气候变化领域集成服务门户(CCPortal): Synthetic aperture radar (SAR) detects large gas seeps in Alaska lakes

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DOI	10.1088/1748-9326/ad2b2a
	Synthetic aperture radar (SAR) detects large gas seeps in Alaska lakes
	Engram, Melanie; Anthony, Katey Walter
发表日期	2024
ISSN	1748-9326
起始页码	19
结束页码	4
卷号	19 期号:4
英文摘要	Reservoirs of C-14-depleted methane (CH4), a potent greenhouse gas, residing beneath permafrost are vulnerable to escape where permafrost thaw creates open-talik conduits. However, little is known about the magnitude and variability of this methane source or its response to climate change. Remote-sensing detection of large gas seeps would be useful for establishing a baseline understanding of sub-permafrost methane seepage, as well as for monitoring these seeps over time. Here we explored synthetic aperture radar's (SAR) response to large sub-permafrost gas seeps in an interior Alaskan lake. In SAR scenes from 1992 to 2011, we observed high perennial SAR L-band backscatter (sigma(0)) from a similar to 90 m-wide feature in the winter ice of interior Alaska's North Blair Lake (NBL). Spring and fall optical imagery showed holes in the ice at the same location as the SAR anomaly. Through field work we (1) confirmed gas bubbling at this location from a large pockmark in the lakebed, (2) measured flux at the location of densest bubbles (1713 +/- 290 mg CH4 m(-2) d(-1)), and (3) determined the bubbles' methane mixing ratio (6.6%), radiocarbon age (18 470 +/- 50 years BP), and delta C-13(CH4) values (-44.5 +/- 0.1 parts per thousand), which together may represent a mixture of sources and processes. We performed a first order comparison of SAR sigma(0) from the NBL seep and other known sub-permafrost methane seeps with diverse ice/water interface shapes in order to evaluate the variability of SAR signals from a variety of seep types. Results from single-polarized intensity and polarimetric L-band SAR decompositions as well as dual-polarized C-band SAR are presented with the aim to find the optimal SAR imaging parameters to detect large methane seeps in frozen lakes. Our study indicates the potential for SAR remote sensing to be used to detect and monitor large, sub-permafrost gas seeps in Arctic and sub-Arctic lakes.
英文关键词	synthetic aperture radar; SAR; lake; methane; ebullition; geologic seep; C-14-depleted methane
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS类目	Environmental Sciences ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:001188028600001
来源期刊	ENVIRONMENTAL RESEARCH LETTERS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/304518
作者单位	University of Alaska System; University of Alaska Fairbanks
推荐引用方式 GB/T 7714	Engram, Melanie,Anthony, Katey Walter. Synthetic aperture radar (SAR) detects large gas seeps in Alaska lakes[J],2024,19(4).
APA	Engram, Melanie,&Anthony, Katey Walter.(2024).Synthetic aperture radar (SAR) detects large gas seeps in Alaska lakes.ENVIRONMENTAL RESEARCH LETTERS,19(4).
MLA	Engram, Melanie,et al."Synthetic aperture radar (SAR) detects large gas seeps in Alaska lakes".ENVIRONMENTAL RESEARCH LETTERS 19.4(2024).