Potential temperature
The temperature of a parcel of air would
have if moved adiabatically to the surface
Adiabatic process no change in internal energy (entropy)
P0
= T
P
R
Cp
Atmospheric boundary layer
Free atmosphere
Entrainment layer
capping i
Typical Culvert Shapes
Shown: Large PipeArch Culvert
being installed under road crossing
Single (le>) versus MulAple Barrel (right)
Embedded with Natural Materials
SquareEdged Entrance/exit
Open BoJom with Natural Materia
Radiation
Net radiation:
Rn = S n + Ln
[MJ/(m2d)]
e e
(RN G ) + a C p s a
ra
1
Et =
w
rs
+ 1 +
r
a
Net shortwave radiation Sn very hard. Some ball park methods in book.
However we can get data from models or observations
http:/snowdog.larc.nasa.
Energy conservation
Energy equation
The steady-state energy equation is given by
e v ndA =
dQh dW
dt
dt
A
V2
+ u . The work
with energy per unit mass given by e = gz +
2
done due to pressure forces is
dW
=
dt
p v ndA
A
Substituting, the energy equation be
From last lecture
!
Types of pumps
!
Afinity laws:
!
Eficiency:
!Positive
Displacement
!Rotodynamic
!
Multiple pumps:
!Series:
!Parallel:
Example 2: Multiple-Pumps
A pump has a performance curve of
hp = 10 0.1Q2
(a) If we run three of these pumps in
serie
Types of Pumps
!
Positive Displacement
! Deliver
xed quantity of
liquid per revolution
! Theoretically produce
same (constant) ow
regardless of pressure
head
!
Rotodynamic
! Add
energy to the uid
(increases ow)
www.emt-india.net/equipment_tips/fans_pumps
To see all the details that are visible on the
screen, use the "Print" link next to the map.
Map data 2012 Google -
Salt Lake City Population Growth
200,000
180,000
Declining Growth P(t)=Psat-(PSat-Po)e-kt
160,000
140,000
Pupluation
120,000
100,000
Arithm
Water in the atmosphere
The water cycle
WWW.CNES.NAU.EDU
Where s our water?
Where s our water?
Only earth and Titan
Energy in the atmosphere
Potential temperature
The temperature a parcel of air would
have if moved adiabatically to the surface
Adiabatic
= 2501000 2361Ts 2440000 [J/kg]
Latent heat of
vaporization
Potential evapotranspiration
Same as P-M actual evaporation, only with rs = 0
And
2
2
4.72 ln
z0 , z 0.00137
ra =
0
1 + 0.536U 2
Index of dryness:
Id =
Ep
es ea
(RN G ) + a C p r
1
a
Ep =