Connecting Satellite and Surface Measures of Spring's Onset

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Abstract ATM-9510342 Schwartz, Mark D. University of Wisconsin, Milwaukee Title: Connecting Satellite and Surface Measures of Spring's Onset Interactions between the atmosphere and biosphere are a key component of the Earth's physical system. Understanding the interaction is a crucial part of efforts to improve global change simulation models. While atmospheric data generally are available for most land areas, no such network exists to collect comparable information about biosphere activity. Recent satellite information can contribute to the development of global biosphere databases. In order to realize this potential, these remotely sensed data must be carefully calibrated with surface information. This approach is the most straightforward way of deducing the physical basis of, and developing a historical context for, the satellite's observations. This study will take advantage of a unique surface vegetation data set to develop a physical interpretation of satellite data measuring the first appearance of spring foliage, commonly called the "green wave", across eastern North America. The green wave is particularly important because it is one of the crucial biospheric variables necessary for accurate modeling of process such as water balance and net primary productivity. The project will first develop empirical models to simulate surface green wave data (needed to supplement actual data limitations). Next, the relationship between satellite information and surface data will be determined for selected land cover types (biome). Lastly, detailed meteorological information from selected sites will produce a preliminary physical model of the green wave. These results will permit the satellite information to broaden existing surface green wave chronologies. In turn these lay the foundation for a future mid-latitude green wave model, which would assess the impact of climate variability on this aspect of the biosphere. Therefore, this project will serve as an example of how satellite bioclimatology in concert with surface phenology can produce physical interpretations of observed events, providing needed information for atmosphere-biosphere simulation models and global change monitoring.