Atmospheric Measurements

In November 2004, a team led by Dr. J. William MUNGER (Harvard School of Engineering and Applied Sciences), Chris P. NIELSEN (Harvard-China Project), and Prof. HAO Jiming (Tsinghua University School of Environment) deployed a permanent observational station at Miyun, north of Beijing, for use in the Project's atmospheric research. Still in operation, the station is now led on the Tsinghua side by Profs. WANG Yuxuan and WANG Shuxiao, both alumna of the Harvard-China Project. 

Click on "More Publications" below for a full list of publications supported by the Harvard-China Project using data from the station. 
 
The station makes continuous observations of key trace gases, including CO, CO2, O3, SO2, NO/NOy, as well as black carbon and local meteorological conditions. A CH4 analyzer will soon be added. The station is sited in a rural area 100 km north of Beijing, to distance it from the influence of individual sources and to measure a variety of conditions as local meteorology shifts, from relatively clean background air to polluted urban plumes.
 
Researchers have compared or incorporated the measurements of atmospheric species at the Miyun station with emissions estimates and GEOS-Chem modeling, and have conducted research on levels and trends in concentrations of O3, NOX, and BC, CO2:CO ratios, and the effects of control policies on diverse atmospheric pollutants and GHGs. The detailed CO2 record has now been extensively analyzed in research on the Chinese carbon cycle forthcoming in journal submissions and a Ph.D. dissertation by student Archana DAYALU, advised by MUNGER and Prof. Steven C. WOFSY. 

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The China Project's atmospheric research is committed to building observationally validated, fundamental research on the physical and chemical dimensions of China’s atmospheric environment and the emissions that influence it, at local, regional, and global scales. In addition to the observational research described below, it includes modeling research described here and bottom-up emissions research described here.

Acknowledgment: Some of the material summarized here is based on work supported in part by the National Science Foundation under Grants No. ATM-1019134 or ATM-0635548 (indicated by acknowledgments in the papers). Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

 

Related Publications

Xuan Wang, Yuxuan Wang, Jiming Hao, Yutaka Kondo, Martin Irwin, J. William Munger, and Yongjing Zhao. 2013. “Top-down estimate of China's black carbon emissions using surface observations: Sensitivity to observation representativeness and transport model error.” Journal of Geophysical Research, 11, 118: 5781-5795. Publisher's Version Abstract

This study examines the sensitivity of “top-down” quantification of Chinese black carbon (BC) emissions to the temporal resolution of surface observations and to the transport model error associated with the grid resolution and wet deposition. At two rural sites (Miyun in North China Plain and Chongming in Yangtze River Delta), the model-inferred emission bias based on hourly BC observations can differ by up to 41% from that based on monthly mean observations. This difference relates to the intrinsic inability of the grid-based model in simulating high pollution plumes, which often exert a larger influence on the arithmetic mean of observations at monthly time steps. Adopting the variation of BC to carbon monoxide correlation slope with precipitation as a suitable measure to evaluate the model's wet deposition, we found that wet removal of BC in the model was too weak, due in part to the model's underestimation of large precipitation events. After filtering out the observations during high pollution plumes and large precipitation events for which the transport model error should not be translated into the emission error, the inferred emission bias changed from −11% (without filtering) to −2% (with filtering) at the Miyun site, and from −22% to +1% at the Chongming site. Using surface BC observations from three more rural sites (located in Northeast, Central, and Central South China, respectively) as constraints, our top-down estimate of total BC emissions over China was 1.80 ± 0.65 Tg/yr in 2006, 0.5% lower than the bottom-up inventory of Zhang et al. (2009) but with smaller uncertainty.

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