Abstract ATM-9532006 Kritz, Mark A., State University of New York-Albany Title: Acquisition and Use of 222Rn Measurements in the Development and Validation of a Global Transport Model The primary objective of this program is to obtain and use a set of free tropospheric radon (222Rn) measurements in the development and validation of an off-line global 3-D model under development at the Climate and Global Dynamics Group at the National Center for Atmospheric Research. To this end the PI will work interactively with members of the NCAR group on questions of transport parameterization and sub-grid scale processes, flight planning and sampling strategy, and the application of the results. There are also two secondary objectives: First in cooperation with Dr. Pieter Tans (NOAA/CMDL) Boulder) to acquire simultaneous CO, CO2, CH4 Measurements in the course of those flights, for use in model validation and to further our understanding of the global carbon budget. Second, by concentrating the flights in one season, to acquire a data set which will be useful in the development and validation of other regional and global models as well, such as 3-D GCM-based climate and chemical transport models. Measurements will be made aboard a NASA Lear 24 jet aircraft flying in the central and western United States, using a fast sampling system which the PI has flown aboard NASA C-141 and C-130 aircraft. The flight series will consist of five round trip flights between Moffett Field, CA and Minneapolis, MN (with a refueling stop in Colorado) and five local (offshore) flights out of Moffett Field, to be flown over a five week period in the summer of 1996. The sampling strategy for both the outbound and return flight will be similar, with vertical profiles obtained over specified locations in Colorado and Minnesota, and upper level observations made in the course of the flight legs between Moffett, Colorado and Minnesota locations. Present plans call for the outbound legs to be fl own on Tuesdays of the five successive weeks, and the returns on Thursday or Friday; however there is enough flexibility in the timing of the outbound and return legs to avoid possible problems due to aliasing, or recurrent synoptic situations. Vertical profiles in the vicinity of Moffett, and 200 miles offshore will be acquired on each of the offshore flights, to investigate modeling artifacts associated with boundary layer parameterization and continental edge effects. The PI will work with NCAR and other interested modeling groups in the application of the radon data, and with NOAA and others on the application of the trace constituent data set. The radon results will be archived and made available via anonymous ftp and "3.5 floppy discs. This research is important because it will provide valuable observations that are needed to test and evaluate atmospheric general circulation models that are being developed to include chemistry processes.