Bioprecipitation, the concept of rain-making bacteria, was proposed by David Sands from Montana State University. Such microbes – called ice nucleators – are found in rain, snow, HP Pavilion dm4-1008tu Battery and hail throughout the world. These bacteria may be part of a constant feedback between terrestrial ecosystems and clouds and may even have evolved the ability to promote rainstorms as a means of dispersal. They may rely on the rainfall to spread to new habitats, much as some plants rely on windblown pollen grainsHP Pavilion dm4-1008tx Battery.
Similar patterns also occur at higher latitudes in both hemispheres. Upward currents of air along the polar fronts diverge at high tropospheric altitudes. HP G62-120EQ BatterySome of the diverging air moves to the poles where air mass subsidence inhibits cloud formation and leads to the creation of the polar areas of high pressure. Divergence occurs near surface level resulting in a return of the circulating air to the polar fronts where rising air currents can create extensive cloud cover and precipitation. This vertical cycle comprises the polar cell in each latitudinal hemisphere. HP G62-120ER BatterySome of the air rising at the polar fronts diverges away from the poles and moves in the opposite direction to the high level zones of convergence and subsidence at the subtropical ridges on each side of the equator. These mid-latitude counter-circulations create the Ferrel cells that encircle the globe in the northern and southern hemispheres. HP G62-120ES Battery
Latin nomenclature: historical background
Altocumulus lenticularis forming over mountains in Wyoming with lower layer of cumulus mediocris and higher layer of cirrus spissatus. HP G62-120ET Battery
Luke Howard, a methodical observer with a strong grounding in the Latin language, used his background to categorize the various tropospheric cloud types and forms during December 1802. He believed that the changing cloud forms in the sky could unlock the key to weather forecasting. HP G62-120EY BatteryJean-Baptiste Lamarck worked independently on cloud categorization and came up with a different naming scheme that failed to make an impression even in his home country of France because it used unusual French names for cloud types. HP G62-120SE Battery His system of nomenclature included twelve categories of clouds, with such names as (translated from French) hazy clouds, dappled clouds and broom-like clouds. Howard used universally accepted Latin, which caught on quickly. HP G62-120SL Battery As a sign of the popularity of the naming scheme, the German dramatist and poet Johann Wolfgang von Goethe composed four poems about clouds, dedicating them to Howard. Classification systems would be proposed by Heinrich Dove of Germany in 1828 and Elias Loomis of the United States in 1841, HP G62-120SS Batterybut neither became the international standard that Howard’s system became. It was formally adopted by the International Meteorological Commission in 1929.