气候变化领域集成服务门户(CCPortal): Hoar crystal development and disappearance at Dome C, Antarctica: Observation by near-infrared photography and passive microwave satellite

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DOI	10.5194/tc-7-1247-2013
	Hoar crystal development and disappearance at Dome C, Antarctica: Observation by near-infrared photography and passive microwave satellite
	Champollion N.; Picard G.; Arnaud L.; Lefebvre E.; Fily M.
发表日期	2013
ISSN	19940416
卷号	7 期号:4
英文摘要	Hoar crystals episodically cover the snow surface in Antarctica and affect the roughness and reflective properties of the air-snow interface. However, little is known about their evolution and the processes responsible for their development and disappearance despite a probable influence on the surface mass balance and energy budget. To investigate hoar evolution, we use continuous observations of the surface by in situ near-infrared photography and by passive microwave remote sensing at Dome C in Antarctica. From the photography data, we retrieved a daily indicator of the presence/absence of hoar crystals using a texture analysis algorithm. The analysis of this 2 yr long time series shows that Dome C surface is covered almost half of the time by hoar. The development of hoar crystals takes a few days and seems to occur whatever the meteorological conditions. In contrast, the disappearance of hoar is rapid (a few hours) and coincident with either strong winds or with moderate winds associated with a change in wind direction from southwest (the prevailing direction) to southeast. From the microwave satellite data, we computed the polarisation ratio (i.e. horizontal over vertical polarised brightness temperatures), an indicator known to be sensitive to hoar in Greenland. Photography data and microwave polarisation ratio are correlated, i.e. high values of polarisation ratio which theoretically correspond to low snow density values near the surface are associated with the presence of hoar crystals in the photography data. Satellite data over nearly ten years (2002-2011) confirm that a strong decrease of the polarisation ratio (i.e. signature of hoar disappearance) is associated with an increase of wind speed or a change in wind direction from the prevailing direction. The photography data provides, in addition, evidence of interactions between hoar and snowfall. Further adding the combined influence of wind speed and wind direction results in a complex picture of the snow-atmosphere interactions in Antarctica which deserves further quantification and modelling. © 2013 Author(s).
学科领域	air-snow interaction; algorithm; cryosphere; energy budget; hoar frost; observational method; photography; polarization; satellite data; snow cover; time series; Antarctica; Dome Concordia; East Antarctica
语种	英语
scopus关键词	air-snow interaction; algorithm; cryosphere; energy budget; hoar frost; observational method; photography; polarization; satellite data; snow cover; time series; Antarctica; Dome Concordia; East Antarctica
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/120277
作者单位	UJF - Grenoble 1, CNRS, Laboratoire de Glaciologie et Géophysique de Lenvironnement (LGGE) UMR5183, Grenoble, 38041, France
推荐引用方式 GB/T 7714	Champollion N.,Picard G.,Arnaud L.,et al. Hoar crystal development and disappearance at Dome C, Antarctica: Observation by near-infrared photography and passive microwave satellite[J],2013,7(4).
APA	Champollion N.,Picard G.,Arnaud L.,Lefebvre E.,&Fily M..(2013).Hoar crystal development and disappearance at Dome C, Antarctica: Observation by near-infrared photography and passive microwave satellite.Cryosphere,7(4).
MLA	Champollion N.,et al."Hoar crystal development and disappearance at Dome C, Antarctica: Observation by near-infrared photography and passive microwave satellite".Cryosphere 7.4(2013).