Improved Priority‐Flood method for depression filling by redundant calculation optimization in local micro‐relief areas

Depression filling is a critical step in distributed hydrological modeling using digital elevation models (DEMs). The traditional Priority‐Flood (PF) approach is widely used due to its relatively high efficiency when dealing with a small‐sized DEM. However, it seems inadequate and inefficient when dealing with large high‐resolution DEMs. In this work, we examined the relationship between the PF algorithm calculation process and the topographical characteristics of depressions, and found significant redundant calculations in the local micro‐relief areas in the conventional PF algorithm. As such calculations require more time when dealing with large DEMs, we thus propose a new variant of the PF algorithm, wherein redundant points and calculations are recognized and eliminated based on the local micro‐relief water‐flow characteristics of the depression‐filling process. In addition, depressions and flatlands were optimally processed by a quick queue to improve the efficiency of the process. The proposed method was applied and validated in eight case areas using the Shuttle Radar Topography Mission digital elevation model (SRTM‐DEM) with 1 arc‐second resolution. These selected areas have different data sizes. A comparative analysis among the proposed method, the Wang and Liu‐based PF, the improved Barnes‐based PF, the improved Zhou‐based PF, and the Planchon and Darboux (P&D) algorithms was conducted to evaluate the accuracy and efficiency of the proposed algorithm. The results showed that the proposed algorithm is 43.2% (maximum) faster than Wang and Liu's variant of the PF method, with an average of 31.8%. In addition, the proposed algorithm achieved similar performance to the improved Zhou‐based PF algorithm, though our algorithm has the advantage of being simpler. The optimal strategies using the proposed algorithm can be employed in various landforms with high efficiency. The proposed method can also achieve good depression filling, even with large amounts of DEM data.     

Analysis on the Characteristics of the Coseismic Response of Water Levels Recorded in Three Wells in Hainan,China to the Two Sumatra-Andaman Strong Earthquakes

The characteristics of seismic water level fluctuations of the two Sumatra-Andaman strong earthquakes with magnitude 8.7 and 8.5 on December 26,2004 and March 29, 2005 recorded at Jiaji well, Qionghai, Hainan were analyzed, the features of the infrequent ＂step＂ changes of well water level after the two earthquakes were also analyzed and the mechanism of the ＂step change＂ of well water level was discussed. Then the high-sample-rate digital observation data of seismically-induced water level fluctuations of the Sumatra-Andaman strong earthquakes with magnitude 8.7 and 8.5 recorded at Nanbin well, Sanya and Tanniu well, Wenchang were analyzed. The results suggest that the dominant period of the seismic well water level fluctuation in all three wells was comparatively accordant, the amplitudes of seismic water level fluctuation of the same earthquake in different wells were clearly different, the time duration of seismic water level fluctuations of different earthquakes at the same well was also clearly different.     

Provenance and Tectonic Implications of Paleozoic Strata in the South Yellow Sea Basin,China–Revealed from the Borehole CSDP-2

Well CSDP-2 is a fully coring deep drilling hole, penetrating the thick Paleozoic marine strata in the South Yellow Sea Basin(SYSB) in the lower Yangtze Block(LYB). Based on the petrological and geochemical analysis of 40 sandstone samples from the core CSDP-2, the provenance and tectonic features of Paleozoic detrital rocks from SYSB are analyzed and systematically delineated in this article. The results show that the Silurian – Carboniferous sandstones are mature sublitharenite, while the Permian sandstones are unstable feldspathic litharenite. The average CIA(chemical index of alteration) is 74.61, which reflects these sediments were derived from source rocks with moderate chemical weathering. The REE(rare earth element) patterns are characterized by LREE enrichment, flat HREE and obviously negative Eu anomaly, which are similar to that of the upper continental crust. Dickinson QFL discrimination results indicate the recycled orogeny provenance. Various diagrams for the discrimination of sedimentary provenance based on major and trace element data show all the sediments were derived predominantly from quartz sedimentary rocks, of which the Permian strata contain more felsic sedimentary rocks. Geochemical data for these detrital rocks suggest they occur at the passive continental margin and island arc settings, and the Permian sandstone presents active continental margin setting.     

青藏高原平流层臭氧和气溶胶的变化趋势研究

通过分析SAGEⅡ资料,发现青藏高原平流层臭氧存在递减趋势,15—50 km臭氧的变化对臭氧总量变化贡献最大,其中25—50 km和15—25 km两层的贡献大致相当。通过青藏高原和中国东部地区平流层臭氧变化的对比,清楚地看出:两地臭氧总量变化的差异主要是由于在15—25 km臭氧变化不同所致。5—7月臭氧变化趋势的情况与年平均的变化类似,两地臭氧变化的差异主要在平流层低层,即15—25 km。青藏高原平流层气溶胶面密度的时间变化序列显示:大的火山喷发对青藏高原平流层气溶胶具有重要影响,其影响可持续6年左右。从1997年至今,青藏高原18—25 km气溶胶面密度增加,最大的增长出现在23 km,每年大约增长4%—5%。而在16—17 km气溶胶的面密度出现减少趋势。与此同时,在37 km以下,青藏高原的温度出现递减的趋势,而且其递减速度比中国东部地区快;在37—50 km,温度出现增加的趋势,青藏高原的增温也比中国东部地区快。青藏高原平流层低层气溶胶的增加和温度的降低都将增强该区域非均相反应的作用。     

Electrical conductivity of hydrous silicate melts and aqueous fluids: Measurement and applications

The combination of magnetotelluric survey and laboratory measurements of electrical conductivity is a powerful approach for exploring the conditions of Earth’s deep interior. Electrical conductivity of hydrous silicate melts and aqueous fluids is sensitive to composition, temperature, and pressure, making it useful for understanding partial melting and fluid activity at great depths. This study presents a review on the experimental studies of electrical conductivity of silicate melts and aqueous fluids, and introduces some important applications of experimental results. For silicate melts, electrical conductivity increases with increasing temperature but decreases with pressure. With a similar Na⁺ concentration, along the calc-alkaline series electrical conductivity generally increases from basaltic to rhyolitic melt, accompanied by a decreasing activation enthalpy. Electrical conductivity of silicate melts is strongly enhanced with the incorporation of water due to promoted cation mobility. For aqueous fluids, research is focused on dilute electrolyte solutions. Electrical conductivity typically first increases and then decreases with increasing temperature, and increases with pressure before approaching a plateau value. The dissociation constant of electrolyte can be derived from conductivity data. To develop generally applicable quantitative models of electrical conductivity of melt/fluid addressing the dependences on temperature, pressure, and composition, it requires more electrical conductivity measurements of representative systems to be implemented in an extensive P-T range using up-to-date methods.     

潮沟系统水沙输运研究——以长江口崇明东滩为例

本研究以崇明东滩2015年4月实测潮间带水沙数据为基础,分析了潮沟、盐沼及光滩的水沙特征,重点研究了潮沟系统及邻近潮滩潮周期内悬沙通量情况。结果表明:（1）潮沟表层沉积物比潮滩细,二者平均中值粒径分别为21.7 μm和33.0 μm,悬沙粒径由海向陆逐渐变小;（2）大、小潮沟潮周期内潮流均以往复流为主,垂向平均流速分别为15.4 cm/s和34.6 cm/s;盐沼界和光滩则以旋转流为主,平均流速分别为11.3 cm/s和28.9 cm/s;（3）潮沟中的高悬沙浓度出现在涨潮初期,最大可达7.5 kg/m3,而潮滩高悬沙浓度则出现在潮落潮中期和高水位时刻;大、小潮沟和盐沼界站涨潮阶段平均悬沙浓度大于落潮阶段,光滩站则相反。潮沟悬沙主要来自邻近水域,而潮滩悬沙则与滩面表层沉积物密切相关;（4）潮沟在潮周期内净输沙方向均指向滩地,大潮沟潮周期单宽净输沙量可达4.0 t/m;盐沼界处垂直岸线和沿岸输沙强度相近,净输沙由海向陆,潮周期离岸输沙强度为1.0 t/m;光滩沿岸输沙强度远大于垂直岸线输沙,光滩净输沙由陆向海。研究揭示了潮间带潮沟系统的强供沙能力以及研究区域光滩冲蚀,盐沼植被带淤积的动力地貌过程。     

基于Keithley 2000实现多路地温传感器数据采集

利用VB环境下的串行通信控件,借助于Keithley 2000多路扫描卡,实现Keithley 2000数字多用表与计算机的串行通信及4线电阻测量方式下10路地温传感器数据自动化批量采集,从而解决自动站铂电阻温度传感器室内校准中依靠自动站采集器存在通道误差、校准精度不高的问题。业务应用表明:使用该系统校准地温传感器,具有检定结果精度高、数据刷新快捷等优点,提高了工作效率。     

不同灌溉对阜康地区冬小麦产量及土壤水分动态变化的影响

根据阜康生态试验站试验小区1999－2000年冬小麦不同灌溉量控制试验，验证了冬小麦水分敏感期为拔节－灌浆期，探讨了该区冬小麦产量与灌水量之间的关系。提出了阜康地区冬小麦返青水应采用“小水”灌溉的方式。同时通过对小区冬小麦成熟期灌水过程不同深度土壤水分含量的动态观测分析，提出冬小麦在成熟期对灌溉水分的消耗利用集中在0－30cm土壤层内的观点。     

Effects of chemical ecological adjustment and control experiment on phytoplankton community in the Aoshan Bay

There is a low nutrient level in the Aoshan Bay. In June 1999, the chemical adjustmentand control experiment was made in the Aoshan Bay. Following tracts investigation was carried out before the experiment and on the 1st, 2nd, 4th, 5th, 6th and 45th day/after the experiment. While the variance of amount of phytoplankton, the replacement of superior species and the species composition of phytoplankton were researched. The results show that the amount of phytoplankton in the Aoshan Bay rises gradually after the experiment. Ceratium macroceros Cleve of pyrophyta was the dominant species before the experiment, its dominant index was 37.7％. Six days after the experiment, its dominant index dropped to 17.6％ . Meanwhile the dominant index of Asterionella japanics Cleve rose from 7.1％ to 39.2％ , it became the first dominant species. Forty-five days after the experiment, the amount of phytoplankton in the Aoshan Bay was 5.15 to 137.32 times more than that in 1997.