A Two-Year Comparison of the Surface Water and Energy Budgets between Two OASIS Sites and NCEP–NCAR Reanalysis Data

Abstract

Few surface-observation networks exist that provide comprehensive multiyear, multiseason observations of surface energy fluxes and subsurface soil moisture and temperature, combined with near-surface atmospheric data. More such networks are needed to validate, improve, and calibrate current global weather and climate models, including those used as the backbone or background models in global reanalysis. One such measurement system is the Oklahoma Mesonet?Oklahoma Atmospheric Surface-layer Instrumentation System (OASIS), which provides atmospheric, surface, and soil data in real time. This study compares 2 yr of surface energy and water budget data from two OASIS sites located in two distinct climate zones with NCEP?NCAR global reanalysis (GR) estimates. The intraseasonal hydrological and thermodynamic cycles are discussed. Results show generally good agreement between most reanalysis values and observations. Incoming and reflected shortwave radiation are largely overestimated by the GR, and incoming longwave radiation is slightly underestimated by the GR when compared to OASIS observations. The GR significantly overestimates latent heat (LE) at the Idabel, Oklahoma (IDAB) site. Furthermore, the GR likely underestimates entrainment of drier air from above the PBL and mixes the turbulent fluxes over too shallow of a layer. Both the reanalysis and observations find a positive water residual for the easternmost site (IDAB) but estimate a negative near-surface water residual for the western site [Boise City, Oklahoma (BOIS)]. Overall, surface fluxes and thermodynamic properties were well analyzed by the reanalysis at capturing the unique features associated with each OASIS site.