Study debunks theory of a global cooling phase compensating for global warming
The next cycle of Sun’s activity starting in 2020, also known as the Solar Cycle 25, will be either slightly stronger or similar to the previous cycle (Solar Cycle 24), finds a research paper published by Indian scientists in the journal Nature Communications on December 6.
The Sun’s activity, influenced by its magnetic nature, fluctuates in 11 year cycles and affects the atmospheric conditions on Earth through changes in the Sun’s radiation and sudden bursts of solar energy known as solar flares.
Apart from flares other types of extreme space weather events such as geo magnetic storms and blasts of particles can be a cause for concern for artificial satellites, communication systems, the navigation of aircrafts over the planet’s Polar regions and the smooth functioning of electrical power grids.
The report by Dibyendu Nandy and Prantika Bhowmik at the Centre for Excellence in Space Sciences of the Indian Institute of Science Education and Research in Kolkata studied the occurrence of sun spots over a 100 year period between 1913 and 2016.
This is the first time that such century-long data of solar activity has been studied by scientists. These sun spots are magnetic in nature and are responsible for much of the space weather that impacts our planet. They usually occur in pairs and are therefore known as Bipolar Magnetic Regions (BMRs).
The most essential aspects of Sun spots are their fluxes, tilt angles, locations on the surface and timing of occurrence. Sun spots are the most observable part of the Sun’s activity and its cycles. They have been observed for over four centuries and these observations are the longest running, continuous time series of any natural phenomena in the Universe.
The last few cycles of the Sun have shown a weakening trend and some scientists had even proposed that this would touch a record minimum known as a Maunder minimum, the likes of which were last seen between 1645 and 1715. During this period astronomers observed no sun spots.
This weakening of the Sun’s activity led to speculation that a mini ice age is on the anvil and that disastrous effects of human-induced global warming could be partially offset by global cooling.
The occurrence of such a minimum over decades would have led to a much cooler global climate. The current prediction reverses this trend and debunks the theory of a global cooling phase compensating global warming due to green house gas emissions, which has reached a record high.
Prediction of solar activity is a very complicated process, in fact, sustained long-term forecasting of solar cycles are not possible. For the current cycle, scientists had made multiple forecasts but none of them had reached a consensus. Some of them even differed significantly in their outcomes.
Nandy and Bhowmik claim to have made significant improvements in predicting solar activity. For example earlier the forecasts could be made only 5 years in advance, but the paper demonstrates a new model by which this period can be expanded to 10 years.
They have done this by understanding the complicated flow of material (plasma) on the surface and the interior of the Sun and its interaction with the magnetic field of the Sun which produces the sun spots and their cycles.
They were able to predict the strength of the minimum of Sun’s activity in the upcoming cycle and using this information as input for a predictive model, they can expand the predictive window to 10 years.
Through its analysis of historical data, the study also finds that the changes in the intensity of sunspot cycles over decades or even the past century is determined by the tilt angle distribution of sunspots and their evolution on the solar surface.
Such significant observations would be essential for the preparation and execution of India’s first solar probe, Aditya L1, in 2020. It will help the scientists design the satellite in a better way and also create better models for the behaviour of the satellite in space, especially close to the Sun.
(With inputs from India Science Wire)
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