On the surface energy balance closure at different temporal scales

摘要: Abstract Measurements of the surface energy fluxes (turbulent and radiative) other ancillary atmospheric/soil parameters made in Columbia River Basin (Oregon) an area complex terrain during a 10-month long portion second Wind Forecast Improvement Project (WFIP 2) field campaign are used to study budget (SEB) over different temporal scales. This analyzes discusses SEB closure based on half-hourly, daily, monthly, seasonal, sub-annual (~10-month) averages. The data were collected all four seasons for states underlying ground (dry, wet, frozen). Our half-hourly direct measurements balance show that sum turbulent sensible latent heat systematically underestimate positive net radiation by around 20–30% daytime overestimate negative at night. imbalance is comparable terrestrial sites. However, average, residual significantly reduced weekly, monthly averaging timescales, moreover, can be closed this site within reasonable limits seasonal timescales (311-day entire dataset). Increasing time daily longer intervals substantially reduces flux storage terms, because locally entering soil, air column, vegetation morning released afternoon evening. Averaging also random instrumental measurement errors uncertainties as well smooths out hysteresis effect (phase lag) relationship between components. shows better dry soils compared wet statistical dependence freezing soil surfaces appears weak, if not non-existent, apparently due lack fusion term traditional equation.