The characteristics of heat, water, CO_2 and chemical cycles in permafrost regions in Inertia Alaska.

惯性阿拉斯加多年冻土区热、水、CO_2和化学循环特征。

基本信息

批准号：
13573015
负责人：
ISHIKAWA Nobuyoshi
金额：
$ 6.98万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13573015/
关键词：
water balance heat balance CO_2 concentration turbulent heat flux evapo-transpiration soil respiration runoff chemical content 蒸発量顕熱水循環地下水位拡散法

项目摘要

For understanding the heat, water and carbon cycles of high latitudes, meteorological and hydrological researches have been carried out at the experimental watershed in Interior Alaska from 2001 to 2004. Observed items were radiation, sensible heat, evapo-transpiration, CO_2 concentration above vegetation floor, soil respiration, soil moisture, soil temperature, runoff and chemical contents of river water, groundwater and precipitation. Underground structure was obtained by geophysical exploration and confirmed by well borings at three different points in the watershed.The main observational results are : (1) Evaporation with the magnitude of 2 to 4 mm/day was obtained in the watershed during summer except over the stream, where condensation occurred because of the low water temperature due to the permafrost thawing. (2) Groundwater of a shallow well showed daily fluctuation, which was influenced by precipitation and evaporation, but not at a deeper well. (3) Soil moisture content in the surface layer depended on slope aspect and micro-topography. (4) Soil CO_2 efflux had a good relationship with soil temperature and water content. The net CO_2 flux at the height of 4m was well estimated by the soil CO_2 efflux and global radiation. (5) Runoff showed the clear dependency with slope aspects ; the runoff radio of the watershed with north-facing slope was larger, but south-facing slope watershed the ratio became small. These results shows that the existence of the frozen soil affects many fields such as surface vegetation, soil moisture, ground water level, evaporation, soil respiration and runoff.

为了了解高纬度地区的热、水和碳循环，2001-2004年在阿拉斯加内陆实验流域开展了气象和水文研究。观测项目为辐射、感热、蒸散、植被地面以上CO_2浓度。、土壤呼吸、土壤湿度、土壤温度、径流以及河水、地下水和降水的化学含量。通过地球物理勘探获得了流域的地下结构，并通过在流域内三个不同点的钻孔证实。主要观测结果是：（1）除夏季外，流域夏季蒸发量为2～4毫米/天。由于永久冻土融化导致水温较低，因此发生了凝结。（2）浅井地下水呈现日波动，受降水和蒸发影响，而深井则无此影响。 (3)表层土壤含水量取决于坡向和微地形。 (4)土壤CO_2流出量与土壤温度、含水量有良好的关系。通过土壤CO_2流出和全球辐射很好地估算了4m高度处的净CO_2通量。 (5)径流与坡向呈明显的相关性；朝北坡的流域径流比率较大，而朝南坡的流域则较小。这些结果表明，冻土的存在影响着地表植被、土壤湿度、地下水位、蒸发、土壤呼吸和径流等多个领域。