Trend and long-range correlation characteristics analysis of runoff in upper Fenhe River basin

In order to explore long-term evolution rule and future trend of runoff time series, and exactly detect its tendency and long-range correlation characteristics, runoff data covering 1952–2012 from 3 stations across the upper Fenhe River basin were analyzed. The moving average method, Empirical Mode Decomposition (EMD) method and Mann-Kendall (M-K) trend test method were simultaneously applied to analyze the trend characteristics firstly. Then Rescaled Range analysis (R/S) and Detrended Fluctuation Analysis (DFA) methods were employed to research the long-range correlation characteristics and length of non-periodic cycle of hydrological time series, they can systematically detect and overcome non-stationarity at all time scales. Finally, predict the future trend by combining the trend characteristics with the long-range correlation characteristics and length of non-periodic cycle. The results illustrate the annual runoff series is non-linear, non-normal time series, and have 10 years non-periodic cycle length and noticeable descending trend. This descending trend will continue in a period time of future.     

COVID-19疫情防控中的中国公众舆情时空演变特征

COVID-19疫情是全球面临的重大公共卫生危机。客观认识疫情期间的公众舆情响应和区域差异,对于提高重大公共卫生事件的政策调控和科学治理具有现实意义。本文以新浪微博为数据源,基于潜在狄利克雷分配主题模型和随机森林算法构建了主题抽取和分类模型,识别微博文本中的13个舆情话题,并从数量、空间、时间、内容等方面分析了2020年1月9日—3月10日在湖北省、京津冀、长三角、珠三角、成渝等城市群及沿边口岸等重点区域分布特点。结果表明：中国公众的响应总体是理性和积极的,但各舆情话题在区域内部的空间分布差异明显。各区域热点分布中,京津冀以首都北京为中心,长三角以上海为中心,辅以南京、杭州等热点,珠三角以广州、深圳为两核,湖北省以武汉为中心。建议应持续加强重点区域的疫情舆情关注和因地制宜的差异化精准响应。     

Comparison of column-integrated aerosol optical and physical properties in an urban and suburban site on the North China Plain

The column-integrated optical properties of aerosol in Beijing and Xianghe, two AErosol RObotic NETwork(AERONET)sites situated on the North China Plain(NCP), are investigated based on Cimel sunphotometer measurements from October2004 to June 2012. The outstanding feature found is that the seasonal medians of aerosol optical depth(AOD) at the two stations are in good agreement. The correlation coefficients and the absolute differences between AOD at the two stations are larger than 0.84 and less than 0.05, respectively. Good agreement in AOD at these two sites(one urban and the other suburban; 70 km apart) indicates that aerosol pollution in the Greater Beijing area is regional in nature. However, we find significant differences in the absorption ?Angstr ¨om Exponent(AAE), the real and imaginary part of the refractive index, and thereby the single scattering albedo(SSA), and the difference is seasonally dependent. The feature is found to be more prominent in fall when the fine-mode fraction(FMF) and fine-mode effective radius are significantly different at the two stations,besides the parameters mentioned above. The SSA in Beijing at four wavelengths shows lower values as compared to those in Xianghe, although the difference is not significant in some cases. Significant differences in AAE and fine-mode effective radius indicate that there are differences in aerosol physical and chemical properties in urban and suburban regions on the NCP.     

Resazurin as an indicator of reducing capacity for analyzing the physiologic status of deep-sea bacterium Photobacterium phosphoreum ANT-2200

Journal of Oceanology and Limnology - Resazurin (RZ) is a weakly fluorescent blue dye and can be reduced irreversibly to highly fluorescent pink resorufin (RF) that is reduced reversibly to...     

地磁Z分量日变形态畸变与周边低点位移异常关系初探

通过对2010年1月1日至2011年12月31日期间中国大陆地磁低点位移异常数据及蒙城地震台地磁垂直分量日变形态畸变统计,按低点位移分界线到蒙城地震台的距离,分段探讨该台地磁垂直分量日变形态畸变与其周边低点位移异常的关系.     

Spatio-temporal Distribution of Drought in the Belt and Road Area During 1998-2015 Based on TRMM Precipitation Data

Drought is a worldwide natural disaster that has long affected agricultural production as well as social and economic activities. Frequent droughts have been observed in the Belt and Road area, in which much of the agricultural land is concentrated in fragile ecological environment. Based on the Tropical Rainfall Measuring Mission Satellite (TRMM) 3B43 precipitation data, we used the Precipitation Abnormity Percentage drought model to study the monthly spatio-temporal distribution of drought in south region of N50° of the Belt and Road area. It was observed that drought during winter was mainly distributed in Northeast Asia, Southeast Asia, and South Asia, while it was mainly distributed in Central Asia and West Asia during summer. The occurrence of historical droughts indicates an obvious seasonal cycle. The regional variations in drought were analyzed using the Breaks for Additive Season and Trend tool (BFAST) in six sub-regions according to the spatial distribution of six economic corridors in the Belt and Road area. The average drought conditions over the 18 years show a slight decreasing trend in Northeast Asia, West Asia, North Africa, South Asia, Central and Eastern Europe, and a slight increasing trend in Central Asia. However, it was a fluctuating pattern of first increasing and then decreasing in Southeast Asia. The results indicate that the total drought area in the Belt and Road region showed a general decreasing trend at a rate of 40,260 km2 per year from 1998 to 2015.     

晚第四纪湖泊沉积物盐类与碎屑矿物反相关关系的沉积学解释

湖泊沉积物中矿物组合是古气候环境研究的敏感性指标之一, 充分认识湖泊沉积物中各类矿物组合类型、沉积过程, 对正确解释矿物学指标有重要意义. 我国晚第四纪湖泊沉积记录中, 盐类矿物与碎屑矿物含量普遍存在反相关关系, 影响了矿物组合作为气候指标的解释和应用. 从地球科学的角度正确理解这种关系, 可以为湖泊动力学以及古气候环境定量研究提供重要的科学依据. 选择甘肃民勤盆地石羊河下游终端湖猪野泽不同位置5个全新世剖面, 在明确湖泊沉积物来源、搬运方式和沉积动力机制的基础上, 研究了以碳酸盐矿物为主的盐类矿物含量与粒度指标之间的关系. 结果表明:猪野泽各剖面砂层富含的中砂、细砂沉积物主要是来自于巴丹吉林沙漠和腾格里沙漠的风成砂; 水动力作用主导了湖相沉积层200 μm以下沉积物的沉积, 风力作用对20~70 μm粉砂组分沉积也有所贡献. 同时, 猪野泽湖相沉积层中高含量的碳酸盐主要来自于流水搬运, 湖相沉积层位200 μm以下的粉砂和极细砂是碳酸盐的主要富集区. 综上所述, 干旱区湖泊沉积物中盐类矿物含量与其沉积过程密切相关, 盐类矿物在全球变化研究中的应用要建立在充分研究其沉积动力机制的基础上.     

碳酸盐成岩作用研究现状与前瞻

碳酸盐成岩作用是沉积学最为活跃的领域之一,与之有关的研究成果会直接影响人们对碳酸盐油气储层形成机制和层控矿床形成机制的理解。近年来,碳酸盐成岩作用在多个领域取得了令人瞩目的研究成果,主要包括以下几个方面:(1)实验室沉淀白云石获得成功:人们模拟海水(泻湖)条件下的细菌硫酸盐还原环境,在常温下沉淀出具有序反射的白云石。(2)热液白云化作为新的主流模式成为关注的热点:人们已认识到热液白云岩储层、沉积-喷流型铅锌矿床和Mississippi河谷型铅锌矿床具有共同的形成机制,它们均受构造(伸展、走滑构造)和热流体流动的强烈控制。(3)深埋藏条件下封闭系统的白云化作用受到关注:一些对油气储集空间和层控矿床有较大意义的白云化作用主要是在相对封闭条件下发生的,在对岩石储集空间的变化的贡献上以及在相应的地球化学指标上不同于开放条件下的白云化作用。(4)混合水白云化模式受到质疑:人们重新研究了作为混合水白云化典型地点的美国威斯康星弧碳酸盐的成岩作用,根据流体包裹体分析、阴极发光分析、偏光显微镜观察及稳定同位素分析等方法并结合有机物成熟度的数据,得出威斯康星弧与白云化有关的水-岩相互作用是由与温度升高有关的浓卤水导致的,白云化作用是热水成岩作用的结果。(5)淡水环境的成岩机制受到挑战:新近研究证明,大范围的低位体系域中可以没有具化学活性的淡水透镜体,海水环境同样可以产生成熟的石灰岩,细菌硫酸盐还原作用可以引起海水对碳酸盐的不饱和。(6)锶同位素在海相碳酸盐研究中的广泛应用:由于锶同位素不像氧、碳同位素那样因温度、压力和微生物作用而分馏,矿物可直接反映流体的同位素组成,地质历史中海水锶同位素组成也具有独特的长期变化趋势,这使得海相碳酸盐的锶同位素组成在沉积期后流体示踪中得到广泛应用。(7)硫酸盐还原作用对碳酸盐成岩作用的影响受到重视:如BSR和TSR可减小SO42-对白云石沉淀(或白云化)的动力学屏障,其产物H2S和CO2可在不同条件下对碳酸盐储层产生影响,BSR和TSR可提高成岩流体锶含量,甚至在形成天青石矿床中也具极大的潜在价值。     

甘孜南部核桃栽培技术

以自然条件恶劣的四川省甘孜州得荣县为典型研究区。根据当地干旱少雨、土壤贫瘠、土层浅薄,但阳光充足、适合核桃种植的自然环境特点和核桃发展的落后现状,从苗圃建设、引种及良种培育、栽培技术、管理水平等方面,探索出一套适合当地的、较为完善的栽培技术,为当地大量栽培核桃,提高当地的核桃发展水平,振兴民族地区经济提供了科学支撑。     

Resazurin as an indicator of reducing capacity for analyzing the physiologic status of deep-sea bacterium Photobacterium phosphoreum ANT-2200

Resazurin(RZ)is a weakly fl uorescent blue dye and can be reduced irreversibly to highly fl uorescent pink resorufi n(RF)that is reduced reversibly to colorless dihydroresorufi n(hRF)by photodeoxygenation,chemical reaction and reductive organic compounds produced through cell metabolism.Because of the reliable and sensitive fl uorescence-color change and noninvasive features,RZ has been used widely as a redox indicator in cell viability/proliferation assays for bacteria,yeast,and mammalian cells.However,RZ is used rarely for physiological characterization of marine microorganisms.Here,we developed a custom-made irradiation and absorption-analysis device to assess the reducing capacity and physiologic status of marine bacterial cultures.We measured the absorption spectra of RZ,RF,and hRF in the presence of the reducing compound Na 2 S and under visible-light irradiation.After establishing appropriate parameters,we monitored the color changes of RZ and its reduced derivatives to evaluate the coherence between reducing capacity,bioluminescence and growth of the deep-sea bacterium Photobacterium phosphoreum strain ANT-2200 under various conditions.Emission of bioluminescence is an oxidation process dependent upon cellular reducing capacity.Growth and bioluminescence of ANT-2200 cell cultures were impeded progressively with increasing concentrations of RZ,which suggested competition for reducing molecules between RZ at high concentration with reductive metabolism.Therefore,caution should be applied upon direct addition of RZ to growth media to monitor redox reactions in cell cultures.Analyses of the instantaneous reduction velocity of RZ in ANT-2200 cell cultures showed a detrimental eff ect of high hydrostatic pressure and high coherence between the reducing capacity and bioluminescence of cultures.These data clearly demonstrate the potential of using RZ to characterize the microbial metabolism and physiology of marine bacteria.