Submitted to: International Association of Hydrological Science
Publication Type: Proceedings
Publication Acceptance Date: April 7, 2000
Publication Date: N/A
Technical Abstract: Variability of albedo has important implications for the regional energy balance. Assessments of albedo changes throughout a year over large areas are scarce. Surface albedo data for Iowa were constructed from AVHRR data for 16 biweekly 1990 data sets. Data were examined with spatial and time series statistics. The study was conducted to assess the temporal changes in spatial trends and correlation scales. Each data set generally exhibited large scale trend especially in the north-south direction until full crop cover occurred. Areal correlation scales for nonharvest periods varied greatly over the growing season and showed a correlation with the previous period's estimate. They ranged from 340 to 2010 km**2, suggesting averaging areas for reliable, independent areal albedo estimates that are double those of the correlation scales. The utility of conducting large scale analysis over space and time is thus shown. The end result is that albedo values used in regional energy balance models are improved.