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Research on air pumping effects over central Japanese Alps in summer

日本中部阿尔卑斯山夏季空气抽吸效应研究

基本信息

批准号：
13680601
负责人：
OSADA Kazuo
金额：
$ 2.37万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

Air pumping effects over mountain areas are caused by solar heating of the mountain slope. The air pumping effect may inject significant amount of polluted air into the free-troposphere over Japan. To characterize the air pumping effect over the central Japanese Alps, we conducted in-situ measurements on atmospheric aerosol particles, ozone, and radon concentrations with meteorological parameters at Mt.Norikura during the study period of 2001 and 2002. We observed column amount and vertical distribution of aerosols by using a sky-radiometer and a ceilometer. Size-segregated aerosol particles for chemical analysis were also sampled during intensive observation periods during summer and early fall.Under the clear sky conditions in summer, polluted air from mountain valley area is lifted up about 4km of altitude (1km above the mountain top) over Mt.Norikura. The ratio of aerosol volume concentration for daytime (polluted valley wind) to nighttime (clean free-tropospheric) conditions was about 10. The air pumping effects over central Japanese Alps carry about 10 time higher concentration of aerosols to the free-troposphere over Japan in summer. Under the high pressure system centered over the northwest Pacific in typical summer condition, backward air trajectories were originated from the northwest Pacific to Mt.Norikura and forward trajectories returned to the north Pacific with some deviations to east Russia and the Kurile Islands. The air pumping effects over mountain area provide a strong pollution source mechanism to the free-troposphere over the western Pacific region including east Asia.

山区的抽气效应是由山坡的太阳加热引起的。空气泵效应可能会将大量的污染空气注入日本上空的自由对流层。为了描述日本阿尔卑斯山中部地区的空气抽运效应，我们在2001-2002年的研究期间，利用气象参数对日本中部阿尔卑斯山的大气气溶胶粒子、臭氧和氡浓度进行了现场测量。我们使用天空辐射计和Ceileter观测了气溶胶的柱数和垂直分布。在夏季和初秋的密集观测期间，还采集了用于化学分析的尺寸分离的气溶胶粒子。在夏季晴朗的天空条件下，来自山谷地区的污染空气被提升到诺里库拉山上空约4公里(山顶以上1公里)的高度。白天(受污染的谷风)和夜间(清洁的自由对流层)的气溶胶体积浓度之比约为10。夏季，日本中部阿尔卑斯山上空的抽气效应使日本上空自由对流层的气溶胶浓度增加了约10倍。在典型夏季以西北太平洋为中心的高压系统下，从西北太平洋到名古拉山的后向气流轨迹返回北太平洋，并与俄罗斯东部和千岛群岛有一些偏离。山区的抽气效应为包括东亚在内的西太平洋地区自由对流层提供了较强的污染源机制。