Pearl River Delta (PRD)

The distribution of city clusters in China

Analysis and numerical simulation on a server Fan Qi1,Yu Wei1, Luo Xuyu1,

(1. Department of Atmospheric Sciences, 2. GuangZhou central meteorological Bureau,

3. Macao Meteorological and Geophysical Bureau, E-mail:eesfq@mail.sysu.edu.cn;

1. Introduction of the server air pollution episode in PRD region, China

There appeared a server air pollution episode in Pearl River Delta (PRD) region, China from 22 Nov to 29 Nov, 2009. The regional air quality index (RAQI) of many cities in PRD region reached the maximum level 5. The maximum concentration of PM10 was about 0.192mg/m3 in Guangzhou city .

MM5Meteorological

model

MCIP

SMOKEEmission

model

CMAQAir quality model

Meteorological data

Data format transfer

Model settings：

Three domains center：23°N ， 113°EGrid distrance：36km 、 12km 、 4km

air pollution episode in Pearl River Delta Region Fan Shaojia1, Feng Ye Rong2, Feng Ruiquan3Sun yat-sen University, Guangzhou, China;Guangzhou, China;Macao, China)(Abstract Reference Number: EGU2011-1539)

2. Model settings and emission data

Distribution of SO2 emissions in Guangdong province of China calculated by SMOKE model

Emission data

3. model results by MM5/SMOKE/CMAQ model

The simulated wind speed, 2m temperature and PBL height by MM5 were almost consistent with the measurements.

The small wind speeds, the inversion near surface and the low PBL height on 25 Nov were all benefit to the accumulation of air pollutants.

The higher air concentrations on 28 Nov were more dominated by the subsidence which was caused by typhoon. The inversion layer was located in a higher region. The air pollutants were transported to the west of PRD region by the horizontal wind fields under PBL.

The simulated temperature cross section along 23°N at 1200LST on 25 Nov and 28 Nov by MM5

The simulated wind cross section along 23°N at 1200LST on 25 Nov and 28 Nov by MM5

The simulated 900hPa wind fields at 1200LST on 25 Nov and 28 Nov by MM5

4. Summary

1)The simulations by MM5 and CMAQ models were consistent with the measurements. The maxima concentrations and the lowest visibilities were located in the west of Pearl River Estuary.

2) It can be seen that the meteorological conditions influencing this server air pollution episode included the stable PBL, inversion, calm wind and the subsidence by typhoon.

3)The high concentration regions in 25 Nov were mainly caused by the local emission. The contributions from transportation were small. But in 28 Nov, the most air pollutants in Guangzhou and Foshan cities were transported to the northwest regions.

observations（ 24,Nov）

Simulated maximum daily average concentration

Simulated maximum hourly concentraion at

Guangzhou

observations（ 25,Nov）

Simulated maximum daily

average concentration

Simulated maximum hourly concentraion at

Guangzhou

SO2 0.0490.040（↓ 18%）

0.039（↓ 21%） 0.065

0.061（↓ 6%）

0.052（↓ 20%）

NOX 0.1180.086（↓ 17%）

0.067（↓ 43%） 0.148

0.085（↓ 43%）

0.087（↓ 41%）

PM10 0.1480.084（↓ 43%）

0.098（↓ 34%） 0.192

0.116（↓ 40%）

0.126（↓ 34%）

The calculated visibility distribution at 0800LST on 25 Nov by CMAQ model

Table1: the comparisons of the calculated concentrations by CMAQ model with the measurements

The regional distribution of PM10 at 0800LST on 25 Nov calculated by CMAQ model

The regional distribution of PM10 at 0900LST on 28 Nov calculated by CMAQ model