Spatiotemporal Decompositions of Summer Drought in China and Its Teleconnection with Global Sea Surface Temperatures during 1901–2012

Abstract

AbstractThe teleconnection between the summer (June?August) Palmer drought severity index (PDSI) in China and seasonal global sea surface temperatures (SSTs) is investigated at both spatial and temporal scales during 1901?2012. Three pairs of coupled spatial patterns for China?s PDSI and global SST anomalies are identified using the singular value decomposition (SVD) method. With a combination of ensemble empirical mode decomposition (EEMD) and multiple linear regression (MLR) analysis, it is found that the first mode, the sea ice loss?global warming pattern, causes wetness over north and northeastern China and drying over Inner Mongolia. The North Pacific Current (NPC) mode shows that a warmer NPC corresponds to a wetter summer over eastern China and a drier one over the Tibetan Plateau. Both NPC and Pacific decadal oscillation (PDO) affect moisture variability in northern China and over the Tibetan Plateau, with the NPC mode more important in the centennial scale, while the PDO mode is more important in the multidecadal scale.