High aerosol load over the Pearl River Delta, China, observed with Raman lidar and Sun photometer

Ansmann, Albert; Engelmann, Ronny; Althausen, Dietrich; Wandinger, Ulla; Hu, Min; Zhang, Yuanghang; He, Qianshan

doi:10.1029/2005gl023094

Cited by 80 publications

(61 citation statements)

References 6 publications

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“…The LIDAR ratio during the experiment was in the range between 29.0sr (28 May) and 70.9sr (1 June), and the average value was 48.5±9.9sr, which is close to the mean value of 46.7±5.6sr found in south China [6]. The corresponding TDR was 8.1±5.2% with the minimal value of 2.2% (4 June) and the maximum value of 21.9% (20 May).…”

Section: Resultssupporting

confidence: 57%

Aerosol Observation with Raman LIDAR in Beijing, China

Xie¹,

Zhou²,

Sugimoto³

et al. 2010

Journal of the Optical Society of Korea

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Aerosol observation with Raman LIDAR in NIES (National Institute for Environmental Studies, Japan) LIDAR network was conducted from 17 April to 12 June 2008 over Beijing, China. The aerosol optical properties derived from Raman LIDAR were compared with the retrieved data from sun photometer and sky radiometer observations in the Aerosol Robotic Network (AERONET). The comparison provided the complete knowledge of aerosol optical and physical properties in Beijing, especially in pollution and Asian dust events. The averaged aerosol optical depth (AOD) at 675 nm was 0.81 and the Angstrom exponent between 440 nm and 675 nm was 0.99 during experiment. The LIDAR derived AOD at 532 nm in the planetary boundary layer (PBL) was 0.48, which implied that half of the total AOD was contributed by the aerosol in PBL. The corresponding averaged LIDAR ratio and total depolarization ratio (TDR) were 48.5sr and 8.1%. The negative correlation between LIDAR ratio and TDR indicated the LIDAR ratio decreased with aerosol size because of the high TDR associated with nonspherical and large aerosols. The typical volume size distribution of the aerosol clearly demonstrated that the coarse mode radius located near 3 μm in dust case, a bi-mode with fine particle centered at 0.2 μm and coarse particle at 2 μm was the characteristic size distribution in the pollution and clean cases. The different size distributions of aerosol resulted in its different optical properties. The retrieved LIDAR ratio and TDR were 41.1sr and 19.5% for a dust event, 53.8sr and 6.6% for a pollution event as well as 57.3sr and 7.2% for a clean event.In conjunction with the observed surface wind field near the LIDAR site, most of the pollution aerosols were produced locally or transported from the southeast of Beijing, whereas the dust aerosols associated with the clean air mass were transported by the northwesterly or southwesterly winds.

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Section: Resultssupporting

confidence: 57%

Aerosol Observation with Raman LIDAR in Beijing, China

Xie¹,

Zhou²,

Sugimoto³

et al. 2010

Journal of the Optical Society of Korea

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“…Under the influence of Asian pollutants, high values of LR, up to 100 sr, and an average of 59±24 sr have been measured during the FebruaryMarch 1999 INDOEX intensive field experiment (Franke et al, 2001). The monthly mean extinction-to-backscatter ratio of the haze layer over the PRD region in October 2004 is 46.7 sr (Ansmann et al, 2005). Therefore, the higher LR values in spring are quite realistic and due to the influence of the continental outflow over Southern China.…”

Section: Overview Of Lr Characteristicsmentioning

confidence: 85%

“…The scattering coefficients measured by the visibility sensor do not include the absorption coefficients. In highly turbid areas such as the PRD, the influence of absorbing aerosol on the extinction coefficient could not be neglected (Ansmann et al, 2005). Considering the above two causes, the aerosol scattering coefficients from the visibility sensor are converted into extinction coefficients at the same wavelength as that of LIDAR according to a single scattering albedo of 0.90 and aerosolÅngström exponent of 1.0, and the scatter plots of disposed results are represented as asterisks.…”

Section: Inter-comparison Of Mpl Retrieved Extinction Coefficient Witmentioning

confidence: 99%

A study on the aerosol extinction-to-backscatter ratio with combination of micro-pulse LIDAR and MODIS over Hong Kong

Mao

et al. 2006

Atmos. Chem. Phys.

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Abstract. The aerosol extinction-to-backscatter ratio is an important parameter for inverting LIDAR signals in the LI-DAR equation. It is a complicated function of the aerosol microphysical characteristics. In this paper, a method to retrieve the column-averaged aerosol extinction-to-backscatter ratio by constraining the aerosol optical depths (AOD) from a Micro-pulse LIDAR (MPL) by the AOD measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. Both measurements were taken on cloud free days between 1 May 2003 and 30 June 2004 over Hong Kong, a coastal city in south China. Simultaneous measurements of aerosol scattering coefficients with a forward scattering visibility sensor are compared with the LI-DAR retrieval of aerosol extinction coefficients. The data are then analyzed to determine seasonal trends of the aetrosol extinction-to-backscatter ratio. In addition, the relationships between the extinction-to-backscatter ratio and wind conditions as well as other aerosol microphysical parameters are presented. The mean aerosol extinction-to-backscatter ratio for the whole period was found to be 29.1±5.8 sr, with a minimum of 18 sr in July 2003 and a maximum of 44 sr in March 2004. The ratio is lower in summer because of the dominance of oceanic aerosols in association with the prevailing southwesterly monsoon. In contrast, relatively larger ratios are noted in spring and winter because of the increased impact of local and regional industrial pollutants associated with the northerly monsoon. The extended LIDAR measurements over Hong Kong provide not only a more accurate retrieval of aerosol extinction coefficient profiles, but also significant substantial information for air pollution and climate studies in the region.

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“…Observations in Asia (e.g. Sasano, 1996;Ansmann et al, 2005;Chiang et al, 2007) obtained these kinds of profiles.…”

Section: Radiative Transfer Modelling and The Retrieval Of The Aerosomentioning

confidence: 99%

MAX-DOAS measurements in southern China: retrieval of aerosol extinctions and validation using ground-based in-situ data

et al. 2010

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Abstract. We performed MAX-DOAS measurements during the PRiDe-PRD2006 campaign in the Pearl River Delta region 50 km north of Guangzhou, China, for 4 weeks in June 2006. We used an instrument sampling at 7 different elevation angles between 3 • and 90 • . During 9 cloud-free days, differential slant column densities (DSCDs) of O 4 (O 2 dimer) absorptions between 351 nm and 389 nm were evaluated for 6 elevation angles. Here, we show that radiative transfer modeling of the DSCDS can be used to retrieve the aerosol extinction and the height of the boundary layer. A comparison of the aerosol extinction with simultaneously recorded, ground based nephelometer data shows excellent agreement.

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High aerosol load over the Pearl River Delta, China, observed with Raman lidar and Sun photometer

Cited by 80 publications

References 6 publications

Aerosol Observation with Raman LIDAR in Beijing, China

Aerosol Observation with Raman LIDAR in Beijing, China

A study on the aerosol extinction-to-backscatter ratio with combination of micro-pulse LIDAR and MODIS over Hong Kong

MAX-DOAS measurements in southern China: retrieval of aerosol extinctions and validation using ground-based in-situ data

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