Why winds are slowing

This includes the sea surface temperature, atmospheric pressure and the intensity and direction of local winds. They also analysed data related to the satellite imagery and warm sea pockets to simulate the cyclone.

Yet, Fani kept IMD on its toes till the landfall. In fact, it just refused to move and kept meandering over the sea for 11 long days, making it the longest observed lifecycle of a cyclone over the Bay of Bengal. This slow movement was largely because of localised winds that steer the cyclones towards warmer ocean waters where it can gather more moisture and energy.

But these localised winds are not easy to record. But they do not provide images of required resolution. The data will be ready for commercial use by the end of the year. But a number of scientists say clear disruptions in wind patterns are evident across the globe. These disruptions are making natural phenomena like cyclones, cold waves and monsoon currents more erratic and unpredictable.

Their research is based on the analysis of wind speeds between and , which they measured using trace metals like manganese in coral skeletons. Concentration of trace metals usually spike in coral skeletons when stronger winds blow from the west carrying trace metals washed away from lagoon sediments. Pacific trade winds remain weaker during such periods. At Tarawa Atoll, for instance, they have found that the trade winds had weakened between and , which was the first phase of global warming.

Between and , temperatures were more stable, and the trade winds were stronger. The slowing down of winds is, however, not a localised occurrence. Winds all across the world seem to be slowing down close to the land surface. The phenomenon is now referred to as stilling. One effect of global warming is to flatten those differences. The poles are warming faster than the equator, winters are warming faster than summers, and nights warming faster than days. What does the drop in wind speed mean?

The decrease in evaporation has immediate implications for the precision calculations used in modern irrigation, and more complex effects on rainfall patterns.

While less evaporation may be good for some plants in arid areas, stilling may make others less able to disperse wind-blown seed to suitable new habitats, and hence less resilient to climate change. Less wind could also hurt city-dwellers. Potential effects on wind power are another area of concern, though there does not appear to be anything to worry about in the short term. Stilling has so far been detected only at heights up to 10 metres, while turbines harvest their energy 50 to metres above the ground.

One difficulty with prediction is a lack of observations. The age of anemometers — the devices that measure wind speed — can affect readings but, by compiling a single set of quality-controlled data, Azorin-Molina hopes to determine whether stilling is purely a recent phenomenon or if similar declines have happened in the past. Originally published by Cosmos as The wind is slowing down. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science.

Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Temperature and precipitation get all the glory in the discussions surrounding climate change. Ocean acidification has earned itself a seat at the table as well.

But nobody has really paid any attention to wind. Thanks to new research by Brandon Barton , a Univiersity of Wisconsin—Madison postdoctoral researcher in the Department of Zoology, wind may finally get its moment in the climate change spotlight. Wind is created thanks to differences in temperature. And since the poles are warming faster than the equator, there is a smaller global temperature differential, reducing the speed of wind.

In his paper, online this month in the journal Ecology , Barton points out that global wind speeds have decreased by some 5 to 15 percent over the last three decades, and are expected to decrease another 15 perfect in the coming century.

Physical, manmade structures are blocking the flow of wind, at least on a local scale. So are trees. Ecologists have long investigated the affects of wind on seed dispersal and pollination, or on the ways that winds modify ocean currents. But the affects of wind on predator-prey dynamics have been largely ignored.

Barton set out to change all that by looking at the way that wind altered the dynamics between ladybugs in particular, the multicolored Asian lady beetle Harmonia axyridis , and their prey, the soybean aphids Aphis glycines , pests who can ravage soy plants.