Meteorology Flashcards
What types of meteorological hazards are there?
- Visibility
- Fog
- Wind/Changes in wind
- Cloud height
- Turbulence (E.g. in clouds)
- Icing
- Lightning
- Weather fronts
What does WAFS stand for and what does it do?
- World Area Forecast System
- Supplies meteorological authorities and other users with forecasts of global meteorological parameters like upper wind and temperature information as well as forecasts of significant weather phenomena.
What does WAFC stand for?
There are 2 WAFCs within the WAFS. Where are these located?
- World Area Forecast Centre
- London and Washington
Why has an ICAO/International Standard atmosphere been defined?
To establish standards for:
- Calibration of instruments.
- Vertical separation of ACFT.
- To compare power parameters of different ACFT and engines.
Describe ISA at MSL
- Temperature: +15°C
- Pressure: 1013.25 hPA = 29.92 inch HG
- Barometric Lapse Rate: 30ft/1hPA
- Density: 1.225kg/m^3
- Relative humidity: 0%
What is the gas composition of ISA?
What is the maximum percentage composition that water can reach within the atmosphere?
- 78% Nitrogen (N2)
- 21% Oxygen (O2)
- 0.9% Argon (Ar)
- 0.03% Carbon Dioxide (CO2)
- No water by ISA Definition (In reality can be up to 4% all within the troposphere)
Describe the ISA Troposphere in terms of vertical limits and temperature gradient.
What is the name of the boundary between the troposphere and the stratosphere?
- Extends from MSL to approximately 6-8km (pole), 11km/36100ft (45° latitude) and 16-18km (Equator).
- Temperature Gradient: approximately -2(°C)/1000ft.
- Boundary between troposphere and stratosphere called the Tropopause.
Describe the ISA Lower Stratosphere in terms of vertical limits and temperature gradient.
- Extends from tropopause to around 20km/65600ft.
- Isothermal Layer - Temperature remains constant - around -56.5°C.
Describe the ISA Upper Stratosphere in terms of vertical limits and temperature gradient.
Where does ISA definition end?
- Extends from around 20km/65600ft to around 50km.
- Inversion - Temperature begins to increase.
- Temperature Gradient: around +0.3K(°C)/1000ft.
ISA definition ends at around 32km/105,000ft.
How is heat transferred from the surface to the overlying atmospheric layers?
Mainly by conduction and convection.
Where do almost all clouds and weather occur and why?
Within the troposphere due to water content.
Why do high temperatures occur in the upper stratosphere?
- Because of the presence of ozone between 20km and 50km which absorbs ultra violet radiation from the sun.
Note: Up to 50°C.
What is the atmospheric layer above the stratosphere called?
What are the vertical limits of this layer?
What happens to temperature with altitude within this later?
- Mesosphere.
- Extends from stratosphere to around 80km.
- Temperature decreases with altitude.
What is the atmospheric layer above the mesosphere called?
What are the vertical limits of this layer?
What happens to temperature with altitude within this later?
- Ionosphere
- Extends from mesosphere to around 400km
- Temperature increases again due to low air density - very little energy is required from the sun to heat the air.
What is the layer beyond the ionosphere called?
Exosphere
How is air pressure measured?
Which units are used?
Barometer (hPA, inch Hg)
How is air temperature measured?
Which units are used?
Thermometer (°C)
How is air density measured?
Which units are used?
It is calculated (kg/m^3)
How is dew point measured?
Which units are used?
It is calculated (°C)
How is relative humidity measured?
Which units are used?
Hygrometer (%)
How is cloud cover measured?
Which units are used?
Ceilometer (okta)
How is cloud base measured?
Which units are used?
Ceilometer (ft)
How is precipitation measured?
Which units are used?
Rain gauge (mm)
How is ground visibility measured?
Which units are used?
Estimated by observer (m)