The global annual averaged Surface Air Temperature Anomaly （SATA） in 2015 and its rank in the historical instrumental records are analyzed using the CRU, NASA, and NOAA datasets. All datasets indicate that 2015 is t...The global annual averaged Surface Air Temperature Anomaly （SATA） in 2015 and its rank in the historical instrumental records are analyzed using the CRU, NASA, and NOAA datasets. All datasets indicate that 2015 is the warmest year, which is 0.74℃ warmer than normal years from 1961 to 1990 in the HadCRUT4 data-set. The most evident warm anomaly occurs over land, especially at high latitudes. The averaged SATA over land is 1.13 ℃, which is 0.54℃warmer than that over oceans （0.59℃）. Because an El Niffo event occurred in 2015 and 1998 and 1998 is also the warmest year in the twentieth century, these two years are compared to explain the formation of the warmest climate. A statistical approach that is known as the Ensemble Empirical Mode Decomposition （EEMD） is employed to isolate the components with different timescales, which range from interannual to centennial and a long-term trend. In 2015 the developing El Niffo may have contributed an anomaly of 0. 1 0℃, while this value is 0.1 8 ℃ for 1998. The contribution of the decadal-multidecadal variability and beyond to 2015 is 0.64℃, which is significantly larger than that of the interannual anomaly components （0.10 ℃）. This indicates that the warmest climate in 2015 occurred in the context of the tirnescales beyond the interannual.展开更多
基金supported by the National Natural Science Foundation of China[grant number 41421004]the National Key Basic Research and Development Program of China[grant numbers 2016YFA0601802 and 2015CB453202]
文摘The global annual averaged Surface Air Temperature Anomaly （SATA） in 2015 and its rank in the historical instrumental records are analyzed using the CRU, NASA, and NOAA datasets. All datasets indicate that 2015 is the warmest year, which is 0.74℃ warmer than normal years from 1961 to 1990 in the HadCRUT4 data-set. The most evident warm anomaly occurs over land, especially at high latitudes. The averaged SATA over land is 1.13 ℃, which is 0.54℃warmer than that over oceans （0.59℃）. Because an El Niffo event occurred in 2015 and 1998 and 1998 is also the warmest year in the twentieth century, these two years are compared to explain the formation of the warmest climate. A statistical approach that is known as the Ensemble Empirical Mode Decomposition （EEMD） is employed to isolate the components with different timescales, which range from interannual to centennial and a long-term trend. In 2015 the developing El Niffo may have contributed an anomaly of 0. 1 0℃, while this value is 0.1 8 ℃ for 1998. The contribution of the decadal-multidecadal variability and beyond to 2015 is 0.64℃, which is significantly larger than that of the interannual anomaly components （0.10 ℃）. This indicates that the warmest climate in 2015 occurred in the context of the tirnescales beyond the interannual.
