COST-728 Workshop on Model urbanization strategy UKMO, Exeter, UK, 3-4 May 2007 UNIVERSITY OF ATHENS...

COST-728 Workshop on‘Model urbanization strategy’UKMO, Exeter, UK, 3-4 May 2007

UNIVERSITY OF ATHENS FACULTY OF PHYSICSDEP. OF APPLIED PHYSICSLAB. OF METEOROLOGY

Sensitivity tests in the Sensitivity tests in the ‘‘dynamicaldynamical’’ and and ‘‘thermalthermal’’ part of the part of the MRF-urban PBLMRF-urban PBL scheme scheme

in the MM5 model in the MM5 model

Aggeliki Dandou, Maria Tombrou


Meteorological Model

MM5 (Version 3-6)

The Penn State/NCAR Mesoscale Model MM5 (Grell et al., 1994) is a terrain following numerical weather prediction model, with a multiple-nest capability, nonhydrostatic dynamics and a four-dimensional data assimilation capability.

• ‘simple ice’ Hsie et al. (1984), for the moisture parameterization

• ‘cloud-radiation scheme’ Dudhia (1989), for the radiation parameterization

• ‘Grell’ (1993), for the clouds parameterization

• ‘Five-Layer Soil model’ (Dudhia, 1996), for the soil parameterization

Parameterization schemes considered:

1


Meteorological Model MM5 (Version 3-6)

MRF (Hong and Pan, 1996): high resolution non-local scheme based on Troen and Mahrt (1986) representation of counter gradient term and K profile in the well mixed PBL MRF-urban (Dandou et al., 2005): a modified version of MRF whereby urban features were introduced both in the thermal part and the dynamical part:

• Anthropogenic heat: as a temporal and spatial function of the diurnal variation of the anthropogenic emissions

• Heat storage: the OHM scheme (Grimmond et al., 1991)

PBL parameterization schemes:

• Heat and momentum fluxes (under unstable conditions): according to Akylas et al. (2003)

• Diffusion coefficients (under stable conditions): according to King et al. (2001)

• Updated field for the roughness length: based on literature values in combination with satellite detailed information on land use (spatial resolution 30 m)

2

MRF-not urban: a modified version of MRF, whereby the city of Athens is replaced by dry cropland and pasture surface, as the surrounding area


Area of application

Meteorological data ECMWF (0.5o x 0.5o) every 6 hours

Sea Surface Temperature SST (1o x1o) every 6 hours

USGS data (25 categories) (30’’ x 30’’) for topography and land use

Two-way nesting

Input dataInput data

3

Ground stations

• National Observatory of Athens (NOA), an urban station (4 km inland from the shore), located in a park, on top of a hill (107 m asl), with urban characteristics 85% and z0=0.8 m

• Marousi, a suburban station (13 km inland from the shore), inside a grove surrounded by buildings of different heights, with urban characteristics 52% and z0=0.5 m

• Peiraias, an urban station at the harbor, with urban characteristics 100% and z0=1 m

1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

1 1 0

1 2 0

1 3 0

(x 6

km)

5 10 15 20 25 30 35 40 45 50 55

(x 2 k m )

5

10

15

20

25

30

35

40

45

(x 2

km) (x 6 k m )

M a ro u si

P e ira ia sN O A


4

Available measurementsAvailable measurements

14 September 1994 (MEDiterranean CAmpaign of PHOtochemical Evolution

MEDCAPHOT-TRACE experiment, Ziomas, 1998)

• Air temperatureAir temperature

• Sensible heat fluxSensible heat flux ( (sonic anemometer)sonic anemometer)• Friction velocity (sonic anemometer)Friction velocity (sonic anemometer)

• Wind velocityWind velocity

NOA, Marousi

NOA, Marousi, Peiraias

• Landsat TM satellite imageLandsat TM satellite image (acquisition date(acquisition date: 13 : 13 JouneJoune 1993)1993)


5

ResultsResults

Surface fluxesSurface fluxes

Air TemperatureAir Temperature

Diffusion coefficientsDiffusion coefficients

PBL heightPBL height



6

Diurnal variation of surface fluxes (MRF-urban scheme)

Peiraias

-100

0

100

200

300

400

500

600

700

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LST

W/m

2

Q*

QH

QE

QF

ΔQs

Marousi

-100

0

100

200

300

400

500

600

700

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LST

W/m

2

Q*

QH

QE

QF

ΔQs

NOA

-100

0

100

200

300

400

500

600

700

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LST

W/m

2

Q*

QH

QE

QF

ΔQs

Q*- net all wave radiation

QH-sensible heat flux

QE-latent heat flux

QF-anthropogenic heat

ΔQs-heat storage

(urban, downtown)

(urban, at the harbor)

(semi-urban)


7

Diurnal variation of sensible heat fluxDiurnal variation of sensible heat flux

• NOANOA : larger values due to : larger values due to

NOA

-50

0

50

100

150

200

250

300

350

400

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

sen

sib

le h

est

flu

x (W

/m2 )

mesurements

Marousi

-50

0

50

100

150

200

250

300

350

400

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

sen

sib

le h

eat

flu

x (W

/m2 )

measurements

soil characteristics (bare rocks) and surface cover (olive tree soil characteristics (bare rocks) and surface cover (olive tree plantation)plantation)

• MarousiMarousi: turbulence characteristics of the grove and not the surrounded built-up area: turbulence characteristics of the grove and not the surrounded built-up area

NOA

-50

0

50

100

150

200

250

300

350

400

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

sen

sib

le h

eat

flu

x (W

/m2 )

MRF-urban

MRF

MRF-dyn

MRF-ther

Marousi

-50

0

50

100

150

200

250

300

350

400

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

sen

sib

le h

eat

flu

x (W

/m2 )

MRF-urban

MRF

MRF-dyn

MRF-ther

Model results versus measurements

• MRFMRF: substantially higher values than the measurements : substantially higher values than the measurements

• MRF-urbanMRF-urban: in better agreement with the measurements: in better agreement with the measurements

Decrease

MANGE 40%

Decrease

MANGE 29%

Schemes intercomparison

• During the night:During the night: increase (absolute values) due to the ‘thermal’ part increase (absolute values) due to the ‘thermal’ part

• During the dayDuring the day: decrease due to the smaller temperature gradients produced by the ‘thermal’ part : decrease due to the smaller temperature gradients produced by the ‘thermal’ part and the zand the z00

Measurements (Batchvarova and Gryning, 1998)

temperature gradients (higher location)temperature gradients (higher location)

m

j ji

jijin

i OBS

OBSPRED

nmMANGE

1 ,

,,

1

1

PRED -predicted values

OBS -observed values

(Mean Absolute Normalized Gross Error)


8

-300

-250

-200

-100

-50

-25

-20

-15

050100

150

200

250

300

350

400

450

500

W/m

2

Spatial distribution of the sensible heat fluxSpatial distribution of the sensible heat flux

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasNOA

M arousi

MRF

3:00 LST

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasNOA

M arousi

14:00 LSTMRF

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasNOA

M arousi

MRF-dyn

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasNOA

M arousi

MRF-dyn

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasNOA

M arousi

MRF-ther

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasNOA

M arousi

MRF-ther

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasNOA

M arousi

MRF-urban

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasNOA

M arousi

MRF-urban


9 Diurnal variation of friction velocityDiurnal variation of friction velocity

• Max values ~0.5 m/s at both sites, although VMax values ~0.5 m/s at both sites, although VNOANOA (~4 m/s) > V (~4 m/s) > VMAROUSIMAROUSI (~2 m/s), due to its higher (~2 m/s), due to its higher

locationlocation

• Marousi:Marousi: the nonhomogeneity of the surrounding buildings, interchanged with the green areas the nonhomogeneity of the surrounding buildings, interchanged with the green areas cause higher valuescause higher values

NOA

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

fric

tion

vel

ocit

y (m

/s)

measurements

NOA

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

fric

tion

vel

ocit

y (m

/s)

MRF-urban

MRF

MRF-dyn

MRF-ther

Marousi

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

fric

tion

vel

ocit

y (m

/s)

mesurements

Decrease

MANGE 6%

Decrease

MANGE 2%

Marousi

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

fric

tion

vel

ocit

y (m

/s)

MRF-urban

MRF

MRF-dyn

MM58-ther

Measurements (Batchvarova and Gryning, 1998)Model results versus measurements

• During the night:During the night: any comparison with the measurements is meaningless (<0.1 m/s, the model’s any comparison with the measurements is meaningless (<0.1 m/s, the model’s threshold)threshold)

• During the day:During the day: decrease in the MRF-urban, closer to the measurementsdecrease in the MRF-urban, closer to the measurements

• MarousiMarousi: smaller decrease because the z: smaller decrease because the z00 did not change significantly. Higher values at noon due did not change significantly. Higher values at noon due

to the wind speed increase to the wind speed increase


• Differences due to the different profile functions and zDifferences due to the different profile functions and z00

• During the nightDuring the night: increase due to the increase of instability: increase due to the increase of instability

increase of z0

increase in the diffusion processes

decrease in the wind speed

increase of u*

normalization in temperature gradients

decrease of u*

decrease of u*• During the dayDuring the day::


10

Spatial distribution of the friction velocitySpatial distribution of the friction velocity

MRF

3:00 LST

14:00 LSTMRF

MRF-dyn

MRF-dyn

MRF-ther

MRF-ther

MRF-urban

MRF-urban

m/s 0.

050.

100.

150.

200.

250.

300.

350.

400.

450.

500.

550.

600.

650.

700.

750.

800.

850.

900.

951.

00

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi


5

ResultsResults








11 Diurnal variation of air temperature (at 10 m agl)Diurnal variation of air temperature (at 10 m agl)

MeasurementsMeasurements• During the night:During the night: development of an urban heat island development of an urban heat island

• During the day:During the day: lower maximum values at the urban stations (NOA and Peiraias), compared to lower maximum values at the urban stations (NOA and Peiraias), compared to the suburban station (Marousi)the suburban station (Marousi)

• MRF-urbanMRF-urban: decrease in the temperature amplitude wave, in better accordance with the : decrease in the temperature amplitude wave, in better accordance with the measurementsmeasurements

• NOANOA: differences with measurements due to its location on top of the hill, not resolved by the : differences with measurements due to its location on top of the hill, not resolved by the model’s spatial resolution (2 km) model’s spatial resolution (2 km)

NOA

20

22

24

26

28

30

32

34

36

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

tem

pera

ture

(oC

)

measurements

Peiraias

20

22

24

26

28

30

32

34

36

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

tem

pera

ture

(oC

)

measurements

Marousi

20

22

24

26

28

30

32

34

36

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

tem

per

atu

re (o C

)

measurements

NOA

20

22

24

26

28

30

32

34

36

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

tem

pera

ture

(oC

)

MRF-urban

MRF

MRF-dyn

MRF-ther

Marousi

20

22

24

26

28

30

32

34

36

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

tem

per

atu

re (o C

)

MRF-urban

MRF

MRF-dyn

MRF-ther

Decrease

MANGE 53%

Decrease

MANGE 38%

Decrease

MANGE 41%

20

22

24

26

28

30

32

34

36

0 2 4 6 8 10 12 14 16 18 20 22 24

time (h) LT

tem

pera

ture

(oC

)

MRF-urban

MRF

MRF-dyn

MRF-ther


• During the nightDuring the night: increase due to the ‘thermal’ part

increase due to the ‘dynamical’ part

decrease due to the ‘thermal’ parttotal decrease • During the dayDuring the day::

Model results versus measurements


12

Spatial distribution of the Spatial distribution of the air temperature (at 2m agl)air temperature (at 2m agl)

MRF-urban

MRF-urban

MRF-dyn - MRF

MRF-dyn - MRF

MRF-ther - MRF

MRF-ther - MRF

MRF-urban - MRF

MRF-urban - MRF

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

o C

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

ΔΤ

(oC

)

Spatial distribution of the air temperature Spatial distribution of the air temperature differences (at 2m agl)differences (at 2m agl)

3:00 LST

14:00 LST

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

-2.4

to

-2.

1

-2

.1 t

o -

1.8

-1

.8 t

o -

1.5

-1

.5 t

o -

1.2

-1

.2 t

o -

0.9

-0

.9 t

o -

0.6

-0

.6 t

o -

0.3

-0

.3 t

o 0

.0

0.

0 to

0.3

0.

3 to

0.6

0.

6 to

0.9

0.

9 to

1.2

1.

2 to

1.5

1.

5 to

1.8

1.

8 to

2.1

2.

1 to

2.4

2.

4 to

2.8

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

3:00 LST 3:00 LST 3:00 LST

14:00 LST 14:00 LST 14:00 LST


5

ResultsResults









13

Diffusion coefficient profilesDiffusion coefficient profiles

• During the day:During the day:

NOA3:00 LST

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0.1 1 10

Diffusion coefficient (m2/s)

Hei

ght

(m)

agl

MRF-urban

MRF

MRF-dyn

MRF-ther

NOA14:00 LST

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 20 40 60 80 100 120 140 160 180 200 220

Diffusion coefficient (m2/s)

Hei

ght

(m)

agl

MRF-urban

MRF

MRF-dyn

MRF-ther


decrease due to the ‘thermal’ part total decrease

Schemes intercomparisonSchemes intercomparison• During the night:During the night: increase in the lower atmosphere due to the ‘dynamical’ and ‘thermal’ part increase in the lower atmosphere due to the ‘dynamical’ and ‘thermal’ part


14

Spatial distribution of diffusion coefficients at the surface layerSpatial distribution of diffusion coefficients at the surface layer

MRF

3:00 LST

14:00 LSTMRF

MRF-dyn

MRF-dyn

MRF-ther

MRF-ther

MRF-urban

MRF-urban

246810121416182022242628303234363840424446

m2/s

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi


5

ResultsResults










15 Diurnal variation of the PBL heightDiurnal variation of the PBL height

Schemes intercomparisonSchemes intercomparison• During the nightDuring the night: increase due to the ‘thermal’ part: increase due to the ‘thermal’ part

NOA

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

0 2 4 6 8 10 12 14 16 18 20 22 24

time (LST)

m

MRF

MRF-urban

MRF-dyn

MRF-ther

Marousi

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

0 2 4 6 8 10 12 14 16 18 20 22 24

time (LST)

m

MRF

MRF-urban

MRF-dyn

MRF-ther

NOA

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

0 2 4 6 8 10 12 14 16 18 20 22 24

time (LST)

m

Blackadar

Gayno-Seaman

Pleim-Xiu

Marousi

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

0 2 4 6 8 10 12 14 16 18 20 22 24

time (LST)

m

Blackadar

Gayno-Seaman

Pleim-Xiu


decrease due to the ‘thermal’ parttotal decrease

• Delay (~1 h) in max value (MRF-urban), due to the delay in the sea-breeze developmentDelay (~1 h) in max value (MRF-urban), due to the delay in the sea-breeze development

• During the dayDuring the day::


16 Diurnal variation of the PBL heightDiurnal variation of the PBL height

NOA

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

0 2 4 6 8 10 12 14 16 18 20 22 24

time (LST)

Hei

ght

(m)

agl

IBL measurements

MRF-urban

MRF

Gayno-Seaman

Blackadar

Pleim-Xiu

max kv

Tombrou et al. (2006)

Penteli (rural station)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

0000 0300 0600 0900 1200 1500 1800 2100 0000

time (LST)

Hei

ght

(m)

agl

exp

MRF-urban

MRF

Gayno-Seaman

Pleim-Xiu

Blackadar

kv (middle)

20-9-2002

15-9-1994

Zografou (suburban station)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

0 2 4 6 8 10 12 14 16 18 20 22 24

time (LST)

hei

ght

(m)

agl

mesurements

MRF-urban

MRF

Gayno-Seaman

Blackadar

Pleim-Xiu

kv (middle)

20-9-2002


17

Spatial distribution of the PBL heightSpatial distribution of the PBL height

MRF

3:00 LST

14:00 LSTMRF

MRF-dyn

MRF-dyn

MRF-ther

MRF-ther

MRF-urban

MRF-urban

m

50100

150

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi


18 Summarizing the resultsSummarizing the results

5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5

( x 2 k m )

5

1 0

1 5

2 0

2 5

3 0

3 5

4 0

4 5

(x 2

km)

nt

MRFMRFurbantherMRFdynnt

,,11

n=77 (number of grids)

t=12 (number of hours for the day and night)

Day(0700-1800 LST)

MRF-dynall - MRF(%)

MRF-ther - MRF(%)

MRF-urban - MRF(%)

Sensible heat -1.92 -28.15 -28.99

Friction velocity

-3.98 -10.84 -10.79

Air temperature

+2.10 -15.21 -9.12

Diffusion coefficients

+36.58 -34.58 -20.97

Wind speed +6.87 -4.85 -6.47

PBL height +10.45 -10.47 -5.11

Night(0000-0600 LST,

1900-2300 LST)

MRF-dynall - MRF(%)

MRF-ther - MRF(%)

MRF-urban - MRF(%)

Sensible heat -3.38 -47.70 -51.79

Friction velocity

+1.19 +7.69 +7.65

Air temperature

+1.08 +3.80 +4.03

Diffusion coefficients

+10.21 +5.30 +83.9

Wind speed +0.53 +64.90 +60.06

PBL height +5.95 +86.40 +88.30


19

m/s

0.250.500.751.001.251.501.752.002.252.502.753.003.253.503.754.004.254.504.755.005.255.506.00

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

MRF-urban

14:00 LST

3:00 LST

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Peira iasN O A

M arousi

Thrakom akedones

14:00 LST

-1 .50 to -1 .25

-1 .25 to -1 .00

-1 .00 to -0 .75

-0 .75 to -0 .50

-0 .50 to -0 .25

-0 .25 to 0.00

0.00 to 0.25

0.25 to 0.50

0.50 to 0.75

0.75 to 1.00

1.00 to 1.25

1.25 to 1.50

1.50 to 1.75

1.75 to 2.00

2.00 to 2.25

2.25 to 2.50

2.50 to 2.75

2.75 to 3.00

m/s

5 10 15 20 25 30 35 40 45 50 55

(x 2km )

5

10

15

20

25

30

35

40

45

(x 2

km)

Pe ira iasN O A

M arousi

Thrakom akedones

3:00 LST

Spatial distribution of the wind Spatial distribution of the wind velocity (at 10 m)velocity (at 10 m)

MRF-urban

Spatial distribution of the wind speed Spatial distribution of the wind speed differences (at 10m)differences (at 10m)

MRF-urban – MRF-not urban

MRF-urban – MRF-not urban


20

Vertical cross sections of the wind velocity along the sea-breeze axisVertical cross sections of the wind velocity along the sea-breeze axis

m/s

MRF-urban

0

500

1000

1500

2000

2500

m (

agl)

PeiraiasÍ Ï Á

Marousi

Thrakomakedones

57000 m

MRF-not urban

14:00 LST

0.250.500.751.001.251.501.752.002.252.502.753.003.253.503.754.004.254.504.755.005.255.506.00

0

500

1000

1500

2000

2500

m (

agl)

PeiraiasÍ Ï Á

Marousi

Thrakomakedones

57000 m

0

500

1000

1500

2000

2500

m (

agl)

PeiraiasÍ Ï Á

Marousi

Thrakomakedones

57000 m

14:00 LST

3:00 LST

0

500

1000

1500

2000

2500

m (

agl)

PeiraiasÍ Ï Á

Marousi

Thrakomakedones

57000 m

3:00 LST

0.4

m/s

4 m/s


21

ConclusionsConclusions

Both modifications play an important role and improve the model’s resultsBoth modifications play an important role and improve the model’s results

During the day:During the day:

• The increase in The increase in temperaturetemperature and and diffusion coefficientsdiffusion coefficients calculated calculated by the ‘dynamical’ part is compensated by the decrease in the by the ‘dynamical’ part is compensated by the decrease in the ‘thermal’ part, resulting in a total decrease‘thermal’ part, resulting in a total decrease

• A decrease in A decrease in turbulenceturbulence and and fluxesfluxes is calculated by both is calculated by both modificationsmodifications

• A slowing in the sea-breeze front and a frictional retard A slowing in the sea-breeze front and a frictional retard concerning its penetration over the Athens city is calculated due concerning its penetration over the Athens city is calculated due to the increased roughness lengthto the increased roughness length

During the night:During the night:

• The total increase in The total increase in temperaturetemperature, , diffusion coefficientsdiffusion coefficients, , turbulenceturbulence and and fluxesfluxes is due to both modifications is due to both modifications

• The maximum The maximum wind speedswind speeds calculated in the lower atmosphere is calculated in the lower atmosphere is due to the urban heat islanddue to the urban heat island

COST-728 Workshop on Model urbanization strategy UKMO, Exeter, UK, 3-4 May 2007 UNIVERSITY OF ATHENS...

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Transcript of COST-728 Workshop on Model urbanization strategy UKMO, Exeter, UK, 3-4 May 2007 UNIVERSITY OF ATHENS...