Network design for soil CO2 monitoring of the northern North American region

Soil respiration represents a source of CO2 that greatly exceeds that of fossil fuel use and requires close monitoring in order to account for its contribution to net carbon exchange. While technological innovations continue to improve the quality of respiration monitoring, considerably less effort has been invested in the conceptual framework for monitoring networks. A network architecture and planning process is needed that allows us to anticipate the evolution of significant changes in this carbon pool, to ensure that expertise and resources are available at the appropriate times.In this study we outline a Monte Carlo network design process for large-area soil CO2 respiration monitoring using ground-based soil efflux equipment. Our effort is designed to accommodate many different possible network parameters, such as various temporal evolutions of soil respiration, deployment schedules and the accessibility of remote areas. Sensitivity tests are used to show the dependence of an optimized network to each factor in order to inform the decision making process about the scope and distribution of required monitoring. We also evaluate whether inexpensive and already existing proxy sensors can augment the network performance.The soil region under consideration was predicted to cumulatively respire approximately 200 Pg of carbon over the next 50 years, with results suggesting the need for soil flux observational nodes in several parts of the North American Arctic, but especially in northwestern Canada, Alaska, and at points in the eastern Canadian Arctic Archipelago. The ideal network locations proved most sensitive to moisture and temperature changes and the associated response of the soil. Correspondingly, the sensitivity analysis showed that accurate temperature, moisture and respiration data is crucial to efficient network placement.

► We outline a network design process for large-area soil CO2 respiration monitoring.
► This method examines multiple constraints on network design.
► Important North American locations include the northwest and eastern Arctic.
► Network locations were most sensitive to temperature and moisture soil response.