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Welcome to the Pico Mountain atmospheric observatory's website

The Pico Mountain station (also known as PICO-NARE) is an air pollution observatory. Measurements at Pico Mountain are able to study the free atmosphere (not directly affected by the ocean) and see pollution transport events originating in North America and Europe. The station was developed to study the global impacts of human activities on the atmosphere. It has also proven valuable for learning about the effects of large wild fires in North America and even Siberia.

The station is owned and operated by the University of the Azores, which has committed to work to develop the station into a long-term, Global Atmosphere Watch station. The station attracts researchers from other nations. Currently, scientists from Michigan Tech, the University of Colorado and the U.S. National Oceanic and Atmospheric Administration are also studying the atmosphere at the Pico Mountain station. Measurements at the site began in mid-July, 2001.
Este projecto estuda os impactos que os poluentes emitidos na América do Norte e Europa têm sobre Oceânico Atlântico Norte. Estas medidas permitirão um melhor conhecimento da atmosfera sobre os Acores e à escala global.
This project is designed to study the impacts that air pollutants emitted in North America and Europe have on the atmosphere over the North Atlantic Ocean. These measurements will improve our understanding of the environment in the Azores and globally.


The Pico Mountain station is located on the summit caldera of Pico mountain, an inactive volcano on Pico island in the Azores, Portugal (38 degrees, 28.226 minutes N latitude, 28 degrees, 24.235 minutes W longitude, 2225 m altitude).

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Current Site Status

The Pico Mountain station is currently operating for the 2009 field season. Michigan Tech staff from the United States reconnected the power cable and initiated station operation in February-March 2009. Researchers from Michigan Tech, the University of Colorado, and the U.S. National Oceanic and Atmospheric Administration have installed and begun operation of instruments at the station to measure carbon monoxide, ozone, nitrogen oxides, and non-methane hydrocarbons; black carbon measurements from the University of the Azores will begin soon.

Plans for the Regional Government of the Azores to connect the station to a new power generator or power cable during summer 2008 were cancelled in early spring 2009, and the station is operating this summer using the original diesel generator. Michigan Tech supported fuel and maintenance costs for the startup through mid-March (using National Science Foundation support), and the Regional Government of the Azores and University of the Azores are supporting operation costs for the remainder of the spring-summer season. Station operation beyond summer 2009 will be dependent on development of power and power cable infrastructure by the Regional Government of the Azores and/or the Portuguese Meteorological Institute.

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Findings: What have we learned so far?

The PICO-NARE station was originally developed to study the impacts of continental air pollution outflow upon the atmosphere over the North Atlantic Ocean, Europe, and downwind regions. However, research at the station has led to important findings on several topics. These findings are summarized here, on the topics of pollution outflow, impacts of wildfires, African dust, and the value of the Pico station. They have also been documented in the scientific literature. Links to these publications are provided in section:Documents.

Findings on pollution outflow

Findings on the atmospheric impacts of boreal wildfires

Findings on African desert dust transport and measurement

Using measurements of light-absorbing particles, several events in which African desert dust was carried to the Azores have been identified. Fialho and coworkers [2005, 2006] have developed a technique to identify these events and separate them from biomass-burning and anthropogenic particles. This technique is based on light absorption measurements at multiple wavelengths, and is described in detail in those two publications.

Findings on the value of atmospheric measurements on Pico mountain

The PICO-NARE station was located on Pico summit in order to sample the free troposphere (the region of the atmosphere above the marine boundary layer, that is, above the marine cloud layer), and to ensure that local pollution emissions do not affect the measurements. The station was located in the Azores in order to sample the remote marine environment, and thereby to determine the impacts of long-range transport and mixing of emissions from upwind continents on the regional atmosphere. We have analyzed each of these issues, and find that Pico summit is ideal for sampling the regional free troposphere, that it is rarely if ever affected by local Azorean pollution emissions, and that it provides an excellent platform for observing the seasonal and interannual variations of atmospheric composition for assessments of human-influenced and natural emission impacts. To date, most analyses of PICO-NARE data have focused on summertime measurements. However, the seasonal cycle of non-methane hydrocarbons (presented by Tanner 2006), ozone, and carbon monoxide in the background northern hemisphere is clearly detected at the Pico station.

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Recent Weather

The following sections show the most recent data and images from the station. During periods when the station is turned off, these are simply the last images and data downloaded before the station was shut down.

Please see the site status section for information on site operation that may affect the quality or validity of these data.

Note that these data may be several hours to several days old at times, due to delays in transferring data from the station. Wind direction is not shown, as wind directions at Pico summit are not the same as wind direction away from the mountain, due to turbulence over the summit. (A related plot of concentrations measured at the station is available below.)

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Site Photographs

Due to a loss of a camera server, only one camera is currently being used at the station. The latest photo from that camera is shown below. Depending on conditions, this photo may show either a view of inside the building (showing instrument racks) or a view outside.

Views from the station View toward the North (over the cliff) View toward the West (toward Madalena) View looking toward the East (the northern edge of Piquinho is visible when it is clear)
Most recent photo, usually taken within the last hour. (Check the date and time to be sure.)
Older photos taken on clear days
Other Images All images from the last 2 days Sign posted at the station Photo of site setup crew
Click for several nice station photos Snow-covered Pico Summit The building being carried to the mountaintop by the Portuguese Air Force View inside the building
  Station in March 2003


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Recent Measurements

The data plots below are meant to be a quick look at recent preliminary measurements. Scientists interested in using data from the station should refer to the PICO-NARE data exchange web page for more information.

The station is currently operational, and all instruments are working. Measurements of carbon monoxide (CO), ozone (O3), non-methane hydrocarbons, and aerosol black carbon (BC), and standard meteorological parameters are being made. Nitrogen oxides measurements are not funded this summer.

Recently obtained data are shown in the figure below, and recent photos are shown above. Occasional periods when data are not transferred have been occurring recently, due to heavy icing at Pico summit, which covers the cell phone antenna and prevents data transfer. Data are still obtained during these periods, and show up in the plot below when the ice melts.

The most recently processed data are shown in the following plot. Note that this plot contains preliminary data, which may change significantly when they are carefully analyzed. In addition, periods of instrument tests may be included.

Shown are CO (carbon monoxide) in ppb (parts per 10^9) and O3 (ozone) in ppb. The temperature inside the station is also shown on the ozone plot, and the third plot shows wind speed. (A related plot of weather at the station is available above.)

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Additional details and documents

Publications in the scientific literature

Findings from the following publications are summarized above, in section Findings.
  1. Regional and hemispheric impacts of anthropogenic and biomass burning emissions on summertime CO and O3 in the North Atlantic lower free troposphere, R. E. Honrath, R. C. Owen, M. Val Martin, J. S. Reid, K. Lapina, P. Fialho, M. P. Dziobak, J. Kleissl, and D. L. Westphal, J. Geophys. Res., 109, D25310, doi:10.1029/2004JD005147, 2004. (available here).
  2. An analysis of the mechanisms of North American pollutant transport to the central North Atlantic lower free troposphere, R. C. Owen, O. Cooper, A. Stohl, and R. E. Honrath, J. Geophys. Res., 111, D23S58, doi:10.1029/2006JD007062. (available here).
  3. Evidence of significant large-scale impacts of boreal fires on ozone levels in the midlatitude Northern Hemisphere free troposphere, K. Lapina, R. E. Honrath, R. C. Owen, and M. Val Martin, Geophys. Res. Lett., 33, L18015, doi:10.1029/2006GL025878, 2006. (available here).
  4. Significant enhancements of nitrogen oxides, black carbon and ozone in the North Atlantic lower free troposphere resulting from North American boreal wildfires, M. Val Martin, R. E. Honrath, R. C. Owen, G. Pfister, P. Fialho, and F. Barata, J. Geophys. Res., 111, D23S60, doi:10.1029/2006JD007530, 2006. (available here).
  5. Ozone production from the 2004 North American boreal fires, G. G. Pfister, L. K. Emmons, P. G. Hess, R. Honrath, J.-F. Lamarque, M. Val Martin, R. C. Owen, M. A. Avery, E. V. Browell, J. S. Holloway, P. Nedelec, R. Purvis, R. B. Ryerson, G. W. Sachse, and H. Schlager, J. Geophys. Res., 111, D24S07, doi:10.1029/2006JD007695 2006.
  6. The occurrence of upslope flows at the Pico mountain observatory: a case study of orographic flows on small, volcanic islands, J. Kleissl, R. E. Honrath, R. C. Owen, M. Val Martin, and M. P. Dziobak, J. Geophys. Res., 112, doi:10.1029/2006JD007565, 2007. (available here).
  7. Aethalometer calibration and determination of iron concentration in dust aerosols, P. Fialho, M. C. Freitas, F. Barata, B. Vieira, A. D. A. Hansen, and R. E. Honrath, J. Aerosol Sci., 37, 1497-1506, 2006. (available here).
  8. Gas chromatography system for the automated, unattended, and cryogen-free monitoring of C2 to C6 non-methane hydrocarbons in the remote troposphere, D. Tanner, D. Helmig, J. Hueber, and P. Goldan, J. Chromatography A, 1111, 76-88, 2006.
  9. Analysis and application of Sheppard's airflow model to predict mechanical orographic lifting and the occurrence of mountain clouds, J. Kleissl and R. E. Honrath, J. Appl. Met. and Clim., Vol. 45, No. 10, pages 1376-1387, 2006. (available here).
  10. Absorption coefficients by aerosols in remote areas: a new approach to decouple dust and black carbon absorption coefficients using seven-wavelength Aethalometer data, P. Fialho, A. D. A. Hansen, and R. E. Honrath, J. Aerosol Sci. (in press), 2005.
    (available here).
  11. International Consortium for Atmospheric Research on Transport and Transformation (ICARTT): North America to Europe--Overview of the 2004 summer field study, F. C. Fehsenfeld et al., J. Geophys. Res., 111, D23S01, doi:10.1029/2006JD007829, 2006.
  12. PICO-NARE, R. E. Honrath and P. Fialho,IGACtivities Newsletter (International Global Atmospheric Chemistry Project), August 2001 issue (available here).

General information on atmospheric measurements in the Azores

Note: The following list has not been updated recently; some of the material included here is outdated.


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Groups and agencies who have helped with the project

This project is possible as a result of the assistance of several agencies and groups. They include the following.


Funding for this project has been provided by the following agencies.

Additional support

Original Station Development

The station was originally developed by Michigan Technological University using funding from NOAA. On June 29, 2006, Michigan Technological University donated the PICO-NARE station to the University of the Azores, at a ceremony in Ponta Delgada. The Regional Government of the Azores and the Portuguese Institute of Meteorology participated in the ceremony and demonstrated their commitment to support the further development of the station, to create a permanent, Global Atmosphere Watch station at Pico summit. International research will continue to be welcomed during and after the transition to a permanent station.
(View the Michigan Tech news release on this topic)

Contract support


The PICO-NARE logo was created by Madalena Fialho.

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