Impact of different ocean reanalyses on decadal climate prediction
Impact of different ocean reanalyses on decadal climate prediction
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不同海洋再分析对十年间气候预测的影响
DOI：
10.1007/s00382-012-1310-7
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发表时间：
2010
期刊：
影响因子：
4.6
通讯作者：
Jin
中科院分区：
文献类型：
--
作者：
J. Kröger;W. Müller;Jin
我们研究了三种海洋状态估计(GECCO，SODA，[ECMWF]-ORA-S3)对一个特定预报系统--汉堡马克斯·普朗克气象研究所的地球系统模型--年代际可预测性的影响。预报程序分两步进行。首先，观测估计的温度和盐度的异常被同化到我们的耦合模式中。其次，同化运行然后被用来初始化从1960年到2001年的每一年开始的长达10年的事后预报/预报。评估单个海洋状态估计的影响，既取决于预报系统采用海洋状态估计的气候变化的程度(“保真度”)，也取决于相应的后播实验的预测技巧。评估的重点是北大西洋(NA)海表面温度(SST)、高层(0-700米)NA海洋热含量(OHC)和大西洋经向翻转环流(MOC)。在保真度方面，除了GECCO同化中的NA OHC外，对于NA SST和NA OHC，观测值与同化运行之间的相关性一般都很高。当GECCO和苏打被同化时，MOC的变化经历了强烈的修改，而当同化ORA-S3时，MOC的变化就更小了。在预报技巧方面，当使用ORA-S3和SODA进行初始化时，NAOHC与观测值的相关性很高，而NA SST与观测的相关性中等。另一方面，在GECCO的情况下，NA SST的相关性很高，而NA OHC的相关性中等。在热带和亚热带的GECCO和50N以北的ORA-S3的前五年，后遗症与各自的同化运行之间的MOC相关性相对较高。当MOC信号去趋势时，相关性大大降低。同化运行的趋势在某种程度上是同化过程的产物。因此，我们对交通部的潜在可预测性是对可预测性上限的乐观估计。然而，从同化过程的总体保真度和对北大西洋高层OHC的预测来看，ORA-S3再分析为我们的预报系统提供了最好的结果。
We study the impact of three ocean state estimates (GECCO, SODA, [ECMWF]-ORA-S3) on decadal predictability in one particular forecast system, the Earth system model from the Max Planck Institute for Meteorology in Hamburg. The forecast procedure follows two steps. First, anomalies of temperature and salinity of the observational estimates are assimilated into our coupled model. Second, the assimilation runs are then used to initialize 10-year-long hindcasts/forecasts starting from each year between 1960 and 2001. The impact of the individual ocean state estimates is evaluated both by the extent to which climate variations from the ocean state estimates are adopted by the forecast system (‘fidelity’) and by the prediction skill of the corresponding hindcast experiments. The evaluation focuses on North Atlantic (NA) sea surface temperature (SST), upper-level (0–700 m) NA ocean heat content (OHC) and the Atlantic meridional overturning circulation (MOC). Regarding fidelity, correlations between observations and the assimilation runs are generally high for NA SST and NA OHC, except for NA OHC in the GECCO assimilation. MOC variations experience strong modifications when GECCO and SODA are assimilated, much less so when assimilating ORA-S3. Regarding prediction skill, when initializing with ORA-S3 and SODA, correlations with observations are high for NA OHC and moderate for NA SST. Correlations in case of GECCO, on the other hand, are high for NA SST and moderate for NA OHC. Relatively high MOC correlations between hindcasts and respective assimilation run appear in the first five years in GECCO in the tropics and subtropics and in ORA-S3 north of 50N. Correlations are largely reduced when the MOC signals are detrended. The trends in the assimilation runs are to some extent artifacts of the assimilation procedure. Hence, our potential predictabilities of the MOC are optimistic estimates of the upper limits of predictability. However, the ORA-S3 reanalysis gives the best results for our forecast system as measured by both overall fidelity of the assimilation procedure and predictions of upper-level OHC in the North Atlantic.