Aerosol distribution in the Northern Hemisphere during ACE‐Asia: Results from global model, satellite observations, and Sun photometer measurements

Abstract

[1] We analyze the aerosol distribution and composition in the Northern Hemisphere during the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) field experiment in spring 2001. We use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model in this study, in conjunction with satellite retrieval from the Moderate-Resolution Imaging Spectroradiometer (MODIS) on EOS-Terra satellite and Sun photometer measurements from the worldwide Aerosol Robotic Network (AERONET). Statistical analysis methods including histograms, mean bias, root-meansquare error, correlation coefficients, and skill scores are applied to quantify the differences between the MODIS 1°Â 1°gridded data, the daytime average AERONET data, and the daily mean 2°Â 2.5°resolution model results. Both MODIS and the model show relatively high aerosol optical thickness (t) near the source regions of Asia, Europe, and northern Africa, and they agree on major features of the long-range transport of aerosols from their source regions to the neighboring oceans. The t values from MODIS and from the model have similar probability distributions in the extratropical oceans and in Europe, but MODIS is approximately 2-3 times as high as the model in North/Central America and nearly twice as high in Asia and over the tropical/subtropical oceans. Comparisons with the AERONET measurements in the Northern Hemisphere demonstrate that in general the model and the AERONET data have comparable values and similar probability distributions of t, whereas MODIS tends to report higher values of t over land, particularly North/Central America. The MODIS high bias is primarily attributed to the difficulties in land algorithm dealing with surface reflectance over inhomogeneous and bright land surfaces, including mountaintops, arid areas, and areas of snow/ice melting and with land/water mixed pixels. The model estimates that on average, sulfate, carbon, dust, and sea salt comprise 30%, 25%, 32%, and 13%, respectively, of the 550-nm t in April 2001 in the Northern Hemisphere, with $46% of the total t from anthropogenic activities and 66% from fine mode aerosols.

Interannual variation in the fine-mode MODIS aerosol optical depth and its relationship to the changes in sulfur dioxide emissions in China between 2000 and 2010

“…In this study, to investigate long-term trends in AOD, we used MODIS/Terra data from satellite observations. The MODIS algorithm for determining aerosol characteristics performs well within an expected error when compared to co-located ground-based observation data obtained from the Aerosol Robotic Network (AERONET) direct sun/sky radiometers over both land (Chu et al, 1996) and ocean . Over East Asia, the MODIS measurements have been well validated through many studies (e.g.…”

“…Over East Asia, the MODIS measurements have been well validated through many studies (e.g. Chin et al, 2004;Park et al, 2011). The Level 3 MODIS/Terra daily products (MOD08 D3) for a 1 • × 1 • equal-angle global grid were obtained from http://ladsweb.nascom.nasa.gov/.…”

“…In a short-term episodic observation of East Asian aerosol characteristics and components, Carmichael et al (1996) showed annual mean non-sea-salt (nss) sulfate (nss-SO 2− 4 ) and nitrate mass concentrations of 6.9 µg m −3 and 1.2 µg m −3 , respectively, from ground-based tape-air sampler measurements on Jeju Island (33.17 • N, 137.33 • E, 2770 m above sea level (a.s.l. )), Korea, between March 1992and May 1993.…”

Overview of the Mount Tai Experiment (MTX2006) in central East China in June 2006: studies of significant regional air pollution

“…A one-box model was used to study photochemical production and loss of O 3 by fixing the key species and parameters to observed values (Kanaya et al, 2009). Two different three-dimensional chemical transport models (3-D CTM) were used; one is NAQPMS, developed by Z. , and the other is Community Multiscale Air Quality Modeling System (CMAQ), developed by Byun and Ching (1999). The NAQPMS was used for studying source attribution and outflow of O 3 at Mt.…”

Comparison of in situ and columnar aerosol spectral measurements during TexAQS-GoMACCS 2006: testing parameterizations for estimating aerosol fine mode properties

“…Recently, satellite retrieval algorithms have been developed to quantify the contribution of the fine mode fraction to the column AOD . Such information is critical for models to calculate the climate forcing by anthropogenic aerosols (Chin et al, 2004;Kleidman et al, 2005;Bates et al, 2006;Yu et al, 2006). However, due to the generally high uncertainties of satellite retrievals, those methods are less effective unless supported by in situ measurements.…”