Do astrologers consider sun spots?

Pablo Mauas and colleagues at the University of Buenos Aires and the National Institute of Agricultural Technology have shown that the Rio Paraná’s flow at Corrientes – about 900 km upstream from Buenos Aires – is strongly correlated to the number of sunspots visible on the surface of the sun at that time (Phys. Rev. Lett. 101 168501). . .

According to Mauas, the flow of a major river is a good indicator of how much precipitation has fallen over its basin because – unlike other ways of measuring rainfall – it smoothes out local variations. Mauas believes that the increased rainfall could be caused by higher temperatures in tropical regions during periods of high solar irradiance. This, he believes causes greater evaporation in the tropics with this moist air transported southward to the Paraná basin.

The team is now working on a way to use sunspot number and the el Niño index, which quantifies the oscillation, to predict future water levels on the Paraná.

Over five years ago I posted about an article from The American Scientist on Ethnoclimatology in the Andes. The link has rotted but a quoted graf is still interesting and relevant.

"For at least the past four centuries, indigenous potato farmers of the Peruvian and Bolivian Andes have gathered in midwinter to gaze up into the night sky and observe the Pleiades. If this star cluster appears big and bright to them, they think that they will have plentiful rains and big harvests the next summer; if the cluster appears small and dim, they anticipate less abundance. Their belief is so strong that they time the planting of their crops accordingly. One might imagine that this practice amounts to nothing more than an odd superstition, but it turns out that this scheme actually works: The apparent size and brightness of the Pleiades varies with the amount of thin, high cloud at the top of the troposphere, which in turn reflects the severity of El Niño conditions over the Pacific. Because rainfall in this region is generally sparse in El Niño years, this simple method provides a valuable forecast, one that is as good or better than any long-term prediction based on computer modeling of the ocean and atmosphere."

I wonder if there are some local growers in Argentina who have a hundreds of years old tradition of gazing at sunspots to predict floods? I wonder how many other "superstitions" will one day be understood and validated? This sort of observational stuff is different than rain dances or other more clearly superstitious behaviors, and it isn't psychist cant of the fortune telling variety. It's science. It could be mistaken, or partial, but it is evidence based and time tested.

Update: I found the article but it is paywalled.

Update: I also found a bit more at Access my Library.

Our project began after two of us (Orlove and Cane) independently heard of these forecasts. Orlove first came across them in 1973, while conducting field research in the southern Peruvian Andes for his doctoral dissertation in anthropology. Curious to witness the yearly event, he arranged to join a group of indigenous farmers who gathered atop the nearest large mountain to await the appearance of the Pleiades above the horizon. He wrote an article about this practice, which is part of the festival of San Juan, celebrated each June 24th. But he focused on the social mechanisms that led people to form the groups and didn't consider the accuracy of the forecasts themselves. And once that article was finished, he dropped the topic. His notes from that first field work remained buried in a drawer.

Cane learned about this Andean ritual much later, while on vacation in Peru in 1994. On a hike with his wife--less than 150 kilometers from Orlove's field site--he struck up a conversation with the local guide about weather and climate. The guide mentioned the forecasts to him. They tickled his curiosity. It seemed to him, a specialist in climatology, that there might be some scientific basis to them. He took detailed notes, including the name of the Pleiades in Quechua, the indigenous language. After his return home, he raised the subject from time to time with people who he thought would be interested. One day in 1996, a graduate student in anthropology whom Cane knew suggested that he might discuss the matter with Ben Orlove--a not-so-common name that Cane recognized immediately. As it happens, the two had grown up six blocks from each other in Brooklyn and attended the same schools. Although they had been in regular touch as children and as teenagers, they had not seen each other in a quarter-century

An exchange of email messages ensued, and as they began to discuss the stories they had heard in South America, they found that they shared a common set of reactions. On the one hand, it seemed completely extraordinary. How could the appearance of stars possibly be connected to rainfall? And how, indeed, could people even remember the appearance of stars from one year to the next? Their belief, and the agricultural practices connected to it, seemed as implausible as foretelling the outcome of a battle by examining the intestines of a sacrificed bull. On the other hand, it wasn't impossible. There are many areas in which indigenous knowledge of this sort has shown its worth. Aspirin and quinine, for example, were once no more than folk remedies. Agronomists often turn to peasant farmers for their knowledge of local crop varieties. And in many parts of the world, architects are adopting the traditional building styles of desert peoples in recognition that these designs represent energy-efficient solutions for arid climates. If some cases of traditional knowledge have a sound footing in medicine, agriculture and architecture, there might be such instances in atmospheric science as well.

Update:

Perhaps you are wondering if the idea of pre-Columbian growers monitoring sunspots is a non-starter?

For the ancient peoples of Peru, the Inca and the Maya, the sun was a god, and they carefully observed and recorded the changing arc that the sun inscribed in the sky throughout the year, forming detailed calendars. According to archeoastronomer and stellar physicist David Dearborn, there is reason to believe that some Meso-American cultures recognized sunspots. And although there is no clear evidence that the Inca or the Maya noticed sunspots, the Aztec myth of creation involves a sun god with a pock-marked face, which strongly suggests that they had seen dark blemishes on the sun.

Who first noticed sunspots?

It's hard to say, as the records left by many ancient peoples have been lost (or not kept in the first place). But as early as 28 B.C., astronomers in ancient China recorded systematic observations of the cycles of what looked like small, changing dark patches on the surface of the sun. And there are some early references to sunspots in the writings of Greek philosophers from the fourth century B.C. However, none of the early observers could explain what they were seeing. What could sunspots be?

Sometimes, strongly held beliefs interfered with the process of understanding. The ancient Greeks, and other Europeans after them, were highly influenced by the teachings of Aristotle, a Greek philosopher who held that the sun and the heavens were ideal, an embodiment of unblemished perfection.

And so, sunspots ceased to exist in Europe. Aristotle said so. How modern. It seems to me that there is still a great deal of this going on. Ideals trump evidence quite often . . . at least for a time.