FISICA AMBIENTALE 1
Plumes gaussiani nell’aria
Antonio Ballarin Denti
[email protected]
Horizontal transport of pollutants in the atmosphere
Distance
Time scale
1 – 10 m
3 – 30 km
100 – 1000 km
Hemisphere
Globe
Seconds
Hours
Days
Months
Years
Vertical transport of pollutants in the atmosphere. Time
scales for vertical transport of pollutants from the ground
to the layers indicated. The boundaries of the layers vary
with day and night.
Layer
Extension
Time scale
Boundary layer
Troposphere
Stratosphere
Ground - 100 m/3 km
100 m/3 km - 10 m/15 km
10 m/15 km - 50 km
Minutes to hours
Days to weeks
Years
The troposphere determines the weather
The stratosphere acts as a lid
PLUMES SHAPES FROM A HIGH CHIMNEY FOR SEVERAL STABILITY CONDITIONS
Behaviour of a
parcel of air,
reflected in the
plume shape on
the right
Adiabatic T
profiles
as a function of
altitude and the
drawn curves the
‘real’profile for
several cases
Sorgente emissiva puntuale e costante
Dispersion coefficients and as a funcion of the distance
from the source for the atmospheric stability conditions.
Plume gaussiani da un camino alto
A livello del suolo :
Lungo l’asse del plume
y=0
Ground level concentration underneath
the axis of a horizontal plume.
Here a = σy / σz
Determinazione diretta di sy e sz
Pasquil stability categories