乐山市水资源承载力分析及开发潜力研究

水资源的供需关系已演变为限制经济社会不断发展的一个关键障碍,所以对水资源承载力展开探究,以支撑经济和社会的不断发展,将会具有现实意义和至关重要的影响,本文从水资源负载指数和承载指数模型出发,根据当前乐山市水资源情况现状,对当地水资源承载力进行分析。     

Faecal indicator bacteria in New Zealand freshwater fish: a pilot study

Recent studies have suggested that poikilothermic animals, such as fish, may represent a previously overlooked source of the faecal indicator bacteria (FIB) used for the assessment of water quality. However, quantitative studies of FIB in poikilotherms are scarce. We investigated the presence of FIB in the faeces of five freshwater fish species. E. coli and enterococci were detected in 71 and 76% of faecal samples, respectively. Concentrations were highly variable, with maximum concentrations (2.1?×?10⁴ E. coli and 1.3?×?10⁶ enterococci per gram of faecal material) up to four orders of magnitude higher than present in the water column. FIB were not detected in faecal samples from marine fish. Our findings suggest that FIB ingested from the environment may be capable of replication within the fish gut, making fish a potential source and transport mechanism for FIB in New Zealand freshwaters. This may have implications for water quality monitoring.     

Analytical convolution model for shipping water evolution on a fixed structure

The shipping of water is a problem that affects naval and offshore structures. Estimating its propagation on the decks of these structures by using analytical methods has been a main concern of projects. However, classical approaches disregard the decay tendency of water elevation time series and tend to overestimate the resultant water on deck. This paper is concerned with estimating the evolution of water along the deck of a fixed structure due to shipping water events. An analytical convolution model is proposed to estimate water elevations. The model considers the freeboard exceedance time series and the mean shipping flow velocity as inputs and the frictional effects of the bottom by resistance coefficients, which enables an approximated representation of the water elevation time series over the deck. It was validated with experiments of isolated shipping water events that were generated with the wet dam-break approach. The results obtained with the proposed model captured the experimental results, approximating the peak values and the decay trend of time series. Improvement of the proposed approach over classical models to represent shipping water elevations was demonstrated by comparing the results obtained with those of the dam-break model of Stoker.     

围海造陆条件下排海高温浓盐水对渤海湾温盐场分布影响模拟及预测

自2000年以来围绕渤海湾的围海工程剧增,致使工程区附近潮流场发生变化,进而影响排海高温浓盐水的时空分布特征。本文通过建立2000年和2015年两种不同岸线、地形条件下的三维数学模型对渤海湾沿岸3个电厂高温浓盐水表层排海问题进行模拟,研究结果表明,渤海湾的潮流场和高温浓盐水输移扩散特征在近十几年发生了较大变化:工程后,渤海湾平均盐度增大0.203,平均温度升高了0.105℃,同时曹妃甸附近海域浓盐水输移扩散速度明显增加。增大排放口流量至12.7 m3/s,湾内最高温度为26.46℃,较2015年最高温度增加了2.72℃。本文模型可准确模拟及预测排海废水盐度、温度分布特征,为合理布置水电联产设备排放口的位置提供理论基础。     

卡里马塔海峡水体交换的季节变化

Four trawl-resistant bottom mounts, with acoustic Doppler current profilers(ADCPs) embedded, were deployed in the Karimata Strait from November 2008 to June 2015 as part of the South China Sea-Indonesian Seas Transport/Exchange and Impact on Seasonal Fish Migration(SITE) Program, to estimate the volume and property transport between the South China Sea and Indonesian seas via the strait. The observed current data reveal that the volume transport through the Karimata Strait exhibits significant seasonal variation. The winteraveraged(from December to February) transport is –1.99 Sv(1 Sv=1×10~6 m~3/s), while in the boreal summer(from June to August), the average transport is 0.69 Sv. Moreover, the average transport from January 2009 to December2014 is –0.74 Sv(the positive/negative value indicates northward/southward transport). May and September are the transition period. In May, the currents in the Karimata Strait turn northward, consistent with the local monsoon. In September, the southeasterly trade wind is still present over the strait, driving surface water northward, whereas the bottom flow reverses direction, possibly because of the pressure gradient across the strait from north to south.     

印尼贯穿流源区马鲁古海与哈马黑拉海水团来源的季节和年际变化

So far, large uncertainties of the Indonesian throughflow(ITF) reside in the eastern Indonesian seas, such as the Maluku Sea and the Halmahera Sea. In this study, the water sources of the Maluku Sea and the Halmahera Sea are diagnosed at seasonal and interannual timescales and at different vertical layers, using the state-of-the-art simulations of the Ocean General Circulation Model(OGCM) for Earth Simulator(OFES). Asian monsoon leaves clear seasonal footprints on the eastern Indonesian seas. Consequently, the subsurface waters(around 24.5σ_θ and at ～150 m) in both the Maluku Sea and the Halmahera Sea stem from the South Pacific(SP) during winter monsoon, but during summer monsoon the Maluku Sea is from the North Pacific(NP), and the Halmahera Sea is a mixture of waters originating from the NP and the SP. The monsoon impact decreases with depth, so that in the Maluku Sea, the intermediate water(around 26.8σ_θ and at ～480 m) is always from the northern Banda Sea and the Halmahera Sea water is mainly from the SP in winter and the Banda Sea in summer. The deep waters(around27.2σ_θ and at ～1 040 m) in both seas are from the SP, with weak seasonal variability. At the interannual timescale,the subsurface water in the Maluku Sea originates from the NP/SP during El Ni?o/La Ni?a, while the subsurface water in the Halmahera Sea always originates from the SP. Similar to the seasonal variability, the intermediate water in Maluku Sea mainly comes from the Banda Sea and the Halmahera Sea always originates from the SP. The deep waters in both seas are from the SP. Our findings are helpful for drawing a comprehensive picture of the water properties in the Indonesian seas and will contribute to a better understanding of the ocean-atmosphere interaction over the maritime continent.     

2003-2016年北极净初级生产力时空变化

The area of Arctic sea ice has dramatically decreased, and the length of the open water season has increased;these patterns have been observed by satellite remote sensing since the 1970 s. In this paper, we calculate the net primary productivity(NPP, calculated by carbon) from 2003 to 2016 based on sea ice concentration products,chlorophyll a(Chl a) concentration, photosynthetically active radiation(PAR), sea surface temperature(SST), and sunshine duration data. We then analyse the spatiotemporal changes in the Chl a concentration and NPP and further investigate the relations among NPP, the open water area, and the length of the open water season. The results indicate that(1) the Chl a concentration increased by 0.025 mg/m~3 per year;(2) the NPP increased by 4.29 mg/(m~2·d) per year, reaching a maximum of 525.74 mg/(m~2·d) in 2016; and(3) the Arctic open water area increased by 57.23×10~3 km~2/a, with a growth rate of 1.53 d/a for the length of the open water season. The annual NPP was significantly positively related to the open water area, the length of the open water season and the SST.The daily NPP was also found to have a lag correlation with the open water area, with a lag time of two months.With global warming, NPP has maintained an increasing trend, with the most significant increase occurring in the Kara Sea. In summary, this study provides a macroscopic understanding of the distribution of phytoplankton in the Arctic, which is valuable information for the evaluation and management of marine ecological environments.     

黄河三角洲孤东近岸冲淤演变及其影响因素

为更好地了解近40年来孤东近岸的演变过程,以研究区剖面水深地形、Landsat影像和利津站水沙数据为数据源,采用遥感技术及数理统计法对研究区域岸线及面积变化进行监测计算,并分析1976—1986年、1986—1996年、1996—2002年、2002—2014年4个不同阶段的冲淤演变及影响因素。结果表明:(1)孤东近岸经历"强淤积-冲淤平衡-侵蚀-强侵蚀"4个阶段。孤东近岸海域由淤积向侵蚀转变始于1996年,且在2002—2014年间侵蚀最为严重,大部分近岸海域蚀深达到6～8 m,侵蚀最大深度超过8 m;(2)等深线变化时空差异明显,蚀退最先出现在北侧,且近岸5 m水深区域内冲淤变化较水深10 m内敏感;(3)研究区近岸侵蚀,离岸淤积,剖面冲淤平衡位置由CS19剖面的11 m水深变化到CS21剖面的5m水深;(4)黄河入海水沙的减少、河口人工改汊、孤东大堤建设和海洋动力作用都对孤东近岸的冲淤演变产生影响,维持研究区冲淤平衡的年均来沙阈值为3.78亿t/a。通过此来进一步探究孤东近岸演变进程,为孤东近岸防护提供科学指导。     

地震后水汽异常变化初探

研究东日本地震、汶川地震和玉树地震震中及其附近区域在地震前后的水汽时间序列变化。首先分析震中MODIS水汽序列和震中附近探空站点水汽序列在地震前后的变化;然后基于GNSS ZTD与水汽之间的高相关性,以GNSS ZTD代替GNSS水汽,讨论震源区周围IGS站点的ZTD序列变化。研究发现,震后震中及其附近区域水汽值变化出现异常,且距离越近所受影响越大;水汽不断聚积,达到峰值后发生降水。