The ThreeThree-Dimensional Circulation
1
Steady Flow:
   Frad kˆ  Fconv kˆ   VE   0,
where
1
2
E  c pT  gz  Lv q  | V |
2
Integrate from surface to top of atmosphere:
   VE  FradTOA   Frad  Fconv  surface  0
2
What causes lateral enthalpy
py trans port byy
atmosphere?
1: Large-scale, quasi-steady
overturning motion in the Tropics,
Tropics,
2: Eddies with horizontal dimensions
of ~ 3000 km in middle and high
l tit des
latitud
3
Observed Characteristics of the
Ti
Time
Mean
M
Tropical
T i lA
Atmosphere
h
• Monthly and seasonal means
• Zonal means
4
Objective Analysis
Provides “Best Guess” as to the State of the Atmosphere
1. Start with “First Guess” Analysis
2 Ingest Data
2.
-Radiosondes
-Surface Observations
-Ship Reports and Buoy Observations
-Aircraft Observations
-Satellite Observations
3. Data Assimilation
-Blend data to produce an “initialized” (balanced)) analyysis
(or not....)
4. Run General Circulation Model to Obtain next First Guess
5
6
Mean January Outgoing Longwave Radiation (OLR),
1979-2001
Shading at 10 W m-2 intervals,
starting at 260 W m-2
7
Mean April Outgoing Longwave Radiation,
1979-2001
Shading at 10 W m-2 intervals,
starting at 260 W m-2
8
Mean July Outgoing Longwave Radiation,
1979-2001
Shading at 10 W m-2 intervals,
starting at 260 W m-2 9
Mean October Outgoing Longwave Radiation,
1979-2001
Shading at 10 W m-2 intervals,
starting at 260 W m-2
10
Mean January 200 hPa Total Wind,
O tgoing Longwave
Outgoing
Long a e Radiation
1979-2001
Wind (vectors, largest around 70 m s-1)
OLR ((shading
h di at 10 W s-22 intervals)
l )
11
Mean April 200 hPa Total Wind,
O tgoing Longwave
Outgoing
Long a e Radiation
1979-2001
Wind (vectors, largest around 70 m s-1)
OLR (shading at 10 W s-2 intervals)
12
Mean July 200 hPa Total Wind,
Outgoing Longwave Radiation
1979-2001
Wind (vectors, largest around 70 m s-1)
OLR (shading at 10 W s-2 intervals)
13
Mean October 200 hPa Total Wind,
O tgoing Longwave
Outgoing
Long a e Radiation
1979-2001
Wind (vectors, largest around 70 m s-1)
OLR (shading at 10 W s-2 intervals)
14
Mean January 850 hPa Total Wind,
Outgoing Longwave Radiation
1979-2001
Wind (vectors, largest around 10 m s-1)
OLR (shading at 10 W s-2 intervals)
15
Mean April 850 hPa Total Wind,
O tgoing Longwave
Outgoing
Long a e Radiation
1979-2001
Wind (vectors,
(vectors largest around 10 m s-11)
)
OLR (shading at 10 W s-2 intervals)
16
Mean July 850 hPa Total Wind,
Outgoing Longwave Radiation
1979-2001
Wind (vectors, largest around 10 m s-1)
OLR (shading at 10 W s-2 intervals)
17
Mean October 850 hPa Total Wind,
Outgoing Longwave Radiation
1979-2001
Wind (vectors,
(vectors largest around 10 m s-11)
)
OLR (shading at 10 W s-2 intervals)
18
19

 v
 u
    V 

 x
 y

Vorticity
Divergence

D    V 

Streamfunction
Velocity
Potential


2
u
v

x
y

 

 D
2
20
Non-divergent (Rotational) Wind
u


 
y
v



x
Divergent Wind
u


 
x
v
21



y
Mean January 200 hPa Streamfunction
1979-2001
1979
2001
Conttour int
i tervall 1.0
1 0 X 107 m2 s-11
22
Mean January 200 hPa Velocity Potential
and Divergent
Di ergent Wind
1979-2001
6 m2 s-1
1
Contour interval 1.0
1 0 X 106
Largest vector is about 5 m s-1
23
Mean January 200 hPa Divergent Wind,
Outgoing Longwave Radiation
1979-2001
Div. Wind (vectors, largest around 15 m s-1)
OLR (shading at 10 W s-2 intervals)
24
Mean April 200 hPa Divergent Wind,
Outgoing Longwave Radiation
1979-2001
Div. Wind (vectors, largest around 15 m s-1)
OLR (shading at 10 W s-2 intervals)
25
Mean July 200 hPa Divergent Wind,
Outgoing Longwave Radiation
1979-2001
Div. Wind (vectors, largest around 15 m s-1)
OLR (shading at 10 W s-2 intervals)
26
Mean October 200 hPa Divergent Wind,
Outgoing Longwave Radiation
1979-2001
Div. Wind (vectors, largest around 15 m s-1)
OLR (shading at 10 W s-2 intervals)
27
28
Annual Mean Precipitation
29
30
31
January Zonal Mean Meridional Wind 1979-1993 from ECMWF
Contour interval .2 m s-1 Shading Red Positive (Southerly)
32
April Zonal Mean Meridional Wind 1979-1993 from ECMWF
C t
Contour
inttervall .2
2 m s-11
Shading Red Positive (Southerly)
33
July Zonal Mean Meridional Wind
ECMWF
1979-1993 from Contour interval .2 m s-1
Shading Red Positive (Southerly)
34
October Zonal Mean Meridional Wind
ECMWF
1979-1993 from Contour interval .2 m s-1
Shading Red Positive (Southerly)
35
January Zonal Mean OLR, Vertical and Meridional Wind, 19791993 from ECMWF
latitude
Contour interval 1 mm s-1
Shading Red Positive (Upward)
36
April Zonal Mean OLR, Vertical and Meridional Wind, 19791993 from ECMWF
latitude
Contour interval 1 mm s-1
Shading Red Positive (Upward)
37
July Zonal Mean OLR, Vertical and
Meridional Wind, 19791993 from ECMWF
latitude
Contour interval 1 mm s-1
Shading Red Positive (Upward)
38
October Zonal Mean OLR, Vertical and
Meridional Wind, 19791993 from ECMWF
latitude
Contour interval 1 mm s-1
Shading Red Positive (Upward)
39
January Zonal Mean Zonal Wind 1979-2001
1979
2001 from NCEP
NCEP
Contour interval 5 m s
s-11
Shading Red Positive (Westerly)
40
July Zonal Mean Zonal Wind 1979-2001
1979
2001 from NCEP
NCEP
C t
Contour
int
i tervall 5 m s-11
Shading Red Positive (Westerly)
41
Annual Mean
42
December January
December,
January, February
43
June July
June,
July, August
44
MIT OpenCourseWare
http://ocw.mit.edu
12.811 Tropical Meteorology
Spring 2011
For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.
45