Comment on ‘García‐Santos G,Bruijnzeel LA. 2011. Rainfall,fog and throughfall dynamics in a subtropical ridge top cloud forest,National Park of Garajonay (La Gomera,Canary Islands,Spain). Hydrological Processes 25: 411–417’     

Axel Ritter  Carlos M. Regalado 《水文研究》2013,27(7):1123-1128

A previous study aiming to characterize the water dynamics of a cloud forest in the Garajonay National Park (La Gomera) from measurements taken in a plot located in the upper part of a selected watershed within the park is here commented. Reported magnitudes of hydrological variables and conclusions based on them are in disagreement with those of numerous studies carried out previously at the same site. Large data dispersion and inapplicability of some of the hypothesis assumed are shown to invalidate most of the results. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Biomarker characterisation and hydrous pyrolysis of bitumens from Tertiary volcanics, queen Charlotte islands, British Columbia, Canada     

M.G. Fowler  L.R. Snowdon  P.W. Brooks  T.S. Hamilton 《Organic Geochemistry》1988,13(4-6)

A number of bitumen samples have been recovered from vugs and fractures in outcropping Tertiary basalts of the Queen Charlotte Islands off the west coast of British Columbia, Canada. n-Alkanes and acyclic isoprenoids are not present and the polycyclic biomarker distribution of the four samples analyzed by GC and GC-MS has been altered. One sample contains no remaining recognizable biomarkers. Two bitumens were also obtained from Lower Jurassic potential source rocks, including one from the Sandilands Formation, which was considered previously to be the most likely source of the Tertiary bitumens. Although these two bitumens were also taken from outcrops, they are considerably less biodegraded. The Sandilands Formation bitumen contains 28, 30-bisnorhopanes and since these compounds were not detected in the Tertiary bitumens, there is no evidence from the initial results for a Sandilands Formation contribution to the hydrocarbons in the Tertiary basalts. The presence of 18α(H)-oleanane in the saturate fraction of two of the Tertiary bitumens from widely separated locations indicates that they are at least partially sourced from Tertiary organic matter.Because the distribution of biomarkers in some samples has been severely affected by biodegradation, the asphaltenes of the bitumens were hydrously-pyrolysed and the saturate fractions of the resulting pyrolysates analysed for possible additional information on the origin of the bitumens. The pyrolysates from the more degraded samples contain compounds not detected in the saturate fractions of the original bitumen and show some of the expected characteristics of the original non-degraded bitumen. However, the compounds most useful for correlation are not present in the pyrolysates apparently due to their non-incorporation into the kerogen macromolecule. Our results suggest that hydrous-pyrolysis of asphaltenes is of limited use in the correlation of biodegraded samples and in determining their origins.  相似文献   

Statistical analysis and long-term prediction of seismicity for linear zones   总被引：2，自引：0，他引：2  

A. M. Shurygin 《Mathematical Geology》1993,25(7):759-772

The model of the Poisson point process is too vague for earthquake locations in space and time: earthquakes tend to cluster in middle distances and to repulse in large ones. The Poisson point model with variable density makes it possible to describe the tendency for clustering but does not reveal the periodicity of clusters. The author proposes the point-process model where locations of points are determined not by densities of point distribution, but by densities of interpoint differences distribution. In the model, a latent periodicity is revealed and used for prediction of a point process. In 1983, the point-process model prediction was made for the Kuril Islands for 1983–1987 and two signs of danger in time and location were determined. Then they were confirmed by strong earth-quakes. In 1989, a similar prediction was made for North Armenia. The Spitak earthquake in 1988 is clearly seen from the data of previous earthquakes.  相似文献   

Palaeozoic and early Mesozoic fish faunas of the Japanese Islands   总被引：2，自引：0，他引：2  

MASATOSHI GOTO 《Island Arc》1994,3(4):247-254

Abstract In recent years, many fish teeth and scales have been found from the Palaeozoic and Mesozoic age strata of the Japanese Islands. This study is a compilation of the Japanese fish record from the Palaeozoic and early Mesozoic age deposits. Based on the published and unpublished data, the fossil fishes from the Palaeozoic and Early Mesozoic of Japan can be classified into 27 genera and 33 species, that is, one species of Devonian placoderms, 19 species of Permian to Jurassic elasmobranchs, three species of Permian cochliodonts, seven species of Carboniferous to Permian petalodonts, and three species of Triassic to Jurassic osteichthyans.  相似文献   

南沙群岛景观及区域古地理   总被引：6，自引：1，他引：6  

赵焕庭  袁家义 《地理学报》1995,50(2):107-117

本文论述了南沙群岛的海底地形、海底表层沉积、珊瑚礁景观、区域新生代古地理、以永暑礁为代表的古气候与古海面，以及本区古海洋等自然地理特征。  相似文献   

Potentialities,uncertainties and complexities in the response of coral reefs to future sea-level rise     

T. Spencer 《地球表面变化过程与地形》1995,20(1):49-64

Coral islands formed of largely unconsolidated sands only a few metres above sea level are thought to be particularly vulnerable to sea-level rise consequent upon global warming. However, scenarios which predict catastrophic flooding and loss of island area need reassessment, particularly in the light of the continued downwards revision of projected rates of future sea-level rise. Revised questions concern the interactions between reef growth and sea-level change, biophysical constraints on coral growth, and the importance to reef systems of potential changes in the magnitude, frequency and location of tropical cyclones and hurricanes. It is clear that most reefs have the growth potential to meet even the highest of future sea-level rise scenarios, but too little is known about physiological and physical constraints to reef growth to adequately evaluate the importance of these two factors in constraining this potential at the present time. Future sea-level rise in the tropical oceans, and coral reef responses, will take place against a backdrop of inter-regional differences in Holocene sea levels, resulting from the varying interaction of eustatic and hydro-isostatic processes. These differences have generated varying constraints on the development of modern reefs and varying inherited topographies upon which future sea-level changes will be superimposed. These controls are particularly important in assessing differences in vulnerability to future sea-level rise for reef islands in the Pacific Ocean and the Caribbean Sea.  相似文献   

Characteristics of horizontal crustal deformation in Japan as deduced from frequency distribution of maximum shear strain rate     

Yoichiro Fujii 《Pure and Applied Geophysics》1995,144(1):19-37

In order to study characteristics of horizontal crustal strains, we divide the Japanese Islands into 14 tectonic provinces consistent with the suggestion given byMatsuda (1990). We calculate frequency distribution of strain rates using the results of the Precise Control Survey initiated by the Geographical Survey Institute in 1973. This survey is a revision of old first- and second-order triangulation networks by trilateration. The principal axes and principal strains inside all the geodetic triangles are deduced from the comparison of the old triangulation and the new trilateration networks. The maximum shear strain rates are calculated by dividing the accumulated strains with the time intervals. The frequency distribution of strain rates is counted for each tectonic province and for the entire Japanese Islands. It is proved that the maximum shear strain rate with highest frequency ranges from 0.10–0.15 microstrain/a for 4409 data in the Japanese Islands. The mean value of the strain rates throughout the Japanese Islands is deduced to be 0.18 microstrain/a. We also calculated a mean value of strain rates for each tectonic province. Comparison is made between mean geodetic strain rates in the provinces and Quaternary strain rates estimated by geomorphic data. It is found that 0.3–0.4 microstrain/a of the highest order strain rate is now prevailing in the Izu province, the south Fossa-Magna collision zone, and some special provinces along the eastern part of the Japan Sea coast.  相似文献   

千岛岛弧大震前哈佛大学矩心矩张量（CMT）解一致性的预测意义s   总被引：12，自引：1，他引：12       下载免费PDF全文

王俊国  刁桂苓 《地震学报》2005,27(2):178-183

千岛岛弧地区属于全球地震活动最为活跃的地区之一. 本文利用哈佛大学测定的千岛岛弧地区地震的矩心矩张量（CMT）解， 分析该地区震源机制的一致性特征， 提出利用震源机制和构造应力场的一致性参数a进行地震预测的思路. 研究结果表明，MＷge;7.5地震之前， 都有一致性参数a降低的现象，a的低值起始的时间在发生大震之前的10多天至110多天， a的低值截止的日期距大震在30多天至2天. 相互之间虽然并不完全一致， 但是差别不大. 这种现象的稳定性， 尚需时间的检验， 但是设想在长达数百公里的地区， 连续发生MＷge;5.3的地震的震源机制都与构造应力场一致， 应当不是随机的现象， 而是一种具有预测意义的现象. 当积累的震例足够多时， 则有可能确定统一的评判标准和预测准则.   相似文献   

A MASCOTTE-based characterization of MCSs over Spain, 2000–2002     

R. García-Herrera  E. Hernndez  D. Paredes  D. Barriopedro  J.F. Correoso  L. Prieto 《Atmospheric Research》2005,73(3-4):261-282

A 3-year Mesoscale Convective Systems (MCSs) database, which extends from 2000 to 2002, has been built for the Iberian Peninsula and the Balearic Islands using the objective method MASCOTTE (MAximum Spatial COrrelation Technique). It was originally developed to track the evolution of convective systems over the Amazon region; after modifications, it is able to track MCS evolution even with an hour and a half of missed images and provides essential information of both dynamical and morphological characteristics of MCSs. MASCOTTE is tested against a visual and subjective method, and is found to offer advantages such as automation and a simple and efficient operation that make it very useful for building large MCS databases.Thirty-five MCSs were found between June and October, most of them originated along the Mediterranean coast and near the Pyrenees, showing an increasing occurrence from June to September, when the maximum is found. The regions most influenced by MCS occurrences are Balearic Islands, Valencia, Catalonia, Murcia and the Basque Country. The MCSs tend to be small, short-lived and linear, usually moving eastward or northeastward with low velocities.The MCSs-associated precipitation presents high variability, ranging from 80 to 0 mm h⁻¹ as maximum hourly records. Two different convective regions are identified based on MCS behavior in extreme precipitation events: Northern Spain (the Basque Country) with abundant and continuous precipitation regime but little MCS influence, and the Mediterranean coast, where precipitation is sporadic but much more intense.  相似文献   

ARE ISLANDERS INSULAR? A PERSONAL VIEW*     

KENNETH R. OLWIG 《Geographical review》2007,97(2):175-190

ABSTRACT. I use my personal experience as an islander doing fieldwork among islanders in the West Indies to explore the meaning of “insularity.” I then expand on that personal experience by drawing on literary sources, particularly Homer's the Odyssey and Herman Melville's Moby Dick, both of which express an island worldview. The island worldview is contrasted and compared with the continental worldview on the basis of differing modes of navigation and cartography and differing modes of orientation as defined by cognitive psychologists.  相似文献