Calima - a weather phenomenon on the Canary Islands with far-reaching consequences
The desert storms move across the Atlantic:
Blessing or a curse? – That is the question here!
La Palma-residents know the phenomenon, but tourists rub their eyes and be amazed: Suddenly, it is so light on the- and Sun-drenched island views of sea and mountains as it is today Tan-no longer available. Responsible for the so-called records Calima, a weather location, the Canary Islands to wafting in the sand from the Sahara. No one is thrilled – shows a look outside the box of the archipelago, that the wind-whipped desert dust has incredible implications for ecosystems to water and land. We highlight the multidimensional nature of this weather phenomenon for a change even in an essay.
The Calima – in the Canary Islands as dry fog Bruma Seca may refer to – makes, what he wants. He is up to ten times a year. He can just a few days and – in fortunately rare cases – also once a week or longer. He brings mostly hot air, Oddly enough, he is but also sometimes surprisingly cool. The Calima comes always different and: Time it is accompanied by calm, Once he has a slight breeze in the luggage, and when it comes to the crunch, He sweeps in the form of hot storm winds therefore. But always the air humidity drops rapidly, the ochre covering cars and houses up reddish dust, sneaks into every crevice and irritates the mucous membranes. The health authorities of the Canary Islands Government therefore spend alerts especially for allergic persons and enforced at high concentrations of dust in the air, to reside not in the open air. Making fire and work with sparking devices in the open are now absolutely taboo: In summer, forests and fields dry out in longer-lasting desert winds, the farmers on La Palma complain about some big damage, and the risk of forest fire climbs in the extreme range.
The weather phenomenon originates in the Sahara, reached the Canary Islands West of the African mainland desert but not necessarily from the East: "It may happen quite, that the Sahara sand is blown about Madeira first and later with a North wind, or even from West of the Canary Islands", explained Roger P. Frey in his book "Weather on the island of La Palma".
Calima – Scirocco and Chamsin: the desert winds and their names
The sandy wind cargo has a great potential and by no means limited to the Canary Islands. Because it is created by a powerful Undertow, It is formed, If a high across the Sahara, the temperatures rise and the humidity rapidly sink. Up to 5.000 Meters high are drawn then known as aerosols in the atmosphere, where they drift further depending on the starting point and direction of the wind. The Scirocco drives them to Europe, the Chamsin it blows for South-Eastern Europe and the Middle East, and Passat send the particles on the Cape Verde Islands, in the Canary Islands and some thousands kilometers further across the Atlantic to South America, further north in the Caribbean and sometimes even up to Eastern North America. How these sand flags affect the world's climate, has now become a theme for many scientists, because in particular is the amount of dust in the air in the 20. Century has greatly increased.
Sahara sand: Gone with the wind, he fertilizes the Atlantic…
Climate scientists and marine biologists study for more than ten years, What with the Sahara particles on their journey and their successive “Fallout” happens in West direction over the Atlantic Ocean – among other things by means of buoys, where hang so-called Incrustations traps. Because they gather after – According to their severity – in the sea rippling desert particles on. Accompanying analysis with scanning electron microscopy revealed precise information on the chemical and mineralogical composition of particulate matter and hence on their origin. In the course of these studies, it turned out, that the African dust owners under many other nitrogen, Phosphorus and iron transport. Reason: The Central Sahara was a lake in prehistoric times, and after the dry sand in large part consists of the fertile remains of its once organic inhabitants. Conclusion: In particular the nitrogen-rich components of the Calima “fertilize” the Atlantic Ocean, by promoting the growth of phytoplankton. This has two advantages: The phytoplankton in the oceans forms the basis of the food chain and thus promotes the existence of all possible sea creatures. On the other hand, climate researchers hope, that way the greenhouse effect is minimized. Because the micro-organisms in the sea carbon dioxide from the atmosphere absorb - do you mean: The more phytoplankton in the water, the less CO2 in the air. However, too much dust entry in the Atlantic holds potentially disadvantages: uncontrolled growth of plankton and low-oxygen areas…
Desert dust “feeds” Plants in the Amazon
The sand from Africa has a more important function of fertilizer according to prevailing expert opinion also, for example, in the Amazon basin, where is estimated 28 Accumulate millions of tons per year. Actually, the ground should the green lung the Earth nowadays to be exhausted by situated in the course of time. That the rain forest still grows and thrives, lead scientist on the via “Air cargo” imported, nutrient-rich mineral sand from the Sahara back.
Work in looking at the intercontinental dust drift will not soon go researchers. The variety of the associated biogeochemical processes and their complex interactions are already not yet covered. Among many others, for example, a link between the desert air and hurricanes is suspected, because the driving across the Atlantic and the rippling aerosols can lessen the sunlight on its surface temperature by about one degree. So the chances of the hurricanes fall, because they need warm water, to build up.
Last but not least,: Did anybody actually thoughts about the particles of Saharan dust, you plop down for millennia in the course of their journey west on the Canary Islands? Quite: Inmaculada Menéndez, Professor at the University of Las Palmas de Gran Canaria, estimates, that is because in the course of time a considerable amount has accumulated: “More than 30 Percent of the components of natural soils in the Canary Islands are due beziehungswseise on dust from the Sahara to the Calima…”
This NASA video shows the transatlantishe journey of desert sand in the Amazon rainforest: Title: As Sahara dust feeds the plants…