CROCUS Micronet: A Distributed Urban Observation System in Chicago

Abstract

CROCUS is one of four U.S. Department of Energy Urban Integrated Field Laboratories dedicated to advancing understanding of atmospheric, ecological, and hydrological processes in cities. Central to CROCUS’ measurement strategy is the Micronet – a scalable observational network designed to characterize heterogeneous urban microenvironments. The Micronet addresses the challenge of observing multiple components of the urban system (atmosphere, biosphere, hydrosphere) that operate at distinct spatial and temporal scales. To do this, it couples a three-tier sensor architecture with rugged edge-computing Waggle nodes and LoRaWAN networking to sup-port dense, spatially distributed measurements. Level 1 nodes provide core meteorological and air quality measurements. Level 2 nodes incorporate eddy-covariance flux instrumentation, laser disdrometers, and steerable infrared thermal cameras, with a variant that includes depth-resolved soil-water-heat sensors and sap-flow probes to capture vegetation processes. Level 3 nodes augment the network with remote sensing capabilities, including microwave precipitation radars and dual-polarization ceilometers. The configurable Argonne Deployable Mast provides rapid infill for targeted studies. Twelve sites are operational, three of which are integrated into AmeriFlux as urban flux sites, providing rare long-term eddy-covariance observations in urban settings. The network spans Chicago’s full spectrum of local climate zones, from tree-lined low-rise neighbor-hoods to lakefront rooftops. The Micronet demonstrates a new model for distributed urban sensing, integrating real-time data acquisition with edge processing to support multiscale environmental observations in complex urban environments. These observations support high-resolution atmospheric analyses and provide hydrologic context for urban process studies and multiscale flood-risk assessment in Chicago.