A 31-year Global Diurnal Sea Surface Temperature Dataset Created by an Ocean Mixed-Layer Model

Abstract

A dataset of hourly sea surface temperature (SST) from the period 1 January 1982 to 31 December 2012, and covering the global ocean at a resolution of 0.3° × 0.3°, was created using a validated ocean mixed-layer model (MLSST). The model inputs were heat flux and surface wind speed obtained from the Coupled Forecast System Reanalysis dataset. Comparisons with in-situ data from the Tropical Atmosphere Ocean array and the National Data Buoy Center showed that the MLSST fitted very well with observations, with a mean bias of 0.07°C, and a root-mean-square error (RMSE) and correlation coefficient of 0.37°C and 0.98, respectively. Also, the MLSST fields successfully reproduced the diurnal cycle of SST in the in-situ data, with a mean bias of −0.005°C and RMSE of 0.26°C. The 31-year climatology revealed that the diurnal range was small across most regions, with higher values in the eastern and western equatorial Pacific, northern Indian Ocean, western Central America, northwestern Australia, and several coastal regions. Significant seasonal variation of diurnal SST existed in all basins. In the Atlantic and Pacific basins, this seasonal pattern was oriented north–south, following the variation in solar insolation, whereas in the Indian basin it was dominated by monsoonal variability. At the interannual scale, the results highlighted the relationship between diurnal and interannual variations of SST, and revealed that the diurnal warming in the central equatorial Pacific could be a potential climatic indicator for ENSO prediction.

摘 要

本文利用一个改进的海洋混合层模式制作了一套逐小时的全球高分辨率海表温度(SST)数据. 该数据的水平分辨率为 0.3° × 0.3°, 时间从 1982 年 1 月 1 日到 2012 年 12 月 31 日共 31年. 混合层模式的输入场为 NCEP 耦合预报系统再分析数据(CFSR)的热通量及表面风速. 与热带大气海洋观测计划(TAO)及美国国家数据浮标中心(NDBC)的浮标观测数据对比表明, 该数据的逐时 SST 与浮标观测较为一致, 平均的误差为 0.07°C, 均方根误差为 0.37°C, 相关系数为 0.98. 进一步对比发现, 逐时SST数据很好的再现了浮标观测中的 SST 的日变化特征, SST 日变化的平均误差为 -0.005°C, 均方根误差为 0.26°C. 在气候尺度上, 该数据的 SST 日变化的气候态特征表明, 在全球绝大部分海域, SST 日变化幅度较小, 主要的大值区集中在东西赤道太平洋, 北印度洋, 中美洲西部海域, 澳大利亚西北部海域以及一些沿岸近海海域. 在季节尺度上, 各个海盆的 SST 日变化均表现出显著的季节变化特征. 在大西洋及太平洋海域, 受太阳短波辐射季节变化的影响, SST 日变化随季节呈南北移动的特征; 但在印度洋海域, SST 日变化的季节变化特征主要受季风的调控. 在年际尺度上, SST 日变化与 SST 的年际变率存在着潜在的联系, 其中赤道中太平洋 SST 日变化偏暖现象可能是 ENSO 预测的一个潜在因子.