Coherent interannual and decadal variations in NHSM precipitation. (A) The first empirical orthogonal function (EOF) mode of the annual mean
ENSO-year precipitation in NH monsoon domains. The ENSO year defined from May 1 to the next April 30 concurs with development, maturation, and decay of
normal ENSO. Also shown is the ENSO index measured by Niño-3.4 (5°S–5°N, 120°W–170°W) SST anomalies. (B) The first EOF mode of the 3-y running-mean
MJJAS precipitation in NH monsoon domains. The GPCP, version 2.2 (including operational data in 2011), data were used. The correlation coefficient between
the EOF PC1 of the ENSO-year mean precipitation and Niño-3.4 index (NHSM precipitation index; Fig. 2A) is 0.86 (–0