Test simulation of Aerosol impact on solar radiation with WRF-CHEM

Dust DNI (w/o dust) – DNI (w/ dust)

Positive value indicates the decreased DNI due to the aerosols

Aerosols play a role in scattering the solar radiation in clear sky but current NWP did not consider this effect. NWP with aerosol module could improve the solar radiation by the calculating the aerosol optical depth.

Evaluation of model output by the comparison with Satellite imagery

RMSE of BT for Tucson area (6-22-2013)

Time (UTC)

12 15 18 21 0 3 6 9 12

RM

SE

of B

T a

t 11

m

(K

)

0

5

10

15

20

25

30

35

40

MORRMEYERSASSENWSM

Clear SkyCloudy Sky

Brightness temperature (i.e., irradiation) from satellite imagery could be used to evaluate the model performance for both cloudy and clear skies.

Sensitivity test of microphysics for the successful simulation with WRF

Morrison: Too thick CloudMeyer : Shallower than Morrison

8-13-2013 (WRF-GFS at 12 Z)

Time (LST)

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

DN

I (W

m-2

)

0

200

400

600

800

1000

OBS Morr Meyer

RMSE of BT for Tucson (8-13-2013)

Time (LST)

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5

RM

SE

of B

T (

K)

5

10

15

20

25

30

35

Morr Meyer

Microphysics scheme in NWP calculates the cloud properties but there are several schemes in WRF. For the better simulation, sensitivity tests should be carried out with the understanding the observed characteristics of clouds in Tucson, AZ.

Meyer scheme provides the better results.