Penlee Point Observatory

The Penlee Point Atmospheric Observatory (PPAO) was established by the Plymouth Marine Laboratory in May 2014 for long term observations of ocean-atmosphere interaction. The observatory is only a few tens of metres away from the water edge and 11m above mean sea level.

Location and typical winds

At the mouth of the Plymouth Sound, the site (50° 19.08' N, 4° 11.35' W) is exposed to marine air when the wind comes from 110° - 240°. Typical southwesterly winds tend to bring relatively clean background Atlantic air.  In contrast, winds from the southeast are often contaminated by exhaust plumes from passing ships. The PPAO is in close proximity to marine sampling stations that form the Western Channel Observatory, enabling better understanding of the ocean-atmosphere coupling.

Measurements at PPAO

Continuous gas phase measurements at PPAO include concentrations of sulphur dioxide (SO2), ozone (O3), carbon dioxide (CO2), and methane (CH4) in air.  Aerosol number (>0.003 μm diameter), size distribution (0.24-18.5 μm diameter), composition (major ions, organics, and trace metals) and meteorology are also measured.  We directly quantify the air-sea transport of CO2, CH4, and aerosols using the state-of-the-art eddy covariance technique.  Continuous observations at PPAO also allow us to quantify the impact of anthropogenic activity on the coastal environment as well as the influence of the sea on the nearby land.

Trinity House own the site and have kindly agreed to rent the building to PML so that instrumentation can be protected from the elements. We are able to access the site thanks to the cooperation of Mount Edgcumbe Estate. We would like to thank Universities of Plymouth, East Anglia, Leeds, and National Oceanographic Centre for their collaborative measurements.

Full Data Available

Figures shown below in the data viewer contain averages of the raw, uncalibrated data. If you would like access to the calibrated data, or you would like to know more about the observatory, please contact Tom Bell or Mingxi Yang

Penlee Observatory

Air Temperature & Dew Point

Meteorological data (wind speed, direction, temperature, humidity, dew point, pressure, rain rate) are measured by a Gill Metpak Pro weather station.

Air Temperature and Dew Point time series plot

Air Pressure & Relative Humidity

Meteorological data (wind speed, direction, temperature, humidity, dew point, pressure, rain rate) are measured by a Gill Metpak Pro weather station.

Pressure and Relative Humidity time series plot

Wind Speed & Direction

3­‐D Wind is measured by a Gill Windmaster Pro sonic anemometer.

Wind Speed and Direction time series plot

Rain Rate and Cumulative Rain

Rain rate and cumulative rain rate time series plot

Sulphur Dioxide (SO2) & Ozone (O3)

SO2 is measured by a Thermo Scientific model 43i Trace Level­‐Enhanced Pulsed Fluorescence SO2 analyzer. The instrument has a quoted limit of detection (LOD) of 0.05 parts per billion (ppb) when averaged to a couple of minutes. O3 is measured by 2B Technologies, Inc. Model 205 Ozone Monitor based on the technique of UV absorption. The instrument is set to output at a rate of every 10 seconds. The sampling flow of the analyzer is about 2Lpm.

Suplhur Dioxide and Ozone time series plot

Carbon Dioxide (CO2) and Methane (CH4)

CO2 and CH4 are measured by a cavity ringdown spectroscopy analyzer (Picarro G2311‐f), which is borrowed from the National Oceanography Center, Southampton.

Carbon Dioxide and Methane time series plot



Yang, M., Bell, T. G., Hopkins, F. E., Kitidis, V., Cazenave, P. W., Nightingale, P. D., Yelland, M. J., Pascal, R. W., Prytherch, J., Brooks, I. M., and Smyth, T. J.: Air-sea fluxes of CO2 and CH4 from the Penlee Point Atmospheric Observatory on the south-west coast of the UK, Atmospheric Chemistry and Physics, 16, 5745-5761, 10.5194/acp-16-5745-2016

Yang, M., Bell, T. G., Hopkins, F. E., and Smyth, T. J.: Attribution of atmospheric sulfur dioxide over the English Channel to dimethyl sulfide and changing ship emissions, Atmospheric Chemistry and Physics, 16, 4771-4783, 10.5194/acp-16-4771-2016

Yang, M., Prytherch, J., Kozlova, E., Yelland, M. J., Parenkat Mony, D., and Bell, T. G.: Comparison of two closed-path cavity-based spectrometers for measuring air–water CO2 and CH4 fluxes by eddy covariance, Atmos. Meas. Tech., 9, 5509-5522, doi:10.5194/amt-9-5509-2016