气候变化领域集成服务门户(CCPortal): Comparison of ERA5 and ERA-Interim near-surface air temperature, snowfall and precipitation over Arctic sea ice: effects on sea ice thermodynamics and evolution

CCPortal

DOI	10.5194/tc-13-1661-2019
	Comparison of ERA5 and ERA-Interim near-surface air temperature, snowfall and precipitation over Arctic sea ice: effects on sea ice thermodynamics and evolution
	Wang C.; Graham R.M.; Wang K.; Gerland S.; Granskog M.A.
发表日期	2019
ISSN	19940416
EISSN	13
起始页码	1661
结束页码	1679
卷号	13 期号:6
英文摘要	Rapid changes are occurring in the Arctic, including a reduction in sea ice thickness and coverage and a shift towards younger and thinner sea ice. Snow and sea ice models are often used to study these ongoing changes in the Arctic, and are typically forced by atmospheric reanalyses in absence of observations. ERA5 is a new global reanalysis that will replace the widely used ERA-Interim (ERA-I). In this study, we compare the 2 m air temperature (T2M), snowfall (SF) and total precipitation (TP) from ERA-I and ERA5, and evaluate these products using buoy observations from Arctic sea ice for the years 2010 to 2016. We further assess how biases in reanalyses can influence the snow and sea ice evolution in the Arctic, when used to force a thermodynamic sea ice model. We find that ERA5 is generally warmer than ERA-I in winter and spring (0-1.2 C), but colder than ERA-I in summer and autumn (0-0.6 C) over Arctic sea ice. Both reanalyses have a warm bias over Arctic sea ice relative to buoy observations. The warm bias is smaller in the warm season, and larger in the cold season, especially when the T2M is below -25C in the Atlantic and Pacific sectors. Interestingly, the warm bias for ERA-I and new ERA5 is on average 3.4 and 5.4 C (daily mean), respectively, when T2M is lower than -25C. The TP and SF along the buoy trajectories and over Arctic sea ice are consistently higher in ERA5 than in ERA-I. Over Arctic sea ice, the TP in ERA5 is typically less than 10 mm snow water equivalent (SWE) greater than in ERA-I in any of the seasons, while the SF in ERA5 can be 50 mm SWE higher than in ERA-I in a season. The largest increase in annual TP (40-100 mm) and SF (100-200 mm) in ERA5 occurs in the Atlantic sector. The SF to TP ratio is larger in ERA5 than in ERA-I, on average 0.6 for ERA-I and 0.8 for ERA5 along the buoy trajectories. Thus, the substantial anomalous Arctic rainfall in ERA-I is reduced in ERA5, especially in summer and autumn. Simulations with a 1-D thermodynamic sea ice model demonstrate that the warm bias in ERA5 acts to reduce thermodynamic ice growth. The higher precipitation and snowfall in ERA5 results in a thicker snowpack that allows less heat loss to the atmosphere. Thus, the larger winter warm bias and higher precipitation in ERA5, compared with ERA-I, result in thinner ice thickness at the end of the growth season when using ERA5; however the effect is small during the freezing period.. © Author(s) 2019.
学科领域	air temperature; comparative study; ice thickness; one-dimensional modeling; precipitation (climatology); sea ice; snow; thermodynamics; Arctic; Atlantic Sector; Pacific Sector; Southern Ocean
语种	英语
scopus关键词	air temperature; comparative study; ice thickness; one-dimensional modeling; precipitation (climatology); sea ice; snow; thermodynamics; Arctic; Atlantic Sector; Pacific Sector; Southern Ocean
来源期刊	The Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/118874
作者单位	Department of Research and Development, Norwegian Meteorological Institute, Tromsø, 9293, Norway; Research Department, Fram Centre, Norwegian Polar Institute, P.O. Box 6606 Langnes, Tromsø, 9296, Norway
推荐引用方式 GB/T 7714	Wang C.,Graham R.M.,Wang K.,et al. Comparison of ERA5 and ERA-Interim near-surface air temperature, snowfall and precipitation over Arctic sea ice: effects on sea ice thermodynamics and evolution[J],2019,13(6).
APA	Wang C.,Graham R.M.,Wang K.,Gerland S.,&Granskog M.A..(2019).Comparison of ERA5 and ERA-Interim near-surface air temperature, snowfall and precipitation over Arctic sea ice: effects on sea ice thermodynamics and evolution.The Cryosphere,13(6).
MLA	Wang C.,et al."Comparison of ERA5 and ERA-Interim near-surface air temperature, snowfall and precipitation over Arctic sea ice: effects on sea ice thermodynamics and evolution".The Cryosphere 13.6(2019).