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.
As established by Howard, HP G62-130ET Batteryclouds are grouped into three physical categories: cirriform, cumuliform, and stratiform. These designations distinguish a cloud’s physical structure and process of formation. All weather-related clouds form in the troposphere, the lowest major layer of the Earth’s atmosphere. HP G62-130EV Battery
Vertical family D2 cumulonimbus capillatus with anvil-shaped incus supplementary feature. Higher layer of family A cirrus spissatus near top of image.
Cumuliform-category clouds are the product of localized convective or orographic lift. Incoming shortwave radiation generated by the sun reflects back as longwave radiation when it reaches the earth’s surface, HP G62-130SD Battery a process that warms the air closest to ground. The more the air is heated, the more unstable it will tend to become. If the airmass is only slightly unstable, clouds of limited convection that show both cumuliform and stratiform characteristics will form at any altitude in the troposphere where there is sufficient condensation.HP G62-130SL BatteryIf a poorly organized weather system is present, weak intermittent virga or precipitation may fall from those clouds that form mostly in the lower half of the troposphere. Greater airmass instability caused by more intense radiational surface heating by the sun will create a steeper temperature gradient from warm or hot at surface level to cold aloft. HP G62-134CA BatteryThis may cause larger clouds of free convection to form in the lower half of the troposphere and grow upward to greater heights, especially if associated with fast-moving unstable cold fronts. Large free-convective types can produce light to moderate showers if the airmass is sufficiently moist. HP G62-135EV BatteryThe largest free-convective towering clouds produce thunderstorms and a variety of types of lightning including cloud-to-ground that can cause wildfires. Other convective severe weather may or may not be associated with thunderstorms and include heavy rain or snow showers, hail, strong wind shear, downbursts, and tornadoes. HP G62-140EL Battery