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Duration and seasonality of hourly extreme rainfall in the Central Eastern China

ISSN号：0894-0525
期刊名称：Acta Meteorologica Sinica
时间：2013.12.15
页码：799-807
分类：P731.15[天文地球—海洋科学]
作者机构：[1]南京信息工程大学气象灾害教育部重点实验室,江苏南京210044
相关基金：国家重点基础研究发展计划（973计划）（2012CB417403）；国家自然科学基金创新群体项目（41221064）；长江学者和创新团队发展计划资助（PCSIRT ）；江苏高校优势学科建设工程资助项目（PAPD）；江苏省研究生培养创新工程（N0782002113）。
相关项目：东亚副热带季风变异机理

关键词：北极海冰消融, 北极增温, 季节差异, 延迟放热, Arctic＇s rapidly shrinking sea ice, Arctic warming, seasonal difference, delayed warming effect

中文摘要：

运用哈德莱中心第一套海冰覆盖率（HadISST1）、欧洲中心（ERA＿Interim）的温度以及NCEP第一套地表感热通量、潜热通量等资料，研究了1979-2011年33 a来北极海冰消融的季节特点和空间特征，并从反照率---温度正反馈与地表感热通量、潜热通量等方面分析了海冰减少对北极增温影响的季节差异。结果表明，北极海冰在秋季和夏季的减少范围明显大于冬季和春季，而北极地表升温却在秋季和冬季最显著，夏季最为微弱，且夏季的增温趋势廓线也与秋冬季显著不同。这主要是因为夏季是融冰季，海冰融化将吸收潜热。且此时北极低空大气温度高于海表温度，海水相当于大气的冷源。随着海冰的消融，更多的热量由大气传入海洋用于融冰和加热上层海水，这使得夏季的低空大气不能显著升温。而在秋冬季，海冰凝结释放潜热，且此时低空大气温度远低于海水温度，海冰的减少使得海水将更多热量释放到大气中导致低空大气显著增暖。海水对大气的这种延迟放热机制是北极低空在夏季增温不显著而在秋冬季增温显著的主要原因。此外，秋冬季的海冰减少与北极近地面升温具有非常一致的空间分布，北冰洋东南边缘和巴伦支海北部分别是秋季和冬季海气相互作用的关键区域。

英文摘要：

The sea ice concentration data ,atmospheric temperature data and surface sensible and latent heat net flux data from HadISST1 ,ERA-Interim and NCEP respectively are examined to investigate the seasonal and spatial distribution variation of the diminishing Arctic sea ice from 1979 to 2011 .Moreover ,the seasonal atmospheric tem-perature change responding to Arctic sea ice loss are discussed by analyzing surface albedo feedback ,surface sensi-ble and latent heat net flux .Results show that the strongest surface warming occurs in winter and fall and the lar-gest sea ice reduction takes place in summer and fall .Note that the weakest surface warming occurs in summer . This is principally due to the sea ice melt in summer which absorbs latent heat and the warmer lower atmosphere than ocean surface .With the decreasing sea ice ,more heat is transferred from the atmosphere to ocean leading to the ice-melt and upper level sea temperature warming .As a result ,the near-surface warming is modest in summer . By contrast ,sea ice refreezes in winter and fall and releases latent heat .Meanwhile ,less ice cover causes more heat transferred from ocean to atmosphere which warms the low level air .This delayed warming effect plays an impor-tant role in the different seasonal air temperature change in Arctic .Besides ,the regions of largest warming are co-located with those of greatest sea ice reductions .The southeast Arctic and northern Barents Sea are the key areas of the air-sea interaction in fall and winter ,respectively .