Surface fluxes of trace gases derived from convective-layer profiles
Non-local gradient and variance functions relating the surface and entrainment fluxes of a passive scalar to the mean mixing ratio and variance profiles in the cloud-free, convective boundary layer have been determined from large eddy simulations. These functions can be used to calculate the surface and entrainment fluxes of trace gases over a large area, given profile measurements within the convective boundary layer. This dissertation develops the convective layer gradient technique for estimating fluxes and demonstrates two potentially valuable applications. An attempt is made to verify the large eddy simulation gradient functions with aircraft observations from the First ISLSCP Field Experiment and the San Joaquin Valley Air Quality Study. Results show general agreement with the simulated gradient functions but precise comparison is made difficult by scatter in the aircraft derived functions. The gradient functions are used to estimate forest emissions of nonmethane hydrocarbons using tethered balloon profiles. Mean emission estimates from profiles collected during the Amazon Boundary Layer Experiment 2A and the Rural Oxidants in the Southern Environment I experiment show good agreement with estimates made from budget arguments. Daytime isoprene emissions from the dry season Amazon are estimated. Summer, daytime isoprene, alpha-pinene, and beta-pinene emissions from an Alabama pine-oak forest are estimated. This technique provides a valuable means of measuring biogenic hydrocarbon emissions, a precursor to photochemical ozone production. The convective layer gradient technique holds the potential for remote estimation of surface fluxes over large areas using remote profiling technology, such as Differential Absorption Lidar (DIAL). The minimum signal-to-noise ratio for successful ozone deposition estimates using this DIAL system and the convective layer gradient technique was less than the signal-to-noise level in the analyzed DIAL observations.
- Research Organization:
- Colorado Univ., Boulder, CO (United States)
- OSTI ID:
- 6881843
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ATMOSPHERIC CIRCULATION
COMPUTERIZED SIMULATION
HYDROCARBONS
OZONE
ATMOSPHERIC CHEMISTRY
BOUNDARY LAYERS
CONVECTION
OPTICAL RADAR
CHEMISTRY
ENERGY TRANSFER
HEAT TRANSFER
LAYERS
MASS TRANSFER
MEASURING INSTRUMENTS
ORGANIC COMPOUNDS
RADAR
RANGE FINDERS
SIMULATION
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)