DICTIONARY OF AVIATION 55
circle 'sBzkal intr. ascend or mount in circles, or spirally, as a bird does; turn in a circle or arc of a circle, as an aero- plane does when rounding a curv.
circling 'sBzkz,irj n.
1. the action as of a bird when soaring in circles or in a spiral course, mounting during that part of each lap which is against the wind; gyrating.
2. an instance of this action; a gyration. circulation ^szkQo'Jee-San n. the action of circulating, as
the earth's atmosfere; movement in a circle or circuit.
general circulation of the atmosphere, the wide-spred circulatory movements of the atmosfere or air due to differences of its thermal condition between the polar and equatorial regions.
planetary circulation, the circulation of atmosferic air around the planet; the rotation of air around the earth; the planetary winds collectivly.
tropical circulation, the general circulatory movements of the winds around areas of high and low barometjic pressure in the tjepics.
circumnavigate ,SBzk9m'n3evi,get tr. navigate, sail, or fly around : as, to ^circumnavigate a tower, ^circumnavigate Germany; *circumnavigate the globe.
cirrifonn 'sizi,fe:zm adj. having the ferm of cirrus cloud, shaped like curl-cloud; curly.
cirrocumular ,STzo'kcumjo-l3z: adj. consisting ef or resem- bling cirro-cumulus cloud; cirrocumulous.
cirrocumulated ,sizo'kc.umjo,letid adj. [also spelt cirro* cumulated] of the nature of cirro-cumulus cloud; cirro- cumular.
cirro cumulative ,si^o / kgumjo / letiv adj. [also spelt cirro- cumulativ'} ef or pertaining to cirro-cumulus cloud.
cirro-cumulo-stratus sizo,kgumjo-lo'str,ee-t3s n. a cloud of indefinit structure frem uuhich rain is falling.
cirrocnmulons ,sizo'kcum jo-las adj. [also spelt cirrofcumu- lous'} of the nature of cirro-cumulus cloud; cirrocumular.
cirro-cumulus ,sizo'kcum jo-las n. [also spelt cirro cumulus ' t plural cirr Of cumuli'} a form of compesit cloud combining the the shapes of the cirrus and the cumulus and consisting of a connected system of small uuhite roundish and fleecy cloudlets in close proximity to one another, without shad- ows, but separated by intervals of sky; mackerekback sky; mackerel sky.
cirro-filum ,sizo'fai-}9m n. ice-cloud disposed in threds.
cirro-nebula ,sizo'nebjo-fe n. [ploral cirrotnebulae] a nebu- la or haze in the higher cloud-strata ; a faintly reticulated
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