Aerosol Data From Pico Observatory Now Part of Value-Added Product

Published: 11 March 2013

aod1 — Day with *moderate* aerosol loading (22 June 2010): AOD at five wavelengths (top) and Angstrom exponent (bottom) at the Pico Observatory site.

Aerosol optical depth (AOD) measurements have been provided for the Above-Cloud Radiation Budget field campaign at Pico Observatory, Azores, held in conjunction with the 2010 deployment of the ARM Mobile Facility (AMF) in Graciosa Island, Azores.

AOD measures the total aerosol burden in the atmosphere. The spectral dependence of AOD, typically described by the Angstrom exponent, is also an indicator of particle size. Small Angstrom exponent values (near zero) indicate the presence of large particles, and vice versa.

aod2 — Day with *low* aerosol loading (29 August 2010): AOD at five wavelengths (top) and Angstrom exponent (bottom) at the Pico Observatory site.

The AOD value-added product (VAP) provides both the wavelength-dependent values of AOD and the Angstrom exponent from five spectrally resolved measurements gathered by the multifilter rotating shadowband radiometer (MFRSR). This VAP uses MFRSR-based algorithms originally developed by Michalsky et al. and applied to more than ten years of AOD measurements at the well-established ARM Southern Great Plains (SGP) site. These algorithms were tailored for applications at different places around the world with the temporary deployment (typically up to 12 months) of the AMF. The AOD VAP is regularly updated with data from each new deployment of the AMF. (See previous data announcements here, here, and here.)

During the AMF1 deployment at the Azores, a supplemental site with an MFRSR was set up at the Pico Observatory. Recently, data from this supplemental site were added to the AOD VAP. Clean days with small aerosol loadings (AOD less than 0.1 at 500 nm) were observed quite frequently at this site. The VAP produces reasonable AODs even for these days. The figures to the right show examples of AODs collected for days with moderate and low aerosol loadings. It is expected that a comparison between AODs from the main Azores deployment and from Pico Observatory will provide great opportunities to better understand aerosol entrainment processes and complex issues associated with aerosol-cloud interplay.

More information is available at the VAP web page. To access these data, log in to the Data Archive. (Go here to request an account.)

# # #

The ARM Climate Research Facility is a DOE Office of Science user facility. The ARM Facility is operated by nine DOE national laboratories, including .