Dr. Reid Bryson (1948) noted that anticyclones (high pressure centers) are often displaced northward by a couple degrees of latitude from their mean position, and then pulled approximately 1 to 2 degrees southward from the mean position during the following 2 week period.
Dr Bryson’s studies looked at the mean positions of the subtropical high-pressure belt which is one of the two belts of high atmospheric pressure surrounding the earth. Their mean centers of high pressure are near 30 degrees north latitude and 30 degrees south latitude (Figure 1). Within these belts are the subtropical high pressure centers called oceanic anticyclones (in contrast, a low pressure center is called a cyclone). These centers of high pressure are called oceanic because they are centered and anchored over ocean areas rather than land.
Figure 1: Figure on the left shows the subtropical high-pressure belt near 30 degrees north and south latitudes. Figure on the right shows the semi-permanent high-pressure centers over the Eastern Pacific Ocean and the Atlantic Ocean from the Gulf of Mexico east to Africa. Courtesy Hungarian Meteorological Service. (click image to enlarge)
The subtropical high pressure centers within this belt include what meteorologists call “semi-permanent” areas of high pressure. These semi-permanent high-pressure centers for the most part are located within boundaries of certain geographical areas, and are the major controllers of the earth’s climate and weather. Anomalous displacement of these systems from their mean positions strongly control changes in regional storm tracks, strength of storms, regional monsoon seasons, the El Niño, regional droughts and the overall weather pattern. A longer-term displacement can cause an overall change in regional climate, or the earth’s climate.
Two very important northern hemisphere semi-permanent high pressure centers are the Pacific High anchored off the southwest coast of the United States and Mexico, and the Bermuda High stretching from the Gulf of Mexico eastward across the Atlantic Ocean to near Africa. Any meandering or anomalous displacement of the Bermuda High strongly determines the path of the Atlantic and Gulf of Mexico hurricanes. Any changes in the Eastern Pacific High from year to year strongly determine the strength and position of the Aleutian Low Pressure Center near Alaska, formation and tracks of Pacific hurricanes and typhoons, and the weather patterns over much of the western portion of North America.
Other displacements of semi-permanent high-pressure systems within the earth’s subtropical high-pressure belt can force other climate and weather oscillations around the world, including but not limited to the formation of the El Niño, monsoons, regional droughts and severe winters.
Recognizing that anomalous latitudinal positional changes of the Eastern Pacific Sub-Topical High can vastly implement changes in regional weather and climate, Dr. Bryson used 530 case studies to determine the anomalous latitudinal displacements of the mean position of certain high pressure systems. These anomalous displacements of the highs were then correlated with the monthly 13.5 day northward, and 13.5 southward progression of the moon’s declination cycle (apparent position in the sky in relation to the equator).
Dr. Bryon then took the 530 case studies of the Eastern Pacific semi-permanent High-Pressure centers and compared them to the meridional gravitational tidal component of the moon. This is basically the monthly 13.5 day cycle of the northward progression of the moon’s declination cycle and its associated latitudinal changes in the atmospheric and oceanic tidal forces portrayed onto the earth.