The Change of Meteorological The Change of Meteorological Parameters with Land Use in MM5Parameters with Land Use in MM5

Jaemeen Baek

Dec. 01. 2003

OverviewOverview

It has been widely accepted that land surface processes and their modeling play an important role in meteorology models (F. Chen et al., 2001)

The change of meteorological parameters that affect air quality, for example, boundary layer depth, vertical diffusivity, etc., was analyzed as the land use and grid size varies in MM5.

Model DomainModel Domain

Lambert conformal conic projection Central meridian: 97W, Origin of projection: 40N, 97

W, Standard Parallels: 33N, 45N Pleim-Xiu land-surface model 24 land use categories The original domain covers whole Georgia

3x3 cells for a 36km resolution and 9x9 cells for a 12km resolution were chosen around Lake Lanier

Dates 2001/07/01-2001/07/10, 2002/01/01-2002/01/10

Land Use CharacteristicsLand Use Characteristics

Due to the grid size difference, the land use distribution for 12km and 36km resolution grids are different

Cat Land use 12km (%) 36km (%)

1 Urban 960 (3.7) 240 (8.3)

2 Dry land crop 2400 (9.3)  

11 Deciduous broadleaf 480 (1.8)  

14 Evergreen broadleaf 20640 (79.6) 2640 (91.7)

15 Mixed forest 1200 (4.6)  

16 Water 240 (0.9)  

Expected Results – Direct Expected Results – Direct Interactions of ParameterizationsInteractions of Parameterizations

Microphysics Cumulus

Radiation

Surface

PBL

Cloud detrainment

Cloud effectsCloud fraction

Downward SW, LWSurface

emission/albedo

Surface fluxesSH, LH

Surface T, QV, wind

12km vs. 36km – Ground 12km vs. 36km – Ground TemperatureTemperature

Jun 2001 (14-14)

280

285

290

295

300

305

310

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24time

12km36km

Jan.2002 (14-14)

260

265

270

275

280

285

290

295

300

305

310

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24time

12km36km

Jun 2001(16-14)

280

285

290

295

300

305

310

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24time

12km36km

Jan.2002 (16-14)

260

265

270

275

280

285

290

295

300

305

310

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24time

12km36km

12km vs. 36km – Sensible Heat 12km vs. 36km – Sensible Heat FluxFlux

Jun 2001 (14-14)

-40

-20

0

20

40

60

80

100

120

140

160

180

200

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

12km36km

Jun 2001 (14-14)

-40

-20

0

20

40

60

80

100

120

140

160

180

200

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

12km36km

Jun 2001(16-14)

-40

-20

0

20

40

60

80

100

120

140

160

180

200

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

12km36km

Jan. 2002(16-14)

-40

-20

0

20

40

60

80

100

120

140

160

180

200

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

12km36km

Data AnalysisData Analysis

The 1st Analysis The ratio of normalized variance of water area (12km r

esolution) to that of evergreen broadleaf (36km resolution)

To screen which parameters could vary significantly w

ith land use Parameters whose ratios are more than 0.05 are selected Ground temperature, PBL height, sensible heat flux, latent heat

flux, outgoing short wave radiation, winds

Variance(water)/mean2(water)Variance(EB)/mean2(EB)

Results of 1Results of 1stst Analysis Analysis – Jun/01 and Jan/02– Jun/01 and Jan/02

-0.5

0

0.5

1

1.5

2

2.5

23-02 03-06 07-10 11-14 15-18 19-22

tg

pblh

pblr

shf

lhf

0

0.05

0.1

0.15

0.2

0.25

23-02 03-06 07-10 11-14 15-18 19-22

ust

sw d

lw d

sw o

lw o

t2m

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

23-02 03-06 07-10 11-14 15-18 19-22

tg

pblh

pblr

shf

lhf

0

0.05

0.1

0.15

0.2

0.25

23-02 03-06 07-10 11-14 15-18 19-22

ust

sw d

lw d

sw o

lw o

t2m

Data AnalysisData Analysis

The 2nd Analysis To prove that different land use would result in

significant changes in meteorological parameters Assumptions

If the land uses are same, differences between outputs from 12km resolution and from 36km resolution can be ignored

Sets of [(Outputs)12km – (Outputs)36km] for same land use(evergreen broadleaf, A), and sets of output differences for different land use area (B) are compared

F-test - The variance of A is same as that of B T-test - The mean of A is same as that of B

Results of F-testResults of F-test

1 14 1 14

Jan Jun Jan Jun Jan Jun Jan Jun

1 O O     1 O O    

2     O O 2     O X

11     X X 11     O X

15     X X 15     X X

16     O O 16     O O

Ground temperature PBL Height (O: Rejected)

Results of T-testResults of T-test

Ground temperature PBL Height (O: Rejected)

1 14 1 14

Jan Jun Jan Jun Jan Jun Jan Jun

1 O O   

1 O O   

2   

O O 2   

O O

11   

O X 11   

X X

15   

X X 15   

X X

16   

O O 16   

O O

ConclusionsConclusions

We can say that ground temperature, PBL height, sensible heat flux, and friction velocity changes a lot with land use

This cause discontinuity between adjacent cells In the mixed land use area, meteorological

parameters predicted in MM5 could have big errors

The accuracy of land surface classification is also important

Improvement Improvement

Calculating averaged physical parameters of each cell during TERRAIN process The original land-use data has percentages of

all land uses in a grid cell

Smoothing results For some land-use categories, like water,

average outputs from MM5 with outputs from the adjacent grid cells