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Field Report
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The MIRAGE Project - by Julien Wang
In March 2006, SOARS Protégé Julien Wang joined NCAR scientists on the MIRAGE project in Veracruz, Mexico. The first goal of the MIRAGE program is to characterize the chemical/physical transformations and the ultimate fate of pollutants exported from urban areas. The second goal is to assess the current and future impacts of these exported pollutants on regional and global air quality, ecosystems, and climate. Here you can read her field report.
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My name is Julien Wang and I am an undergraduate at Johns Hopkins University, pursuing a Bachelor of Science in Environmental Engineering. My interest in air pollution stemmed from growing up in a very industrial city in the northeastern province of China. When I was little, I remember that every time I went outside to play, I would come back and there would be a lot of sand and dirt on my clothes. Even then, the air was so dirty and the soils covered with sand that the slightest breeze would pick them up and deposit them upon people. I went back to visit China two years ago and when I looked out of the airplane window as it flew over Beijing, there was a large white cloud hovering over the city. That cloud was smog and it covered Beijing like a blanket. As I came out of the Beijing airport, I saw that buildings, cars, and people disappeared into the distant smog that was only a few hundred feet down the street. Taxis had to carry around these machines in their trunks that were supposed to filter out air pollutants from the engine exhaust before it was released into the atmosphere. It was a meek effort from the Chinese government to improve air conditions for the 2008 Olympics. In this way, I began to realize that air pollution can have a negative impact on public health and the overall outlook of a city or country.
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 A few months ago, I learned about the MIRAGE-Mex (Megacity Impacts on Regional and Global Environments) project that was led by the National Center for Atmospheric Research (NCAR) and looked at how Mexico city plumes would affect the rest of the country. I became interested in it because it dealt with the problem of urban air pollution and the problems that it may inflict upon the public. The field campaign of 2006 was taking place in Veracruz for a month and many NCAR scientists were working on collecting data to be used for modeling pollution transport. I was interested in joining in with research in the summer of 2006, so I would have the opportunity of working with the collected data. It was then that Raj suggested that I take a trip down to Veracruz and take a look at how the data collection and organization is done. I thought that this was a good idea as it would give me a better understanding of the overall project as well as the data itself.
Upon entering Veracruz, I met Danny Mckenna, director of NCAR's ACD division. He showed me around the Operations Center in the Camino Real hotel where most of the ground crew was working. I soon met some of the other scientists, Jerome Fast, Louisa Emmons, and Marcelo Mena, who worked on putting together the daily weather briefing which consisted of pollutant concentration forecast graphs and the CO plume over Mexico City for the next few days. |
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Image: Flight plan of the twin otter
Courtesy of
Bob Yokelson
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I then learned that the data collecting was done not only from ground stations but also by aircrafts, satellites, and CMET balloons. Danny showed me how to track the path of one of the planes using Google Earth. The plane would fly north and then down over to Mexico City, then turn back to Veracruz. The plane was collecting data on a large number of parameters, such as NOx, SO2, NOy, ozone, CO, VOCs, and more. Later on, I looked more closely at the daily weather briefing and learned how to generate some of the graphs using MOZART, WRF, STEM, FLEXPART. MOZART was a simulation tool for making forecast maps of Mexico City's fossil fuel biomass burning. WRF displayed the wind profiles and a few pollutant concentrations for the day. STEM was a regional chemical transport model. The University of Iowa put together a 12km simulation over Mexico for this field compaign. It made 4-layer horizontal plots of chemical concentrations over the city. Lastly, FLEXPART was a pollution transport modeling tool for predicting tracers. Here, the scientists were only interested in carbon monoxide tracers in Mexico City. All of these tools were for forecasting the plumes of pollutants in the Mexico City area and the plane's flight plans were based on the plumes' movement. |
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After looking at flight plans and pollution forecasts, I got to visit the C130 that flew over to Mexico City. Some of the scientists told me that the flight takes approximately eight hours, where the cabin temperature reaches close to 100 degrees Fahrenheit because of the air pumps. I was very surprised that all the large instruments and computers were able to withstand the heat. Right before takeoff, I spoke with Lee Mauldlin who told me about these tube-like structures mounted on the side of the plane. Their job was to pick up hydroxyl radicals in the air, along with traces of sulfuric acid, and nitric acid, and HO 2. I spoke to a few other scientists with instruments on board and most of their instruments were used to pick up other chemicals in the air such as carbon monoxide, water particles, N2O, and more.
Afterwards, I had the opportunity to fly on the Twin Otter plane from the US Forest Service. The pilots told me that they flew the plane down from Utah specifically for this field campaign. There were five scientists on board, each with complicated instruments hooked up to two or three computers at once. One of them was Koji Adachi who told me that he was collecting soot particles to examine how they age over time. Apparently, when soot is initially produced from a fire, they are rather large. Over time, they react with chemicals and water droplets in the atmosphere and become compacted.
The Twin Otter was supposed to fly east to look for forest fires in Chiapas, and then land in Tapachula to refuel. At around 10:30am, we took off smoothly for an hour or so, then we started spotting forest fires around sample fires in the mountains near the Tuxtla Gutierrez so the plane spiraled downward so the scientists could collect data.
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There were air tubes running through the plane that took smoke samples. As the plane spiraled down towards each forest fire, the air got very brown. There were five fires total and in all of the cases, all I could see was smoke. Most of them were natural, caused by biomass burning. They also took air samples in the boundary layer and free troposphere.
As with any field experience, I felt that I learned more about the technical details of data collection than I did about the science of air pollution. I have come to appreciate data collection much more now since I have seen how much effort goes into flying the planes, setting up the instruments, and monitoring the plane's flight from the ground. I believe that this field campaign definitely achieved its goal of improving the current understanding of the chemistry, dispersion and transport processes of the pollutants emitted to the atmosphere in Mexico. I believe that I would like to be part of this kind of scientific research that involves both field work and technical work. It would give me the opportunity to see the hands-on aspect of air pollution research as well as the technical aspect of using computer models to predict pollution plumes. I'm just not sure I would like to fly for eight hours on a turbulent plane with the cabin at 100 degrees Fahrenheit!" |
Image:
One of the fires we saw during the flight
Courtesy of Bob Yokelson |
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