Search for: All records

Predictions of changes of the land monsoon rainfall (LMR) in the coming decades are of vital importance forsuccessful sustainable economic development. Current dynamic models, though, have shown little skill in thedecadal prediction of the Northern Hemisphere (NH) LMR (NHLMR). The physical basis and predictability forsuch predictions remain largely unexplored. Decadal change of the NHLMR reflects changes in the total NHcontinental 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 isshown that the decadal variability of the NHLMR is rooted primarily in (i) the north–south hemispheric thermalcontrast 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 anextended El Niño–Southern Oscillation (XEN) index. Results from a 500-yr preindustrial control experimentdemonstrate that the leading mode of decadal NHLMR and the associated NAID and XEN SST anomalies maybe largely an internal mode of Earth’s climate system, although possibly modified by natural and anthropogenicexternal forcing. A 51-yr, independent forward-rolling decadal hindcast was made with a hybrid dynamic con-ceptual model and using the NAID index predicted by a multiclimate model ensemble. The results demonstratethat the decadal changes in the NHLMR can be predicted approximately a decade in advance with significantskills, opening a promising way forward for decadal predictions of regional land monsoon rainfall worldwide.