The researchers studied the relationship between ocean temperatures in the Indian Ocean and the strength of the South China Sea summer monsoon. They found that when the Indian Ocean Dipole Mode is positive (negative), the monsoon tends to be weak (strong). This correlation is significant during certain phases of long-term trends. Additionally, a strong (weak) monsoon in the South China Sea is followed by a positive (negative) phase of the Indian Ocean Dipole Mode in the next fall season.