The Global Ecosystem Dynamics Investigation (GEDI) is a NASA mission to place a waveform lidar instrument on the International Space Station. It will collect billions of measurements of the vertical distribution of vegetation within 22-m circular footprints worldwide to quantify aboveground carbon stocks in the world’s forests. This effort will provide a quantitative, globally consistent, and transparent […]
We use remote sensing and statistics to quantify the structure and condition of ecosystems and to test mechanistic hypotheses about how forests work. Central to our approach is the ability to collect frequent measurements at high spatial resolution. To achieve these objectives, we worked with commercial partners to develop the Brown Platform for Autonomous Remote Sensing (B-PAR).
B-PAR is a suite of sensors carried by a helicopter drone. It solves two problems. The most obvious of these is spatial resolution. The most highly resolved satellite data available today produce observations close to 1 m resolution (meaning that a single pixel represents 1 m on the ground). B-PAR increases this resolution by up to two orders of magnitude. For example, the VNIR imaging spectrometer has a spatial resolution of 0.025 m from 100 m altitude or 0.05 m from 200 m altitude. Measurements at the scale of a few cm open new opportunities to advance our conceptual understanding of ecosystems, because they more closely correspond to real-world objects, like leaves and branches, and because they are visually intuitive. Patterns become clear when viewed at the right scale.
The second problem that B-PAR addresses is time. Ecosystems are dynamic. Imaging spectroscopy has shown great promise to address mechanistic questions in plant physiology and the coupling between forests and the atmosphere. Realizing this promise requires the ability to deploy instruments with surgical precision to generate data at specific places at specific times, and the ability to produce time series separated by minutes to hours.
Canopy trees are long-lived organisms that produce a staggering number of offspring (seeds) in their lifetimes, very few of which will survive through juvenile life stages to eventually become adults themselves. What sets apart these proven winners in the competition for a position in the canopy? This project addresses this question in two ways. By […]
Each day, forests take up a tremendous quantity of carbon by way of photosynthesis. Over time, this carbon accumulates in plant tissues, where it resides until trees are cut down or die naturally and decompose, or are burned to clear land for agriculture. In addition to sequestering carbon through photosynthesis, forests continually release carbon to […]