Lessons in New Measurement Technologies: From Instrumenting Trees to the Trans-African Hydrometeorological Observatory

Abstract

Ecohydrological monitoring technology is experiencing unprecedented expansion in capacity at ever lower costs. This allows for monitoring of systems at new scales spatially and allows for completely new strategies in observation. To represent the scale of this transformation, we present the framework for establishing a novel ecohydrological observation platform across the African continent (addressing the transformative opportunities made possible by wide-scale GPRS communication systems combined with solid-state sensing technology), as well as a strategy to leverage newly available accelerometer systems to monitor the dynamics of aboveground tree mass. The African observations are organized under the Trans-African Hydrometeorological Observatory (TAHMO.org), currently with about 500 installed stations across 20 African countries. Specific sensor technologies also open completely new approaches to measure key environmental variables. Aboveground mass of trees reflects, among other processes, the interception of rain, fog and snow, delivery of sap, addition of leaves, and loss of stem water. We demonstrate that passive sensing of tree acceleration due to wind can be used to evaluate change in mass caused by events such as leafing out or loss of leaves. We conclude by exploring the implications of ecohydrological observation at ever greater resolution and richness of variables.