On the role of 2400-yr cycle in the paleoclimatogy

txtNL 9 engl (26.06.2009) The ignoring of the modulating influence of the 2400-year climatic cycle in the stucture of the databases, dealing with the variations of the continental surface humidity during Holocene and, as a result, the low informative database value.

Many works and projects that deal with studies of water archives appeared recently. In particular, great databases that reflect changes of inland continental water reservoirs during Holocene were created. E.g.: Lake level status grids. 2002. - Laboratory for paleoclimatology and climatology, University of Ottawa.
 But as it seems to me, essential drawback of this and other known to me databases is that they wer composed without taking into account the 2400-year climatic cycle as the principal factor that modulates levels of inland water reservoirs.

Thus, as principal time points of those databases the dates 0 , 3,000 , 6,000, 9,000 and 12,000 years ago were selected. Let's look to which phases of the 2400-year climatic cycle those points correspond
  I present my localization of this cycle's extremums:

max       1600BP       4000BP        6400BP        8800BP         11200BP      
min  400BP     2800BP         5200BP        7600BP       10000BP           12400BP
 
  Then it appears that the dates 0 and 3,000ВР correspond to the phases min - 400 and min + 200 ;  6,000BP and 9,000BP  -  to phases  max + 200 and  max - 400  correspondingly.  This means that the first and the second, the third and the fourth dates in couples fall approximately on the same phases of the 2400-year climatic cycle - the principal factor that determins the level of moisturing of inland continental surface and, therefore mean level of continental water reservoirs.

The most remarkable closeness of the mean levels of the inland water reservoirs for the  dates 0 and 3000 BP, as well as for 6000 BP and 9000 BP, is demonstrated by the maps included in the said database provided by the University if Ottawa for the North American territory (see the maps: Lake status at 0 ka.; Lake status at 3 ka; Lake status at 6 ka; Lake status at 9 ka at
On these maps, the level distribution for the North American lakes are practically identical when compared in pairs. The same is true for other continents, where the water regimes are very similar, taken in pairs, too. Naturally, these local-in-time pairwise synphase coincidences, necessarily arising out of the cyclical nature of the process give insufficient information about the process per se (about amplithude, for example).

However, the picture would be quite different, if instead of the 3000-year interval between the base dates, there was chosen a 1200-year interval, i.e. the interval equal to the half-period of the 2400-year cycle, and base dates were located near the cycle extremums. I am sure that for two such points as, say, 400 BP and 1600 BP we would get wholly opposite pictures with the relevant low and high mean levels of inland water reservoirs. If the authors of the lake level project  have selected sush a way, the nature of variation, during Holocene, of the continent surface humidity levels and of the global climate in general would be more distinct.