Cryosphere glossary
psychrometer
an instrument used for measuring the water vapor content of the atmosphere; a type of hygrometer; it consists of two thermometers, one of which (the dry bulb) is an ordinary glass thermometer, while the other (wet bulb) has its bulb covered with a jacket of clean muslin which is saturated with distilled water prior to an observation; when the bulbs are suitably ventilated, they indicate the thermodynamic wet- and dry-bulb temperatures of the atmosphere; one variety is the assman psychrometer (a special form of aspiration psychrometer for which the ventilation is provided by a suction fan).
psychrometric tables
tables prepared from psychrometric data and used to obtain vapor pressure, relative humidity, and dew point from wet- and dry-bulb temperatures.
puddle
an accumulation of melt water on an ice surface, mainly due to melting snow, but in later stages also to the melting of ice; the initial stage consists of patches of slush.
push moraine
moraine built out ahead of an advancing glacier.
Image
The Columbia Glacier surged (advanced rapidly) earlier this century, part of it flowing into a forest. The push moraine in this photograph from 1914 shows Columbia Glacier literally pushing up trees and dirt as it advanced.
D.K. Handy, archived at the World Data Center for Glaciology, Boulder, CO