Projected sea surface temperatures over the 21st century: Changes in the mean, variability and extremes for large marine ecosystem regions of Northern Oceans
Projected sea surface temperatures over the 21st century: Changes in the mean, variability and extremes for large marine ecosystem regions of Northern Oceans
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DOI：
10.1525/elementa.191
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发表时间：
2018-01-26
影响因子：
3.9
通讯作者：
Thomas, Andrew C.
中科院分区：
文献类型：
--
作者：
Alexander, Michael A.;Scott, James D.;Thomas, Andrew C.
全球气候模式被用于评估北方海洋的平均、变率和极端海表温度的变化，重点是邻近北美、欧洲和北冰洋的大型海洋生态系统。结果来自社区模型相互比较项目第5阶段（CMIP 5）档案中的26个模型和国家大气研究中心大型Enclosure社区项目（CESM-LENS）的30个模拟。所有的模拟都使用了1976-2005年观测到的温室气体浓度和RCP8.5“一切照旧”的21世纪剩余时间温室气体情景。一般来说，模式之间的差异远大于CESM-LENS模拟之间的差异，表明SST变化受模式制定的影响比内部气候变率更大。1976-2099年，18个大海洋生态系统的年SST趋势均为正值，变化范围为0.05 - 0.5 ℃（-1）。世纪末SST的变化主要是由于大多数大海洋生态系统的平均值出现正移，变异性变化不大，导致极端温暖事件大幅增加，极端寒冷事件减少。平均值的变化是如此之大，以至于在许多地区，2070-2099年的SST将始终比1976-2005年最热的一年温暖。夏季的SST趋势通常比冬季强，因为夏季的温室气体加热比冬季的气候混合层深度要浅得多，这放大了21世纪SST的季节性循环。在北极，平均SST及其变率在夏季无冰时大幅增加，但在冬季当一层薄冰重新形成且SST保持在冰点附近时不会增加。
Global climate models were used to assess changes in the mean, variability and extreme sea surface temperatures (SSTs) in northern oceans with a focus on large marine ecosystems (LMEs) adjacent to North America, Europe, and the Arctic Ocean. Results were obtained from 26 models in the Community Model Intercomparison Project Phase 5 (CMIP5) archive and 30 simulations from the National Center for Atmospheric Research Large Ensemble Community Project (CESM-LENS). All of the simulations used the observed greenhouse gas concentrations for 1976-2005 and the RCP8.5 "business as usual" scenario for greenhouse gases through the remainder of the 21st century. In general, differences between models are substantially larger than among the simulations in the CESM-LENS, indicating that the SST changes are more strongly affected by model formulation than internal climate variability. The annual SST trends over 1976-2099 in the 18 LMEs examined here are all positive ranging from 0.05 to 0.5 degrees C decade(-1). SST changes by the end of the 21st century are primarily due to a positive shift in the mean with only modest changes in the variability in most LMEs, resulting in a substantial increase in warm extremes and decrease in cold extremes. The shift in the mean is so large that in many regions SSTs during 2070-2099 will always be warmer than the warmest year during 1976-2005. The SST trends are generally stronger in summer than in winter, as greenhouse gas heating is integrated over a much shallower climatological mixed layer depth in summer than in winter, which amplifies the seasonal cycle of SST over the 21st century. In the Arctic, the mean SST and its variability increases substantially during summer, when it is ice free, but not during winter when a thin layer of ice reforms and SSTs remain near the freezing point.