【作者】 王昊；

【导师】 许士国；

【作者基本信息】 大连理工大学 ， 水文学及水资源， 2006， 博士

【摘要】 湿地是多功能的独特生态系统,是自然界最富有生物多样性的生态景观和人类重要的生存环境之一,具有调节河川径流、防止水旱灾害、净化污染的功能和很高的生产力,对维持自然生态平衡和促进国民经济发展起到着不可替代的作用。受我国人口增长、工农业用水持续紧张、全球气候变化等一系列因素的影响,我国大部分湿地面临严峻考验,出现湿地面积迅速减小、生物多样性下降、敏感物种消失等严重后果,对湿地的保护、恢复工作亟待进行。水是形成和维系湿地生态系统的重要因子,湿地水量变化对湿地功能及临界状态研究具有重要意义,在湿地水循环要素中,水生植物蒸散耗水量最难直接确定,其变化规律是进行湿地水循环与水量动态变化研究的关键。本文研究了沼泽湿地原形条件下蒸散发的测量问题,通过实验测量和模型分析,评估了湿地区域主要下垫面类型芦苇沼泽和自由水面条件下不同时间尺度的蒸散耗水量,研究了湿地大型水生植物对湿地水面蒸发的影响机理及变化规律,分析了湿地区域气象因子的变化趋势及其对蒸散耗水的影响,对未来时期湿地芦苇沼泽蒸散耗水的可能变化趋势做出了预测,为全面科学的进行湿地水资源管理、制定湿地保护计划提供科学的依据。本文的研究以扎龙湿地为背景,主要研究内容和成果如下：(1)大型水生植物蒸散耗水量直接测定,蒸散耗水过程的数学模型描述对国内外不同下垫面蒸散耗水直接测量方法进行了系统的评述,研究了不同学科领域蒸散耗水的测算方法,根据扎龙湿地的实际水文地质情况,研制了“三筒补偿式蒸渗仪”,适合测量下垫面经常处于饱和状态的芦苇沼泽蒸散耗水量,其方法、装置分获两项国家发明专利授权。研究对2004年、2005年扎龙湿地芦苇生长期内的蒸散耗水量进行了对比观测,分析了湿地大型水生植物芦苇对自由水面蒸发的影响,建立了耦合当地微气象观测数据及芦苇生理指标的多元回归模型,具有很好的相关性。(2)扎龙湿地区域参照蒸散发估算的经验模型的构建对湿地周边气象站历史数据进行了整理分析,使用FAO56单系数法计算了湿地区域的参照作物蒸散量,通过统计参照蒸散量与多个气象因子的相关关系,以相关平方系数和均方误差为拟合评价指标,尝试使用不同拟合模型和气象因子组合方式建立了拟合Penman-Monteith模型结果的经验公式,该公式耦合了湿地最高气温、最低气温、降雨量、风速四个因子,能够很好地估算湿地区域逐月参照蒸散耗水量。(3)湿地区域蒸散耗水变化的气候学原因分析以扎龙湿地周边的齐齐哈尔、富裕、林甸、杜蒙、泰来五气象站1961～2000年的逐月气象数据估算了湿地区域40年的蒸散耗水量。对五站最高气温、最低气温、降雨量、风速四因子的40年变化趋势进行了分析,结果表明湿地区域最高气温具有不显著的上升趋势,最低气温具有显著的上升趋势,二者的变化是不对称的,平均风速具有显著的下降趋势,而降雨量的变化不明显。经验模型各气象因子的敏感性分析说明了最高气温、最低气温是影响湿地蒸散耗水变化的主要因子,二者的变化率决定了蒸散耗水的变化趋势。在最高气温、最低气温均上升的时期,平均气温的上升并不一定意味着蒸散耗水的增加,最低气温的显著上升会抵消最高气温对蒸散的正面影响,使蒸散量有可能呈现下降的趋势,研究给出了描述三者变化率关系的微分方程。(4)未来时期,扎龙湿地区域芦苇沼泽可能的蒸散耗水量预测利用建立的经验模型,在气象因子线性外延及HadCM3、CCSRNIES、CSIRO-Mk2、CGCM1四个大气环流模型气候情景下估算了扎龙湿地区域未来60年(2001～2060年)的蒸散耗水时间分布情况,计算了气候变化影响的蒸散耗水增加量。更多还原

【Abstract】 Wetland is the unique multi-purpose ecosystem and the ecological landscape with biodiversity, and it is also the most important living conditions for human being. Wetlands function as the downstream receiver of water and waste from both natural and human sources, they stabilize water supplies, thus ameliorating both floods and drought, and they also have high productivity to provide multiform resource for human society, therefor, wetlands play an irreplaceable role in maintaining ecological balance and promoting national economic growth. However, affected by a series of factors, such as the rapid increasement of population in China, continuous shortage of industrial and agricultural water use, global climate change, wetlands in China have faced severe situations, as a result, many wetlands disappear at alarming rates, and considerable parts can never be resumed, whereas, wetlands protection and restoration become the foremost problem to be resolved.Water is the prime factor to shape and maintain the wetland ecosystem, the change of water status is very meaningful for wetland function study and critical stage judgement. Of the water circle factors in wetland, the aquatic macrophytes evapotranspiration (ET) is very difficult to measured derectly, and it is also a key point for the study of water dynamic variety in wetland. By experimental test and model estimation, Mulit-temporal scale ET of the main underlying type in wetland, reed swamp and open water, is evaluated, the effect of aquatic macrophytes ET on open water and the change laws of ET are investigated, the climatologic characteristics that affect wetland ET is analysed, and the possible change trend of ET loss in future period is predicted. The study in this paper can provide comprehensive support for wetland hydrology management and wetland protection. Zhalong wetland is chosen for studing in this paper, the main contents and achievements are as followed:(1):Derect measurement for ET of aquatic macrophytes in wetland, simulation of ET process by mathematical modelSystemic summarization is made for ET evaluating methods on different underlying types, considerable contrasts are made for different mathods, as a result, "compensatory lysimeter with three cylinders" is developed according to the characteristics of Zhalong wetland, and it is proved that this lysimeter is befitting for measuring ET loss of the saturated reed swamp, the patent applications of the measuring method and device are authorized by the State Intellectual Property Office of PRC. Contrastive experimental test is carried out in Zhalong wetland from 2004 to 2005 (during reed growing season from May 16 to Oct.16), and the function of reed ET to open water is analysed, by use of the actually observed data, a simulation equation of the ET in Zhalong reed belt is established with a high correlative coefficient, which is concerned to the factors of air temperature, wind speed, relative humidity, and reed height and leaf area.(2):The establishement of empirical model for evaluating reference crop ET in Zhalong wetland regionBy analyzing the relationships between FAO56 reference evapotranspiration (RET) and each meteorological variable (the data set is from eight meteorological stations around Zhalong wetland), a statistical model for estimating RET is established. The correlation coefficients (R2) and root-mean-square error (RMSR) are chosen for evaluating the fitting efficiency to RET. After selecting from the meteorological variables that influence ET processes, the essential variables are chosen and some collinearity variables are removed. Through permuting and combining, the essential variables and other candidate variables, different combinations are introduced in various fitting expressions, finally, the model couped with monthly maximum temperature (Tmax), minimum temperature (Tmin), precipitation (P) and wind speed at 2 meter height (U2) is established. Application shows that it can serve as a valuable tool for wetland ET evaluation.(3):The analysis of climatic reasons that affect wetland ET changeData set of five meteorological stations around Zhalong wetland viz. Qiqihar, Fuyu, Lindian, Dumeng and Tailai is used for wetland ET estimating in the period from 1961 to 2000, the annual ET on reed swamp shows degressive tendency, the decrease in recent 40 years is 92mm. The change trend of meteorological factors in wetland area is detected, the results show that significant increasing trend is found of Tmin in recent 40 years in the wetland, however, no significant increasing trend is found of Tmax, and their change shows asymmetry, the U2 shows significant degressive trend, and no evident change of P in study site is detected, the sensitivity analysis shows that Tmax and Tmin are two dominating factors that influence ET markedly, and the difference of rising rate between Tmax and Tmin determines the change trend of ET, the rising of average temperature does not means the increasing trend of ET, in the periods that the rising rate of Tmin exceeds that of Tmax obviously, Tmin counteracts the positive influence of Tmax to ET, the ET can show a decreasing trend as a result. The differential eguation described the change rate of ET, Tmax and Tmin is provided in this study.(4):The possible ET loss prediction of wetland in future period, the calculation of additional water consumption by ET based on climate change.With the empirical model and two climatic scenarios, in future period from 2001 to 2060, viz. linear extrapolation of climatic trends and the predictions of four GCMs (Hadcm3, CCSRNIES, CSIRO-Mk2 and CGCM1) are assumed to calculate the possible ET loss in Zhalong wetland.更多还原