Separation of dwarf and giant stars with ROTSE–IIId     

S. Bilir  T. Güver  M. Aslan 《Astronomische Nachrichten》2006,327(7):693-697

136 stars which were known to be members of the open cluster NGC 752 were observed at the R band with the ROTSE–IIId telescope located at the Turkish National Observatory (TUG) site. The data had been evaluated together with BV and 2MASS photometric data. A new practical method for separating dwarf and giant was described and applied. Evaluating the colour magnitude–diagrams with Padova isochrones revealed for the open cluster NGC 752 a metallicity similar to the Sun and an age of 1.41 ± 0.20 Gyr. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

海洋水色遥感资料红光波段的大气纠正     

陈楚群 《热带海洋学报》1998,(2)

通常的大气纠正方法不考虑对红光波段进行大气纠正,文章在阐述海洋水色遥感资料大气纠正基本原理和方法的基础上,提出了简单可行的方法,对红光波段与其它波段一同进行大气纠正,并用C语言完成了该纠正方法的程序编制和调试,使海洋水色遥感资料的大气纠正更加完善,有利于更好地对近岸海区开展海洋水色遥感应用研究。  相似文献   

Plankton sample colour as a determinant of the abundance of stage I eggs in the western mackerel (Scomber scombrus L.) stock     

Findlay  Malcolm; Lansley  Jon 《ICES Journal of Marine Science》1998,55(1):141-144

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Tectono-thermal evolution in a region with thin-skinned tectonics: the western nappes in the Cantabrian Zone (Variscan belt of NW Spain)     

F. Bastida  C. Brime  S. García-López  G. N. Sarmiento 《International Journal of Earth Sciences》1999,88(1):38-48

 The palaeotemperature distribution in the transition from diagenesis to metamorphism in the western nappes of the Cantabrian Zone (Somiedo, La Sobia and Aramo Units) are analysed by conodont colour alteration index (CAI) and illite crystallinity (IC). Structural and stratigraphic control in distribution of CAI and IC values is observed. Both CAI and IC value distributions show that anchizonal conditions are reached in the lower part of the Somiedo Unit. A disruption of the thermal trend by basal thrusts is evidenced by CAI and IC values. There is an apparent discrepancy between the IC and CAI values in Carboniferous rocks of the Aramo Unit; the IC has mainly anchizonal values, whereas the CAI has diagenetic values. Discrepant IC values are explained as a feature inherited from the source area. In the Carboniferous rocks of the La Sobia Unit, both IC and CAI indicate diagenetic conditions. The anchimetamorphism predated completion of emplacement of the major nappes; it probably developed previously and/or during the early stages of motion of the units. Temperature probably decreased when the metamorphosed zones of the sheets rose along ramps and were intensely eroded. In the context of the Iberian Variscan belt, influence of tectonic factors on the metamorphism is greater in the internal parts, where the strain and cleavage are always present, than in the external parts (Cantabrian Zone), where brittle deformation and rock translation are dominant, with an increasing role of the burial on the metamorphism. Received: 11 May 1998 / Accepted: 19 January 1999  相似文献   

Incorporation of dietary carotenoids into the fins of yellow- and red-finned Eurasian perch Perca fluviatilis     

《Limnologica》2017

The colour of the ventral, anal and caudal fins of Eurasian perch can range from pale yellow to intense red. Within spatially separated populations, however, individuals are usually very uniform in colour. We fed astaxanthin- and canthaxanthin-enriched dry feed to juvenile perch from a yellow-finned and a red-finned population to compare the influence of dietary carotenoids on fin colour between these two populations. In this way we wanted to test whether fin colour in perch is predominantly a phenotypically plastic trait or whether differently coloured individuals represent colour morphs. The ventral fins of perch from the red-finned population always exhibited significantly more intense redness when their feed was supplemented with either one or both carotenoid additives. Perch from both populations deposited more canthaxanthin in their ventral fins than astaxanthin, red-finned perch in particular. Yellow-finned perch probably converted canthaxanthin into β-carotene, which was the dominant carotenoid in their ventral fins, whereas the fins of red-finned perch contained only trace amounts of β-carotene. We conclude that these two populations represent colour morphs that differ fundamentally in their ability to metabolise and deposit dietary carotenoids into their ventral fins. Considering the multiple physiological functions of carotenoids, these fundamental differences in carotenoid metabolism between perch colour morphs may have far-reaching consequences for the performance of different populations, for example in their response to parasite infections.  相似文献   

A spectral response approach for detecting dominant phytoplankton size class from satellite remote sensing   总被引：1，自引：0，他引：1  

Robert J W Brewin  Samantha J Lavender  Nick J Hardman-Mountfor  Takafumi Hirata 《海洋学报(英文版)》2010,29(2):14-32

An important goal in ocean colour remote sensing is to accurately detect different phytoplank- ton groups with the potential uses including the validation of multi-phytoplankton carbon cycle models; synoptically monitoring the health of our oceans, and improving our understanding of the bio-geochemical interactions between phytoplankton and their environment. In this paper a new algorithm is developed for detecting three dominant phytoplankton size classes based on distinct differences in their optical signatures. The technique is validated against an independent cou- pled satellite reflectance and in situ pigment dataset and run on the 10-year NASA Sea viewing Wide Field of view Sensor (SeaWiFS) data series. Results indicate that on average 3.6% of the global oceanic surface layer is dominated by microplankton, 18.0% by nanoplankton and 78.4% by picoplankton. Results, however, are seen to vary depending on season and ocean basin.  相似文献   

由TSRB辐射计数据估算海面离水辐亮度的经验方法   总被引：1，自引：0，他引：1  

张亭禄  刘斌  邱国强 《中国海洋大学学报(自然科学版)》2010,40(1)

为建立基于经验统计的TSRB辐射计数据估算离水辐亮度的方法,利用SeaBASS数据库中640多个现场测量的辐亮度和辐照度光谱剖面数据,建立向上辐亮度衰减系数K_(lu)的经验算法.此算法为幂指数形式,输入变量为水下0.65 m的向上辐亮度(490 nm)与海面上向下的辐照度(555 nm或665 nm)之比(即为TSRB直接测量的两个参数).当水体较清时,输入为蓝绿波段之比,当水混浊时,采用蓝红波段之比.获得了K_(lu)后,海面以上的辐亮度(离水辐亮度)由z=0.65 m处的辐亮度外推获得.初步的检验结果表明,该方法对一类和二类水域都有很好性能,且算法实现简单,运行速度快.  相似文献   

Combined UBV and uvby photometry of open clusters. I. NGC 1502     

H.-G. Reimann  W. Pfau 《Astronomische Nachrichten》1987,308(2):111-119

For at all 24 stars in the field of the heavity reddened open cluster NGC 1502 we obtained UBV and uvby photometry. 19 of these stars we classified definitely as members. From the photometric results we derived 1·1 × 10⁷ years as the cluster age, 960 pc as its distance, and <E(B—V)> = 0·78 mag as mean reddening of the cluster. From the reddening of the foreground stars we evaluated that the intracluster reddening has to be smaller than 0·2 mag. The value of the colour excess ratio E(b—y)/E(B—V) = 0·770 leads us to the conclusion that in the spectra of the cluster stars a very broadband structure (VBS) with a central depth of about 0·04 mag is present.  相似文献   

Remotely sensed seasonality in the spatial distribution of sea-surface suspended particulate matter in the southern North Sea     

Marieke A. Eleveld  Reinold Pasterkamp  Hendrik J. van der Woerd  Julie D. Pietrzak 《Estuarine, Coastal and Shelf Science》2008

An algorithm is presented for estimating near-surface SPM concentrations in the turbid Case 2 waters of the southern North Sea. The single band algorithm, named POWERS, was derived by parameterising Gordon's approximation of the radiative transfer model with measurements of Belgian and Dutch inherent optical properties. The algorithm was used to calculate near-surface SPM concentration from 491 SeaWiFS datasets for 2001. It was shown to be a robust algorithm for estimating SPM in the southern North Sea. Regression of annual geometric mean SPM concentration derived from remote sensing (SPM_rs), against in situ (SPM_is) data from 19 Dutch monitoring stations was highly significant with an r² of 0.87. Further comparison and statistical testing against independent datasets for 2000 confirmed the consistency of this relationship. Moreover, time series of SPM_rs concentrations derived from the POWERS algorithm, were shown to follow the same temporal trends as individual SPM_is data recorded during 2001. Composites of annual, winter and summer SPM_rs for 2001 highlight the three dominant water masses in the southern North Sea, as well as their winter–fall and spring–summer variability. The results indicate that wind induced wave action and mixing cause high surface SPM signals in winter in regions where the water column becomes well mixed, whereas in summer stratification leads to a lower SPM surface signal. The presented algorithm gives accurate near-surface SPM concentrations and could easily be adapted for other water masses and seas.  相似文献   

FerryBox and MERIS – Assessment of coastal and shelf sea ecosystems by combining in situ and remotely sensed data     

W. Petersen  H. WehdeH. Krasemann  F. ColijnF. Schroeder 《Estuarine, Coastal and Shelf Science》2008

An automatic measuring system called “FerryBox” was installed in the North Sea on a ferry travelling between Germany (Cuxhaven) and Great Britain (Harwich), enabling online oceanographic and biological measurements such as salinity, temperature, fluorescence, turbidity, oxygen, pH, and nutrient concentrations. Observations made along the ferry transect reveal characteristic phenomena such as high salinity inflow through the Channel into the Southern Bight, algal bloom dynamics and related oxygen and pH changes. Combination of these online observations with remote sensing enhances the spatial resolution of the transect related measurements. Several examples of the synergy between these two measuring strategies are shown, both for large-scale algal blooms in the North Sea as well as for local intense but short-term blooms in the German Bight. Coherence of the data sets can be gained and improved by using water transport models in order to obtain synoptic overviews of the remotely sensed and FerryBox related parameters. Limitations of the currently used algorithms for deriving chlorophyll-a from remote sensing images for coastal and shelf seas (Case-2 water) are discussed, as well as depth related processes which cannot be properly resolved on the basis of water intake at a fixed point. However, in unstratified coastal waters under normal conditions FerryBox data represent average conditions. The importance of future applications of this combination of methods for monitoring of coastal waters is emphasized.  相似文献