气候变化领域集成服务门户(CCPortal): Ice and mixed-phase cloud statistics on the Antarctic Plateau

CCPortal

DOI	10.5194/acp-21-13811-2021
	Ice and mixed-phase cloud statistics on the Antarctic Plateau
	Cossich W.; Maestri T.; Magurno D.; Martinazzo M.; Di Natale G.; Palchetti L.; Bianchini G.; Del Guasta M.
发表日期	2021
ISSN	1680-7316
起始页码	13811
结束页码	13833
卷号	21 期号:18
英文摘要	Statistics on the occurrence of clear skies, ice clouds, and mixed-phase clouds over Concordia Station, in the Antarctic Plateau, are provided for multiple timescales and analyzed in relation to simultaneous meteorological parameters measured at the surface. Results are obtained by applying a machine learning cloud identification and classification (CIC) code to 4 years of measurements between 2012-2015 of downwelling high-spectral-resolution radiances, measured by the Radiation Explorer in the Far Infrared-Prototype for Applications and Development (REFIR-PAD) spectroradiometer. The CIC algorithm is optimized for Antarctic sky conditions and results in a total hit rate of almost 0.98, where 1.0 is a perfect score, for the identification of the clear-sky, ice cloud, and mixed-phase cloud classes. Scene truth is provided by lidar measurements that are concurrent with REFIR-PAD. The CIC approach demonstrates the key role of far-infrared spectral measurements for clear-cloud discrimination and for cloud phase classification. Mean annual occurrences are 72.3%, 24.9%, and 2.7% for clear sky, ice clouds, and mixed-phase clouds, respectively, with an inter-annual variability of a few percent. The seasonal occurrence of clear sky shows a minimum in winter (66.8%) and maxima (75%-76%) during intermediate seasons. In winter the mean surface temperature is about 9 C colder in clear conditions than when ice clouds are present. Mixed-phase clouds are observed only in the warm season; in summer they amount to more than one-third of total observed clouds. Their occurrence is correlated with warmer surface temperatures. In the austral summer, the mean surface air temperature is about 5gC warmer when clouds are present than in clear-sky conditions. This difference is larger during the night than in daylight hours, likely due to increased solar warming. Monthly mean results are compared to cloud occurrence and fraction derived from gridded (Level 3) satellite products from both passive and active sensors. The differences observed among the considered products and the CIC results are analyzed in terms of footprint sizes and sensors' sensitivities to cloud optical and geometrical features. The comparison highlights the ability of the CIC-REFIR-PAD synergy to identify multiple cloud conditions and study their variability at different timescales. © 2021 William Cossich et al.
语种	英语
scopus关键词	algorithm; cloud classification; ice cover; identification method; infrared spectroscopy; machine learning; spectral resolution; statistical analysis; Antarctic Plateau; Antarctica; East Antarctica
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/246575
作者单位	Physics and Astronomy Department, Alma Mater Studiorum, University of Bologna, Italy; Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Italy
推荐引用方式 GB/T 7714	Cossich W.,Maestri T.,Magurno D.,et al. Ice and mixed-phase cloud statistics on the Antarctic Plateau[J],2021,21(18).
APA	Cossich W..,Maestri T..,Magurno D..,Martinazzo M..,Di Natale G..,...&Del Guasta M..(2021).Ice and mixed-phase cloud statistics on the Antarctic Plateau.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(18).
MLA	Cossich W.,et al."Ice and mixed-phase cloud statistics on the Antarctic Plateau".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.18(2021).