冲绳海槽中段地球物理场及对其新生洋壳的认识

通过对冲绳海槽中的磁场进行分析，在海槽轴部追踪到了线性磁条带异常。另外，在扩张轴附近也拖到了新鲜拉斑玄武岩。重力自由空气异常值较低。根据这是由于深部地幔大幅上升所致。地震剖面及磁力资料显示在海槽轴部有强磁性浅层侵入体及海底山，这些侵入体很可能来自于深部地幔。高温地幔物质上涌在海槽轴部形成高热流、强磁异常、多火山以及热液活动。上述现象说明冲绳海槽中段张裂轴部大陆岩石圈已经破裂，并可能已有新生洋壳形成。     

带乘性噪声系统在加性噪声相关时的最优固定域平滑及反褶积算法

最优平滑及最优反褶积在石油地震勘探、通讯工程、语音处理等应用领域都具有十分重要的意义。以往的带乘性噪声系统的平滑及反褶积大都对系统模型的噪声特性有着较强的限制条件 ,要求动态噪声及观测噪声互相独立或只能在同时刻相关。该文给出了一种在动态噪声为有色噪声及动态噪声和量测噪声在有限时间段上相关的情形下带乘性噪声系统的固定域平滑及反褶积算法 ,该算法在线性最小方差意义下是最优的。通过仿真计算 ,说明了该算法的有效性。     

多种水面类型蒸发的研究

分析有水草水面、污水面、受热水面、盐水（盐水）面等特定水面类型的蒸发量，并与清水、淡水对照，求出蒸发比，还计算了太湖地区有水草水面和受热水面的蒸发模型，为确定湖泊的蒸发量提供一新途径，最后建议用水生植物的蒸腾规律来控制水面蒸发，调节水面温度。     

Ultimate Strength Analysis of Offshore Jacket Platform

- The ultimate strength analysis of offshore jacket platforms is a research project which has been developed in recent years. With the rapid development of marine oil industry, the departments of design and IMR (Inspection, Maintenance and Repair) in the offshore engineering have attached great importance to this project. The research procedure applies to both the stress check of new design platforms and the whole safety assessment of existing platforms. In this paper, we combine the pseudo non-linear technique with the linear analysis program and successfully analyze the ultimate strength of the space frame structure subject to the concentrated load and a real jacket platform subject to the dead load and environmental load.     

A NUMERICAL STUDY ON THE MEDIUM-RANGE RESPONSES OF THE ATMOSPHERE TO THE ABNORMAL SOIL MOISTURE*

By employing the improved T42L9 spectral model introduced by NMC (Beijing) from ECMWF and utilizing the FGGE-IIIb data covering the period of 14-19 June 1979, the atmospheric responses to the abnormal soil moisture during the medium-range period have been studied numerically. According to the initial field at 12 GMT 14 June, a five-day numerical experiment under different conditions of the soil moisture has been carried out respectively. The monthly mean climatological soil moisture for June has been used in the control experiment in the initial time and it changes with time according to the moisture budget equation at the land surface. Comparing with the experiments with dry or wet soil. one can conclude that: 1) Source of precipitation over continents in summer consists of the land-surface evaporation and the moisture transfer from oceans. Their intensities are comparable during the medium-range time scale when the soil evaporates its moisture sufficiently. Therefore, the soil moisture can influence the global precipitation and the general circulation significantly; 2) By influencing the thermodynamic difference between land and sea,the soil moisture can change the intensity of monsoon and precipitation distribution; 3) The response of the atmosphere to the abnormal soil moisture has the characteristics of geographical distribution and nonlinear interactions; 4) Human activities on the world can influence the environment greatly.     

Further evaluation of the Sim-ReSET model for ET estimation driven by only satellite inputs

Abstract

A simple remote sensing evapotranspiration (ET) model (Sim-ReSET) has been proposed but only tested using field measurements at a site with a semi-arid climate. Its performance for mapping ET using only satellite data remained unknown. In this study, the Sim-ReSET model was further evaluated for ET estimation driven by only MODIS data products. The estimated ET rates were compared with ground-based observational data from a variety of ecosystems and climates across China. The results show that MODIS-based ET estimates are consistent with both the ET measurements from eddy covariance flux towers and those from the Penman-Monteith method combined with micrometeorological data. Evaporation fraction (EF) is indicative of land surface moisture. The derivative EF maps demonstrate that the proposed ET data set obtained from the Sim-ReSET model and MODIS data is capable of capturing the spatio-temporal pattern of land surface moisture for different land covers with different climates.

Editor Z.W. Kundzewicz

Citation Sun, Z.G., Wang, Q.X., Matsushita, B., Fukushima, T., Ouyang, Z., Watanabe, M., and Gebremichael, M., 2013. Further evaluation of the Sim-ReSET model for ET estimation driven by only satellite inputs. Hydrological Sciences Journal, 58 (5), 994–1012.     

Precipitation stable isotope variability and subcloud evaporation processes in a semi‐arid region

The stable isotopic (²H/¹H and ¹⁸O/¹⁶O) composition of precipitation has been used for a variety of hydrological and paleoclimate studies, a starting point for which is the behaviour of stable isotopes in modern precipitation. To this end, daily precipitation samples were collected over a 7‐year period (2008–2014) at a semi‐arid site located at the Macquarie Marshes, New South Wales (Australia). The samples were analysed for stable isotope composition, and factors affecting the isotopic variability were investigated. The best correlation between δ ¹⁸O of precipitation was with local surface relative humidity. The reduced major axis precipitation weighted local meteoric water line was δ ²H = 7.20 δ ¹⁸O + 9.1. The lower slope and intercept (when compared with the Global Meteoric Water Line) are typical for a warm dry climate, where subcloud evaporation of raindrops is experienced. A previously published model to estimate the degree of subcloud evaporation and the subsequent isotopic modification of raindrops was enhanced to include the vertical temperature and humidity profile. The modelled results for raindrops of 1.0 mm radius showed that on average, the measured D‐excess (=δ ²H ? 8 δ ¹⁸O) was 19.8‰ lower than that at the base of the cloud, and 18% of the moisture was evaporated before ground level (smaller effects were modelled for larger raindrops). After estimating the isotopic signature at the base of the cloud, a number of data points still plotted below the global meteoric water line, suggesting that some of the moisture was sourced from previously evaporated water. Back trajectory analysis estimated that 38% of the moisture was sourced over land. Precipitation samples for which a larger proportion of the moisture was sourced over land were ¹⁸O and ²H‐enriched in comparison to samples for which the majority of the moisture was sourced over the ocean. The most common weather systems resulting in precipitation were inland trough systems; however, only East Coast Lows contributed to a significant difference in the isotopic values. Copyright © 2016 Australian Nuclear Science and Technology Organisation. Hydrological Processes. © 2016 John Wiley & Sons, Ltd.     

Identifying surface water evaporation loss of inland river basin based on evaporation enrichment model

Accurately quantifying the evaporation loss of surface water is essential for regional water resources management, especially in arid and semi-arid areas where water resources are already scarce. The long-term monitoring of stable isotopes (δ¹⁸O and δ²H) in water can provide a sensitive indicator of water loss by evaporation. In this study, we obtained surface water samples of Shiyang River Basin from April to October between 2017 and 2019. The spatial and temporal characteristics of stable isotopes in surface water show the trend of enrichment in summer, depletion in spring, enrichment in deserts and depletion in mountains. The Local Evaporation Line (LEL) obtained by the regression of δ²H and δ¹⁸O in surface water has been defined by the lines: δ²H = 7.61δ¹⁸O + 14.58 for mountainous area, δ²H = 4.19δ¹⁸O − 17.85 for oasis area, δ²H = 4.08δ¹⁸O − 18.92 for desert area. The slope of LEL shows a gradual decrease from mountain to desert, indicating that the evaporation of surface water is gradually increasing. The evaporation loss of stable isotopes in surface water is 24.82% for mountainous area, 32.19% for oasis area, and 70.98% for desert area, respectively. Temperature and air humidity are the main meteorological factors affecting the evaporation loss, and the construction of reservoirs and farmland irrigation are the main man-made factors affecting the evaporation loss.     

Compressibility and permeability of sand–kaolin mixtures. Experiments versus non‐linear homogenization schemes

This study deals with the behaviour of mixtures of sand and saturated kaolin paste considered as composite materials made of permeable and deformable (with non‐linear behaviour) matrix (the kaolin paste) with rigid and impervious inclusions (the sand grains). Oedometric and permeability tests highlight the key role of the state of the clay paste, and show the existence of a threshold of sand grain concentration above which a structuring effect influences both compressibility and permeability. At the light of these experiments two homogenization schemes (with simplifying assumptions to make the problem manageable) are considered to model these two parameters. Qualitative and quantitative comparisons with experimental data point out their respective domain of interest and limitations: a tangent homogenization scheme is shown to be sufficient to describe the macroscopic properties for dilute sand concentration; above the concentration threshold, the structuring effect is captured by the new homogenization scheme developed in this paper. Copyright © 2010 John Wiley & Sons, Ltd.     

局部凸线性拓扑空间Kannan型非扩张集值映射不动点定理

在Hausdorff局部凸线性拓扑空间中得到了Kannan型非扩张集值映射不动点定理,附带给出单值映射族具有公共不动点的结果。