The Amazon rainforest interacts with the atmosphere by exchanging many substances. Many of these, such as carbon dioxide, methane, ozone, and organic compounds, are produced by the vegetation. They are very influential in both the regional and global climates. Until now, the estimates of their emission and absorption rates are based on classical theories. But those were developed over relatively short vegetation and are valid for the so-called the “inertial sublayer.”
Cléo Quaresma Dias‐Júnior and co-authors now checked if such an inertial sublayer even exists over the Amazon, where trees grow much higher. With an average tree height of some 40 meters, they expected it at around 100 meter above the forest floor.
They measured a number of atmospheric parameters that typically change between layers at different heights of the ATTO 80m tower and the Tall Tower. However, they found no evidence that such an inertial sublayer exists. Instead the roughness sublayer (the layer directly above the surface) directly merges with the convective mixed layer above. Crucially, this means that new methods and theories will be needed to address the absence of the inertial sublayer to improve the estimates of fluxes over the Amazon rainforest.
The paper was recently published in Geophysical Research Letters: 10.1029/2019GL083237