Observations & History Flashcards
How many land stations does Met Office have?
> 200
What separation of land stations is Met Office?
40 km
Land stations are referred to as
Automated Weather Stations
Name of Manchester’s automatic weather station
Whitworth Observatory
Sea surface stations are powered by
Solar energy
How many stations over the sea?
<20
How far up do radiosondes measure?
~25 km
How do radiosondes infer wind speed?
GPS
What do radiosondes measure?
Temperature, pressure, humidity
What does radar stand for?
Radio detection and ranging
What do radars measure?
Precipitation
What does the radar doppler effect measure?
Wind speeds
When was the first meteorological satellite?
1960
Geostationary satellites have ___ temporal resolution and ___ spatial resolution
High, low
How many geostationary satellites give coverage of whole earth
5 or 6
Altitude of polar-orbiting satellites
700-800 km
Orbit time of polar orbiting satellite
100 minutes
Altitude of geostationary satellites
36,000 km
Thin cloud (cirrus) and night time observations not good for ___ wavelengths
Visible
Wavelength directly related to altitude of cloud
Infrared
Passive sensors monitor radiation such as
Visible, infrared and microwave
Active sensors ___ radiation
Emit
Active sensor retrievals require
Calibration
Visible imagery gives a high amount of ___
Detail
Four processes in forecast
Observation, computer model, human forecaster, end user
Modern meteorology began in
Norway
Who began modern meteorology?
Bjerknes
Two components needed for forecast
Initial observations and sufficient knowledge of the physical laws
Who tried to do the “human computer” approach?
Richardson
When was the first computer-generated forecast?
1950
How many land surface observations are made globally?
100,000
How many sea surface observations are made globally?
2,000
How many radiosonde sites globally per day?
1,000
How many aircraft observations per day?
300,000
How many wind profilers globally?
4,000
How many satellite observations per day?
1.5 million
What is an analysis?
A model observation merge
Forecasts always begin with an
Analysis
The analysis is adjusted according to…
Observations
Two masses conserved in the atmosphere
Water and air
Forecasts have improved by roughly 1 day every ___ years
10
Examples of imperfect knowledge of initial conditions
Resolution too low, instrument error
Examples of imperfect computer model
Need more powerful computers for higher resolution, better understanding of physics
Why processes are parameterised?
Not well understood, not measured, smaller than grid box
Example of chaos theory
Model is sensitive to the initial conditions
When one point diverges from another
Bifurcation
Chaos theory limits forecasts to
14 days
