Correlations Between Top-of-atmosphere Net Radiation and Ocean Heat Content

Abstract:

The relationships between observed monthly mean top-of-atmosphere net downward radiation flux (R_T), sea surface temperature (SST), and ocean heat content (O_E) were investigated globally and locally, using EBAF Ed2.8 of CERES and ORAS4 of ECMWF. The tendency of anomalies of global mean SST was correlated (0.5) with the global mean R_T with half-month leads. Local correlations were significant (95%) over 40% area of the ice-free ocean, mostly in the middle latitudes, when the tendency of SST leads R_T by a half month, indicating that the change in SST modifies cloud and atmospheric circulation. The tendency of the global sum of O_E above 100 m for trend length of one month has a contemporary correlation (0.7) with the global mean of R_T anomalies in the 12-month running mean time series, while the size of storage exceeds the amount explained by R_T  as shwon in the attached Figure which covers the period from March 2000 to December 2014. Variances with time scales longer than one year for O_E and SST dominated in the Eastern Equatorial Pacific, while those of R_T were relatively smaller there. The maximum and minimum O_E tendencies were found in the tropics, while those of R_T were found at off-equatorial latitudes, indicating oceanic and atmospheric processes connect them. The equivalent ocean depth under the influence of inter-annual R_T variations is uncertain due to limited accuracy of the current datasets.