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101.
The environment evolution of Wuliangsuhai wetland since 1986 is analyzed based on the remote sensing principle. The total water area of Wuliangsuhai lake has been increased during the past 17 years. The open water area had an increasing trend before 1987, and the trend was decreasing up to 1996, then the trend has increased again since 2000; the variation of the water area with dense aquatic weed is basically contradictory to the variation of open water area. The natural reed area had been decreased before 1987, and then it has been increased. The areas of shallow water and swamp have been slightly increased, in fact, the variations are quite steady. The artificial reed area has been increased since the reed plantation was started in 1988. The relationships of the water environment, the climate, hydrology and different types of areas are discussed, and then the technological measures for sustainable development and utilization of Wuliangsuhai lake water environment are proposed. 相似文献
102.
利用黄河源区玛曲观测站2016年涡动相关系统和微气象梯度塔观测资料,分析了高寒草地 大气间水热交换通量的特征。结果表明:夜间地表各通量值很小,净辐射和感热通量为负值,潜热通量的值较小但始终为正。日出后随着太阳辐射和地表加热作用各通量迅速增大,在14时左右达到峰值。暖季(6—8月)夜间感热通量占净辐射的比例(H/Rn)高于感潜通量占净辐射的比例(LE/Rn),日出后LE/Rn开始升高而H/Rn减小,日间LE/Rn大于H/Rn。冷季(12月—次年2月)H/Rn始终大于LE/Rn,感热通量在冷季的能量分配中占据主导地位。暖季LE/Rn、H/Rn均随土壤温度升高而升高。冷季H/Rn与5 cm深度土壤温度表现出了更为明显的二次关系,随着温度升高先降低后升高,当温度小于-7 ℃时H/Rn降低,大于-6 ℃时H/Rn增大。暖季H/Rn随着土壤湿度增大先降低后升高,LE/Rn先升高后降低。在0—1.5 kPa,暖季饱和水汽压差与LE/Rn、H/Rn均呈线性关系,并随着饱和水汽压差增大,LE/Rn增大而H/Rn减小;1.5 kPa之后,LE/Rn、H/Rn变化特征均保持其原有趋势。 相似文献
103.
Jianbu Wang Zhaoyang Lin Yuanqing Ma Guangbo Ren Zijun Xu Xiukai Song Yi Ma Andong Wang Yajie Zhao 《海洋学报(英文版)》2022,41(6):31-40
Spartina alterniflora as an alien invasive plant, poses a serious threat to the ecological functions of the coastal wetland of the Jiaozhou Bay. As of 2019, the distribution area of S. alterniflora in the Jiaozhou Bay has reached more than 500 hm2. For this reason, combined with field surveys, remote sensing monitoring of the invasion S.alterniflora in the Jiaozhou Bay has been carried out. To accurately identify S. alterniflora within the Jiaozhou Bay coastal wetland, we used a new m... 相似文献
104.
依托中分辨率成像光谱仪完整的数据序列和丰富的光谱信息,遥感特征指数在湿地生态系统发展变化的状态、趋向和规律研究方面发挥着不可替代的优势。传统类间距离判别的遥感特征指数选取中常存在过分依赖数据统计特征、入选指数与目标地类间生态学意义不明确、分类模型普适性差等局限性。基于此,本研究以河北省白洋淀湿地自然保护区为例,提出类可分离性距离判别(Class Separation Discrimination,CSD)与类间距离判别(Class Distance Discrimination,CDD)相结合的方法构建最优遥感特征指数集,并采用QUEST算法和马氏距离判别法构建分类决策树模型用于白洋淀湿地信息的提取研究,尝试克服传统类间距离指数选取中的不足。结果表明:运用CSD和CDD相结合的方法所选取的遥感特征指数在研究区湿地信息提取过程中的总体分类精度达到了91.32%,Kappa系数0.88,较传统的分类与回归树(Classification and Regression Tree,CART)方法,分类精度提高了1.67%;其次选取的最优指数与待提取的湿地类型均具有明确的生态学意义,如挺水植物在立地干湿交替条件下的潴育化过程决定了氧化铁比率IO可成功的将混分的耕地和挺水植物进一步分离;进一步将基于研究区2017年OLI影像构建的CSD和CDD相结合方法与CART方法的模型分别应用于研究区2019年OLI影像进行分类,基于CSD和CDD相结合方法构建的模型分类总体精度和Kappa系数分别为:86.97%、0.83,基于CART方法构建的模型无法满足分类需求,研究结果较好地证明了基于CSD和CDD相结合方法构建的模型在年际之间具有良好的适用性和稳定性。总之,CSD和CDD相结合的方法在不降低湿地信息提取精度的基础上,有效避免了传统遥感特征指数选择方法的局限性,提高了分类模型的普适性,是遥感特征指数选择算法和决策树相结合在湿地信息提取方面的有益尝试。 相似文献
105.
Ecosystem health assessment of Honghu Lake Wetland of China using artificial neural network approach 总被引:3,自引:0,他引:3
Minghao Mo Xuelei Wang Houjian Wu Shuming Cai Xiaoyang Zhang Huiliang Wang 《中国地理科学(英文版)》2009,19(4):349-356
Honghu Lake, located in the southeast of Hubei Province, China, has suffered a severe disturbance during the past few decades.
To restore the ecosystem, the Honghu Lake Wetland Protection and Restoration Demonstration Project (HLWPRDP) has been implemented
since 2004. A back propagation (BP) artificial neural network (ANN) approach was applied to evaluatinig the ecosystem health
of the Honghu Lake wetland. And the effectiveness of the HLWPRDP was also assessed by comparing the ecosystem health before
and after the project. Particularly, 12 ecosystem health indices were used as evaluation parameters to establish a set of
three-layer BP ANNs. The output is one layer of ecosystem health index. After training and testing the BP ANNs, an optimal
model of BP ANNs was selected to assess the ecosystem health of the Honghu Lake wetland. The result indicates that four stages
can be identified based on the change of the ecosystem health from 1990 to 2008 and the ecosystem health index ranges from
morbidity before the implementation of HLWPRDP (in 2002) to middle health after the implementation of the HLWPRDP (in 2005).
It demonstrates that the HLWPRDP is effective and the BP ANN could be used as a tool for the assessment of ecosystem health. 相似文献
106.
Impacts of soil fauna on litter decomposition at different succession stages of wetland in Sanjiang Plain, China 总被引:1,自引:0,他引:1
Litter decomposition is the key process in nutrient recycling and energy flow. The present study examined the impacts of soil
fauna on decomposition rates and nutrient fluxes at three succession stages of wetland in the Sanjiang Plain, China using
different mesh litterbags. The results show that in each succession stage of wetland, soil fauna can obviously increase litter
decomposition rates. The average contribution of whole soil fauna to litter mass loss was 35.35%. The more complex the soil
fauna group, the more significant the role of soil fauna. The average loss of three types of litter in the 4mm mesh litterbags
was 0.3–4.1 times that in 0.058mm ones. The decomposition function of soil fauna to litter mass changed with the wetland succession.
The average contribution of soil fauna to litter loss firstly decreased from 34.96% (Carex lasiocapa) to 32.94% (Carex meyeriana), then increased to 38.16% (Calamagrostics angustifolia). The contributions of soil fauna to litter decomposition rates vary according to the litter substrata, soil fauna communities
and seasons. Significant effects were respectively found in August and July on C. angustifolia and C. lasiocapa, while in June and August on C. meyeriana. Total carbon (TC), total nitrogen (TN) and total phosphorus (TP) contents and the C/N and C/P ratios of decaying litter
can be influenced by soil fauna. At different wetland succession stages, the effects of soil fauna on nutrient elements also
differ greatly, which shows the significant difference of influencing element types and degrees. Soil fauna communities strongly
influenced the TC and TP concentrations of C. meyeriana litter, and TP content of C. lasiocapa. Our results indicate that soil fauna have important effects on litter decomposition and this influence will vary with the
wetland succession and seasonal variation.
Foundation item: Under the auspices of State Key Development Program for Basic Research of China (No. 2009CB421103), Key Program
of National Natural Science Foundation of China (No. 40830535/D0101), Knowledge Innovation Programs of Chinese Academy of
Sciences (No. KZCX2-YW-BR-16, KSCX2-YW-N-46-06) 相似文献
107.
Dae-In Lee Jeong-Min Choi Yeon-Gyu Lee Moon-Ock Lee Won-Chan Lee Jong-Kyu Kim 《Estuarine, Coastal and Shelf Science》2008,80(4):495-508
An eco-hydrodynamic model was used to estimate the carrying capacity of pollutant loads and response of water quality to environmental change in Yeoja Bay, Korea. An energy-system model also was used to simulate the fluctuation in nutrients and organic matter in the bordering wetland. Most water quality factors showed a pulsed pattern, and the concentrations of nutrients and organic matter of seawater increased when input loads of nutrients increased due to freshwater discharge. The well-developed tidal zones and wetlands in the northern area of the bay were highly sensitive to input loads. Residence times of water, chemical oxygen demand (COD), and dissolved inorganic nitrogen (DIN) within the bay were estimated to be about 16 days, 43.2 days, and 50.2 days, respectively. Water quality reacted more sensitively to the effects of nitrogen and phosphorus input than to COD. A plan to reduce the present levels of COD and dissolved inorganic phosphorus (DIP) by 20–30% and DIN by at least 50% in pollutant loads is needed for satisfying the target water quality criteria. The natural removal rate of nutrients in wetlands by reeds was assessed to be approximately 10%. 相似文献
108.
蔡述明 《中国地理科学(英文版)》1995,5(3):242-247
THEDEVELOPMENTANDPROTECTIONOFWETLANDSINTHEFOURLAKEAREAOFJIANGHANPLAINCaiShuming(蔡述明)(InstituteofGeodesyandGeophysics,theChine... 相似文献
109.
110.
Yang Ji-song Liu Jing-shuang Yu Jun-bao Wang Jin-da Qin Sheng-jin Li Xin-hua 《中国地理科学(英文版)》2005,15(3):262-268
Soil respiration is a main dynamic process of carbon cycle in wetland. It is important to contribute to global climate changes.
Water table and nutritious availability are significant impact factors to influence responses of CO2 emission from wetland soil to climate changes. Twenty-four wetland soil monoliths at 4 water-table positions and in 3 nitrogen
status have been incubated to measure rates of CO2 emission from wetland soils in this study. Three static water-table controls and a fluctuant water-table control, with 3
nitrogen additions in every water-table control, were carried out. In no nitrogen addition treatment, high CO2 emissions were found at a static low water table (I) and a fluctuant water table (IV), averaging 306.7mg/(m2·h) and 307.89mg/(m2·h), respectively, which were 51%–57% higher than that at static high water table (II and III). After nitrogen addition, however,
highest CO2 emission was found at II and lowest emission at III. The results suggested that nutritious availability of wetland soil might
be important to influence the effect of water table on the CO2 emission from the wetland soil. Nitrogen addition led to enhancing CO2 emissions from wetland soil, while the highest emission was found in 1N treatments other than in 2N treatments. In 3 nutritious
treatments, low CO2 emissions at high water tables and high CO2 emissions at low water tables were also observed when water table fluctuated. Our results suggested that both water table
changes and nutritious imports would effect the CO2 emission from wetland.
Foundation item: Under the auspices of the National Natural Science Foundation of China (No. 90211003) and the Knowledge Innovation
Program of Chinese Academy of Sciences (No. KACX3-SW-332)
Biography: YANG Ji-song (1978-), male, a native of Chengwu of Shandong Province, Ph.D. candidate, specialized in environmental
ecology and wetland biogeochemistry. E-mail: yangjisong@neigae.ac.cn 相似文献