Effective medium approximation model of sea foam layer microwave emissivity of a vertical profile

doi:10.1080/01431161.2012.718461

IOCAS-IR > 海洋环流与波动重点实验室

	Effective medium approximation model of sea foam layer microwave emissivity of a vertical profile
	Wei, En-Bo; Wei, EB
	2013
发表期刊	INTERNATIONAL JOURNAL OF REMOTE SENSING
ISSN	0143-1161
卷号	34 期号:4 页码:1180-1193
文章类型	Article
摘要	A sea foam layer produced by wave breaking consists of seawater-coated air bubbles, fluid water, and air. The non-uniformity and microstructure of the air-water mixture in a foam layer can cause some important effects on microwave or optical properties. Considering the vertical non-uniformity of the air-water volume, the air-volume fraction is derived as a function of the foam depth variable, coated air bubble velocity, and foam temperature using the gas convection-diffusion equation. For a vertical graded profile of the air volume fraction, we discuss the effects of the coated air bubble velocity parameter and the air-sea temperature difference on the air volume fraction. The results show that the coated air bubble velocity is a key parameter that widely modulates the air volume fraction. Furthermore, an effective medium approximation (EMA) of spherical shell microstructures is proposed to investigate the graded foam effective permittivity and the emissivity of the sea surface covered with the foam layer of the graded air volume fraction in a vertical profile, and good agreement is obtained on comparing the EMA results with the experimental data of foam layer microwave emissivities at frequencies 1.4, 10.8, and 36.5 GHz. In our EMA model, the depth average of graded foam permittivity is adopted. This model can produce reasonable results by only tuning the air bubble velocity. It indicates that the EMA model can combine the effects of graded foam permittivity and foam microstructures into the coated air bubble velocity parameter. Meanwhile, we have qualitatively discussed the influence of air-sea temperature difference on the brightness temperature of the foam layer. It is shown that a negative (or positive) air-sea temperature difference enhances (or reduces) the sea surface brightness temperature, and the brightness temperature difference increases with an increase in microwave frequency.; A sea foam layer produced by wave breaking consists of seawater-coated air bubbles, fluid water, and air. The non-uniformity and microstructure of the air-water mixture in a foam layer can cause some important effects on microwave or optical properties. Considering the vertical non-uniformity of the air-water volume, the air-volume fraction is derived as a function of the foam depth variable, coated air bubble velocity, and foam temperature using the gas convection-diffusion equation. For a vertical graded profile of the air volume fraction, we discuss the effects of the coated air bubble velocity parameter and the air-sea temperature difference on the air volume fraction. The results show that the coated air bubble velocity is a key parameter that widely modulates the air volume fraction. Furthermore, an effective medium approximation (EMA) of spherical shell microstructures is proposed to investigate the graded foam effective permittivity and the emissivity of the sea surface covered with the foam layer of the graded air volume fraction in a vertical profile, and good agreement is obtained on comparing the EMA results with the experimental data of foam layer microwave emissivities at frequencies 1.4, 10.8, and 36.5 GHz. In our EMA model, the depth average of graded foam permittivity is adopted. This model can produce reasonable results by only tuning the air bubble velocity. It indicates that the EMA model can combine the effects of graded foam permittivity and foam microstructures into the coated air bubble velocity parameter. Meanwhile, we have qualitatively discussed the influence of air-sea temperature difference on the brightness temperature of the foam layer. It is shown that a negative (or positive) air-sea temperature difference enhances (or reduces) the sea surface brightness temperature, and the brightness temperature difference increases with an increase in microwave frequency.
学科领域	Remote Sensing ; Imaging Science & Photographic Technology
DOI	10.1080/01431161.2012.718461
URL	查看原文
收录类别	SCI
语种	英语
WOS研究方向	Remote Sensing ; Imaging Science & Photographic Technology
WOS类目	Remote Sensing ; Imaging Science & Photographic Technology
WOS记录号	WOS:000310208000010
WOS关键词	MONTE-CARLO SIMULATIONS ; TEMPERATURE DIFFERENCE ; OCEANIC WHITECAPS ; DENSE MEDIA ; WIND-SPEED ; WATER ; FREQUENCIES ; BUBBLES ; SURFACE
WOS标题词	Science & Technology ; Technology
引用统计	被引频次：11[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/16405
专题	海洋环流与波动重点实验室
通讯作者	Wei, EB
作者单位	Chinese Acad Sci, Inst Oceanol, Qingdao 266071, Peoples R China
推荐引用方式 GB/T 7714	Wei, En-Bo,Wei, EB. Effective medium approximation model of sea foam layer microwave emissivity of a vertical profile[J]. INTERNATIONAL JOURNAL OF REMOTE SENSING,2013,34(4):1180-1193.
APA	Wei, En-Bo,&Wei, EB.(2013).Effective medium approximation model of sea foam layer microwave emissivity of a vertical profile.INTERNATIONAL JOURNAL OF REMOTE SENSING,34(4),1180-1193.
MLA	Wei, En-Bo,et al."Effective medium approximation model of sea foam layer microwave emissivity of a vertical profile".INTERNATIONAL JOURNAL OF REMOTE SENSING 34.4(2013):1180-1193.

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