The fine details of overmarsh circulation remain largely unexplored and yet they are typically assumed to control many attributes of salt marsh material cycling, transport, and accretion. We characterized the spatial and temporal variability in overmarsh circulation at a 2 km² Georgia, USA, salt marsh using field observations, dye tracer, and numerical simulations. The marsh bathymetry was created with a high‐precision Global Positioning System survey that details the geomorphic structure of intertidal creeks and salt marsh platform features greater than about 1 m in width. We assessed flow path dynamics at four spatial scales ranging from 1 m to 1000 m. Results show the development and decay of simultaneous flow divergence and convergence, concentrated flow and large‐scale rotational flow, and strong differences between flood and ebb pathways. This current complexity is set by submergence and emergence of subtle salt marsh platform geomorphic structure, and it highlights the role of topography in system‐wide flow processes.

A mathematical model for simulation of winds over mountain slopes was developed and tested withobservations from Australia and the western United States. The model computes profiles of wind andtemperature normal to the slope. The model also computes soil heat fluxes, the mechanical and radiativeeffects of trees, terrestrial radiation fluxes and their modification by clouds, and turbulent heat and momentum fluxes. All variables are integrated over a slope of specified length and steepness. Comparison ofavailable observations to simulated wind profiles showed general agreement, with the best agreement at siteson uniform slopes, and poorest agreement in complex terrain. The model is sensitive to variations in cloudheight, forest coverage, slope parameters, and ambient winds and temperatures. This sensitivity implies thataccurate simulations of drainage winds by multidimensional models will require inclusion of the sameexternal parameters. Abstract A mathematical model for simulation of winds over mountain slopes was developed and tested withobservations from Australia and the western United States. The model computes profiles of wind andtemperature normal to the slope. The model also computes soil heat fluxes, the mechanical and radiativeeffects of trees, terrestrial radiation fluxes and their modification by clouds, and turbulent heat and momentum fluxes. All variables are integrated over a slope of specified length and steepness. Comparison ofavailable observations to simulated wind profiles showed general agreement, with the best agreement at siteson uniform slopes, and poorest agreement in complex terrain. The model is sensitive to variations in cloudheight, forest coverage, slope parameters, and ambient winds and temperatures. This sensitivity implies thataccurate simulations of drainage winds by multidimensional models will require inclusion of the sameexternal parameters.

We compare three-dimensional simulations of two cooling lakes at the Savannah River site to calibrated temperature data derived from high resolution thermal imagery and to data from two dye tracer experiments. The observed temperatures include detailed surface temperature maps created from calibrated thermal imagery and vertical temperature profiles measured at five locations across one of the cooling lakes. The dye tracer data consist of time series of concentrations recorded near the cooling water outlet of one of the cooling lakes. There is generally good agreement between observed and measured quantities, but the agreement is best for the smaller cooling lake that had a relatively higher heat load. We suggest that wind stress variability may have been at least partially responsible for the poorer agreement between observation and simulation for the larger cooling lake. The primary conclusion from this study is that thermal imagery is an excellent additional data source to dye tracer data for cooling l...

The Multispectral Thermal Imager (MTI) is a research and development project sponsored by the Department of Energy and executed by Sandia and Los Alamos National Laboratories and the Savannah River Technology Center. Other participants include the U.S. Air Force, universities, and many industrial partners. The MTI mission is to demonstrate the efficacy of highly accurate multispectral imaging for passive characterization of industrial facilities and related environmental impacts from space. MTI provides simultaneous data for atmospheric characterization at high spatial resolution. Additionally, MTI has applications to environmental monitoring and other civilian applications. The mission is based in end-to-end modeling of targets, signatures, atmospheric effects, the space sensor, and analysis techniques to form a balanced, self-consistent mission. The MTI satellite nears completion, and is scheduled for launch in late 1999. This paper describes the MTI mission, development of desired system attributes, some trade studies, schedule, and overall plans for data acquisition and analysis. This effort drives the sophisticated payload and advanced calibration systems, which are the overall subject of the first session at this conference, as well as the data processing and some of the analysis tools that will be described in the second segment.