This globe from the atmospheric moisture investigation shows specific humidity, with blue and green being highest. What is a possible explanation for why specific humidity values are relatively low in the ocean adjacent to the western coast of southern Africa

Due to temperature.

Explanation:

The values of specific humidity are relatively low in the ocean adjacent to the western coast of southern Africa because of the presence of temperature of large water bodies around the area. Humidity depends on the temperature of the air means if the temperature is higher than there is high humidity in the air because the air has the ability to hold more water vapors which ultimately increases humidity.