气候变化领域集成服务门户(CCPortal): Relationships between snowfall density and solid hydrometeors, based on measured size and fall speed, for snowpack modeling applications

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DOI	10.5194/tc-10-2831-2016
	Relationships between snowfall density and solid hydrometeors, based on measured size and fall speed, for snowpack modeling applications
	Ishizaka M.; Motoyoshi H.; Yamaguchi S.; Nakai S.; Shiina T.; Muramoto K.-I.
发表日期	2016
ISSN	19940416
卷号	10 期号:6
英文摘要	The initial density of deposited snow is mainly controlled by snowfall hydrometeors. The relationship between snowfall density and hydrometeors has been qualitatively examined by previous researchers; however, a quantitative relationship has not yet been established due to difficulty in parameterizing the hydrometeor characteristics of a snowfall event. Thus, in an earlier study, we developed a new variable, the centre of mass flux distribution (CMF), which we used to describe the main hydrometeors contributing to a snowfall event. The CMF is based on average size and fall speed weighted by the mass flux estimated from all measured hydrometeors in a snowfall event. It provides a quantitative representation of the predominant hydrometeor characteristics of the event. In this study, we examine the relationships between the density of newly fallen snow and predominant snow type as indicated by the CMFs. We measured snowfall density at Nagaoka, Japan, where riming and aggregation are predominant, simultaneously observing the size and fall speed of snowfall hydrometeors, and deduced the predominant hydrometeor characteristics of each snowfall event from their CMFs. Snow density measurements were carried out for short periods, 1 or 2h, during which the densification of the deposited snow was negligible. Also, we grouped snowfall events based on similar hydrometeor characteristics. As a result, we were able to obtain not only the qualitative relationships between the main types of snow and snowfall density as reported by previous researchers, but also quantitative relationships between snowfall density and the CMF density introduced here. CMF density is defined as the ratio between mass and volume, assuming the diameter of a sphere is equal to the CMF size component. This quantitative relationship provides a means for more precise estimation of snowfall density based on snow type (hydrometeor characteristics), by using hydrometeor size and fall speed data to derive initial densities for numerical snowpack models, and the snow-to-liquid ratio for winter weather forecasting. In fact, we found that this method can more accurately estimate snowfall density compared with using meteorological elements, which is the method generally used in current snowpack models, even though some issues remain in parameterization for practical use. Transferability of the method developed in the temperate climate zone, where riming and aggregation are predominant, to other snowy areas is also an issue. However, the methodology presented in this study would be useful for other kinds of snow.
学科领域	density; hydrometry; methodology; numerical method; parameterization; quantitative analysis; snow accumulation; snowpack; weather forecasting; Chubu; Honshu; Japan; Nagaoka; Niigata
语种	英语
scopus关键词	density; hydrometry; methodology; numerical method; parameterization; quantitative analysis; snow accumulation; snowpack; weather forecasting; Chubu; Honshu; Japan; Nagaoka; Niigata
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119541
作者单位	Snow and Ice Research Center, National Research Institute for Earth Science and Disaster Resilience, Nagaoka, 940-0821, Japan; Department of Electronics and Computer Engineering, National Institute of Technology, Toyama College, Toyama, 933-0293, Japan; Department of Emeritus, Kanazawa University, Kanazawa, 920-1192, Japan
推荐引用方式 GB/T 7714	Ishizaka M.,Motoyoshi H.,Yamaguchi S.,et al. Relationships between snowfall density and solid hydrometeors, based on measured size and fall speed, for snowpack modeling applications[J],2016,10(6).
APA	Ishizaka M.,Motoyoshi H.,Yamaguchi S.,Nakai S.,Shiina T.,&Muramoto K.-I..(2016).Relationships between snowfall density and solid hydrometeors, based on measured size and fall speed, for snowpack modeling applications.Cryosphere,10(6).
MLA	Ishizaka M.,et al."Relationships between snowfall density and solid hydrometeors, based on measured size and fall speed, for snowpack modeling applications".Cryosphere 10.6(2016).