A  ·  S  ·  R  ·  C

My research is focused on the measurement and analysis of interactions between land and water surfaces and the atmosphere. Examples of projects include ocean cruises to measure air-sea trace gas exchange, the use of tall towers in the Amazon rainforest to measure carbon dioxide and energy exchange, measurements from a unique spar buoy (R/P FLIP) to study the physics of wind-wave interactions, and the conversion of an Amazon riverboat into a floating laboratory to measure river-atmosphere carbon dioxide exchange. These measurements are used to address questions regarding processes controlling ocean-atmosphere and land-atmosphere exchange and biogeochemical cycles. This broad range of topics has required collaborations with physical and chemical oceanographers, ecologists, biologists, hydrologists, and meteorologists.

The field projects incorporate micrometeorological methods to measure exchange (flux) in the atmospheric surface layer, the lowest 100 m or so above the earth or ocean surface. The eddy correlation technique is used, which provides a direct flux measurement by correlating vertical wind velocity fluctuations with quantities of interest. For example, the correlation (or covariance) of vertical wind and carbon dioxide concentration is proportional to the carbon dioxide flux. The use of this technique requires relatively fast sensors (10 Hz) that have sufficient sensitivity to measure the turbulent atmospheric fluctuations. For more detail, see the web pages for the different projects, and the linked publications.