水稻叶面积指数(leaf area index,LAI)是评价其长势的重要农学参数,高光谱遥感能够实现叶面积指数的快速无损监测。为了寻找反演水稻LAI的最优植被指数,扩展水稻LAI高光谱估测模型的普适性,选取宁夏引黄灌区水稻为研究对象,通过设置不...水稻叶面积指数(leaf area index,LAI)是评价其长势的重要农学参数,高光谱遥感能够实现叶面积指数的快速无损监测。为了寻找反演水稻LAI的最优植被指数,扩展水稻LAI高光谱估测模型的普适性,选取宁夏引黄灌区水稻为研究对象,通过设置不同氮素处理,借助相关分析、回归分析等方法研究高光谱植被指数与水稻LAI之间的定量关系,并通过确立的最优波段组合,构建4种植被指数与水稻LAI的高光谱反演模型。结果表明,水稻LAI在抽穗末期达到最大值,并随氮素水平的增加而增加;水稻冠层原始光谱反射率在400~722nm和1 990~2 090nm波段与LAI达到极显著负相关水平,在近红外区域760~1 315nm与LAI呈极显著正相关。模型检验结果表明,以比值植被指数RVI(850,750)为变量建立的水稻LAI估测模型最佳,研究结果可为水稻LAI的高光谱估测提供地域参考。展开更多
Water resource management is critical to Turkey’s economy and environment. The country has about 112 billion m<sup>3</sup> per year of economically exploitable water. However, population growth, climate c...Water resource management is critical to Turkey’s economy and environment. The country has about 112 billion m<sup>3</sup> per year of economically exploitable water. However, population growth, climate change and pollution of water bodies are putting increasing pressure on these resources. In this context, understanding the contribution of water to the economy and environment is crucial for its conservation. To meet this need, the World Bank launched a program aiming at improving valuation and accounting systems of natural resources in Turkey. As part of this program, this article estimates in monetary terms the economic value of water in Bey?ehir Lake, the largest freshwater lake in Turkey. Valuation is based on the Total Economic Value concept, which includes use and non-use values. The results show that the economic value of water is about seven times higher than its financial value. In addition, the economic value of water allocated for municipal use (TL5/m<sup>3</sup>) is substantially greater than that supplied for irrigation (TL0.5/m<sup>3</sup>). The analysis suggests that allocation of water from Bey?ehir Lake among different uses is inefficient. To validate this conclusion and improve allocation, a more comprehensive assessment of the economic benefits of water resources is needed, particularly of water supply for irrigation, municipal use, recreation and biodiversity. The analysis also indicates that economic valuation can be a powerful tool to improve water management at the river basin level.展开更多
文摘Water resource management is critical to Turkey’s economy and environment. The country has about 112 billion m<sup>3</sup> per year of economically exploitable water. However, population growth, climate change and pollution of water bodies are putting increasing pressure on these resources. In this context, understanding the contribution of water to the economy and environment is crucial for its conservation. To meet this need, the World Bank launched a program aiming at improving valuation and accounting systems of natural resources in Turkey. As part of this program, this article estimates in monetary terms the economic value of water in Bey?ehir Lake, the largest freshwater lake in Turkey. Valuation is based on the Total Economic Value concept, which includes use and non-use values. The results show that the economic value of water is about seven times higher than its financial value. In addition, the economic value of water allocated for municipal use (TL5/m<sup>3</sup>) is substantially greater than that supplied for irrigation (TL0.5/m<sup>3</sup>). The analysis suggests that allocation of water from Bey?ehir Lake among different uses is inefficient. To validate this conclusion and improve allocation, a more comprehensive assessment of the economic benefits of water resources is needed, particularly of water supply for irrigation, municipal use, recreation and biodiversity. The analysis also indicates that economic valuation can be a powerful tool to improve water management at the river basin level.
