全球气候变化下南海诸岛保护优先区识别分析   总被引：3，自引：1，他引：2  

左秀玲  苏奋振  张宇  吴文周  吴迪 《地理学报》2020,75(3):647-661

全球变化下,珊瑚礁保护区是保护生物多样性、增强珊瑚礁对气候变暖抵抗力的有效方式,而维持珊瑚礁弹性是其核心内容。针对珊瑚礁最具有威胁性的热压力因子,基于南海1982—2009年卫星观测海表面温度（SST）数据和CMIP5加拿大地球系统模式CanESM2模型预估的2006—2100年南海SST数据构建热压力强度模型,从维持珊瑚礁弹性的角度识别IPCC RCP 4.5和RCP 8.5情景下南海诸岛保护优先区。结果表明：RCP 4.5和RCP 8.5情景下13%左右的南海诸岛珊瑚礁识别为保护优先区。根据热压力强度与珊瑚抵抗力及避难所关系,西沙群岛七连屿和晋卿岛近年观测与未来预估的热压力强度均比较低,在保障其服务功能的基础上建议实施完全保护;东沙群岛东沙环礁和中沙环礁排洪滩近年观测急性热压力强度较高但未来预估热压力强度较低,建议实施50%禁止利用保护;中沙群岛黄岩岛近年观测和未来预估的急性热压力强度均比较低,建议实施50%多用途保护。南沙群岛有14%左右的珊瑚礁识别为保护优先区,根据其热压力强度可实施30%~100%禁止利用保护或30%~50%多用途保护。RCP 4.5和RCP 8.5情景下的南海诸岛保护优先区及保护对策,可为维持珊瑚礁生态弹性及应对全球气候变化提供重要的参考价值。  相似文献   

The characteristic pattern of multiple colored layers in coastal stratified lakes in the process of separation from the White Sea   总被引：1，自引：1，他引：0  

Krasnova  Elena D.  Matorin  Dmitry N.  Belevich  Tatiana A.  Efimova  Ludmila E.  Kharcheva  Anastasiia V.  Kokryatskaya  Natalia M.  Losyuk  Galina N.  Todorenko  Daria A.  Voronov  Dmitry A.  Patsaeva  Svetlana V. 《中国海洋湖沼学报》2018,36(6):1962-1977

An unusual feature of the saline stratified lakes that were formed due to ongoing postglacial uplift on the White Sea coast is the presence of several differently colored thin layers in the zone with sharp gradients. Colored layers in five lakes at various stages of separation from the sea were investigated using optical microscopy, spectrophotometry, spectrofluorimetry, and photobiology. The upper greenish colored layer located in the aerobic strata of all lakes near the compensation depth of 1% light penetration contains green algae. In the chemocline, another layer, brightly green, red or pink, is dominated by mixotrophic flagellates. Despite the very low light intensities and the presence of H 2 S, active photosynthesis by these algae appears to be occurring, as indicated by high values of the maximum quantum yield of primary photochemistry, electron transport activity, photosynthetic activity of photosystem II, the fraction of active centers, and low values of heat dissipation. In the reduced zone of the chemocline, a dense green or brown suspension of anoxygenic phototrophs(green sulfur bacteria) is located.  相似文献   

Long Term Evolution of Solar Meridional Circulation and Phase Synchronization Viewed Through a Symmetrical Kuramoto Model     

Elena Blanter  Jean-Louis Le Mouël  Mikhail Shnirman  Vincent Courtillot 《Solar physics》2018,293(10):134

The solar-cycle oscillations of the toroidal and poloidal components of the solar magnetic field in the northern solar hemisphere have a persistent phase difference of about \(\pi \). We propose a symmetrical Kuramoto model with three coupled oscillators as a simple way to understand this anti-synchronization. We solve an inverse problem and reconstruct natural frequencies of the top and bottom oscillators under the conditions of a constant coupling strength and a non-delayed coupling. These natural frequencies are associated with angular velocities of the meridional flow circulation near the solar surface and in the deep layer of the solar convection zone. A relationship between our reconstructions of the shallow and the deep meridional flow speed during recent Solar Cycles 21?–?23 is in agreement with estimates obtained in helioseismology and flux-transport dynamo modeling. The reconstructed top oscillator speed presents significant solar-cycle like variations that agree with recent helioseismical reconstructions. The evolution of reconstructed natural frequencies strongly depends on the coupling strength. We find two stable regimes in the case of strong coupling with a change of regime during anomalous solar cycles. We see the onset of a new transition in Solar Cycle 24. We estimate the admitted range of coupling values and find evidence of cross-equatorial coupling between solar hemispheres not accounted for by the model.  相似文献   

V2213 Cyg is a New W Uma-Type System     

Elena Pavlenko  Anna Litvinchova 《Astrophysics and Space Science》2005,296(1-4):297-300

V2213 Cyg was discovered as a variable star by Pavlenko (1999) in 1998. We present our photometry of V2213 Cyg from 1998–2003 based on CCD observations with the K-380 Cassegrain telescope of CrAO and the 60 cm Zeiss telescope of SAI. Observations have been carried out mostly in R and sometimes in B and V Johnson system. The total amount of data is 2270 points, covering ∼50 nights. We classify this binary as a W UMa-type contact system. Using all data we determined the orbital period to be 0.350079 ± 0.000007 day. The mean brightness varies between R = 14.35 and 14.05. The mean 1999–2003 orbital light curve has two humps and a primary minimum (I), which is 0.04 mag brighter than the deeper secondary one (II). The mean humps have slightly different height. The difference between two individual maxima varies within 0.1 mag, which may indicate an activity of the components. The highest hump is an asymmetrical one: it has sort of a shoulder at phases 0.75–0.80, before entering the less deep primary minimum (phase 0.0). The system is rather reddened, its colour indices are: B−V ∼ 0.8 and V−R ∼ 0.7, and give a spectral class of V2213 Cyg earlier than K.  相似文献   

A Unified Model for Black Hole X-Ray Binary Jets?     

Rob Fender  Tomaso Belloni  Elena Gallo 《Astrophysics and Space Science》2005,300(1-3):1-13

We have recently put forward a ‘unified’ semi-empirical model for the coupling between accretion and jet production in galactic black hole X-ray binaries. In this paper, we summarise this model and briefly discuss relevant considerations that have arisen since its publication.  相似文献   

Stellar populations in the nuclear regions of nearby radio galaxies     

Itziar Aretxaga  Elena Terlevich †  Roberto J. Terlevich ‡  Garret Cotter  Ángeles I. Díaz 《Monthly notices of the Royal Astronomical Society》2001,325(2):636-648

We present optical spectra of the nuclei of seven luminous ( P _178 MHz≳10²⁵ W Hz⁻¹ Sr⁻¹) nearby ( z <0.08) radio galaxies, which mostly correspond to the FR II class. In two cases, Hydra A and 3C 285, the Balmer and λ 4000-Å break indices constrain the spectral types and luminosity classes of the stars involved, revealing that the blue spectra are dominated by blue supergiant and/or giant stars. The ages derived for the last burst of star formation in Hydra A are between 7 and 40 Myr, and in 3C 285 about 10 Myr. The rest of the narrow-line radio galaxies (four) have a λ 4000-Å break and metallic indices consistent with those of elliptical galaxies. The only broad-line radio galaxy in our sample, 3C 382, has a strong featureless blue continuum and broad emission lines that dilute the underlying blue stellar spectra. We are able to detect the Ca  ii triplet in absorption in the seven objects, with good quality data for only four of them. The strengths of the absorptions are similar to those found in normal elliptical galaxies, but these values are consistent both with stellar populations of roughly similar ages (as derived from the Balmer absorption and break strengths) and with mixed young+old populations.  相似文献   

Testing the consistency of the Starburst scenario for active galactic nuclei     

María Luisa García Vargas  Angeles Díaz  Roberto Terlevich  Elena Terlevich 《Astrophysics and Space Science》1993,205(1):77-84

In the frame of the Starburst Model, we show that the evolution of a massive stellar cluster in a high metallicity environment can reproduce the observed emission-line spectrum and the UV-optical Spectral Energy Distribution of the Seyfert 2 galaxies and LINERs. We apply the results of our models to three objects: NGC 5506, NGC 5643 and Mk 348.  相似文献   

On determining the cluster abundance normalization     

Elena Pierpaoli  Stefano Borgani  Douglas Scott  Martin White 《Monthly notices of the Royal Astronomical Society》2003,342(1):163-175

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PKI中RA的功能模型及一种实现方式     

张元茂  刘玓 《成都信息工程学院学报》2005,20(1):12-15

网络安全是近年来研究的热点，各种新技术不断涌现，身份认证是安全应用中最重要的一个问题，也是PKI的核心服务之一。PKI作为信息安全的基石经过几年的发展不断走向成熟，在许多领域发挥着重要的作用。针对目前对PKI中的重要部件RA的研究很少的状况，着重对RA的实现模型进行了探讨。  相似文献   

Growth, interaction and seismogenic potential of coupled active normal faults (Isernia Basin, central-southern Italy)     

Daniela Di Bucci  Giuseppe Naso  Sveva Corrado  Igor M. Villa 《地学学报》2005,17(1):44-55

The inception and growth of the active Carpino-Le Piane Basin Fault System (CLPBFS; central-southern Apennines, Italy) was analysed with respect to the neighbouring Isernia and Surrounding (ISFS) and Boiano Basin (BBFS) extensional Fault Systems. ³⁹Ar–⁴⁰Ar dating showed that the BBFS was already active 649 ± 21 ka bp and that the ISFS was active at least 476 ±10 ka bp , whereas the activity of the CLPBFS started certainly later than 253 ± 22 ka bp , and very probably as recently as <28 ka bp . These ages, combined with structural data (geometry and kinematics of the fault systems), indicate that the inception and development of the CLPBFS could be strictly related to the stress changes caused by earthquakes occurring on the BBFS.  相似文献