Additionally, ocean surface temperatures over the
higher latitudes of the northwestern Pacific are correlated
with the pattern of typhoon landfalls. When
temperatures are cooler than normal, typhoons are relatively
more likely over southern China. A linear regression
model that includes sea level pressure differences
between Mongolia and western China and SST
over the northwestern Pacific explains 26% of the interannual
variability of the LI. A stronger than normal
surface pressure gradient increases the easterly wind
flow over China forcing the fledgling storms to track
westward toward the southern coast. Moreover, colder
water over the WNP shifts the subtropical high pressure
farther to the west and south, thus keeping tropical
cyclones over lower latitudes and tracking them
toward Hong Kong. These results are consistent with
the speculation put forth in Liu et al. (2003) that typhoons
are more abundant across Guangdong when
the climate is drier and windier in northern and central
China.