Investigation 9A 2024-25

The focus of Investigation 9A is on the planetary scale circulation. I begin with a discussion of general belts of high and low pressure and their associated wind patterns and then move on to discuss Figure 9A-2, which shows average mean sea level pressure across the globe during January and July.

The remainder of the video focuses on El Niño/La Niña phenomena, which result from anomalous sea surface temperatures in the tropical Pacific Ocean. El Niño/La Niña are important because they lead to climatic variations across the globe. I begin by describing tropical Pacific sea surface temperature (SST) and wind patterns as well water movement, the thermocline and the location of organized thunderstorm activity during years with “normal conditions,” “El Niño conditions,” and “La Niña conditions (an amplification of normal conditions).” Warm season and cold season climatic variations ("teleconnections") around the globe during El Niño and La Niña events are then described at the end of the video.