DOI: 10.5194/cp-10-377-2014
Scopus记录号: 2-s2.0-84896853748
论文题名: What controls the isotopic composition of Greenland surface snow?
作者: Steen-Larsen H.C. ; Masson-Delmotte V. ; Hirabayashi M. ; Winkler R. ; Satow K. ; Prié F. ; Bayou N. ; Brun E. ; Cuffey K.M. ; Dahl-Jensen D. ; Dumont M. ; Guillevic M. ; Kipfstuhl S. ; Landais A. ; Popp T. ; Risi C. ; Steffen K. ; Stenni B. ; Sveinbjörnsdottír A.E.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2014
卷: 10, 期: 1 起始页码: 377
结束页码: 392
语种: 英语
Scopus关键词: air mass
; data interpretation
; ice core
; isotopic composition
; metamorphism
; paleoclimate
; precipitation (climatology)
; recrystallization
; snowmelt
; stable isotope
; Arctic
; Greenland
英文摘要: Water stable isotopes in Greenland ice core data provide key paleoclimatic information, and have been compared with precipitation isotopic composition simulated by isotopically enabled atmospheric models. However, post-depositional processes linked with snow metamorphism remain poorly documented. For this purpose, monitoring of the isotopic composition (δ18O, δD) of near-surface water vapor, precipitation and samples of the top (0.5 cm) snow surface has been conducted during two summers (2011-2012) at NEEM, NW Greenland. The samples also include a subset of 17O-excess measurements over 4 days, and the measurements span the 2012 Greenland heat wave. Our observations are consistent with calculations assuming isotopic equilibrium between surface snow and water vapor. We observe a strong correlation between near-surface vapor δ18O and air temperature (0.85 ± 0.11‰ °C-1 (R = 0.76) for 2012). The correlation with air temperature is not observed in precipitation data or surface snow data. Deuterium excess (d-excess) is strongly anti-correlated with δ18O with a stronger slope for vapor than for precipitation and snow surface data. During nine 1-5-day periods between precipitation events, our data demonstrate parallel changes of δ18O and d-excess in surface snow and near-surface vapor. The changes in δ18O of the vapor are similar or larger than those of the snow δ18O. It is estimated using the CROCUS snow model that 6 to 20% of the surface snow mass is exchanged with the atmosphere. In our data, the sign of surface snow isotopic changes is not related to the sign or magnitude of sublimation or deposition. Comparisons with atmospheric models show that day-to-day variations in near-surface vapor isotopic composition are driven by synoptic variations and changes in air mass trajectories and distillation histories. We suggest that, in between precipitation events, changes in the surface snow isotopic composition are driven by these changes in near-surface vapor isotopic composition. This is consistent with an estimated 60% mass turnover of surface snow per day driven by snow recrystallization processes under NEEM summer surface snow temperature gradients. Our findings have implications for ice core data interpretation and model-data comparisons, and call for further process studies. © Author(s) 2014. 资助项目: NERC, Natural Environment Research Council
; NSF, National Science Foundation
; OPP, Office of Polar Programs
; AXA Research Fund
Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49307
Appears in Collections: 气候变化与战略
There are no files associated with this item.
Recommended Citation:
Steen-Larsen H.C.,Masson-Delmotte V.,Hirabayashi M.,et al. What controls the isotopic composition of Greenland surface snow?[J]. Climate of the Past,2014-01-01,10(1)