Cloud cover over the Tibetan Plateau and eastern China: a comparison of ERA5 and ERA-Interim with satellite observations

This study examines the progress made by reanalyses and satellite products in the estimation of cloud cover over China: the ECMWF reanalyses ERA5 and ERA-Interim, geostationary satellite observation Himawari-8 (H8) and the International Satellite Cloud Climatology Project H-series (ISCCP) product. There is great similarity in spatial patterns of cloud cover in reanalyses and satellite observations, especially between ERA5 and H8. Distinct characteristics of the seasonal evolution of cloud cover are shown over the Tibetan Plateau (TP), the southeast (SE) and northeast (NE) of China. Differences in magnitudes of cloud cover exist. Overestimations are about 10% for reanalyses and about 20% for ISCCP in compared with certain cloud cover in H8. When probable cloud (about 10%) in H8 is included in the estimation, biases reduce the most in ERA5. The cloud hit rate (CHR) and false alarm rate (FAR) in against H8 and ISCCP reveal that simulated clouds in ERA5 have been improved especially over eastern China, but with limited improvement over TP in compared with ERA-Interim. Diurnal variations of cloud cover are characterized by increases during daytime over those three regions. Amplifications of diurnal variation vary over different regions and months. Satellite observations and ERA5 indicate distinguished diurnal cycle of cloud cover over TP, while further investigation based on ERA5 reveals coherent diurnal cycle in meteorological environment. Long-term changes of cloud cover highlight decreasing trends over TP and particular during March in past decades based on ISCCP and ERA5, which require further investigation in future.     

补偿标准参照的比较:机会成本与环境收益——以石羊河流域生态补偿为例

流域生态补偿是当前生态经济研究的热点问题。在简要说明流域内生态系统服务与流域生态补偿的关系之后,从理论上分析了流域生态补偿标准的环境收益参照——机会成本变为环境收益,并以石羊河流域生态恢复目标为例开展实证,在考虑补偿总预算约束下,比较采用两种补偿标准参照生态补偿机制运行的效果。结果表明:采用环境收益代替机会成本作为补偿标准参照,对于提高农户参与生态补偿的积极性、保护生态系统服务行为的约束性作用明显;引入以机会成本与环境收益比值确定的优先补偿指标,在生态补偿资金预算约束下替代机制对完成既定生态恢复目标有显著促进作用。     

The dependence of quasar variability on black hole mass

In order to investigate the dependence of quasar variability on fundamental physical parameters like black hole mass, we have matched quasars from the Quasar Equatorial Survey Team, Phase 1 (QUEST1) variability survey with broad-lined objects from the Sloan Digital Sky Survey. The matched sample contains ≈100 quasars, and the Sloan spectra are used to estimate black hole masses and bolometric luminosities. Variability amplitudes are measured from the QUEST1 light curves. We find that black hole mass correlates with several measures of the variability amplitude at the 99 per cent significance level or better. The correlation does not appear to be caused by obvious selection effects inherent to flux-limited quasar samples, host galaxy contamination or other well-known correlations between quasar variability and luminosity/redshift. We evaluate variability as a function of rest-frame time lag using structure functions and find further support for the variability–black hole mass correlation. The correlation is strongest for time lags of the order of a few months up to the QUEST1 maximum temporal resolution of ≈2 yr, and may provide important clues for understanding the long-standing problem of the origin of quasar optical variability. We discuss whether our result is a manifestation of a relation between characteristic variability time-scale and black hole mass, where the variability time-scale is typical for accretion disc thermal time-scales, but find little support for this. Our favoured explanation is that more massive black holes have larger variability amplitudes, and we highlight the need for larger samples with more complete temporal sampling to test the robustness of this result.     

新型高分辨率自然伽马测井仪器的优化设计与资料处理技术

通过自然伽马响应函数与其探测器长度间关系的研究,选择长度为0.1 m的NaI晶体作为新型高分辨率自然伽马仪器的探测器。为克服短NaI晶体会导致计数率降低和统计涨落误差增大等问题,利用4个大小完全相同的NaI晶体同时测量伽马射线强度,获得4条高分辨率自然伽马测井曲线;然后,对4条测量曲线进行累加并结合带通滤波技术充分降低统计涨落误差;在此基础上,进一步应用正则化反褶积处理提高仪器的纵向分辨率。理论模型和井场试验结果均证明,该新型高分辨率伽马仪器具有0.15 m的纵向分辨率,比常规自然伽马测井仪器的分辨率提高了4倍以上。     

MIS 3以来浙江温瑞平原YQ0902孔古环境与古气候变化记录*

YQ0902孔位于浙江南部瓯江三角洲南侧温瑞平原上。沉积相、粒度分析以及AMS ¹4C测年数据表明,硬土层之下为海洋氧同位素3阶段(MIS 3）形成的潟湖相沉积,据此推测MIS 3高海平面至少达到现今海平面之下30m左右(未经构造升降和沉积物压实作用等影响的校正,下同）。硬土层的成土过程发生于MIS 2,其母质部分为MIS 3的潟湖沉积,部分为河漫滩沉积。硬土层之上是一套形成于全新世的海侵—海退旋回,与长江三角洲南翼前缘的沉积相组合类似。研究钻孔初始海泛面约形成于9 cal ka BP,推算当时的海平面约低于现今海平面25 m。中全新世最大海侵前后,东亚季风较强,通过径流或沿岸流输入本区的沉积物较充足,沉积速率较大。随着海平面相对稳定或略有下降,东亚季风减弱,可容空间减小,中晚全新世(5～2 cal ka BP）沉积速率较低。高分辨率的XRF岩心扫描获得的元素相对含量是古环境与古气候研究的重要指标,其中Cl/Ti、Fe/Ti值可分别作为海相性(与海洋联通程度）与东亚季风强弱的替代指标。     

The concentrations and distribution of mercury in aquatic ecosystem of Baihua Reservoir

1Introduction Thebiogeochemicalcycleofmercuryinaqueous systemisthekeyfactorleadingtotheexpansionof mercurypollutiononaglobalscaleandthesafetyof fishconsumers.Dissolvedgaseousmercury(DGM)e vasionisconsideredasoneofthemostimportantmer curysourcesforatmosphere.Atthesametime,this procedurewillreducetheHgburdeninthewatercol umnandmaythusdecreasemethylmercuryproduction andaccumulationinfish(Nriagu,1994).TheBaihua ReservoirissituatedinGuizhouProvince,andithas sufferedseriousmercurycontaminationfr…     

吾尔塔米斯沟土质滑坡形成机理及稳定性评价

2006年7月吾尔塔米斯沟发生了一起浅层推移式滑坡,坡体处于基本稳定状态,但存在着一定的安全隐患.通过现场勘察总结了滑坡结构特征,并通过实验测试确定了滑坡的物理力学指标,建立起与滑坡主勘探线剖面对应的滑坡稳定性分析模型,运用传递系数法计算该滑坡不同工况的稳定系数,对滑坡体稳定性进行评价.上述研究结果表明,该滑坡稳定系数...     

页岩解吸气地球化学特征及其影响因素分析——以四川盆地焦石坝地区JYA井为例

通过对焦石坝地区JYA井五峰-龙马溪组页岩岩心样品进行现场解吸,计算页岩的总含气量,同时分时段采集解吸气样品进行气组分和稳定碳同位素测定.研究结果表明：1）研究区含气量较高,成分以甲烷为主,为典型干气,含气量主要受控于矿物组成、有机碳含量和含水饱和度等;2）页岩解吸气组分随着解吸时间呈规律性变化,CH4和C2H6含量逐渐升高,CO2含量先降低后升高,N2含量逐渐降低;3）解吸气中δ13C1和δ13C2会出现不同程度的分馏现象,主要受控于吸附-解吸过程;4）不同岩相页岩气解吸过程存在差异,在一阶解吸阶段,富泥硅质混合页岩样品的δ13C1由重变轻,而富硅质页岩样品由轻变重,这可能由于富泥硅质混合页岩无机孔占主导,孔径较大,游离气占总含气量比例较大.     

基于"3N"理念的德化县旅游资源开发思路

现代社会的都市化及人工化,引发人类种种生理、心理问题,生活在钢筋水泥森林中的都市人逃出"现代围城"的欲望日益强烈,让身心回归真正的自然,于是"3N"旅游应运而生.本文结合德化县的实例,探讨"3N"旅游及其产品的开发问题.     

Ordovician metagranitoid from the Anatolide‐Tauride Block,northwest Turkey: geodynamic implications

We report a Middle Ordovician metagranitoid from the northern margin of the Anatolide‐Tauride Block, the basement of which is generally characterized by voluminous Latest Proterozoic to Early Cambrian granitoids. The Ordovician metagranitoid forms an ～400‐m‐thick body in the marbles and micaschists of the Tav?anl? Zone. The whole sequence was metamorphosed in the blueschist facies during the Late Cretaceous (c. 80 Ma). Zircons from the metagranitoid give a Middle Ordovician Pb‐Pb evaporation age of 467.0 ± 4.5 Ma interpreted as the age of crystallization of the parent granitic magma. The micaschists underlying the metagranitoid yield Cambro‐Ordovician (530–450 Ma) and Carboniferous (c. 310 Ma) detrital zircon ages indicating that the granitoid is a pre‐ or syn‐metamorphic tectonic slice. The Ordovician metagranitoid represents a remnant of the crystalline basement of the Anatolide‐Tauride Block and provides evidence for Ordovician magmatism at the northern margin of Gondwana. Prismatic Carboniferous detrital zircons in the micaschists indicate that during the Triassic, the northern margin of the Anatolide‐Tauride Block was close to Variscan terranes.