From the editors     

Xiaozhai QI  George C.LEE 《地震工程与工程振动(英文版)》2018,(4)

正Dear Members of the Editorial Board,Contributors and Friends of EEEV,To commemorate the tenth anniversary of the Wenchuan earthquake disaster,the journal of Earthquake Erngineering and Engineering Vibratiorn will publish special sections with invited papers in 2018.We sincerely appreciate the contributions from the following experts:Professor Akira WADA,and Professor Kuo-Chun CHANG.  相似文献   

Sensitivity evaluation of the flash flood warning system introduced to ungauged small mountainous basins in Korea     

YOO Chulsang  LEE Jinwook  CHANG Kwonhee  YANG Dongmin 《山地科学学报》2019,(5)

This study evaluates the uncertainty involved in the determination of the flash flood guidance(FFG) of the flash flood warning system(FFWS) for a small mountainous region(FFWS_MR)in Korea. The sensitivity is evaluated both at each step to determine the FFG and for all steps together. The results show that the relative difference of the FFG is about 50% of the current system, most of which involves the channel width. Especially, the use of some specific empirical equations to estimate the major parameters results in a considerable amount of the relative difference of the FFG. In addition, though only four basins were field-surveyed, it is found that the indirect estimation of the major parameters always introduces some amount of additional uncertainty. In conclusion, accurate estimation of the major parameters must be the most important procedure to derive an accurate FFG, among which the channel cross-section at the exit of the basin lies at the center.  相似文献   

Seasonal Variations of CH_4 Emissions in the Yangtze River Delta Region of China Are Driven by Agricultural Activities     

Wenjing HUANG  Timothy J. GRIFFIS  Cheng HU  Wei XIAO  Xuhui LEE 《大气科学进展》2021,38(9):1537-1551

Developed regions of the world represent a major atmospheric methane(CH_4) source, but these regional emissions remain poorly constrained. The Yangtze River Delta(YRD) region of China is densely populated(about 16% of China's total population) and consists of large anthropogenic and natural CH_4 sources. Here, atmospheric CH_4 concentrations measured at a 70-m tall tower in the YRD are combined with a scale factor Bayesian inverse(SFBI) modeling approach to constrain seasonal variations in CH_4 emissions. Results indicate that in 2018 agricultural soils(AGS, rice production) were the main driver of seasonal variability in atmospheric CH_4 concentration. There was an underestimation of emissions from AGS in the a priori inventories(EDGAR—Emissions Database for Global Atmospheric Research v432 or v50), especially during the growing seasons. Posteriori CH_4 emissions from AGS accounted for 39%(4.58 Tg, EDGAR v432) to 47%(5.21 Tg, EDGAR v50) of the total CH_4 emissions. The posteriori natural emissions(including wetlands and water bodies) were1.21 Tg and 1.06 Tg, accounting for 10.1%(EDGAR v432) and 9.5%(EDGAR v50) of total emissions in the YRD in2018. Results show that the dominant factor for seasonal variations in atmospheric concentration in the YRD was AGS,followed by natural sources. In summer, AGS contributed 42%(EDGAR v432) to 64%(EDGAR v50) of the CH_4 concentration enhancement while natural sources only contributed about 10%(EDGAR v50) to 15%(EDGAR v432). In addition, the newer version of the EDGAR product(EDGAR v50) provided more reasonable seasonal distribution of CH_4 emissions from rice cultivation than the old version(EDGAR v432).  相似文献   

From the editors     

George C.LEE 《地震工程与工程振动(英文版)》2011,10(1):I0001-I0001

Dear Contributors,Readers and Friends: 2011 milestones the tenth anniversary of the Journal of Earthquake Engineering and Engineering Vibration.we first want to take this opportunity to express our gratitude to those retiring members of the Editorial Board for their valuable contributions in the past,and to welcome those who joined the Editorial Board this year. As we mentioned in our message to you in December 2010,effective 20ll,the journal is officially co-sponsored by the Huixian Earthquake  相似文献   

地表探槽断裂岩岩石磁学揭示汶川地震断裂带不同滑移机制   总被引：3，自引：0，他引：3  

刘栋梁  李海兵  李德贵  孙知明  司家亮  王焕 《地质学报》2015,89(12):2250-2265

岩石磁学能揭示岩石的磁性矿物组合,通过断裂岩不同的磁性矿物组合可揭示地震过程中磁性矿物变化、地震摩擦温度及地震滑移机制等基础地震地质问题。2008年Mw 7.9级汶川地震使两条断裂带同时发生地表破裂,包括映秀-北川和灌县-安县断裂地表破裂带,破裂带上地震断裂岩为岩石磁学提供了大量的研究对象。本研究主要以汶川地震地表破裂带上两个探槽内断裂岩为对象,包括映秀-北川地表破裂带上的八角庙探槽和灌县-安县地表破裂带上的九龙探槽,结合目前已发表的地表及WFSD-1孔的研究成果,从岩石磁学角度探讨汶川地震断裂带经历的地震滑移机制:1综合映秀-北川地震断裂带上八角庙探槽和其它位置的断裂岩岩石磁学研究,结果显示该地震断裂带附近断层泥的高磁化率源于新生的亚铁磁性矿物,如磁铁矿和磁赤铁矿等,故映秀-北川地震断裂曾经历高温快速热增压地震滑移机制;2灌县-安县地震断裂带上九龙探槽内断层泥略低的平均磁化率源于其铁的硫化物含量比断层角砾及侏罗纪砂岩多,铁的硫化物可能源于地震过程或断裂岩抬升到地表后的地表作用,如果断层泥中铁的硫化物多含量源于地震过程,则灌县-安县地震断裂带曾经历低温慢速机械润滑地震滑移机制;3两条断裂经历的不同地震滑移机制可能受控于断裂深部结构,如断层产状,映秀-北川地震断裂带的陡倾角易产生高温快速地震滑移,而灌县-安县地震断裂带的缓倾角更易产生低温慢速地震滑移。  相似文献   

Ex situ echo sounder target strengths of ice krill Euphausia crystallorophias     

Hyoung Sul LA  Hyungbeen LEE  Donhyug KANG  SangHoon LEE  Hyoung Chul SHIN 《中国海洋湖沼学报》2015,33(3)

Ice krill is the keystone species in the neritic ecosystem in the Southern Ocean,where it replaces the more oceanic Antarctic krill. It is essential to understand the variation of target strength(TS in d B re 1 m 2) with the different body size to accurately estimate ice krill stocks. However,there is comparatively little knowledge of the acoustic backscatter of ice krill. The TS of individual,formalin-preserved,tethered ice krill was measured in a freshwater test tank at 38,120,and 200 k Hz with a calibrated split-beam echo sounder system. Mean TS was obtained from 21 individual ice krill with a broad range of body lengths(L :13–36 mm). The length( L,mm) to wet weight( W; mg) relationship for ice krill was W =0.001 218×103 × L 3.53( R 2= 0.96). The mean TS-to-length relationship were TS3 8 k Hz =-177.4+57log 10( L),( R 2 = 0.86); TS 120 k Hz =-129.9+31.56 log 10( L),( R 2 =0.87); and TS 200 k Hz =-117.6+24.66log1 0( L),( R 2 =0.84). Empirical estimates of the relationship between the TS and body length of ice krill were established at 38,120,and 200 k Hz and compared with predictions obtained from both the linear regression model of Greene et al.(1991) and the Stochastic Distorted Wave Born Approximation(SDWBA) model. This result might be applied to improve acoustic detection and density estimation of ice krill in the Southern Ocean. Further comparative studies are needed with in situ target strength including various body lengths of ice krill.  相似文献   

Species delimitation in the green algal genus Codium (Bryopsidales) from Korea using DNA barcoding     

LEE Hyung Woo  KIM Myung Sook 《海洋学报(英文版)》2015,34(4):114-124

Codium, one of the largest marine green algal genera, is difficult to delimit species boundary accurately based on morphological identification only. DNA barcoding is a powerful tool for discriminating species of seaweeds. The plastid elongation factor TU(tuf A) is considered as maker to perform DNA barcoding of green algal species than rbc L gene due to universality and rapid evolution rate. We conducted DNA barcoding application to Codium specimens from the Jeju Island, Korea to overcome the limit of morphological identification and to confirm the species diversity. As a result of applying tuf A marker, we newly generated fifty-five tuf A barcodes to resolve eight species. Tuf A marker exhibited 6.1%–21.8% interspecific divergences, wider than the gap of rbc L exon 1,3.5%–11.5%. Molecular analysis of rbc L exon 1 sequences of Codium revealed eight distinct species like tuf A analysis separated in five phylogenetic groups. DNA barcoding of the genus Codium using tuf A marker is more helpful to overcome the limit of morphological identification, and this is more potential to reveal cryptic species and to resolve the relationships among subspecies than rbc L analysis alone. The complement of tuf A barcoding and rbc L analyses including morphology for the genus Codium in the northwestern Pacific will give much more reliable achievement for discovering species diversity and resolving the phylogenetic relationships.  相似文献   

Improvement in Background Error Covariances Using Ensemble Forecasts for Assimilation of High-Resolution Satellite Data     

Seung-Woo LEE  Dong-Kyou LEE 《大气科学进展》2011,28(4):758-774

Satellite data obtained over synoptic data-sparse regions such as an ocean contribute toward improving the quality of the initial state of limited-area models. Background error covariances are crucial to the proper distribution of satellite-observed information in variational data assimilation. In the NMC (National Meteorological Center) method, background error covariances are underestimated over data-sparse regions such as an ocean because of small differences between different forecast times. Thus, it is necessary to reconstruct and tune the background error covariances so as to maximize the usefulness of the satellite data for the initial state of limited-area models, especially over an ocean where there is a lack of conventional data. In this study, we attempted to estimate background error covariances so as to provide adequate error statistics for data-sparse regions by using ensemble forecasts of optimal perturbations using bred vectors. The background error covariances estimated by the ensemble method reduced the overestimation of error amplitude obtained by the NMC method. By employing an appropriate horizontal length scale to exclude spurious correlations, the ensemble method produced better results than the NMC method in the assimilation of retrieved satellite data. Because the ensemble method distributes observed information over a limited local area, it would be more useful in the analysis of high-resolution satellite data. Accordingly, the performance of forecast models can be improved over the area where the satellite data are assimilated.  相似文献   

The impact of ecosystem functional type changes on the La Plata Basin climate     

Seung-Jae LEE  E. Hugo BERBERY  Domingo ALCARAZ-SEGURA 《大气科学进展》2013,30(5):1387-1405

In this paper, the effects of land cover changes on the climate of the La Plata Basin in southern South America are investigated using the Weather and Research Forecasting (WRF) Model configured on a 30/10km two-way interactive nested grid. To assess the regional climate changes resulting from land surface changes, the standard land cover types are replaced by time-varying Ecosystem Functional Types (EFTs), which is a newly devised land-cover classification that characterizes the spatial and interannual variability of surface vegetation dynamics. These variations indicate that natural and anthropogenic activities have caused changes in the surface physical parameters of the basin, such as albedo and roughness length, that contributed to regional climate changes. EFTs are obtained from functional attributes of vegetation computed from properties of the Normalized Difference Vegetation Index (NDVI) to represent patches of the land surface with homogeneous energy and gas exchanges with the atmosphere. Four simulations are conducted, each experimental period ranging from September to November in two contrasting years, 1988 and 1998. The influence of an identical EFT change on the surface heat fluxes, 2-m temperature and humidity, 10-m winds, convective instabilities and large-scale moisture fluxes and precipitation are explored for 1988 (a dry year) and 1998 (a wet year). Results show that the surface and atmospheric climate has a larger response to the same EFT changes in a dry year for 2-m temperature and 10-m wind; the response is larger in a wet year for 2-m water vapor mixing ratio, convective available potential energy, vertically integrated moisture fluxes and surface precipitation. For EFTs with high productivity and a weak seasonal cycle, the nearsurface temperature during the spring of 1988 and 1998 increased by as much as 1℃ in the central and western portions of La Plata Basin. Additionally, for higher productivity EFTs, precipitation differences were generally positive in both dry and wet years, although the patterns are not uniform and exhibit certain patchiness with drier conditions.  相似文献   

Plant stable isotope composition across habitat gradients in a semi‐arid savanna: implications for environmental reconstruction     

JACQUELINE CODRON  JULIA A. LEE‐THORP  MATT SPONHEIMER  DARYL CODRON 《第四纪科学杂志》2013,28(3):301-310

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