Toward predicting changes in the land monsoon rainfall a decade in advance

Current dynamic models, though, have shown little skill in the decadal prediction of the Northern Hemisphere (NH) LMR(NHLMR). The physical basis and predictability for such predictions remain largely unexplored.

Decadal change of the NHLMR reflects changes in the total NH continental precipitation, tropical general circulation, and regional land monsoon rainfall over northern Africa, India, East Asia, and North America. Using observations from 1901 to 2014 and numerical experiments, it is shown that the decadal variability of the NHLMR is rooted primarily in (i) the north-south hemispheric thermal contrast in the Atlantic-Indian Ocean sector measured by the North Atlantic-south Indian Ocean dipole (NAID) sea surface temperature (SST) index and (ii) an east-west thermal contrast in the Pacific measured by an extended El Nino-Southern Oscillation (XEN) index.