chapter 5 Flashcards
persistence method of forecasting
when conditions are unlikely to change
- in the middle of an air mass
- under a stationary front
- under an occluded low
Analogue method of forecasting
recognizes different patterns from the past
climatological method of forecasting
based on long term average conditions
- examples
- the normal high for today
- november is usually cloudy, so today is cloudy
- our spring winds are usually out of the SW, so today the winds are coming out of the SW
trend method of forecasting
Wx will move based on current speed and direction
Dynamical method of forecasting
based on Thermodynamic Equations
3-d grid simulation of the atmosphere
Statistical method of forecasting
-for individual Wx elements
~ex. high temp. and wind speed
-model output statistics
-often given as probability
Ensemble Method of forecasting
computer generated maps
- many models
- many iterations
- human guidance
Limitations to Wx forecast
-complexity of the atmosphere system
(impossible to model every interaction)
-Chaos
(some inputs and their consequences are not predictable)
-forecast should therefore include a level of confidence
How does wind influence air pollution?
- dilutes
- transports
- concentrates at barriers
how does precipitation influence pollution?
can clean the air
how does topography influence air pollution?
-can trap pollution ~Los angeles -inhibit dilution ~Appalachian mountains -create inversion from cold air drainage ~denver
how does stability influence air pollution?
-Unstable-lots of vertical mixing
-Stable-no vertical mixing
(worse with temperature inversions)
radiation temperature inversion
-when grounds cools quickly at night clear sky long nights dry air calm winds
Advection temperature inversion
- cold air blowing near the ground
- most often from the north
- produces our first hard freeze
cold air drainage temperature inversion
wind produced by either gravity or mountains that cool down the area
subsidence temperature inversion
develops when a widespread layer of air descends and warms up
-Primary pollutant
Particulates
- Sources: industry and agriculture
- effects: respiratory and heart disease
-Primary pollutant
Carbon Monoxide
- Source: incomplete burning
- effects: suffocation
-Primary pollutant
Sulfur Dioxide
- Sources: coal burning, volcanoes, sea spray
- Effects: Sulfuric acid rain
-Primary pollutant
Volatile Organic Compounds
- mostly hydro carbons
- sources: trees, evaporation, incomplete burning
- effects: noxious, flammable, carcinogenic