A note from the Doc: The references to planets and constellations on this site are not astrological in nature, merely the clearest way to reference these positions and angles. For more, please read: Astrology or Astronomy »
The influence of planetary declination on climate patterns is an area of research with much potential. Declination is the angular distance of a celestial object measure north or south of the celestial equator. Angular distance is the distance reckoned in angles of arc on a sphere. 0°angle of arc is the equator, 90°N angle of arc is the North Pole. In the diagram the celestial equator is seen as a projection of the terrestrial equator. The orbit of the sun apparently moving through the heavens in a counter clockwise orbit is depicted in red. It can be seen that the sun does not follow the celestial equator in its apparent orbital path. The green star represents the point where the sun will cross the celestial equator moving from south to north. The green star is the vernal point that designates the position of the sun on March 21 at the spring equinox. From the point of the equinox, the sun rises higher in the sky at noon each day until at the summer solstice it appears at noon at 23°N latitude. From that high declination point the sun appears to drop in celestial latitude towards the equator until at the fall equinox on September 21 the sun is once again on the ecliptic (green dot) moving south each day in celestial latitude until at the winter solstice on December 21 the sun at noon appears at 23°S celestial latitude. The apparent rise and fall in celestial latitude is known as declination. The path the sun takes above and below the celestial equator is known as the ecliptic. This path gets its name from the fact that it is on this path that the sun encounters the moon every six months for the formation of eclipses.
In the second image we can see the solar path with the lunar path included. It takes on year for the sun to go through its apparent path of 360° through the heavens. This path in the ancient world got its name from the constellations of all of the star groups that the sun encounters in a year. The star groups were known collectively as the animal wheel or zodiac. The constellations that the sun passes through in a year are covered in one month by the passage of the moon. Also the 23°of solar declination at maximum southern and northern declination can be exceeded by the moon by 5°. This means that the moon at maximum northern declination can be located at 28°N celestial latitude and likewise for the south.
The lunar orbit is the most erratic and variable of all of the planets. Not only can the moon exceed the solar maximum declination but it can also reach its maximum declination 5° below the solar maximum. That means that in some years the moon only reaches its maximum southern and northern declination at 18° of celestial latitude. Finally it also can reach its maximum and minimum declination in synch with the sun. These rhythms can be seen in the following diagrams.
In figure 3 we see a different view of the solar ecliptic. The chart shows the apparent path of the sun as a dotted curve. The vernal point at the spring equinox is found over western Africa. The winter solstice point is over Central America. The fall equinox is at the dateline in the central Pacific. For articles explaining how the charts placing a planetary position onto earth are made please see other sections of Doc Weather. For other studies on declination of Mars and Mercury see these articles on Doc Weather.
To return to the chart it can be seen that using geodetic equivalency the position of the sun at the winter solstice is due south of Denver, Colorado. This means that the sun transiting the eastern Pacific will always be moving south in latitude to reach a maximum in declination in December. A look at an ephemeris will reveal that any planet transiting the West Coast will always be moving at its lowest declination point in its orbit. This means that the moon also will be moving at its lowest declination as it transits the West Coast each month. Often the movements of the moon transiting the West Coast are accompanied by a shift in the jet stream to the south as the moon passes the coast. This gives the appearance that the southward motion in latitude is accompanied by a southward motion in the jet stream. This is not always the case due to a number of other patterns but it can be thought of as a general rule of thumb.
The phenomenon of the effects of declination on the jet stream of the eastern Pacific can be related to the work of a Chinese researcher LI Guoqing of the Institute of Atmospheric Physics, in Beijing. The paper entitled, 27.3 and 13.6 day Atmospheric Tide and Lunar Forcing on Atmospheric Circulation [PDF] researches the influence of the earth's length of day (LOD) in relation to the geopotential height of the 500mb fields in the eastern Pacific and the declination of the moon. It was found that there is an alternating increase and decrease in geopotential height in the eastern Pacific in approximately seven day cycles that are keyed not to the phases of the moon but to the declination of the moon. The different modes of the declination response were that during the times when the moon was at a maximum declination north or south there was a corresponding speeding up of the earth's rate of diurnal rotation according to measurements done with the atomic clock in France. The speeding up of the earth had the effect of shifting air masses to the west in the eastern Pacific. The concept here is like a ball in the bed of a truck that would be accelerating east. The ball would shift west. The opposite effect occurred when the moon was at the ecliptic near to 0° latitude. The concept here was that the atmosphere bunched up at the equator slowing down the diurnal rotation ever so slightly according to the atomic clock data. This had the effect of shifting air masses to the east like a ball in the bed of an eastward moving truck that was slowing down. Li Guoqing found a strong statistical linkage to the motions of blocking ridges in the eastern Pacific and these fluctuations in lunar declination. This is a fascinating paper and when linked to the work of Harold Stolov in the 60's some implications for setting up a timing protocol for blocking highs and the genesis of storm cycles can be established.
There are further implications however to these two studies. One implication is that the declination of the moon is not stable over time. It fluctuates on an 18.6 year rhythm known as the nodal cycle. The nodal cycle is due to the fact that the node, the place where the moon moves from southern declination to northern declination moves backwards through the zodiac on an 18.6 year cycle.
In figure 3 we saw the solar declination path in which the maximum solar declination at the solstices is 23° of celestial latitude. The moon at certain times follows the sun in what is known as the lunar middle path. That means that at maximum latitude north and south the moon will be at 23°.
In image 4 we can see that the path of the moon is not along the ecliptic. The ecliptic is in blue rendered in small dashes. The lunar high path is depicted in larger red dashes. It can be seen that at maximum south and north latitude the moon is 5° higher than the solar ecliptic. The fall and spring equinoxes are still the crossing points for both paths. It is just that during times of maximum lunar declination on the high lunar path the moon remains at extreme latitudes for much longer periods of time. During those years the passage through the latitudes near to the ecliptic are rapid and very short lived. During those years, according to the research of Stolov there would be much less of a time window for geomagnetic disturbances of the magnetotail and according to the research of Li Guoqing there would also be much less of an effect of air masses being moved to the east by a transiting moon. Spending much more time at high latitudes and much less time at mid latitudes would encourage air masses in the eastern Pacific to be stationed more to the west and to have a tendency not to progress forward as easily as the moon was transiting the high latitudes.
In this image the opposite condition of the lunar low path is illustrated. Again the ecliptic is drawn in blue small dashes. The lunar low path is drawn in green large dashes. It can be seen that the path of the moon at maximum latitudes is 5° lower than the ecliptic in both the maximum south and maximum north positions. It can be seen that in contrast to the high path where the descending and ascending moon crossed the ecliptic in an abrupt and abbreviated time window, the low path has the moon running parallel to the ecliptic in the vicinity of the equator for a long length of time. This would present a simultaneous maximum situation for Stolov's geomagnetic influence and slowing down effect of Li Guoqing to come into play.
Just for clarity, the next image shows all paths on the same chart. The lunar high, mid and low paths are depicted. These cycles take 18.6 years to complete with a half cycle of 9.3 years. These time frames come very close to the standard decadal and inter decadal influences recognized but not understood by contemporary climatology. Perhaps there is something after all to be recognized in the obscure influences of the lunar and solar cycles. However, even with these thought provoking ideas there is still the task of coming up with long range forecasts that can actually be linked to real time events for the rest of the month when the lunar position is not perfect for perturbation of the magnetotail. For that the obscure influences of the moon and the sun need to be integrated into the wholeness of the motion in arc events of all of the other members of the solar system. For that to happen a more whole grid system needs to be in place so that the daily increments of motion in arc can be integrated into the whole, one by one in order to make a more fluid and realistic model for long range forecasts.