DOI: 10.5194/tc-10-727-2016
Scopus记录号: 2-s2.0-84964047114
论文题名: A Retrospective, Iterative, Geometry-Based (RIGB) tilt-correction method for radiation observed by automatic weather stations on snow-covered surfaces: Application to Greenland
作者: Wang W ; , Zender C ; S ; , Van As D ; , Smeets P ; C ; J ; P ; , Van Den Broeke M ; R
刊名: Cryosphere
ISSN: 19940416
出版年: 2016
卷: 10, 期: 2 起始页码: 727
结束页码: 741
语种: 英语
英文关键词: albedo
; climate change
; cloud radiative forcing
; data set
; energy budget
; geometry
; model validation
; satellite
; shortwave radiation
; surface energy
; weather station
; Arctic
; Greenland
; Greenland Ice Sheet
; Kangerlussuaq Fjord
英文摘要: Surface melt and mass loss of the Greenland Ice Sheet may play crucial roles in global climate change due to their positive feedbacks and large fresh-water storage. With few other regular meteorological observations available in this extreme environment, measurements from automatic weather stations (AWS) are the primary data source for studying surface energy budgets, and for validating satellite observations and model simulations. Station tilt, due to irregular surface melt, compaction and glacier dynamics, causes considerable biases in the AWS shortwave radiation measurements. In this study, we identify tilt-induced biases in the climatology of surface shortwave radiative flux and albedo, and retrospectively correct these by iterative application of solar geometric principles. We found, over all the AWS from the Greenland Climate Network (GC-Net), the Kangerlussuaq transect (K-transect) and the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) networks, insolation on fewer than 40% of clear days peaks within ±0.5h of solar noon time, with the largest shift exceeding 3h due to tilt. Hourly absolute biases in the magnitude of surface insolation can reach up to 200W m-2, with respect to the well-understood clear-day insolation. We estimate the tilt angles and their directions based on the solar geometric relationship between the simulated insolation at a horizontal surface and the observed insolation by these tilted AWS under clear-sky conditions. Our adjustment reduces the root mean square error (RMSE) against references from both satellite observation and reanalysis by 16W m-2 (24%), and raises the correlation coefficients with them to above 0.95. Averaged over the whole Greenland Ice Sheet in the melt season, the adjustment in insolation to compensate station tilt is ∼ 11W m-2, enough to melt 0.24m of snow water equivalent. The adjusted diurnal cycles of albedo are smoother, with consistent semi-smiling patterns. The seasonal cycles and inter-annual variabilities of albedo agree better with previous studies. This tilt-corrected shortwave radiation data set derived using the Retrospective, Iterative, Geometry-Based (RIGB) method provide more accurate observations and validations for surface energy budgets studies on the Greenland Ice Sheet, including albedo variations, surface melt simulations and cloud radiative forcing estimates. © Author(s) 2016. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75163
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Department of Earth System Science, University of California, Irvine, CA, United States; Geological Survey of Denmark and Greenland (GEUS), Copenhagen, Denmark; Institute for Marine and Atmospheric Research, Utrecht University (UU/IMAU), Utrecht, Netherlands
Recommended Citation:
Wang W,, Zender C,S,et al. A Retrospective, Iterative, Geometry-Based (RIGB) tilt-correction method for radiation observed by automatic weather stations on snow-covered surfaces: Application to Greenland[J]. Cryosphere,2016-01-01,10(2)