Investigating the topographic influence on short-wave irradiance measurements: A case study for Kanzelhöhe Observatory, Austria

摘要: Abstract We investigate terrain effects on short-wave radiation measurements at Kanzelhohe Observatory (KSO), a mountainous monitoring site in the Austrian Southern Alps, using three-dimensional (3-D) radiative transfer (RT) modeling and observations. The magnitude of global is experimentally assessed through comparison 10-min measurement segments ex−/including reflected radiation. component ex−/included solar irradiance (GLO) horizon shaped metal frame raised/lowered intervals. Additionally we assess influence 3-D RT model simulations performed with an updated version GRIMALDI, allowing for digital elevation inclusion. DEM used representation one arc second Shuttle Radar Topography Mission (SRTM) model. For GRIMALDI consider area averaged albedo 0.30 summer 0.36 winter (0.30 forests 0.90 fresh snow), respectively. surface grid cell interest (KSO location) derived incident domain (SI-GCS) SI-GCS reduced component. Applying 2σ threshold significance GLO measurements, find no significant surrounding during summertime. Also wintertime, vast majority observational increments surrounding. Above threshold, exceedances are small, average 0.2 W m−2. Differences between including excluding small conditions, i.e. always below 1% never exceeding 1 W m−2. Slightly larger differences found including/excluding summertime, reaching noon up to 6.1 W m−2. Both observations indicate that KSO well suited as (close negligible considering instrument specifications) throughout year.