A group of scientists stated that slight variations in the sun's energy output can significantly affect global weather patterns, such as the Indian monsoon intensity, and these changes can be predicted years in advance. The sun goes through an 11-year cycle which is measured by the number of sunspots emitting bursts of energy on its surface. The difference in energy output between a solar maximum and minimum is only about 0.1 percent, making it challenging for meteorologists to determine how this small variation impacts the world's climate. By analyzing a century of weather data and using complex computer models, an international team of scientists led by the National Center for Atmospheric Research (NCAR) in the United States demonstrated that even a small increase in the sun's energy can enhance wind and rainfall patterns. Julie Arblaster, from the Centre for Australian Weather and Climate Research and a co-author of the study published in the journal Science, noted that the effects of small changes in the sun's output during the 11-year solar cycle have long been recognized to influence the global climate system. For the first time, researchers have explained how minor changes are magnified to cause cooler sea surface temperatures in the tropical Pacific and increased rainfall away from the equator. During times of high solar activity, the stratosphere warms up over the tropics due to intense sunlight. This warming affects wind patterns in the upper atmosphere, leading to more rainfall in tropical areas. Additionally, increased sunlight during solar maximum slightly warms ocean surface waters in the subtropical Pacific, where clouds are usually sparse. This additional heat causes increased evaporation, resulting in more water vapor. The surplus moisture is transported by trade winds to the typically wet regions of the western tropical Pacific, causing increased rainfall. Forecasts suggest that in the tropical eastern Pacific, sea surface temperatures will slightly decrease, leading to conditions resembling a La Nina event. La Nina is the opposite of El Nino, bringing more precipitation to the western Pacific and less to parts of South America. Many regional climate patterns, including the Indian monsoon, are heavily influenced by the movement of rising and sinking air in the tropics and subtropics. Solar-cycle predictions could assist meteorologists in estimating how variations in circulation patterns, sea surface temperatures, and regional weather patterns might occur. NCAR scientist Gerald Meehl, the lead author of the study, believes that the sun, stratosphere, and oceans are interconnected and can impact events such as winter rainfall in North America. Understanding the influence of the solar cycle could offer valuable insights as scientists strive to predict regional weather patterns in the coming decades. The sun is currently in a quiet phase following a solar minimum at the end of last year, as reported by the Space Weather Prediction Center at the National Oceanic and Atmospheric Administration in the United States. The next peak in solar activity is expected in May 2013. Brad Carter, a senior lecturer in physics at the University of Southern Queensland, Australia, commented that the paper is a valuable contribution to understanding how solar activity can impact climate. He emphasized that while solar activity can have detectable climatic effects, it is not the cause of global warming in recent years. For more information, visit: www.swpc.noaa.gov/SolarCycle/.