Potential of time-lapse photography for identifying saturation area dynamics on agricultural hillslopes

摘要: Mapping saturation areas during rainfall events is important for understanding the dynamics of overland flow. In this study, we evaluate potential high temporal resolution time-lapse photography mapping (i.e., where water visually ponding on surface) hillslope scale natural rainfall. We take 1 image per minute over a 100 × 15 m2 depression area an agricultural field in Hydrological Open Air Laboratory, Austria. The images are georectified and classified by automated procedure, using grey intensity as threshold to identify area. optimum T obtained comparing from analysis with manual 149 images. found be highly correlated brightness characteristic defined greyscale histogram mode M (Pearson correlation r = 0.91). estimate T = M + C C calibration parameter assumed constant each event. procedure estimates total close mean normalized root square error 9% 21% if calibrated event taken all events, respectively. spatial patterns estimated geometric accuracy index 94% compared same photos. tested against observations one date preliminary demonstration, which yields shortest distance between measured boundary points automatically 23 cm. usefulness illustrated exploring run-off generation processes example Overall, proposed classification method based process varying brightnesses well. It more efficient than tracing large number images, allows exploration surface flow at resolution.