(1) To undergo fusion, or (when used transitively) to cause to undergo fusion. See latent heat of fusion. (2) The liquid produced by the process of fusion (see meltwater).
1. (Also spelled melt?mi.) A strong wind from the northeast or east that often sets in suddenly and blows during the day in summer on the Bulgarian coast and in the Bosporus. 2. Same as monsoon.
The spatial extent (dimension [L2]) of melting on the surface of the glacier. The melt extent can be measured by microwave remote sensing of the brightness temperature with a passive-microwave sensor,
or equivalent analysis of radar or scatterometer imagery. The spatial resolution of passive-microwave radiometers and scatterometers being low at present (several km or coarser), the method is mainly exploited on ice sheets and large ice caps.
A measure, with dimension [L2 T] and units such as km2 d, of the spatiotemporal extent of surface melting. The melting index, usually obtained by remote sensing, is the integral over a defined region
and time span of the time-varying melt extent, and is approximated in practice as a regional sum of products at local scale (such as that of the pixels of a passive-microwave sensor) of the melt extent and the duration of melting. The accuracy of the duration is principally determined by the frequency of imaging, which tends to be high at high latitudes because most orbital sensors are in polar orbits. The melting index is a valuable proxy indicator in the absence of more direct measures of melting. The melting index is sometimes called the melt index or the surface-melt index, and is formulated in slightly different ways by different authors.
The altitude interval throughout which ice-phase precipitation melts as it descends. The top of the melting layer is the melting level. The melting layer may be several hundred meters deep, reflecting
the time it takes for all the hydrometeors to undergo the transition from solid to liquid phase. The temperature of the melting layer is typically 0?C or slightly warmer. See bright band.
The altitude interval throughout which ice-phase precipitation melts as it descends. The top of the melting layer is the melting level. The melting layer may be several hundred meters deep, reflecting
the time it takes for all the hydrometeors to undergo the transition from solid to liquid phase. The temperature of the melting layer is typically 0C or slightly warmer.
The altitude at which ice crystals and snowflakes begin to melt as they descend through the atmosphere. In cloud physics and in radar meteorology, this is the accepted term for the 0?C constant-temper
ature surface (see bright band). It is physically more apt than the corresponding operational term, freezing level, for melting of pure ice must begin very near 0?C, but freezing of liquid water can occur over a broad range of temperatures (between 0? and -40?C; see supercooling). See also freezing point, ice point, melting point.
The altitude at which ice crystals and snowflakes begin to melt as they descend through the atmosphere. In cloud physics and in radar meteorology, this is the accepted term for the 0C constant-tempera
ture surface ( see bright band). It is physically more apt than the corresponding operational term, freezing level, for melting of pure ice must begin very near 0C, but freezing of liquid water can occur over a broad range of temperatures (between 0 and -40C; see supercooling).
The temperature at which a solid substance undergoes fusion, that is, melts, changes from solid to liquid form. The melting point of a substance should be considered a property of its crystalline form
only. At the melting point the liquid and solid forms of a substance exist in equilibrium. All substances of crystalline nature have their characteristic melting points. For very pure substances the temperature range over which the process of fusion occurs is very small. The melting point of a pure crystalline solid is a function of pressure; it increases with increasing pressure for most substances. However, in the case of ice (and a few other substances) the melting point decreases with increasing pressure (see regelation). Under a pressure of one standard atmosphere, the melting point of pure ice is the same as the ice point, that is, 0C.
A pond of liquid water (mostly from melted snow) on the surface of sea ice, usually occurring in the spring. Melt ponds are common in the Arctic but less so in the Antarctic.