The Palau Atmospheric Observatory


The Palau Atmospheric Observatory (PAO) is a temporary research station run by our section in cooperation with other partners (e.g. University of Bremen). It was installed in 2015 on the campus of the Palau Community College in Koror, Palau (7° N, 134° E), an island nation in the center of the Tropical Western Pacific warm pool. Due to the complex interplay of global atmospheric dynamics and chemistry, this region is of key importance for the chemical composition of the global stratosphere. At the same time, Palau is a rare tropical clean air site located within a previous gap in observational networks, which our continuous measurements now fill.

Our research focus is on observations of the upper troposphere and stratosphere. With little local anthropogenic influence, the PAO is ideal for comparisons with other tropical stations and to study the impact of long-range transport of polluted air into the region. The most important elements of this atmospheric region impacting surface climate are ozone and aerosol, the distribution of water vapour and the abundance of several other trace gases. The two laboratory containers of the station host a variety of instruments to measure these atmospheric constituents:

  • ground station and equipment for weather balloon soundings with ozone (ECC), water vapour (CFH) and aerosol (COBALD) sondes
  • a cloud and aerosol LIDAR (Light Detection and Ranging) called ComCAL
  • a solar absorption Fourier Transform Infrared Spectrometer (FTIR) (20 chemical species, incl. ozone and OCS, University of Bremen)
  • a sun photometer called Pandora-2S (ozone, NO2, aerosol, with FU Berlin)
  • a UV-photometer (ground ozone).

While many operations can be controlled remotely, personnel from the local Coral Reef Research Foundation (CRRF) launch ozone sondes twice a month, thus helping us create an unprecedented continuous time series of atmospheric ozone profiles. Our scientists and technicians visit the PAO regularly for maintenance and to run campaigns targeting specific seasons or more measurement parameters - and to share our research with the local public in a variety of outreach activities.

Further reading: