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Global Meteoric Water Line
The Global Meteoric Water Line (GMWL) describes the global annual average relationship between hydrogen and oxygen isotope (Oxygen-18 and Deuterium) ratios in natural meteoric waters. The GMWL was first developed in 1961 by Harmon Craig, and has subsequently been widely used to track water masses in environmental geochemistry and hydrogeology. Development and Definition of GMWL When working on the global annual average isotopic composition of Oxygen-18 and Deuterium (2H) in meteoric water, the geochemist Harmon Craig observed a correlation between these two isotopes. The equation for GMWL was then developed and defined by Harmon Craig: :\delta\ce D = 8.0\cdot\delta^\ce O + 10\ ^\!/\!_ Where ''δ''18O and ''δ''2H (also known as ''δ''D) are the ratio of heavy to light isotopes (e.g. 18O/ 16O, 2H/1H). The relationship of ''δ''18O and ''δ''2H in meteoric water is caused by mass dependent fractionation of oxygen and hydrogen isotopes between evaporation from ocean seawater a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pole, with 0° at the Equator. Lines of constant latitude, or ''parallels'', run east–west as circles parallel to the equator. Latitude and ''longitude'' are used together as a coordinate pair to specify a location on the surface of the Earth. On its own, the term "latitude" normally refers to the ''geodetic latitude'' as defined below. Briefly, the geodetic latitude of a point is the angle formed between the vector perpendicular (or '' normal'') to the ellipsoidal surface from the point, and the plane of the equator. Background Two levels of abstraction are employed in the definitions of latitude and longitude. In the first step the physical surface is modeled by the geoid, a surface which approximates the mean sea level over the oce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity), so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation but colloids, because the water vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers. Moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Cycle
The water cycle, also known as the hydrologic cycle or the hydrological cycle, is a biogeochemical cycle that describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, Saline water, saline water (salt water) and Atmosphere, atmospheric water is variable depending on a wide range of climate change, climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, transpiration, condensation, Precipitation (meteorology), precipitation, Infiltration (hydrology), infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different forms: liquid, solid (ice) and Water vapor, vapor. The ocean plays a key role in the water cycle as it is the source of 86% of global evaporation. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteoric Water
Meteoric water is the water derived from precipitation (snow and rain). This includes water from lakes, rivers, and icemelts, which all originate from precipitation indirectly. While the bulk of rainwater or meltwater from snow and ice reaches the sea through surface flow, a considerable portion of meteoric water gradually infiltrates into the ground. This infiltrating water continues its downward journey to the zone of saturation to become a part of the groundwater in aquifers. Overview Most groundwater is meteoric water. Other forms normally do not play a significant role in the hydrologic cycle. Non-meteoric forms of groundwater are connate water and magmatic water, also termed juvenile water. Connate water is trapped in rock strata at the time of formation. Because rock containing connate water is typically formed from ocean sediments, connate water is normally saline. Magmatic water rises from great depth accompanying magma intrusion and affects mineralogy. In other wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
