Impacts of Cumulus Transport and Spatial Resolution on the Simulated Long-Range Transport and Source-Receptor Relationship T.Y. Lee, J.B. Lee and S.Y. Kim Laboratory for Atmospheric Modeling Research (LAMOR) Department of Atmospheric Sciences, Yonsei University 2 nd Workshop on Air Quality Modeling Challenges, 10 March, 2003, Tsukuba AMOP

 Several efforts are being made to derive source-receptor (S-R) relationship in East Asia (e.g., MICS-Asia, Carmichael et al. 2002)  Numerically simulated S-R relationship contains various uncertainties  Major sources of uncertainties: - meteorological inputs, initial conditions, emission rates, model physics and chemistry, etc. Introduction AMOP

 Two uncertainties concerning the long-term evaluation of S-R relationship: 1) Cold front is not properly simulated by coarse grid model (e.g., 60 km). Does this produce any bias in S-R relationship? 2) Vertical redistribution by cumulus convection is often neglected. Is this a serious problem?  Goals: to find out the impacts of these problems in the derivation of S-R relationship Introduction AMOP

1.Effects of spatial resolution of meteorological fields on S-R relationship - Spatial resolution: 120 km, 60 km, 20km - An extratropical cyclone case : 16–19 June Variation of S - R relationship with the resolution, focusing on the region with a passage of low and cold front 2.Effects of cumulus transport on the S-R relationship - Cumulus model of Walcek and Taylor (1993) - Period: May 1993 (part of MICS-Asia study period) - Horizontal grid size : 100 km Contents AMOP

Impact of Spatial Resolution - An Extratropical Cyclone Case

AMOP Nine source/receptor regions  Transport/deposition model: Yonsei University’s Sulfur Acid Deposition Model (YU-SADM)  Meteorological model: CSU RAMS  Emission rate : EDGAR V2.0 (Oliver et al., 1996) :

120 km 60 km 20 km Vertically Integrated Amount of Condensate

Total precipitation 60km 120km 20km

120 km 60 km 20 km SO 2 concentration at z*=584 m

Dry deposition 120 km 60km 20 km

Wet deposition 120 km 60km 20 km

Source-Receptor Relationship for Dry Deposition Receptor region number EXP3-R (20 km) EXP1-R (120 km)EXP2-R (60 km) S3: S. China S5: Korea S6: Sea (S. of Korea, where the front passes) S8: Japan (where the low center and front pass)

EXP1-R (120 km)EXP2-R (60 km) EXP3-R Receptor region number Source-Receptor Relationship for Wet Deposition Receptor region number EXP3-R (20 km) S3: S. China S5: Korea S6: Sea (S. of Korea, where the front passes) S8: Japan (where the low center and front pass)

120 km 60 km 20 km Source-Receptor Relationship for Wet Deposition at Receptor Region 8

 Enhanced spatial resolution - strengthens the circulations associated with the cyclone and the front - increases the rainfall associated with them  Impacts on simulated deposition and S-R relation: - Enhanced spatial resolution increases the fractional contribution of self emission, but decreases that of foreign emission both for dry and wet deposition in the area around the low center (Region 8), - Improved simulation of cold front appears to increase the contribution of the region to the north of the front - Enhancing the resolution does not significantly affect the deposition and S-R relationship in other regions Summary for the impact of spatial resolution AMOP

Impacts of Cumulus Transport on the Source-Receptor Relationship

Cloud bottom Cloud top F 1 (entrainment ratio and downdraft current ratio in level 2) (1 F 1 ) (updraft current ratio in level 2) (1 F 2 ) (updraft current ratio in level 3) F 2 (entrainment ratio and downdraft current ratio in level 3) Level 2 Level 3 Treatment of Cumulus Transport (Walcek and Taylor, 1986)

Numerical Experiments  Episode : May 1993 (part of MICS-Asia study period)  Transport/deposition model: YU SADM  Grid and model domain: Horizontal grid size : 100 km Domain : 60 X 56 X 30 grids Model top: 23km  Meteorological inputs and emission rates: Fields used for MICS Asia project

Countries/regions sets for source-receptor test Source region number : Ⅰ - Japan, Ⅱ - Korea, Ⅲ - NE China, Ⅳ - CE China, Ⅴ - S China, Ⅵ - Taiwan, Ⅶ - SE Asia, Ⅷ - NW Asia

SO 2 concentration at z*= 52 m Control–exp. Difference (Control exp – CU exp.)

Control–exp. CU–exp. Integrated sulfate concentration and mean wind above 3 km

Dry deposition of sulfur Difference (CU-control)

Wet deposition of sulfur

Dry & wet deposition in each receptor region Region number : 1 : Japan 2 : Korea 3 : NE China 4 : CE China 5 : S China 6 : Taiwan 7 : SE Asia 8 : NW Asia

Source-receptor relationship for dry deposition No convective transport With convective transport Region number : 1 : Japan 2 : Korea 3 : NE China 4 : CE China 5 : S China 6 : Taiwan 7 : SE Asia 8 : NW Asia

Source-receptor relationship for wet deposition No convective transport With convective transport Region number : 1 : Japan 2 : Korea 3 : NE China 4 : CE China 5 : S China 6 : Taiwan 7 : SE Asia 8 : NW Asia

Summary for the impact of convective transport  Surface concentration and dry deposition amount decrease with the convective transport, while wet sulfur deposition tends to increase, especially for eastern China.  The impacts of convective transport on the source-receptor (S-R) relationship : - No significant impact on the S-R relationship for dry deposition. - For wet deposition, the contribution of self emission tends to increase with the convective transport. - Contribution of foreign sources to the wet deposition over the Korean peninsula and Japan shows some sensitivities to the convective activities in their upstream sides.

 Neglect of convective transport and inadequate spatial resolution can be important sources of error  Both enhancing the spatial resolution and including convective transport increase the contribution of local emission to wet deposition.  In this study, both aspects of uncertainties have been studied for just one episode. Concluding remarks AMOP

00 UTC 18 June km 60 km 20 km