- 行业: Weather
- Number of terms: 60695
- Number of blossaries: 0
- Company Profile:
The American Meteorological Society promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. Founded in 1919, AMS has a membership of more than 14,000 professionals, ...
A pyranometer developed by M. Robitzsch. Its design utilizes three bimetallic strips that are exposed horizontally at the center of a hemispherical glass bowl. The outer strips are white reflectors, and the center strip is a blackened absorber. The bimetals are joined in such a manner that the pen of the instrument deflects in proportion to the difference in temperature between the black and white strips and is thus proportional to the intensity of the received radiation. This instrument must be calibrated periodically.
Industry:Weather
A protective structure erected over railroad tracks to prevent deep snow from accumulating on the tracks. They are used in deep cuts in mountains where avalanches are common.
Industry:Weather
A prominent western boundary current in the northern Indian Ocean. During the northeast monsoon season the Somali Current flows southward from 5° to 1°N in December, expanding to 10°N–4°S in January–February and contracting again to 4°N–1°S in March. It is then fed from the North Equatorial Current and discharges into the Equatorial Countercurrent. During all these months its speed is 0. 7–1. 0 m s<sup>−1</sup>. During the southwest monsoon the current develops into an intense northward jet with extreme surface speeds; 2 m s<sup>−1</sup> have been reported for May and 3. 5 m s<sup>−1</sup> for June. The jet is fed from the South Equatorial Current and flows along the eastern coast of the Horn of Africa; part of it continues along the Arabian Peninsula as the East Arabian Current. South of 5°N the jet is shallow; southward flow continues below a depth of 150 m. North of 5°N the jet deepens and embraces the permanent thermocline. During its northward phase the Somali Current is associated with strong upwelling between 2° and 10°N. The upwelled cold water turns offshore near Ras Hafun (11°N), forming a large anticyclonic eddy with a diameter of about 500 km known as the Great Whirl. Eventually the water from the Somali Current enters the Southwest Monsoon Current.
Industry:Weather
A prominent spiral band in a tropical cyclone, generally on the downshear side, where convergence occurs as air moving with the vortex overtakes the environmental flow.
Industry:Weather
A process of water mass formation through a combination of wind action and cooling. A convergence in the wind-driven surface current field pushes water down along constant- density surfaces. During winter this water is convectively mixed as a result of surface cooling. When spring warming sets in, the mixed water is isolated under a thin surface layer of warmer water but continues to move downward on constant-density surfaces in response to the current convergence, eventually moving out of reach of next winter's mixing. It is then injected into the ocean interior as a new water mass contribution.
Industry:Weather
A process of drop growth (primarily of historical interest) suggested originally by O. Reynolds, which involves net evaporation from warmer cloud drops and condensation on cooler drops.
Industry:Weather
A process of charge separation associated with the mechanical disruption of liquid drops and believed to be based on the electrical double layer at the air–water interface. Spray electrification is the common explanation for the electric field generation in the vicinity of waterfalls.
Industry:Weather
A process from which ice splinters are produced due to the pressure buildup in the ice shell when a drop is freezing, resulting from the ice-water expansion on phase change. This causes the shell to deform and crack and eject ice splinters. It has been suggested as one of the ice multiplication mechanisms.
Industry:Weather
A positively charged subatomic particle with a rest mass of 1. 67262 x 10<sup>−27</sup> kg, slightly less than that of the neutron and about 1836 times that of the electron. Atomic nuclei are composed of protons and neutrons bound together by nuclear forces. The common term for neutron or proton is nucleon.
Industry:Weather
A precipitation gauge comprising a tall pipe 30. 5 cm (12 in. ) in diameter designed especially to measure the water content of snow in remote mountainous areas for unattended operation; part of a SNOTEL site. The bottom contains a known amount of an oil–antifreeze mixture. The oil prevents evaporation and the antifreeze melts the snow. A pressure transducer converts the oil–antifreeze–water mixture into a calibrated water depth. Daily changes in depth provide seasonal and annual accumulations.
Industry:Weather
