atmospheric boundary layer evening transitions: a comparison between two experimental sites...
TRANSCRIPT
Atmospheric Boundary Layer evening transitions: a comparison between two
experimental sites (CIBA-Spain and BLLAST-France)
M. Sastre (1), C. Yagüe (1), C. Román-Cascón (1), G. Maqueda (2).
(1) Dept. Geofísica y Meteorología. University Complutense of Madrid, Spain. ([email protected])(2) Dept. Astrofísica y Ciencias de la Atmósfera. University Complutense of Madrid, Spain.
12th EMS Annual Meeting &9th European Conference on Applied Climatology
(ECAC)
EUROPEAN METEOROLOGICAL SOCIETY
11th September 2012
Contents1.- Introduction
2.- Methodology
3.- Experimental data
4.- WRF model
5.- Results
6.- Summary and conclusions
1.- Introduction
• Evening transition processes in the ABL: from convection to stability
• Comparison at two experimental sites
• Simulations: differences between sites?
2.- Methodology
• Data from two experimental sites: CIBA site (Spain) and the BLLAST campaign site (France). x
x
2.- Methodology
1
P
BLLAST campaign site: land-use
Forestpines
moor
cropsForestdeciduous
village
industrial
town
meadow
cornmeadow
2.- Methodology
• Data from two experimental sites: CIBA site (Spain) and the BLLAST campaign site (France).
• Days studied from two summer periods: 2009 (CIBA) and 2011 (BLLAST).
• Times related to sunset for every site and day (t=0 => tsunset).
• Simulations using WRF model.
• MRFD technique employed.
xx
3.- Experimental data
• Sonic anemometer (CIBA and BLLAST)• BLLAST 60m-tower instruments (2, 15, 30, 45, 60 m)• CIBA 10m-mast instruments (1.5, 3, 5, 7.5, 10 m)
4/12)'w'v(2)'w'u(
*U
Focus on:
• Wind speed and direction
• Temperature
• Turbulent parameters
Friction velocity:
4.- WRF model
Initial and boundary conditions from NCEP-NCAR (1º resolution; data every 6 hours).
4 nested domains whose grids are: 27, 9, 3 and 1km.
Time step: 81 seconds. 50 eta vertical levels. Spin up: 12 h. SW radiation: Dudhia (1998). LW radiation RRTM. Microphysics package: WSM3.
• Weather Research and Forecast (WRF) mesoscale model.• Test three PBL parameterizations: MYJ, MYNN, QNSE.
• More about model configuration:
5.- Results• Days selected: 28-29-30 August 2009 (CIBA) and 24-25-26 June
2011 (BLLAST).• Similar synoptic situations: stability and weak pressure gradient.
30/August/2009 – 00:00 UTCGeopotential at 500 hPa (gpdm) and surface pressure reduced to sea level
(reanalysis taken from: www.wetterzentrale.de)
5.- ResultsComparison of MRFD
Friction velocity (U*)
time (h)
Tim
esca
le (
s)
U*
-2 -1 0 1 2 3 410
-1
100
101
102
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
-2 -1 0 1 2 3 410
-1
100
101
102
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
time (h)
Tim
esca
le (
s)
-2 -1 0 1 2 3 410
-1
100
101
102
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
29 Aug 2009 (CIBA) 24 Jun 2011 (BLLAST)
time (h)
Tim
esca
le (
s)
U*
-2 -1 0 1 2 3 410
-1
100
101
102
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
m s-1
t=0 => tsunset
5.- ResultsComparison of MRFD
Friction velocity (U*)
time (h)
Tim
esca
le (
s)
U*
-2 -1 0 1 2 3 410
-1
100
101
102
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
-2 -1 0 1 2 3 410
-1
100
101
102
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
time (h)
Tim
esca
le (
s)
-2 -1 0 1 2 3 410
-1
100
101
102
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
29 Aug 2009 (CIBA) 24 Jun 2011 (BLLAST)
time (h)
Tim
esca
le (
s)
U*
-2 -1 0 1 2 3 410
-1
100
101
102
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
m s-1
t=0 => tsunset
5.- ResultsComparison of temperature and friction velocity
U*T
-2 -1 0 1 2 3 410
15
20
25
30
35
time (h)
Tem
pera
ture
(ºC
)
-2 -1 0 1 2 3 40
0.1
0.2
0.3
0.4
0.5
0.6
0.7
time (h)
U* (
m s
-1)
29 Aug 2009
24 Jun 2011
26 Jun 2011
-2 -1 0 1 2 3 40
0.1
0.2
0.3
0.4
0.5
0.6
0.7
time (h)
U* (
m s
-1)
29 Aug 2009
24 Jun 2011
26 Jun 2011
CIBABLLAST
5.- ResultsKatabatic event - CIBA
-6 -4 -2 0 2 4 6 8 0
50
100
150
200
250
300
350
time (h)
Win
d D
irect
ion
(º)
2009/8/30
1.5m
10m
-6 -4 -2 0 2 4 6 8 0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
time (h)
Hor
izon
tal W
ind
Spe
ed (
m s
-1)
2009/8/30
1.5m
10m
wind speed wind direction
-6 -4 -2 0 2 4 6 8
10-2
10-1
100
time (h)
U*
(m s
-1)
2011/06/26-27
MYJ
MYNN
QNSE
obs.
-6 -4 -2 0 2 4 6 810
-2
10-1
100
time (h)
U*
(m s
-1)
2011/06/26-27
MYJ
MYNN
QNSE
obs.
5.- ResultsWRF simulations
Friction velocity(U*)
26 Jun 2011
-6 -4 -2 0 2 4 6 8 0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
time (h)
U*
(m s
-1)
2009/08/28-29
MYJ
MYNN
QNSE
obs.
28 Aug 2009
-6 -4 -2 0 2 4 6 8 10
-2
10-1
100
time (h)
U*
(m s
-1)
MYJ
MYNNQNSE
obs.30 Aug 2009
CIBA
BLLAST
-6 -4 -2 0 2 4 6 810
-2
10-1
100
time (h)
U*
(m s
-1)
2011/06/24-25
MYJ
MYNNQNSE
obs.
24 Jun 2011
-6 -4 -2 0 2 4 6 810
-2
10-1
100
time (h)
U*
(m s
-1)
2011/06/24-25
MYJ
MYNNQNSE
obs.
5.- ResultsWRF simulations
Temperature
-6 -4 -2 0 2 4 6 817
18
19
20
21
22
23
24
25
26
time (h)
Tem
pera
ture
(ºC
)
obs.
MYJMYNN
QNSE
25 Jun 2011 (BLLAST)
-6 -4 -2 0 2 4 6 8 14
16
18
20
22
24
26
28
30
32
time (h)
Tem
pera
ture
(ºC
)
MYJ
MYNNQNSE
obs.
30 Aug 2009 (CIBA)
5.- ResultsWRF simulations
Wind speed
-6 -4 -2 0 2 4 6 8
1
2
3
4
5
6
7
time (h)
Hor
izon
tal W
ind
Spe
ed (
m s
-1)
obs.
MYJMYNN
QNSE
26 Jun 2011 (BLLAST)
-6 -4 -2 0 2 4 6 8 4
5
6
7
8
9
10
11
time (h)
Hor
izon
tal w
ind
spee
d (m
s-1
)
MYJ
MYNNQNSE
obs.
28 Aug 2009 (CIBA)
6.- Summary and conclusions
Evening transition processes have been evaluated at two different experimental sites.
MRFD timescales: similar evolution, but with some differences.
Radiative cooling: seems to be influenced by soil moisture.
Simulations: tend to overestimate the turbulence after sunset at one of the sites (the less dried).
THANK YOUTHANK YOUFOR YOUR FOR YOUR ATTENTIONATTENTION
Acknowledgements: Spanish Ministry of Science and Innovation projects CGL2006-12474-C03-03, CGL2009-
12797-C03-03 and CGL2011-13477-E . UCM fellowship (reference BE45/10). BLLAST project, especially M. Lothon and F. Saïd for the 60m-tower data. EMS Young Scientist Travel Award (YSTA).