Meteorology Lenka Petrášová 1

Definitions Meteorology – Study of the atmosphere & the processes that causes weather Weather – State of the atmosphere at a particular place & time. Described by T, Humidity, Ppt., Wind speed Climate – Average values of weather conditions at some place for at least 30 years Climatology – Study of climate, control, spatial and temporal variability 2

Climatic Zones 3

Atmosphere Mixture of gases surrounding the earth Devided into layers Troposphere: surface to ft - where most of weather is -Tropopause- top of troposphere, jet stream, turbulence, top of thunderstorms Stratosphere: to feet 4

Composition of the atmosphere Gases - Nitrogen 78% - Oxygen 21% - Other 1% - Water vapour 0% - 4% Pollutants 5

On the Weather Maps Isobars- lines which join the points of equal atm. pressure, identify pressure systems Low pressure High pressure Trough of low (brázda) Ridge of high (hřeben) 6

Fronts Boundaries between air masses COLD- where cold air is overtaking warm air WARM- where warm air is overtaking cold air OCCLUDED- when a warm and cold front meets and the warm air is forced up above ground level STATIONARY- when a warm or cold front stops moving Symbols on map 7

8

Clouds Amount of clouds: Sky cover- sky clear (no clouds); few (1/8-2/8 cloud cover); scattered (3/8-4/8); broken clouds (5/8-7/8); overcast (8/8) Gouped into 3 levels: – Low level: surface to 6500 ft( stratus, cumulus) – Medium level: ft AGL (altostratus, altocumulus, cumulonimbus) – High level: above ft AGL ( cirrus, cirrostratus) 9

10

11

Meteorological phenomena Precipitation (rain, hail, snow, snow grains, sleet, flurry, blizzard, whiteout) Wind ( windshear, gust, squall, breeze, jet streams) Mist- vizibility more than 1 km Fog- vizibility less than 1 km Humidity- the amount of water in the air Dew point- the temperature to which air must be cooled before water vapour turns back to water 12

Danger for flight Turbulence- Turbulence is caused by the relative movement of disturbed air through which an aircraft is flying -arise from strong wind over irregular terrain or obstacles, air movements associated with convective activity (thunderstorms and lightning) 13

CAT- Clear Air Turbulence is defined as turbulence which is NOT associated with cloud and therefore cannot be detected visually or by conventional weather radar. - caused by flow of air in an unstable atmosphere Source of CAT could be a JET STREAM- high level wind which is important to navigation because it blows more than 200 knots -> reduce fuel consumption - generated as a result of the temperature gradient between air masses 14

Icing - Icing conditions exist when the air contains droplets (kapičky)of supercooled liquid water -Removal: a) If there is ice prior to take off on an aircraft: - Application of deicing fluid - Use of infrared heating b) In flight: - Electrical heating - pneumatic deicing boots ( inflated rubber which breaks the ice) - hot air from compressor 15

METAR- Aerodrome routine meteorological report TAF- Aerodrome forecast NOTAM- a notice containing information concerning the establishment, condition or change in any aeronautical facility, service or procedure SIGMET- information concerning en- route weather which may affect the safety of aircraft operations 16

Used sources: Keller,Ladislav. Učebnice pilota