Solar to river flow and lake level correlations

Guest post by David Archibald

Colder is drier.

The figure above is after a figure from Maus et al 2010 “Long term solar activity influences on South American rivers”. It shows a very good correlation between solar activity, as measured by sunspot number, and the flow rate of the Parana River, the second largest river in South America. The Parana River now hosts the Itaipu Dam with installed capacity of 14,000 MW.

A recent paper in an engineering journal shows a similar strong solar control on the level of Lake Victoria in East Africa (Mason March 2010): 

As Mason notes, an interesting correlation was noticed in the early 1900s between lake level and solar activity, in the form of the sunspot number. The interest this caused waned when the correlation seemed to disappear after about 1928. The early 1960s saw a dramatic climate anomaly in East Africa. Lake levels rose significantly, including those of Lake Victoria, and flows in the Tana River in Kenya doubled. The sluice gates at the Owen Falls dam were opened to release the additional water required by the Nile waters agreement and they stayed open, almost continuously, until well into the 1990s. This surplus water also led Uganda to invest in a new hydroelectric power station at Kiira. But the lake level starting falling from 1964 with an oscillation around the falling trend. This oscillation, controlled by solar activity, is shown in the following figure from Mason:

The falling trend in the level of Lake Victoria meant that the new hydro dam at Kiira did not produce any long term, additional energy for Uganda.

Back to South America and the Itaipu Dam – it produces 90% of the electric power consumed by Paraguay and 19% of Brazil’s consumption. As Maus et al note, the relationship between smaller solar activity and low Parana’s discharge can also be found in historical records.

For example, low discharges were reported during the period known as the Little Ice Age (LIA). In particular, a traveller of that period recalls in his diary that in the year 1752 the streamflow was so small that the river could not even be navigated by the ships of that time, which were less than 5 ft draft, to be compared with ships up to 18 ft draft that can navigate it at present as far north as Asuncion in Paraguay.

Our prediction for Solar Cycle 24 in terms of F10.7 flux is shown following:

Given the link between East African and central South American rainfall and solar activity, the list of economic impacts from the current solar minimum (Solar Cycles 24 and 25) can be expanded to:

1. Canadian agricultural will get a severe whacking from a shortened growing season and un-seasonal frosts.
2. 24 year drought in central South America
3. 24 year drought in East Africa
4. Paraguay and Brazil having severe power shortages.

This list is by no means exhaustive. The last time the world witnessed mass starvation was the 1965-67 drought in India which killed 1.5 million people. Things don’t look pretty.

References:

Mauas, P.J..D., A.P.Buccino and E.Flamenco, 2010, Long-term solar activity influences on South American rivers, Journal of Atmospheric and Solar-Terrestrial Physics on Space Climate, March 2010.

Mason, P.J., 2010, Climate variability in civil infrastructure planning, Civil Engineering 163, pages 74-80.

David Archibald

July 2010