May 21 - July 30
Spatial and Temporal Variability of Albedo From Enhanced Radiation Measurements in Oklahoma
Nathan Kelly and Brad Illston
What is already known:
- Albedo is an important factor in boundary layer and surface energy budget parameterizations.
- Current estimates of potential evapotranspiration in Oklahoma, based on the American Society of Civil Engineers standardized equation, rely on an albedo value of 0.23 for all locations and seasons.
- Is the albedo in Oklahoma as measured at 11 Oklahoma Mesonet sites significantly different from 0.23, and how does albedo vary with the seasons?
What this study adds:
- Albedo is lowest in summer and highest in winter, varying by about ~0.04 depending on station.
- On average, albedo is lower than 0.23 in all seasons.
- 0.23 is not a suitable estimate for albedo in Oklahoma across all seasons and locations.
Abstract:
In 1999, the Oklahoma Atmospheric Surface-layer Instrumentation System (OASIS) project placed instrumentation focused on observing the surface energy budget at 89 Oklahoma Mesonet stations. At any given time, 10 stations (designated “super sites”), were outfitted with additional instrumentation including a four component net radiometer with the capability to observe incoming and outgoing shortwave (solar) and longwave radiation. Data are available from the beginning of 2000 until October 2008. This data was filtered to remove observations non-representative of the days albedo (e.g. sunrise and sunset periods, cloudy days, and erroneous instrument readings) and monthly averages were computed for each of the super sites in order to develop a better understanding of the spatial and temporal variability of albedo in Oklahoma.