HR: 09:25h
AN: H31K-06    [Abstracts]
TI: Linking Fluxes with Remote Sensing in Field Studies
AU: * Huemmrich, K F
EM: karl.f.huemmrich@nasa.gov
AF: University of Maryland Baltimore County, NASA's Goddard Space Flight Center, Greenbelt, MD 20771, United States
AU: Gamon, J A
EM: jgamon@gmail.com
AF: California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032, United States
AB: From the beginning in FIFE, flux measurements were key data sets and the sites with flux towers were important anchors in the field campaigns. A key goal of FIFE was to develop connections between remotely sensed observations and fluxes of water vapor and carbon, mostly through providing parameters for models. In the twenty years since FIFE there has been significant changes in both flux measurements and remote sensing technology. Eddy covariance systems for measuring ecosystem carbon and water fluxes have become more reliable and cheaper, resulting in more flux data collected in more locations and over longer time periods. Eddy covariance systems provide temporally rich (but spatially poor) measurements of carbon and water vapor flux at selected locations. On the other hand, satellite-based remote sensing provides a synoptic view of the world, yet has difficulty providing temporally continuous data at a scale that can be directly related to flux measurements. There are a number of issues that must be explored to develop robust links between remote sensed observations and fluxes. The SpecNet (Spectral Network) group of investigators has been formed to address these issues. Many of its members have a background with field experiments. Key issues include both temporal and spatial scaling. Both flux measurements and spectral reflectance measurements can be collected at different spatial scales: leaf, plant, patches, stands, on up to entire landscapes. The SpecNet investigators also have an interest in temporal scaling, collecting both flux and spectral reflectance measurements simultaneously over various time intervals; from minutes, hours, days, growing seasons, to multiple years. To collect these types of data, new field methods and technology are being developed. A particular interest of SpecNet investigators is the detection of changes in reflectance in specific spectral bands that are caused by biochemical changes in leaves as they respond to stresses and downregulating photosynthesis. Changes in apparent reflectance have been observed at the leaf level due to changes in the xanthophyll cycle and also due to solar-induced fluorescence. These changes are subtle, but by tightly linking both optical and gas exchange measurements in space and time, they can be detected at patch on up to stand scales. This presentation will review some of the fieldwork that has emerged to examine the remote sensing of water and carbon fluxes.
UR: http://specnet.info/
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0428 Carbon cycling (4806)
DE: 0480 Remote sensing
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1855 Remote sensing (1640)
SC: Hydrology [H]
MN: 2007 Fall Meeting