“The NASA TRACE-P mission pioneered the use of aircraft measurements to verify emission inventories of environmentally important species from a  large continental source region”

This paper presents an overview of the NASA TRACE-P tropospheric chemistry mission that took place in March and April of 2001, originating out of Hong Kong and Japan. TRACE-P used two aircraft to characterize Asian chemical outflow to the northwest Pacific, with the goal of better quantifying Asian chemical emissions and the chemical evolution of Asian pollution. The mission was highly successful and provided a considerable amount of data on a wide range of chemicals including greenhouse gases, ozone and its precursors, aerosols and their precursors, and halocarbons. A large number of papers are now exploiting the TRACE-P data and citing the overview paper.

The TRACE-P mission was innovative in its integration of aircraft observations with satellite data and 3-D chemical transport models (CTMs) in order to optimize the observational constraints on Asian outflow and Asian sources. For example, it used chemical model forecasts to predict the location of Asian outflow plumes and these were used to guide flight

planning on a day-to-day basis. TRACE-P was also the first tropospheric chemistry mission in which satellite validation was incorporated into the flight plans, for the purpose of obtaining a seamless data set integrating aircraft and satellites.

The NASA TRACE-P mission pioneered the use of aircraft measurements to verify emission inventories of environmentally important species from a large continental source region. Such verification of emissions, leading to better understanding of emission processes, is of crucial importance for the development of future international environmental agreements. East Asia is presently the principal driver of global change in atmospheric composition, and it is important that we characterize its emissions on a regular basis. TRACE-P provided a baseline against which we will be able to assess changes from future observations.

I have been involved in the NASA tropospheric chemistry program, and the associated aircraft missions, for almost 20 years. There is at present considerable interest in better understanding how Asian industrialization is affecting global atmospheric composition. After two exploratory missions in the early 1990s Pacific Exploratory Mission-West (PEM-West), NASA decided to go back to the Asian Pacific Rim in a carefully designed aircraft experiment that would provide quantitative information on Asian sources and their global implications, and that's what we did in TRACE-P, very successfully.