Observation and numerical simulation of the river breeze circulation in the vicinity of

the Tapajós and Amazon rivers

Maria A. F. Silva Dias (1)

Marcos Longo(1)

Pedro L. Silva Dias(1)

David R. Fitzjarrald (2)

A. Scott Denning(3)

Priscila Brier D'Auria(1)(1) Departamento de Ciências Atmosféricas, Universidade de São

Paulo

(2) Atmospheric Science Research Center, State University of New York at Albany

(3) Department of Atmospheric Sciences, Colorado State University

29,0

29,5

30,0

30,5

31,0

31,5

32,0

08:00 11:00 14:00 17:00

Local time (hours)

Wa

ter

tem

pe

ratu

re (

de

g.C

)

0.1m

0.3 m

0.7 m

1.0 m

c

23 July 2001 Tapajós

(from Pindobal to Boim and back)

26

27

28

29

30

31

32

10:00 10:30 11:00 11:30 12:00

Local time (hours)W

ate

r te

mp

era

ture

(d

eg

.C)

0.1m

0.3 m

0.7 m

1.0 m

28 July 2001 Tapajós & Amazonas

(red line: temperature where the two rivers merge)

Sea level pressure and 925 hPa winds from CPTEC analysis

July 29, 2001, 06 UTC

Difference in pressure reduced to sea level between

Manaus and Santarem, from CPTEC analysis

East-West wind component from Belterra Sounding at 950 hPa (~ 500 m)

Pibal balloon data

-4,0

-2,0

0,0

2,0

4,0

0 6 12 18 24

UTC (for Local time subtract 4 hrs)

U (

m/s

)

24 u

26 u

27 u

28 u

29 u

30 u

31 u

1 u

-4,0

-2,0

0,0

2,0

4,0

0 4 8 12 16 20 24

UTC

v (

m/s

)

24 v

26 v

27 v

28 v

29 v

30 v

31 v

1 v

AWS Jamaraquá

24 July / 1 August 2001

West

East

South

North

Fitzjarrald et al, 2000

Fitzjarrald et al, 2000

Winds at Belterra

radiosonde

Pressure (mb)

Winds and potential temperature

Belterra radiosonde

RAMS numerical simulation

• 2 grids

• higher resolution 2 km

• no clouds

• different temperatures in Tapajós and Amazon rivers

• boundary conditions from CPTEC analysis

Wind vector 23 M ABOVE THE SURFACE

Wind vector 23 M ABOVE THE SURFACE

Wind vector 23 M ABOVE THE SURFACE

Wind vector 23 M ABOVE THE SURFACE

Wind vector 23 M ABOVE THE SURFACE

wind – streamlines perpendicular to the Tapajós river

Potencial temperature

RAMS numerical simulation

• 3 grids

• higher resolution 2 km

• clouds from microphysics parameterization

• different temperatures in Tapajós and Amazon rivers

• boundary conditions from CPTEC analysis

Fitzjarrald et al, 2002

Conclusion

River induced local circulation is important in the Amazon region. – local cloudiness - impact in surface

radiation– modulation of rainfall– local transports - impact on trace gas

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