Assessment of surface winds over the Atlantic, Indian, and Pacific Ocean sectors of the Southern Ocean in CMIP5 models: historical bias, forcing response, and state dependence
Assessment of surface winds over the Atlantic, Indian, and Pacific Ocean sectors of the Southern Ocean in CMIP5 models: historical bias, forcing response, and state dependence
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DOI：
10.1002/jgrd.50153
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发表时间：
2013-01-27
影响因子：
4.4
通讯作者：
Wilcox, Laura J.
中科院分区：
文献类型：
--
作者：
Bracegirdle, Thomas J.;Shuckburgh, Emily;Wilcox, Laura J.
对第五个耦合模式比较计划(CMIP5)模式对南大洋大西洋、印度洋和太平洋地区近地表西风急流位置和强度的模拟进行了评估。与再分析气候学相比，纬向平均急流的整体平均位置有3.3度的赤道偏差(模式间标准差为+/-1.9度)。总体平均强度偏弱，太平洋偏强最大(-1.4m/-1.2m/S，-19%)。对仅有大气的(AMIP)实验的分析表明，28%的纬向平均位置偏差来自海洋/冰模式与大气的耦合。对未来排放情景(RCP4.5和RCP8.5)的响应分为两个阶段：(I)臭氧恢复最快的时期(2000-2049年)，在此期间夏季变化不大；(Ii)2050-2098年期间，RCP4.5模拟没有显著变化，但RCP8.5模拟显示极移(大西洋、印度和太平洋地区分别为0.33、0.18和0.27度/十)，强度增加(分别为0.07、0.08和0.15米/S/十)。具有较大赤道位置偏差的模型通常显示较大的极移(即，状态依赖)。这种模式间关系在太平洋地区最强(r=-0.91)，在大西洋地区最弱(r=-0.39)。对急流结构的评估表明，在大西洋地区，急流转移与急流结构指数没有明显的联系，而在太平洋地区，副极地和副热带西风急流之间的距离似乎很重要。引用：Bracegirdle，T.J.，E.Shuckburgh，J.-B.Sallee，Z.Wang，A.J.S.Meijers，N.Bruneau，T.Phillips，and L.J.Wilcox(2013)，在CMIP5模式中评估南大洋大西洋、印度洋和太平洋部分的地面风：历史偏见、强迫反应和国家依赖性，地球物理杂志。大气研究，118547562，DOI：10.1002/jgrd.50153。
An assessment of the fifth Coupled Models Intercomparison Project (CMIP5) models' simulation of the near-surface westerly wind jet position and strength over the Atlantic, Indian and Pacific sectors of the Southern Ocean is presented. Compared with reanalysis climatologies there is an equatorward bias of 3.3 degrees (inter-model standard deviation of +/- 1.9 degrees) in the ensemble mean position of the zonal mean jet. The ensemble mean strength is biased slightly too weak, with the largest biases over the Pacific sector (-1.4 +/- 1.2 m/s, -19%). An analysis of atmosphere-only (AMIP) experiments indicates that 28% of the zonal mean position bias comes from coupling of the ocean/ice models to the atmosphere. The response to future emissions scenarios (RCP4.5 and RCP8.5) is characterized by two phases: (i) the period of most rapid ozone recovery (2000-2049) during which there is insignificant change in summer; and (ii) the period 2050-2098 during which RCP4.5 simulations show no significant change but RCP8.5 simulations show poleward shifts (0.33, 0.18 and 0.27 degrees/decade over the Atlantic, Indian and Pacific sectors, respectively), and increases in strength (0.07, 0.08 and 0.15 m/s/decade, respectively). The models with larger equatorward position biases generally show larger poleward shifts (i. e. state dependence). This inter-model relationship is strongest over the Pacific sector (r = -0.91) and weakest over the Atlantic sector (r = -0.39). An assessment of jet structure shows that over the Atlantic sector jet shift is not clearly linked to indices of jet structure whereas over the Pacific sector the distance between the sub-polar and sub-tropical westerly jets appears to be important. Citation: Bracegirdle, T. J., E. Shuckburgh, J.-B. Sallee, Z. Wang, A. J. S. Meijers, N. Bruneau, T. Phillips, and L. J. Wilcox (2013), Assessment of surface winds over the Atlantic, Indian, and Pacific Ocean sectors of the Southern Ocean in CMIP5 models: historical bias, forcing response, and state dependence, J. Geophys. Res. Atmos., 118, 547 562, doi:10.1002/jgrd.50153.