年3月21-22日影响韩国的沙尘天气分析   总被引：1，自引：0，他引：1  

金正润  牛生杰  河惠卿 《南京气象学院学报》2007,30(5):643-647

利用气象卫星、天气形势场和NCEP/NCAR再分析资料,分析了2002年3月21-22日影响韩国沙尘天气的原因. 结果表明:影响韩国沙尘天气的沙尘主要源地是蒙古国和中国内蒙古地区.沙尘天气发生在地面冷锋后部,高压伸展的前面;19日和20日沙尘暴发生后,沙尘沿着西北风输送,21日早晨影响韩国;PM10最高值达到 2 778.2 μg/m3,由于西北风较强,沙尘暴发生后很快影响到韩国,但在韩国持续的时间较短.  相似文献   

Depth distribution of Calanus finmarchicus and C. glacialis in relation to environmental conditions in the Barents Sea     

KIM H. UNSTAD  KURT S. TANDE 《Polar research》1991,10(2):409-420

Stage composition and vertical distribution of copepodids of Calanus finmarchicus and C. glacialis are described during spring and summer in Atlantic and Arctic waters, respectively. The two species co-occurred in the region of the Polar Front, both in moderate to high population densities. Ontogenetic migration, meaning that the migration range becomes progressively wider with advancing stage, was found in both species. The present study also revealed that C. finmarchicus had modifications in its ontogenetic vertical distribution. The standing crop of phytoplankton, predominantly Phaeocystis pouchetii , appeared to influence the degree of stage-specific segregation. Both low and high food concentrations tended to increase the vertical distribution of the instars. On the other hand, a narrow subsurface stratum of abundant phytoplankton led to an aggregation of copepodids at this depth. In the region of the Polar Front, where the two species co-occur, C. glacialis had a deeper distribution than C. finmarchicus , thus creating a bimodal vertical distribution pattern within the uppermost 200 m.  相似文献