The Boulder Atmospheric Observatory: More than just a Tall Tower!

The Boulder Atmospheric Observatory (BAO) is a research facility located just east of the town of Erie, Colorado maintained by NOAA's Earth System Research Laboratory Physical Sciences Division. Completed in 1977, the BAO (Kaimal and Gaynor, 1983) is a unique facility for studying the planetary boundary layer (BL). The centerpiece of the facility is a 300-m tower that features an inside passenger elevator and an outside instrument carriage and is instrumented with temperature/RH and wind sensors. The capability of the instrument carriage for profiling aids in studying many different aspects of the BL. Several remote sensors, including a laser ceilometer and sodar, are also operated continuously with the purpose of enhancing and complimenting the data collected on the tower. The BAO web site (http://www.esrl.noaa.gov/psd/technology/bao/) provides a link to near real-time data, including current weather conditions, and spectacular web camera images of Denver and the surrounding region. Ongoing research and measurements include solar radiation and greenhouse gases. The BAO has been a contributor to the World Climate Research Programs (WCRP) Baseline Surface Radiation Network (BSRN) for over 25 years. BSRN sites are selected for the site's spatial representativeness and suitability for the applications in climate research involving global climate models and/or satellite-derived related data sets. The BSRN has been designated as a global baseline network for surface radiation for the Global Climate Observing System (GCOS) and contributes to the Global Atmospheric Watch (GAW). For the past 5 years as part of the NOAA ESRL GMD Tall Tower Network the BAO helps provide regionally representative measurements of carbon dioxide (CO2) and related gases in the continental boundary layer. The tall tower sites are part of the North American Carbon Program and are a primary data source for ESRL's Carbon Tracker CO2 data assimilation system. Past research has included several air pollution studies (Denver and Boulder), a nocturnal boundary layer study, a diffusion study, statistics for wind turbine design, wind profiler development, sodar intercomparisons, In-Situ sensor intercomparisons, acoustic tomography, GPS reflectomerty (soil moisture), optical anemometry, infrasound, radiometric measurements, air chemistry, atmospheric gases, aerosols, water vapor, lidar (CO2, range finding, ozone, wind), and dropsonde/parachute testing. A short history of the BAO will be presented along with an overview of the facility and its capabilities both physically and scientifically. Past and current studies conducted at the BAO since its inception in 1977 will be reviewed.