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Meander length

Distance in the general course of the meanders between corresponding points of successive meanders of the same phase.

Melange

A body of rocks consisting of large blocks (mappable size) of different rocks jumbled together with little continuity of contacts.

Meromictic lake

A lake in which some water remains partly or wholly unmixed with the main water mass at circulation periods is said to be meromictic. The process leading to a meromictic state is termed meromixis The perennially stagnant deep layer of a meromictic lake is called the monimolimnion. The part of a meromictic lake in which free circulation can occur is called the mixolimnion. The boundary between the monimolimnion and the mixolimnion is called thechemocline.

Metamorphic rock

Any rock derived from other rocks by chemical, mineralogical and structural changes resulting from pressure, temperature or shearing stress.

Meteorological or precipitation drought

A period of well-below-normal precipitation, generally on the order of months or years, during which the actual moisture supply at a given place rather consistently falls short of climatically appropriate moisture supply. Meteorological droughts relate to deficiencies of water somewhere in the hydrologic cycle.

Meteorology

The science of weather-related phenomena. See weather, climate.

Methane

A gas created by anaerobic decomposition of organic compounds. Natural gas is composed mostly of methane. Methane is a so-called greenhouse gas (see greenhouse effect). Agricultural wastes, especially animal wastes, are a major source of methane releases to the atmosphere.

Methane (CH4)

A hydrocarbon that is a greenhouse gas with a global warming potential most recently estimated at 21. Methane is produced through anaerobic (without oxygen) decomposition of waste in landfills, animal digestion, decomposition of animal wastes, production and distribution of natural gas and petroleum, coal production, and incomplete fossil fuel combustion. The atmospheric concentration of methane as been shown to be increasing at a rate of about 0.6 percent per year and the concentration of about 1.7 per million by volume (ppmv) is more than twice its pre-industrial value. However, the rate of increase of methane in the atmosphere may be stabilizing.

Methanol

A liquid alcohol (also known as methyl alcohol or wood alcohol), formed in the destructive distillation of wood or made synthetically, and used especially as an alternative fuel, a gasoline additive, a solvent, an antifreeze, or a denaturant for ethyl alcohol. As a gasoline additive it lowers the carbon monoxide emissions but increases hydrocarbon emissions.

Methanol (CH3OH)

A colorless poisonous liquid with essentially no odor and little taste. It is the simplest alcohol with a boiling point of 64.7 degrees Celsius. In transportation, methanol is used as a vehicle fuel by itself (M100), or blended with gasoline (M85).

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