The effects of forest and snow cover on the water and chemical cycles in cold snowy watersheds

森林和积雪对冷雪流域水和化学循环的影响

• 批准号: 11490001
• 负责人: ISHIKAWA Nobuyoshi
• 金额: $ 4.61万
• 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: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11490001/
• 关键词: water balance; heat balance; CO_2 concentration; turbulent heat flux; evapo-transpiration; soil respiration; runoff; chemical content; 水循環; 炭酸ガス濃度; 酵素同位体; 蒸発散量; 乱流変動法; 物質循環; 落葉広葉樹林; 熱収支; 酸性度; 顕熱; 樹冠

For understanding the effects of forest and snow cover on the water, CO_2 and chemical cycles were examined at two different experimental watersheds from 1999 to 2003 including three snow cover seasons. One watershed located at the northern part of Hokkaido where the annual temperature range was -30℃ to 25℃ and the maximum snow depth was more than 2m. The other was at the southern part of Hokkaido, where the temperature range was -25℃ to 25℃ and the snow depth was below 50cm. Vegetations of both sites are mixed forests of evergreen needle leaf trees and deciduous broad-leaved trees with bamboo bush undergrowth. Observation items are radiative heat flux, turbulent heat flux, evapo-transpiration, CO_2 concentration above canopy and forest floor, chemical contents of river water, snowmelt water, groundwater and precipitation.The main observational results are : 【○!1】Evapo-transpiration above canopy showed remarkable seasonal variation and even in mid-summer it occupied 30-40% of the net radiation , which was smaller compared with other reports. 【○!2】The absorbed CO_2 by broad-leaved forest was 2680-2200kgC/ha/yr, which qualitatively consists with the growth rates of trees. Soil respiration was 4100-3900kg/C/ha/yr and showed daily and seasonal variations according to the change of soil temperature. 【○!3】CO_2 concentration at the bottm of snow cover in mid-winter sometime exceeded 1200ppm. CO_2 in the atmosphere just above the snow cover showed no daily variation in the mid-winter but clear daily variation appeared after March. 【○!4】During snow melting season the runoff ratio of water was 80-85%, however the chemical balance showed that the outflow of iron exceeded more than two times of the inflow, which suggested the inflow of snow-free season reserved in the watershed for a while and drained in the snowmelt season.

为了了解森林和积雪对水的影响，我们在 1999 年至 2003 年的两个不同的实验流域（包括三个积雪季节）检查了 CO_2 和化学循环，其中一个流域位于北海道北部，其年温度范围为 - 30℃至25℃，最大雪深超过2m；另一个是北海道南部，温度范围为-25℃至25℃，雪深在以下。两地植被均为常绿针叶树与落叶阔叶树及竹丛的混交林，观测项目为辐射热通量、湍流热通量、蒸散量、树冠及林地表层CO_2浓度、化学物质含量。河水、融雪水、地下水和降水的主要观测结果是：【○！1】冠层上方的蒸发蒸腾量表现出明显的季节变化，甚至在盛夏时占净辐射量的30-40%，较其他报道要少【○！2】阔叶林吸收CO_2为2680-2200kgC/ha/yr，与生长量定性相符。树木的土壤呼吸速率为4100-3900kg/C/ha/yr，并且根据【○!3】CO_2 浓度的变化呈现出日变化和季节变化。仲冬积雪底部有时超过1200ppm，积雪上方的大气在仲冬没有表现出日变化，但3月之后出现明显的日变化【○！4】在融雪季节径流。水的比例为80-85%，但化学平衡显示铁的流出量超过流入量的两倍以上，这表明流域保留了无雪季节的流入量。在融雪季节一段时间并排干。

项目成果

Nakabayashi, H. et al.: "Radiative characteristics in a Japanese forested drainage basin during snowmelt"Hydrological Process. 13. 157-167 (1999)

Nakabayashi, H. 等人：“日本森林流域融雪期间的辐射特征”水文过程。

Sato, H., Ishii, Y.: "The effect of inner drainage basins on snowmelt runoff in two adjacent watersheds"Transactions, Japanese Geomorphological Union. 22. 165-183 (2001)

Sato, H.，Ishii, Y.：“内流域对两个相邻流域融雪径流的影响”，日本地貌联盟汇刊。

Ishikawa, N.and et al.: "Characteristics of the water and heat cycles of a discontinuous permafrost region in Interior Alaska."Proceedings of the 12^<th> International Symposium and Workshop. 157-168 (1999)

Ishikawa, N.and 等人：“阿拉斯加内陆不连续永久冻土地区的水和热循环特征。”第 12 届国际研讨会和研讨会论文集。

Nakabayashi, H. et al.: "Radiative characteristics in Japanese forested drainage basin during snowmelt"Hydrological Processes. 13. 157-167 (1999)

Nakabayashi, H. 等人：“融雪期间日本森林流域的辐射特征”水文过程。

Takeuchi, Y. et al.: "The thermal effect of melting snow/ice surface on lower atmospheric temperature"Artic, Antarctic and Alpine Research. 34、1. 20-25 (2002)

Takeuchi, Y. 等人：“融化的雪/冰表面对较低大气温度的热效应”，Artic, Antarctic and Alpine Research 34, 1. 20-25 (2002)。