Aeronautical meteorology
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Aeronautical meteorology

Aeronautical Meteorology

 

Meteorology - the science that studies the physical processes and phenomena occurring in the earth's atmosphere, in their continuous communication and interaction with the underlying surface of the sea and land.

Aeronautical Meteorology - Meteorology Applied branch that studies the impact of meteorological elements and weather phenomena on aircraft operations.

Atmosphere. Air Land shell called the atmosphere.

According to the nature of the temperature distribution in the vertical atmosphere can be divided into four main areas: the troposphere, stratosphere, mesosphere, thermosphere and three transition layer between them: the tropopause, and stratopause mesopause (6).

Troposphere - the lower layer of the atmosphere, the height 7-10 km at the poles and to 16-18 km in equatorial regions. All weather events are developed mainly in the troposphere. In the troposphere, the formation of clouds, the appearance of fog, thunderstorms, snowstorms, icing aircraft is observed, and other phenomena. The temperature in this layer of the atmosphere decreases with an average height of at 6,5 ° C every kilometer (0,65 ° C to 100%).

Tropopause - the transition layer that separates the troposphere from the stratosphere. The thickness of this layer ranges from several hundred meters to several kilometers.

The stratosphere - the layer of the atmosphere lying above the troposphere, up to a height of about 35 km. Vertical movement of the air in the stratosphere (compared to the troposphere) is very weakened or almost absent. For the stratosphere is characterized by a slight decrease in temperature in the layer 11-25 km and increase in the layer 25-35 km.

Stratopause - a transition layer between the stratosphere and the mesosphere.

Mesosphere - a layer of the atmosphere, extending from about 35 80 to km. Characteristic of the layer of the mesosphere is the sharp increase in temperature from the beginning to level 50-55 km and lowering it to the level 80 km.

Mesopause - transition layer between the mesosphere and the thermosphere.

Thermosphere - a layer of the atmosphere above 80 km. This layer is characterized by a continuous sharp rise in temperature with altitude. At the height of 120 km the temperature reaches + 60 ° C, and at an altitude of 150 km -700 ° C.

The circuit structure of the atmosphere to an altitude of 1 00 km presented.

Standard atmosphere - the conditional distribution of the height of average values ​​of the physical parameters of the atmosphere (pressure, temperature, humidity, etc.). For the international standard atmosphere following conditions are accepted:

  • sea ​​level pressure, equal to 760 mm Hg. Art. (1013,2 mb);
  • RH 0%; at sea level, the temperature of -f 15 ° C and drop to behold the height in the troposphere (up to 11 000 m) on 0,65 ° C per m 100.
  • 11 000 m above the temperature is assumed constant and equal -56,5 ° C.

 

See also:

Air masses

Air fronts

Cyclones and anticyclones

Hazardous weather phenomena for aviation

 

meteorological elements

State of the atmosphere and the processes occurring in it, characterized by a number of meteorological elements: pressure, temperature, visibility, humidity, clouds, precipitation and wind.

Aeronautical Meteorology 2

Atmospheric pressure is measured in millimeters of mercury or millibars (1 mmHg -.. 1,3332 mb). For normal pressure taking atmospheric pressure equal to 760 mm. Hg. st., which corresponds to 1013,25 mb. Normal pressure is close to the average pressure at sea level. The pressure varies as continuously at the surface and at altitudes. The change in pressure with height can be characterized by the magnitude of the barometric stage (height to which it is necessary to raise or lower that the pressure was changed to 1 mm Hg. Art., or 1 mb).

The magnitude of the barometric stage is determined by the formula

Temperature describes the thermal state of the atmosphere. Temperature is measured in degrees. The temperature change depends on the amount of heat coming from the sun at this latitude, the nature of the underlying surface and atmospheric circulation.

In the Soviet Union and most other countries of the world adopted centigrade scale. For basic (fiducials) point in the scale adopted: 0 ° C - the melting point of ice and 100 ° C boiling point of water at normal pressure (mm Hg 760..). The gap between these points is divided into equal parts 100. This period is called the "one degree Celsius» - 1 ° C.

Visibility. Under the horizontal visibility at ground level, determined by meteorologists, is meant that the distance at which you can still detect the object (reference) in shape, color, brightness. The visibility range is measured in meters or kilometers.

Humidity - water vapor content in the air, expressed in absolute IPT relative units.

Specific humidity - is the amount of water vapor in grams per 1 air ls3.

Specific humidity - the amount of water vapor in grams per kg of moist air 1.

Relative humidity - the ratio of the contained water vapor in the air to the amount required for the saturation of air at a given temperature, expressed as a percentage. Because the relative humidity can be determined whether this state close to the saturation humidity.

Dew point is the temperature at which the air would reach saturation at a given moisture content and constant pressure.

The difference between the air temperature and the dew point is called the dew point deficit. The dew point temperature is in the air when its relative humidity is 100%. Under these conditions, the condensation of water vapor and the formation of clouds and fogs.

Cloud - accumulation of airborne water droplets or ice crystals, resulting from the condensation of water vapor. In observations of clouds mark the number, shape and height of the lower limit.

Cloud amount estimated by 10-point scale: 0 points means no clouds, 3 points - three-quarters of the sky covered with clouds, 5 points - half of the sky covered by clouds, 10 points - the sky covered with clouds (overcast). The height of the cloud is measured by svetolokatorov, searchlights, balloon pilots and aircraft.

Aeronautical Meteorology 3

All the cloud, depending on the height of the lower boundary is divided into three tiers:

Upper level - above 6000 m, to it are: cirrus, Cirrocumulus, Cirrostratus.

Middle tier - from the 2000 6000 to m, it is treated: Altocumulus, Altostratus.

Lower level - below 2000 m, it is treated: sloistokuchevye, layered, layered rain. The lower tier of the cloud are also extending a significant distance vertically, but the lower limit of which lies in the lower tier. These clouds are cumulus and kuchevodozhdevye. These clouds are allocated to a special group of vertical development of clouds. Rain has the greatest influence on the activity of aviation, since clouds are associated rainfall, thunderstorms, icing and severe turbulence.

Precipitation - water droplets or ice crystals falling from the clouds to the earth's surface. By the nature of precipitation is divided into Widespread, falling from nimbostratus and high-stratus clouds in the form of medium-sized drops of rain, or in the form of snowflakes; rain, falling from cumulonimbus clouds in the form of large drops of rain, snow flakes or hail; morosya- u and e, falling from layered and stratocumulus clouds in the form of very fine drops of rain.

Flying in the zone of precipitation is difficult due to a sharp deterioration in visibility, reducing the height of the clouds, turbulence, icing in freezing rain and drizzle, possible damage to the surface of the aircraft (helicopter) on a roll of hail.

Wind - Air movement relative to the earth's surface. Wind is characterized by two values: speed and direction. The unit of measurement of speed vetra- meter per second (1 m / s) or kilometers per hour (1 km / h). 1 m / sec = = 3,6 km / h.

Wind direction is measured in degrees, it should be borne in mind that counting from the North Pole in a clockwise direction: north direction corresponds 0 ° (or 360 °), east - 90 °, yuzhnoe- 180 °, west - 270 °.

Weather wind direction (blowing from) different from the direction of Air Navigation (which blows) na 180 °. In the troposphere, the wind speed increases with height and reaches a maximum at the tropopause.

The relatively narrow band of strong winds (speeds from 100 km / h and above) in the upper troposphere and lower stratosphere at altitudes close to the tropopause, called jet streams. Part of the jet stream, where the wind speed reaches a maximum value, called the axis of the jet stream.

For its size jet streams extend for thousands of kilometers in length, hundreds of kilometers wide and several kilometers in height.

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