气候变化领域集成服务门户(CCPortal): An assessment of two automated snow water equivalent instruments during the WMO Solid Precipitation Intercomparison Experiment

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DOI	10.5194/tc-11-101-2017
	An assessment of two automated snow water equivalent instruments during the WMO Solid Precipitation Intercomparison Experiment
	Smith C.D.; Kontu A.; Laffin R.; Pomeroy J.W.
发表日期	2017
ISSN	19940416
卷号	11 期号:1
英文摘要	During the World Meteorological Organization (WMO) Solid Precipitation Intercomparison Experiment (SPICE), automated measurements of snow water equivalent (SWE) were made at the Sodankylä (Finland), Weissfluhjoch (Switzerland) and Caribou Creek (Canada) SPICE sites during the northern hemispheric winters of 2013/14 and 2014/15. Supplementary intercomparison measurements were made at Fortress Mountain (Kananaskis, Canada) during the 2013/14 winter. The objectives of this analysis are to compare automated SWE measurements with a reference, comment on their performance and, where possible, to make recommendations on how to best use the instruments and interpret their measurements. Sodankylä, Caribou Creek and Fortress Mountain hosted a Campbell Scientific CS725 passive gamma radiation SWE sensor. Sodankylä and Weissfluhjoch hosted a Sommer Messtechnik SSG1000 snow scale. The CS725 operating principle is based on measuring the attenuation of soil emitted gamma radiation by the snowpack and relating the attenuation to SWE. The SSG1000 measures the mass of the overlying snowpack directly by using a weighing platform and load cell. Manual SWE measurements were obtained at the intercomparison sites on a bi-weekly basis over the accumulation-Ablation periods using bulk density samplers. These manual measurements are considered to be the reference for the intercomparison. Results from Sodankylä and Caribou Creek showed that the CS725 generally overestimates SWE as compared to manual measurements by roughly 30-35ĝ€-% with correlations (r2) as high as 0.99 for Sodankylä and 0.90 for Caribou Creek. The RMSE varied from 30 to 43ĝ€-mm water equivalent (mmĝ€-w.e.) and from 18 to 25ĝ€-mmĝ€-w.e. at Sodankylä and Caribou Creek, which had respective SWE maximums of approximately 200 and 120ĝ€-mmĝ€-w.e. The correlation at Fortress Mountain was 0.94 (RMSE of 48ĝ€-mmĝ€-w.e. with a maximum SWE of approximately 650ĝ€-mmĝ€-w.e.) with no systematic overestimation. The SSG1000 snow scale, having a different measurement principle, agreed quite closely with the manual measurements at Sodankylä and Weissfluhjoch throughout the periods when data were available (r2 as high as 0.99 and RMSE from 8 to 24ĝ€-mmĝ€-w.e. at Sodankylä and from 56 to 59ĝ€-mmĝ€-w.e. at Weissfluhjoch, where maximum SWE was approximately 850ĝ€-mmĝ€-w.e.). When the SSG1000 was compared to the CS725 at Sodankylä, the agreement was linear until the start of ablation when the positive bias in the CS725 increases substantially relative to the SSG1000. Since both Caribou Creek and Sodankylä have sandy soil, water from the snowpack readily infiltrates into the soil during melt, even if the soil is frozen. However, the CS725 does not differentiate this water from the unmelted snow. This issue can be identified, at least during the late spring ablation period, with soil moisture and temperature observations like those measured at Caribou Creek. With a less permeable soil and surface runoff, the increase in the instrument bias during ablation is not as significant, as shown by the Fortress Mountain intercomparison.
学科领域	ablation; assessment method; automation; bulk density; experimental study; gamma ray radiation; instrumentation; Northern Hemisphere; precipitation (climatology); sensor; snow water equivalent; snowpack; soil emission; soil moisture; soil temperature; Alaska; Alberta; Canada; Caribou Creek; Finland; Graubunden; Kananaskis; Lappi [Finland]; Sodankyla; Switzerland; United States; Weissfluhjoch; Rangifer tarandus
语种	英语
scopus关键词	ablation; assessment method; automation; bulk density; experimental study; gamma ray radiation; instrumentation; Northern Hemisphere; precipitation (climatology); sensor; snow water equivalent; snowpack; soil emission; soil moisture; soil temperature; Alaska; Alberta; Canada; Caribou Creek; Finland; Graubunden; Kananaskis; Lappi [Finland]; Sodankyla; Switzerland; United States; Weissfluhjoch; Rangifer tarandus
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/119463
作者单位	Environment and Climate Change Canada, Saskatoon, S7N 3H5, Canada; Finnish Meteorological Institute, Sodankylä, 99600, Finland; Campbell Scientific, Edmonton, T5L 4X4, Canada; Centre for Hydrology, University of Saskatchewan, Saskatoon, S7N 5C8, Canada
推荐引用方式 GB/T 7714	Smith C.D.,Kontu A.,Laffin R.,et al. An assessment of two automated snow water equivalent instruments during the WMO Solid Precipitation Intercomparison Experiment[J],2017,11(1).
APA	Smith C.D.,Kontu A.,Laffin R.,&Pomeroy J.W..(2017).An assessment of two automated snow water equivalent instruments during the WMO Solid Precipitation Intercomparison Experiment.Cryosphere,11(1).
MLA	Smith C.D.,et al."An assessment of two automated snow water equivalent instruments during the WMO Solid Precipitation Intercomparison Experiment".Cryosphere 11.1(2017).