Breakthrough in Measurement of Deposition of Ozone to the Ocean

August 8, 2006

ozone flux instrumentation aboard RV Ronald H. Brown Scientists from NOAA Earth System Research Laboratory (ESRL, Ludovic Bariteau, Chris Fairall, and Eric Williams) have collaborated with scientists from the University of Colorado's Institute for Arctic and Alpine Research (INSTAAR, Detlef Helmig) to perform the first direct ship-borne measurements of the flux of ozone from the atmosphere to the ocean. In August 2006, the group is performing the first-ever direct eddy correlation (EC) measurements of ozone flux from a ship (the NOAA Research Vessel Ronald H. Brown) during the Texas Air Quality Study (TexAQS) in the Houston area.

Near the surface, ozone is an important pollutant but, paradoxically, in the stratosphere ozone protects against harmful UV radiation. It is also a greenhouse gas that can affect the earth's climate by absorbing heat energy from the earth, then releasing it into the atmosphere. While scientists have learned a great deal about how ozone is created and destroyed in the atmosphere, there are still many missing pieces of the puzzle. Using a new instrument designed and constructed in Boulder, our team of researchers are hoping to find out more about destruction of ozone at the ocean surface. Because the oceans cover about two-thirds of the earth's surface, they have a significant effect on feedbacks between atmospheric ozone, other atmospheric pollutants, and the Earth's climate system.

The study area will be Texas and the northwestern Gulf of Mexico. The ozone flux breakthrough was made possible by recent advances in various aspects of EC measurement methods: realtime motion corrections of sonic anemometer signals (ESRL) combined with a new technology in fast ozone measurements (CU). Previously, the transfer rate of ozone into the ocean was estimated by assuming ozone transfer physics and chemistry were the same for all weather conditions and all bodies of water (small fresh lakes to large salty oceans).

This TexAQS intensive field study will focus on providing a better understanding of the sources and atmospheric processes responsible for the formation and distribution of ozone and aerosols in the atmosphere and the influence that these species have on the radiative forcing of climate regionally and globally, as well as, their impact on human health and regional haze. These measurements are expected to provide new insights into the parameterization of ozone deposition (loss) to the ocean and permit further development of the NOAA COARE gas flux parameterizations for use in air quality and climate models.

(Photo: Ozone flux instrumentation aboard the R.V. Ronald H. Brown.)

Contact: Chris Fairall More Information:
- Measuring Trace Gas Exchange Between Air & Sea
- Gas Transfer Parameterizations (via FTP)