A new DRP-4DVar-based coupled data assimilation system for decadal predictions using a fast online localization technique
A new DRP-4DVar-based coupled data assimilation system for decadal predictions using a fast online localization technique
复制标题
一种基于 DRP-4DVar 的新型耦合数据同化系统，使用快速在线定位技术进行年代际预测
DOI：
10.1007/s00382-020-05190-w
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发表时间：
2020
期刊：
影响因子：
4.6
通讯作者：
Peng Yiran
中科院分区：
文献类型：
--
作者：
He Yujun;Wang Bin;Huang Wenyu;Xu Shiming;Wang Yong;Liu Li;Li Lijuan;Liu Juanjuan;Yu Yongqiang;Lin Yanluan;Huang Xiaomeng;Peng Yiran
基于降维投影四维变分资料同化(DRP-4DVar)发展了一个新的十年预报耦合资料同化(CDA)系统，并应用于一个采用快速在线定位技术的FGOALS-G2全耦合模式。改进后的CDA系统比原系统同化了更多的观测信息，观测代价函数的降幅更大，全球平均海洋温度和盐度的偏差和均方根误差(RMSE)更小。与原系统和未初始化的模拟相比，新的CDA系统能更好地再现太平洋和大西洋的同化气候变化，如厄尔尼诺-南方涛动(ENSO)、太平洋年代际涛动(PDO)、北太平洋指数(NPI)、太平洋-北美遥相关(PNA)和大西洋多年代际涛动(AMO)。大西洋经向翻转环流(AMOC)比以往的系统得到了更好的描述。在将初始条件的气候学部分恢复到模式的气候学以消除初始激波后，从1961年到1996年，每年都会开始十人十年预报试验。新系统对北太平洋、大西洋、印度洋和欧亚大陆近地面气温异常的年代际预报能力比CDA系统、持续性和未初始化模拟的高。
A new coupled data assimilation (CDA) system based on dimension-reduced projection four-dimensional variational data assimilation (DRP-4DVar) for decadal predictions is developed and applied to a fully coupled model FGOALS-g2, which applies a fast online localization technique. The improved CDA system can assimilate more observational information than the previous system, with a larger reduction in the observational cost function and smaller biases and root mean square errors (RMSEs) in global mean ocean temperature and salinity. The assimilated climate variabilities in the Pacific and Atlantic, such as El Nino-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), North Pacific index (NPI), Pacific-North American teleconnection (PNA) and Atlantic Multi-decadal Oscillation (AMO), are generally better reproduced by the new CDA system compared to the previous system and the uninitialized simulation. The Atlantic meridional overturning circulation (AMOC) is better described than the previous system. After partially restoring the climatology of the initial condition to that of the model to relieve the initial shock, ten-member decadal prediction experiments are started each year from 1961 to 1996. Higher decadal prediction skills of near-surface air temperature anomalies over the North Pacific, the Atlantic, and the Indian Oceans and the Eurasia Continent are achieved by the new system compared to those obtained by the previous CDA system, persistence and the uninitialized simulation.