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Zhang J.,Qingdao University of Science and Technology | Li J.,Qingdao University of Science and Technology | Liu J.,Qingdao Meteorological Bureau | Yu X.,Qingdao University of Science and Technology
Sensor Letters | Year: 2013

Non-point source pollution from agriculture is an important cause to make water environment polluted, and the non-point source pollution model integrated with spatial information technology plays an important role in research on non-point source pollution. The paper made Dagu River as study area, calculated 3 years' (1995, 2000 and 2009) non-point source pollution in long term in study area respectively based on L-THIA (The Long-Term Hydrologic Impact Assessment, L-THIA) model which used the land use, soil and precipitation data as import parameter, and analyzed the spatial distribution of the non-point source pollution in study area. The result showed the spatial distribution changing of the non-point source pollution loads from 1995 to 2009. Copyright © 2013 American Scientific Publishers. Source


Qu Y.-Y.,First Institute of Oceanography | Zhang Q.-H.,First Institute of Oceanography | Ma Y.,Qingdao Meteorological Bureau
Shuidonglixue Yanjiu yu Jinzhan/Chinese Journal of Hydrodynamics Ser. A | Year: 2010

On the premise of not considering sea bottom friction empirical formula, the equation of tide wave motion was induced directly by solving a three-dimensional movement. The tide wave motion in the ditch with same depth was obtained with spectral method under the basis of this equation and the vertical distribution of the tide flow was further to be acquired. Therefore, the spatial and temporal distributions of sea bottom friction, horizontal flux of current and their "included angle" were calculated. In the traditional sea bottom friction empirical formula, the include angle is supposed to be 180°, that is, the directions of sea bottom friction and horizontal flux of current are opposite. But in the study, the included angles are changed with time and space and all less than 180°by computing at several spatial points. For the diurnal tide, the included angles have a 12-h change cycle and for the semidiurnal tide, have a 6-h change cycle. It is worth to note that the obtained conclusions in the paper are dependent on the positions of selected sites and the distributions of intruded tide wave from overseas. Anyway, for the quasi-geostrophic flow with quasi-periodic changes, the hypothesis for the sea bottom friction and horizontal flux of current with opposite direction is unsuitable. Source


Dai Y.,Ocean University of China | Dai Y.,Sinopec | Qiao L.,Ocean University of China | Xu J.,Ocean University of China | And 4 more authors.
Journal of Ocean University of China | Year: 2015

Laizhou Bay and its adjacent waters are of great importance to China’s marine oil and gas development. It is therefore crucial to estimate return-period values of marine environmental variables in this region to ensure the safety and success of maritime engineering and maritime exploration. In this study, we used numerical simulations to estimate extreme wave height, sea current velocity and sea-level height in western Laizhou Bay. The results show that the sea-level rise starts at the mouth of the bay, increases toward west/southwest, and reaches its maximum in the deepest basin of the bay. The 100-year return-period values of sea level rise can reach 3.4–4.0 m in the western bay. The elevation of the western part of the Qingdong Oil Field would remain above the sea surface during extreme low sea level, while the rest of the oil field would be 1.6–2.4 m below the sea surface. The return-period value of wave height is strongly affected by water depth; in fact, its spatial distribution is similar to the isobath’s. The 100-year return-period values of effective wave height can be 6 m or higher in the central bay and be more than 1 m in the shallow water near shore. The 100-year return-period values of current velocity is about 1.2–1.8 m s−1 in the Qingdong Oil Field. These results provide scientific basis for ensuring construction safety and reducing construction cost. © 2015, Science Press, Ocean University of China and Springer-Verlag Berlin Heidelberg. Source


Zhang J.,Qingdao University of Science and Technology | Shen T.,Beijing University of Civil Engineering and Architecture | Liu M.,Qingdao University of Science and Technology | Wan Y.,Qingdao University of Science and Technology | And 2 more authors.
Mathematical and Computer Modelling | Year: 2011

Non-point source (NPS) pollution originating from agricultural development is the root cause of environmental pollution. Herein, we explore the integration of a NPS pollution model with novel spatial information technology to further understand the effects of enhanced crop development on local water resources. This study was based on land use, soil and precipitation data from studies conducted using the L-THIA (Long-Term Hydrologic Impact Assessment, L-THIA) model, in concert with an analysis of the spatial distribution of NPS pollution within the study area. The L-THIA model was consistent in anticipating increased pollution levels and, therefore, may be used to provide information critical to land use and environmental protection planning. © 2010 Elsevier Ltd. Source


Zhang Q.-H.,First Institute of Oceanography | Yin X.-Q.,First Institute of Oceanography | Qu Y.-Y.,First Institute of Oceanography | Ma Y.,Qingdao Meteorological Bureau
Shuidonglixue Yanjiu yu Jinzhan/Chinese Journal of Hydrodynamics Ser. A | Year: 2012

The dynamical impact of Kuroshio intrusion on the shelf water of the East China Sea contains 2 parts: the direct intrusion of Kuroshio water and the intensive shearing of Kuroshio. In this study, the directly intrusion is studied. Since the intrusion water of Kuroshio (lower level) and the shelf water (upper level) are stratified by two layers, the vorticity equation is modified. In this equation, the shelf and the isobaths are all treated as sector and a polar coordinate and Fourier series is employed to derive the analytical solution. The results indicated that the Kurochio water intrude upon the lower level shelf from north-east of Taiwan Island for a finite distance, then turn to the right along the isobaths of the fan-shaped topography. The intrusion current caused the downwelling of the deeper water and upwelling of the upper water around the north-east of Taiwan Island. The upwelling region is consistent with the location of the cool eddy which is observed from infrared satellite image of sea surface temperature, therefore the formation mechanism of cool eddy is given from the aspect of dynamics. Source

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