Towards estimating root‐zone soil moisture using surface multispectral and thermal sensing: A spectral and hydrometeorological dataset from the Dookie experiment site,Victoria, Australia

This paper describes surface hydrometeorological and spectral datasets collected from two tower sites located in the University of Melbourne's Dookie experimental farm, Victoria, Australia. The datasets were collected from different vegetation types including wheat, canola, and grazed pasture during the 2012, 2013, and 2014 cropping seasons. The dataset includes 30‐min frequency latent and sensible heat flux measurements and layer‐average soil moisture data at profile depths of 0–5, 0–30, 30–60, 60–90, and 90–120 cm. Air temperature, wind speed, wind direction, relative humidity, precipitation, and incoming and outgoing longwave and shortwave radiation data were also collected from two locations in the study area. The dataset described in this paper is available online.     

Drought disaster monitoring and land use dynamics: identification of drought drivers using regression-based algorithms

Natural Hazards - Droughts are particularly disastrous in South Africa and other arid regions that are water-scarce by nature due to low rainfall and water sources. According to some studies,...     

Burial fluxes and sources of organic carbon in sediments of the central Yellow Sea mud area over the past 200 years

Long-term changes of composition,sources and burial fluxes of TOC(total organic carbon) in sediments of the central Yellow Sea mud area and their possible affecting factors are discussed in this paper.Firstly,similarity analysis is employed to confirm that the carbon burial features resulted from two collected cores are typical in the central Yellow Sea mud area where YSWC(Yellow Sea Warm Current) is prevalent.On this basis,the burial flux of TOC here was considered to be 235.5–488.4 μmol/(cm2?a) since the first industrial revolution,accounting for about 70%–90% among burial fluxes of TC(total carbon) in the sediments.Compared TOC/TC ratio in the two cores with that in other marine sediments worldwide,we suggest that the growth of calcareous/non-calcareous organisms and dissolution of IC(inorganic carbon) are important factors controlling the TOC/TC ratio in sediment.Results of two-end mixed model based on δ13C data indicate that marine-derived organic carbon(OCa)is the main part among total burial organic carbon which accounts for a ratio over 85%.Due to the high TOC/TC ratio in the two cores,TC in the sediments also mainly exists as OCa,and the proportion of OCa is about 60%–80%.Away from the shore and relatively high primary production in upper waters are the main reasons that OCa is predominant among all burial OC in sediments of the central Yellow Sea mud area.Burial of OC in this mud area is probably mainly influenced by the human activities.Although the economic development during the late 19 th century caused by the first industrial revolution in China did not obviously increase the TOC burial fluxes in the sediments,the rise of industry and agriculture after the founding of new China has clearly increased the TOC burial flux since 1950 s.Otherwise,we also realize that among TC burial fluxes,TIC account for about 10%–30% in sediments of the central Yellow Sea mud area,so its burial could not be simply ignored here.Distinct from TOC burial,long-term TIC burial fluxes variations relate with climate changes more closely:the East Asian summer monsoon may influence the strength of the Huanghe River(Yellow River) flood,which could further affect the transport of terrestrial IC from land to the central Yellow Sea as well as the burial of these IC in the sediments.     

理学ZSX系列X荧光光谱仪中文软件开发

介绍了日本理学ZSX系列X荧光光谱仪的特点和新开发的中文版软件的功能。     

Inversion of gravity and magnetic anomalies over some bodies of simple geometric shape

The general expression for gravity and magnetic anomalies over thin sheets and sloping contacts may be expressed as a polynomial of the formFx ²+C₁Fx+C₂F+C₃x³+C₄x²+C₅x+C₆. The initial parameters of the source are obtained from the coefficientsC ₁, C₂,..., C₆ which may be solved by inverting a 6×6 matrix. The initial parameters are modified by successive iteration process using the difference formula until the root mean square error between the observed and calculated anomalies is a minimum. The regional background which may be in the form of a polynomial is estimated by the computer itself. This method is applied on a number of field anomalies and is found to yield reliable estimates of depth and other parameters of the source.     

A diatom model for inferring sea level change in the coastal waters of Hong Kong

Diatoms were identified and enumerated from surface sediments of 25 sites in Double Haven, Hong Kong. The relationship between diatom species distribution and 14 environmental variables was examined using Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA). Water depth was identified as the most important environmental variable influencing the distribution of diatoms in Double Haven. Subsequently a Weighted Average (WA) calibration model was developed to infer water depth. The reliability of the model was evaluated by the error of prediction (RMSE_boot= 3.479) and the correlation (r ²= 0.7342) between observed and diatom-inferred values. This predictive calibration model has the potential to infer past sea level change in Hong Kong and the adjacent coastal areas.     

黑河流域节水生态农业与流域水资源集成管理研究领域

概述了中国内陆河流域面临的水问题和日益激化的用水矛盾,强调了内陆河地区支柱产业——绿洲农业应该坚持节水和生态的方向,流域集成管理是持续农业的基础。长期从事该方面研究的黑河流域是个较好借鉴,同时也提供了深入开展相关研究的基础,为此提出了以黑河流域为背景的四大研究流域：水文、生物、经济系统水循环与水资源形成演变,节水农业的生物学研究与抗旱品种繁育,农业节水新材料研发与工程节水技术集成,水资源合理配置与流域集成管理;并简述了各领域的主要方向。     

不同交通方式对旅游效率的影响与评价——以张家界为例

以张家界为案例地,运用数据包络分析法（DEA）、Malmquist指数模型及Tobit回归模型对张家界2005~2015年城市旅游效率进行分析,并从综合效率、纯技术效率、规模效率以及技术进步变化、全要素生产率变化进行实证研究,最后从公路、铁路及民航等不同交通方式探讨张家界对旅游效率的影响程度。结果显示：① 综合效率、纯技术效率呈现先下降后上升的趋势,全生产要素变化基本呈上升趋势。② Tobit回归模型中,劳动力投入、资本投入、旅游资源吸引力以及铁路客运量和航运客运量在0.01的水平上对综合效率、纯技术效率有显著影响,而其他因素对规模效率的影响不大。③ 交通条件的优化对提升旅游交通有着正向影响作用,且铁路、航运对张家界旅游效率有显著影响,而公路对其有影响但不显著,因此针对不同交通方式提出要进一步完善张家界景区内外部交通网络建设,形成公路交通、铁路交通、航空与景区交通无缝对接以及建成立体交通网络体系等优化策略,以提高张家界的旅游效率,实现旅游产业健康快速和可持续发展,这将为张家界实现旅游效率最优化水平提供理论指导。     

基于交通网络视角的跨界旅游区合作的微观机制研究——以武陵山区为例

旅游跨界合作扩大了旅游的场和域。武陵山区作为典型的跨界旅游区,其地域交通网络系统日益成为影响当地旅游合作格局的重要因素。在识别跨界旅游合作主体并分析合作模式的基础上,对当地政府、旅游企业、行业组织三大主体进行调研,并运用结构方程模型构建交通网络优化下的旅游合作模型,探讨交通网络对跨界旅游区合作机制的影响因素和路径。研究发现：① 交通网络优化对旅游合作条件、旅游合作意识有显著正向影响,旅游合作条件、旅游合作意识对旅游合作行为有显著正向影响;交通网络优化对旅游合作行为有间接影响作用,且通过旅游合作条件和合作意识两条路径对合作行为产生正向影响。② 基于各主体在旅游合作进程中的地位不同及其关注点各异,跨界旅游合作机制也存在差异性。研究结论对武陵山区开展跨界旅游合作和旅游产业扶贫具有显著的理论价值和实践意义,同时试图为其他跨界旅游区开展纵深协作融合提供有效借鉴与指导,也可为其他区域旅游发展提供借鉴和参考。     

Enhanced Data Transmission Rate of XCTD Profiler Based on OFDM

An expendable conductivity-temperature-depth profiler(XCTD) is one of the most important instruments used to obtain hydrological data, such as temperature and conductivity, and detect ocean depth in a large area. However, the XCTD channel provides poor time-varying performance, narrowband, and low signal-to-noise ratio(SNR), which severely restricts the data transmission rate. In contrast to conventional single-carrier modulation techniques, such as amplitude-shift keying and differential phase-shift keying, this article provides a new method, based on orthogonal frequency division multiplexing(OFDM) to enhance the data transmission rate of deep-sea abandoned profilers. We apply the OFDM to enhance the SNR of the XCTD, which is achieved by reducing the data transmission rate of each sub-channel. Moreover, the bandwidth utilization may be improved by increasing the number of subcarriers in a given bandwidth, which enhances the data transmission rate. Based on analysis of the XCTD channel model, OFDM with different parameters such as constellation mapping, number of subcarriers, subcarrier spacing, signal period and cyclic prefix are achieved. To verify the effectiveness of the OFDM, this study investigates the influence of different parameters on the data transmission rate at different noise levels, i.e.,-20 dB and-40 d B.