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Measurement and analysis of the radiation budget of a Sand Hills wetland
Abstract
My study addressed several interrelated topics concerning the measurement and analysis of the radiation budget of a lake/wetland system in the Nebraska Sand Hills. These topics included development of techniques for estimating radiation budget components and net radiation using a combination of simulation models and remote sensing techniques; and the use of in-situ instrumentation to assess the diurnal and seasonal behavior of the radiation budget. The remote sensing techniques were tested using both close-range techniques and satellite data. Close range data were collected from the study site at five times distributed throughout the field season. An Exotech model 100A field portable radiometer and Everest infrared thermometer were used to estimate albedo and surface temperature, respectively. These measurements of surface parameters were then combined with simulated values of incoming short and longwave radiation to calculate the surface radiation budget. The techniques were found to work well for the marsh and subirrigated meadow subsystems of the wetland system, producing estimates within 10% of measured values. The techniques were less effective for the open water subsystem. Application of the technique to Landsat Thematic Mapper data acquired at orbital altitudes produced similar results, with accurate estimates of net radiation from the marsh and meadow subsystems and less accurate results for open water. Results from the seasonal analysis of data collected in-situ revealed that each of the three wetland subsystems possesses a unique radiation regime. Seasonal pattern of the marsh and meadow were very similar, although net radiation over the marsh was significantly higher throughout the season. Seasonal net radiation for the open water subsystem showed the highest overall value and a peak which occurred more than two weeks after the two vegetated subsystems. Diurnal analysis of the radiation budget components revealed a highly symmetrical pattern of albedo and net radiation under cloudless conditions. These patterns became less symmetrical as cloud cover increased.
Subject Area
Geography|Remote sensing|Ecology
Recommended Citation
Goodin, Douglas Gard, "Measurement and analysis of the radiation budget of a Sand Hills wetland" (1993). ETD collection for University of Nebraska-Lincoln. AAI9331416.
https://digitalcommons.unl.edu/dissertations/AAI9331416