SAGE II Aerosol and Ozone Measurements Support for the TRACE P Field Experiment

Dr. Charles R. Trepte
NASA Langley

This effort proposes to support TRACE P field mission planning activities and data analysis and interpretation of the TRACE P data set with measurements from the SAGE II satellite experiment.  It further proposes to use TRACE P measurements to aid in the validation of SAGE II data products in the upper troposphere.

During the TRACE P mission, SAGE II aerosol and ozone data will be made available to aid mission planning and post-mission data analysis.  SAGE II will have at least 3 latitudinal sweeps of either SAGE II sunrise or sunset measurements during the TRACE P deployment and 15 sunrise and 15 sunset events per day.  There measurements will provide critical information on the vertical structure of the Asian aerosol plume above 6 km. And enable a more complete characterization of the aerosol distribution over the Northern Hemisphere prior to, during  and after completion of the TRACE P field campaign.

Understanding the primary sources and transport pathways of aerosol in the upper troposphere is the focus of a study (C. Trepe) sponsored by ACMAP.  The TRACE P measurements offer a range of chemical and gas particle information that taken in conjunction with dynamical analyses will enable a fuller understanding of the important aerosol sources and transport routes.

This proposal will also take advantage of results from a numerical weather prediction model to complement the isentropic analysis, which will be provided by Dr. J. Crawford.  As a by-product of Crawford’s simulations, Trepte will make use of the flow fields, trajectories, and potential vorticity, water vapor and initialized tracer distributions together with TRACE P data sets to help   identify locations of aerosol convective mixing and removal and link these regions to the enhanced aerosol features observed by SAGE II.

SAGE II aerosol data has been well validated in the stratosphere.  Much less validation has been carried out in the upper troposphere, partly because of the difficulty in carrying this out in a region where cloud can occur along the optical path, and partly because the primary responsibility of the SAGE instrument series has been to make stratospheric measurements. 

Validation of the SAGE measurements of ozone concentration in the upper troposphere is also needed.  TRACE P will provide measurements with sufficient vertical resolution, accuracy and coincident registration to verify the retrieved SAGE II measurements.  Prior SAGE II measurement comparisons to an occasional coincident intersection with an ozonesonde or comparison with zonal mean averages is inadequate.