The Sensitive Regions of Surface Air Temperature and Terrestrial Precipitation to Global Warming, IPO and AMO

Abstract

Abstract Against the background of global warming (GW), the distribution of decadal (10–20-year), multidecadal (20–50-year) and secular (>50-year) variabilities and their causes of surface air temperature (SAT) and terrestrial precipitation were explored. We applied the singular spectrum analysis method to categorize the low-frequency variabilities of global SAT and terrestrial precipitation anomalies. Three sea surface temperature (SST) modes were identified through singular value decomposition that affect the low-frequency variabilities of global SAT and terrestrial precipitation anomalies—namely, the GW, Interdecadal Pacific Oscillation (IPO) and Atlantic Multidecadal Oscillation (AMO) modes. The sensitive regions of SAT and terrestrial precipitation to GW, IPO and AMO were validated through an information flow method. Significant decadal and multidecadal variabilities of SAT were found to exist over the Pacific and Northern Atlantic, respectively, because of the IPO and AMO. In terms of terrestrial precipitation, a large area with a wet trend was found over Eurasia at mid-to-high latitudes, and this trend was especially remarkable in the boreal winter half-year (November–April), as compared with that in the boreal summer half-year (May–October). As a result, it could be concluded that GW is the trigger of the wet trend. By employing artificial neutral networks with a self-organized map to cluster the key patterns of vertically integrated water vapor flux, we found that the synopitic circulation related to the wet trend is characterized by westerly flow that transports water vapor from the northeastern Atlantic to Eurasia, which is favorable for precipitation there both in the boreal winter and summer half-year.