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331.
Yumin Chen Qiming Zhou Sheng Li Fanrui Meng Xiaomei Bi John P. Wilson 《International journal of geographical information science》2014,28(11):2242-2260
This paper proposes a flow-path network (FPN) model to simulate complex surface flow based on a drainage-constrained triangulated irregular network (TIN). The TIN was constructed using critical points and drainage lines extracted from a digital terrain surface. Runoff generated on the surface was simplified as ‘water volumes’ at constrained random points that were then used as the starting points of flow paths (i.e. flow source points). The flow-path for each ‘water volume’ was constructed by tracing the direction of flow from the flow source point over the TIN surface to the stream system and then to the outlet of the watershed. The FPN was represented by a set of topologically defined one-dimensional line segments and nodes. Hydrologic variables, such as flow velocity and volume, were computed and integrated into the FPN to support dynamic surface flow simulation. A hypothetical rainfall event simulation on a hilly landscape showed that the FPN model was able to simulate the dynamics of surface flow over time. A real-world catchment test demonstrated that flow rates predicted by the FPN model agreed well with field observations. Overall, the FPN model proposed in this study provides a vector-based modeling framework for simulating surface flow dynamics. Further studies are required to enhance the simulations of individual hydrologic processes such as flow generation and overland and channel flows, which were much simplified in this study. 相似文献
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To evaluate the influence of wetland reclamation on vertical distribution of carbon and nitrogen in coastal wetland soils, we measured the soil organic carbon(SOC), soil total nitrogen(STN) and selected soil properties at five sampling plots(reed marsh, paddy field, corn field, forest land and oil-polluted wetland) in the Liaohe River estuary in September 2013. The results showed that reclamation significantly changed the contents of SOC and STN in the Liaohe River estuary(P 0.001). The SOC concentrations were in the order: oil-polluted wetland corn field paddy field forest land reed marsh, with mean values of 52.17, 13.14, 11.46, 6.44 and 6.16 g/kg, respectively. STN followed a similar order as SOC, with mean values of 1351.14, 741.04, 632.32, 496.17 and 390.90 mg/kg, respectively. Interaction of reclamation types and soil depth had significant effects on SOC and STN, while soil depth had significant effects on SOC, but not on STN. The contents of SOC and STN were negatively correlated with pH and redox potential(Eh) in reed marsh and corn field, while the SOC and STN in paddy field had positive correlations with electrical conductivity(EC). Dissolved organic carbon(DOC), ammonium nitrogen(NH_4~+-N) and nitrate nitrogen(NO_3~–-N) were also significantly changed by human activities. NH_4~+-N and NO_3~–-N increased to different degrees, and forest land had the highest NO_3~–-N concentration and lowest DOC concentration, which could have been caused by differences in soil aeration and fertilization. Overall, the results indicate that reed harvest increased soil carbon and nitrogen release in the Liaohe River Estuary, while oil pollution significantly increased the SOC and STN; however, these cannot be used as indicators of soil fertility and quality because of the serious oil pollution. 相似文献
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Naixia Mou Yanci Wang Yunhao Zheng Lingxian Zhang Teemu Makkonen Qi Jiang Tengfei Yang 《Transactions in GIS》2023,27(4):1043-1067
Analyzing tourists' travel behavior at different stages of a trip can help to better understand their travel demands, providing valuable suggestions for destination management. In this article, we propose a research framework that can help in comprehensively analyzing tourists' travel behavior from the perspective of the three main stages: before, during, and after the trip. A case study was conducted based on user-generated content data from the Old Town of Lijiang to verify the feasibility of the proposed research framework. The results show that: (1) before the trip, tourists inquire about destinations and optimal stay; (2) during the trip, tourists are attracted to natural sceneries; (3) after the trip, tourists discuss experience and services. Travel behavior in stages provide detailed (inter-, intra-, and individual attractions) guidance (from tourists) for destinations. The proposed framework provides a novel perspective for exploring the spatiotemporal behavioral features of tourists at different stages of their trips. 相似文献