Priority 2: Investigating the Interactions of the Atmosphere, the Broader Earth System and Human Society

Intercontinental Chemical Transport Experiment-Phase B (INTEX-B)

Background

Air pollution from a given region can be carried across continents and oceans by winds and air currents. The fate of the pollutants during this transport is of considerable concern. At times the pollutants will be mixed relatively quickly with surrounding air during transport and thus diluted to levels that have little impact on air quality. At other times, the pollutants will travel in a plume long enough to undergo significant changes, including the production of ozone. Under both these scenarios, long-lived greenhouse gases, such as carbon dioxide and methane, are mixed into the surrounding air, which increases the concentrations and can have an impact on climate and global warming. Clearly, this is an important subject globally, so in order to understand the transport and fate of air pollution, NCAR scientists have joined with colleagues in the U.S., Europe, and Asia to study pollution near the sources and as it is being transported across continents and oceans. These studies include satellite, aircraft, ground based, and shipboard components. The NASA sponsored Intercontinental Chemical Transport Experiment- North America (INTEX-NA) is one such study. It was a two-phase experiment that was designed to understand the transport and transformation of gases and aerosols going out of and coming into the U.S. The first phase (INTEX-A) was completed in the summer of 2004 and was conducted out of Portsmouth, New Hampshire to look at East coast pollution sources and transport across the Atlantic.

Progress

The second phase (INTEX-B) was completed in the spring of 2006 and had two components, one as part of the Megacity Initiative: Local and Global Research Observations (MILAGRO) experiments to study pollution transport and transformation out of Mexico City and the other to study pollution transport from Asia to the U.S.

Over 20 NCAR scientists participated in INTEX-B. Some had instruments to measure various chemical constituents onboard the NSF/NCAR C-130 or the NASA DC-8. For example, the instruments on the C-130 and DC-8 included advanced optical instruments, the DFG Absorption Spectrometers, to acquire fast and accurate measurements of formaldehyde. These measurements are among those that are critical to understanding the formation of ozone. Other NCAR scientists were involved in aircraft flight forecasting and coordination with satellites that measure some of the same chemicals that are measured on the aircraft. This work included scheduling aircraft flights to occur underneath a give satellite as it flew over the area so direct comparisons could be made between the aircraft and satellite instruments.

Plans

In FY 2007, data processing, quality control, and data interpretation and analysis will be carried out on the data sets. The extensive suite of measurements will be used in measurement-model comparisons to improve model simulations of the atmosphere, knowledge of oxidation processes, and understanding of the Earth system. Once this work is completed, the findings will be released to the broader scientific community through refereed publications.

For further detail, please read the full project report linked below.

EOL Annual Report