气候变化领域集成服务门户(CCPortal): Dual-satellite (Sentinel-2 and Landsat 8) remote sensing of supraglacial lakes in Greenland

CCPortal

DOI	10.5194/tc-12-3045-2018
	Dual-satellite (Sentinel-2 and Landsat 8) remote sensing of supraglacial lakes in Greenland
	Williamson A.G.; Banwell A.F.; Willis I.C.; Arnold N.S.
发表日期	2018
ISSN	19940416
卷号	12 期号:9
英文摘要	Remote sensing is commonly used to monitor supraglacial lakes on the Greenland Ice Sheet (GrIS); however, most satellite records must trade off higher spatial resolution for higher temporal resolution (e.g. MODIS) or vice versa (e.g. Landsat). Here, we overcome this issue by developing and applying a dual-sensor method that can monitor changes to lake areas and volumes at high spatial resolution (10-30 m) with a frequent revisit time ( ~ 3 days). We achieve this by mosaicking imagery from the Landsat 8 Operational Land Imager (OLI) with imagery from the recently launched Sentinel-2 Multispectral Instrument (MSI) for a ~ 12 000 km2 area of West Greenland in the 2016 melt season. First, we validate a physically based method for calculating lake depths with Sentinel-2 by comparing measurements against those derived from the available contemporaneous Landsat 8 imagery; we find close correspondence between the two sets of values (R2 Combining double low line 0.841; RMSE Combining double low line 0.555 m). This provides us with the methodological basis for automatically calculating lake areas, depths, and volumes from all available Landsat 8 and Sentinel-2 images. These automatic methods are incorporated into an algorithm for Fully Automated Supraglacial lake Tracking at Enhanced Resolution (FASTER). The FASTER algorithm produces time series showing lake evolution during the 2016 melt season, including automated rapid ( ≤ 4 day) lake-drainage identification. With the dual Sentinel-2-Landsat 8 record, we identify 184 rapidly draining lakes, many more than identified with either imagery collection alone (93 with Sentinel-2; 66 with Landsat 8), due to their inferior temporal resolution, or would be possible with MODIS, due to its omission of small lakes < 0.125 km2. Finally, we estimate the water volumes drained into the GrIS during rapid-lake-drainage events and, by analysing downscaled regional climate-model (RACMO2.3p2) run-off data, the water quantity that enters the GrIS via the moulins opened by such events. We find that during the lake-drainage events alone, the water drained by small lakes ( < 0.125 km2) is only 5.1 % of the total water volume drained by all lakes. However, considering the total water volume entering the GrIS after lake drainage, the moulins opened by small lakes deliver 61.5 % of the total water volume delivered via the moulins opened by large and small lakes; this is because there are more small lakes, allowing more moulins to open, and because small lakes are found at lower elevations than large lakes, where run-off is higher. These findings suggest that small lakes should be included in future remote-sensing and modelling work. © 2018 All rights reserved.
语种	英语
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/119063
作者单位	Scott Polar Research Institute, University of Cambridge, Cambridge, United Kingdom; Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, United States
推荐引用方式 GB/T 7714	Williamson A.G.,Banwell A.F.,Willis I.C.,et al. Dual-satellite (Sentinel-2 and Landsat 8) remote sensing of supraglacial lakes in Greenland[J],2018,12(9).
APA	Williamson A.G.,Banwell A.F.,Willis I.C.,&Arnold N.S..(2018).Dual-satellite (Sentinel-2 and Landsat 8) remote sensing of supraglacial lakes in Greenland.Cryosphere,12(9).
MLA	Williamson A.G.,et al."Dual-satellite (Sentinel-2 and Landsat 8) remote sensing of supraglacial lakes in Greenland".Cryosphere 12.9(2018).