资源环境科技发展态势分析平台

We investigate the global mean and regional change of sea surface and land surface temperature over 2003-2013, using a large number of different data sets, and compare with changes observed over the past few decades (starting in 1950). We find that over 2003-2013, both global land surface temperature and global sea surface temperature have increased at a rate significantly lower than over the previous decades. While confirming cooling of eastern tropical Pacific during the last decade as reported in several recent studies, our results show that the reduced rate of change of the 2003-2013 time span is a global phenomenon. GMST short-term trends since 1950 computed over successive 11-year windows with 1-year overlap show important decadal variability that highly correlates with 11-year trends of the Atlantic Multidecadal Oscillation index. The GMST 11-year trend distribution is well fitted by a Gaussian function, confirming an unforced origin related to internal climate variability. We evaluate the time derivative of full-depth ocean heat content to determine the planetary energy imbalance with different approaches: in situ measurements, ocean reanalysis and global sea level budget. For 2003-2013, it amounts to 0.5 +/-0.1Wm(-2), 0.68 +/-0.1Wm(-2) and 0.65 +/-0.1Wm(-2), respectively for the three approaches. Comparing with the Energy Balanced and Filled (EBAF) data of the Clouds and Earth's Radiant Energy Systems (CERES) project, we find significant agreement at interannual scales. Finally, using 15-year averages of GMST and total ocean heat content rate, we compute the net radiative forcing since 1970 (this start date being constrained by availability of ocean temperature data). Although the uncertainty is quite large because of considerable errors in the climate sensitivity parameter, we find no evidence of decrease in net radiative forcing in the recent years, but rather an increase compared to the previous decades.