Hurricanes gain strength

March 21, 2013. The number of hurricanes grow and increase their destructive power. This is the conclusion drawn by researchers at Peking University, analyzed the statistics of the past decades. This is due to the deep processes of climate change.

At the beginning of XX century, tropical cyclones seemed to be something not serious and did not present any particular risk for major settlements in the present time, the situation has changed: women's names mentioned hurricanes "Katrina" and "Sandy" now seem likely harbingers of the apocalypse, rather than ordinary natural disasters the forgotten soon as they are completed.

A team of scientists at Peking University came to the conclusion that the main cause of multiple hurricanes gain is notorious global warming. Nevertheless, such a law is relevant mainly for tropical latitudes, as in other parts of the Earth's warming effect on the atmospheric phenomena are completely different: the number of hurricanes Pacific ocean lives up to its name in comparison with the Atlantic, who appeared only in the last year and a half place of education more than a dozen different in strength disasters.

The results of the analysis of the research team were published in the journal Proceedings of National Academy of Sciences. And if the situation in the Pacific has not changed for many years, to make any accurate predictions about the Atlantic is becoming more difficult. This is due to the fact that it is in the Atlantic basin consist truly unique environment. Usually obtained from the ocean storm energy at certain points will begin to weaken it by virtue of the so-called wind shear (wind shear), which literally breaks the cataclysm inside on some parts, as the air mass in the different parts and levels of the tropical cyclone are beginning to seek in different directions. Usually the wind, which is the transport of air masses, has a strong horizontal orientation. In Atlantic same air flows mainly in a vertical direction. Accordingly, the effect of wind shear decreases more and has almost no influence on the motion directly hurricane gain in a certain direction.

Trying to find an explanation for this phenomenon, the staff of the Laboratory for the Study of crustal processes and environmental resources of Beijing University resorted to the statistics of the past years. It was found that from 1923 hurricanes in the Atlantic basin have changed not only quantitatively but also qualitatively: they are much more likely to be formed and became more destructive than before. At the same time, the average temperature water in the Atlantic has increased by about 1 ° C. Comparing the available data, the researchers concluded that the geographical location and temperature water are the very factors that affect the formation of a storm. According to them, in the Atlantic basin, especially in the tropics, has developed a unique situation due to climatic changes the frequency of the formation of hurricanes will increase, as well as their strength. It is significant that since the formation of the hurricane "Katrina" in 2005, the number of hurricanes in the Atlantic has doubled, while the water temperature is increased by only 0,4 ° C.

Climate change continues to affect ordinary people become accustomed to the order of things, while scientists try to explain not only the cause, but also learn how to make accurate predictions of the emergence and development of such phenomena.

Source: Meteovesti

 

The warmer the planet, the stronger hurricanes to floods

View on hurricane Isabel from the International Space Station.

March 19, 2013. Almost every big storm is accompanied by a discussion now about climate change. Everybody wants to know whether the person does not impact on the nature of the cause of the storm. But, as has been said many times, the question is worded in such a way does not make sense. It is impossible to assert that a particular disaster would not have happened, we will not heat the planet by about 1 ° C, because the climate is, by definition, a statistical thing. So widespread analogy with a throw of dice, weighted on one side. In other words, in a world that has become warmer than a hundred years ago, to some extent increases the probability of certain events.

Due to the emphasis on climate change in the United States are honored, of course, hurricanes, but this phenomenon is, alas, is still not well studied. Some experts predict their strengthening and acceleration, while others disagree. More or less credible evidence suggests that hurricanes will become less, but they will be more powerful. But how?

The problem is that global climate models are not able to efficiently compute the small-scale processes in hurricanes. Hence the uncertainty. Besides current observations more accurate than the last, and therefore difficult to identify historical trends for each of the current components.

The new study, published in the Proceedings of the National Academy of Sciences, attempted to circumvent these limitations by analyzing other information about hurricanes — information on storm surge from 1923, according to the six tide gauges installed along the south-east coast of the United States. Plotting of the Gaussian distribution, the experts were able to look at the change extremes and averages over time. However, they have taken into account the rising sea level, in order to estimate the height of the waves more accurately.

The obtained data were also compared with the possible contributing factors: Southern Oscillation (El Niño and La Niney), the global average temperature, the local temperature in different parts of the globe and the temperature of the sea surface in the tropical Atlantic. Since hurricanes are fueled warm surface waters, the data are best correlated with global temperature and sea surface temperature in the region where they are formed.

These relations (recall that managed to cover 90 years) formed the basis of the statistical behavior of hurricanes, which have shown that the increase in global average temperature by 1 ° C increased the likelihood of storm surge comparable to the effects of Hurricane Katrina, 2-7 times! "Apparently, passed the threshold beyond which hurricanes comparable to Katrina, most are caused by global warming than other causes," — wrote the researchers.

This is much higher than the estimates obtained on the basis of climate models. And if you add sea level rise, the coastal cities like New Orleans should prepare for an even more serious damage.

Based on: Ars Technica
Source: Kompyulenta

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