气候变化领域集成服务门户(CCPortal): Influence of meter-scale wind-formed features on the variability of the microwave brightness temperature around Dome C in Antarctica

CCPortal

DOI	10.5194/tc-8-1105-2014
	Influence of meter-scale wind-formed features on the variability of the microwave brightness temperature around Dome C in Antarctica
	Picard G.; Royer A.; Arnaud L.; Fily M.
发表日期	2014
ISSN	19940416
卷号	8 期号:3
英文摘要	Space-borne passive microwave radiometers are widely used to retrieve information in snowy regions by exploiting the high sensitivity of microwave emission to snow properties. For the Antarctic Plateau, many studies presenting retrieval algorithms or numerical simulations have assumed, explicitly or not, that the subpixel-scale heterogeneity is negligible and that the retrieved properties were representative of whole pixels. In this paper, we investigate the spatial variations of brightness temperature over a range of a few kilometers in the Dome C area. Using ground-based radiometers towed by a vehicle, we collected brightness temperature at 11, 19 and 37 GHz at horizontal and vertical polarizations along transects with meter resolution. The most remarkable observation was a series of regular undulations of the signal with a significant amplitude reaching 10 K at 37 GHz and a quasi-period of 30-50 m. In contrast, the variability at longer length scales seemed to be weak in the investigated area, and the mean brightness temperature was close to SSM/I and WindSat satellite observations for all the frequencies and polarizations. To establish a link between the snow characteristics and the microwave emission undulations, we collected detailed snow grain size and density profiles at two points where opposite extrema of brightness temperature were observed. Numerical simulations with the DMRT-ML microwave emission model revealed that the difference in density in the upper first meter explained most of the brightness temperature variations. In addition, we found that these variations of density near the surface were linked to snow hardness. Patches of hard snow -probably formed by wind compaction -were clearly visible and covered as much as 39% of the investigated area. Their brightness temperature was higher than in normal areas. This result implies that the microwave emission measured by satellites over Dome C is more complex than expected and very likely depends on the year-to-year areal proportion of the two different types of snow. © Author(s) 2014. CC Attribution 3.0 License.
学科领域	algorithm; brightness temperature; microwave imagery; numerical model; resolution; satellite imagery; temperature effect; Antarctica; Dome Concordia; East Antarctica
语种	英语
scopus关键词	algorithm; brightness temperature; microwave imagery; numerical model; resolution; satellite imagery; temperature effect; 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/120097
作者单位	University Grenoble Alpes, LGGE UMR5183, 38041 Grenoble, France; CNRS, LGGE UMR5183, 38041 Grenoble, France; Centre d'Applications et de Recherches en Télédé tection (CARTEL), Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, J1K 2R1, Canada
推荐引用方式 GB/T 7714	Picard G.,Royer A.,Arnaud L.,et al. Influence of meter-scale wind-formed features on the variability of the microwave brightness temperature around Dome C in Antarctica[J],2014,8(3).
APA	Picard G.,Royer A.,Arnaud L.,&Fily M..(2014).Influence of meter-scale wind-formed features on the variability of the microwave brightness temperature around Dome C in Antarctica.Cryosphere,8(3).
MLA	Picard G.,et al."Influence of meter-scale wind-formed features on the variability of the microwave brightness temperature around Dome C in Antarctica".Cryosphere 8.3(2014).