Surface broadband shortwave and longwave irradiance are key components of the surface energy budget and give insight on atmospheric constituents like clouds and aerosols as well as provide useful information for model evaluation. Surface irradiance measurements are particularly difficult to make over the ocean where few measurement platforms exist, and where the motion of ships and buoys makes the accuracy of the measurements challenging. During the US DOE ARM Measurements of Aerosols, Radiation, and Clouds over the Southern Ocean (MARCUS) field campaign, new shipborne broadband radiation systems (SHIPRAD) were deployed for the first time to test correction. The systems include pyrgeometer measurements for measuring longwave irradiance, an unshaded pyranometer to measure shortwave irradiance, a navigation system measuring pitch/roll/heading, and an SPN1 shortwave radiometer that measures direct and diffuse components with no moving parts. A tilt correction methodology was used to correct 1 second temporal resolution shortwave irradiance data for ship motion, designed to correct tilts of 10 degrees or less to within 10 W/m2. Two SHIPRAD systems were deployed on the port and starboard sides of the ship, and the measurements were combined in order to be able to eliminate measurements shaded by ship structures. The new methodology allows for high-temporal resolution irradiance measurements with higher accuracy. Results will be presented on the accuracy of the tilt correction methodology and the irradiance measurement results throughout the campaign.

The Chequamegon Heterogeneous Ecosystem Energy-balance Study Enabled by a High-density Extensive Array of Detectors 2019 (CHEESEHEAD19) is an ongoing National Science Foundation project based on an intensive field campaign that occurred from June-October 2019. The purpose of the study is to examine how the atmospheric boundary layer responds to spatial heterogeneity in surface energy fluxes. One of the main objectives is to test whether lack of energy balance closure measured by eddy covariance (EC) towers is related to mesoscale atmospheric processes. Finally, the project evaluates data-driven methods for scaling surface energy fluxes, with the aim to improve model-data comparison and integration. To address these questions, an extensive suite of ground, tower, profiling, and airborne instrumentation was deployed over a 10×10 km domain of a heterogeneous forest ecosystem in the Chequamegon-Nicolet National Forest in northern Wisconsin USA, centered on the existing Park Falls 447-m tower that anchors an Ameriflux/NOAA supersite (US-PFa / WLEF). The project deployed one of the world’s highest-density networks of above-canopy EC measurements of surface energy fluxes. This tower EC network was coupled with spatial measurements of EC fluxes from aircraft, maps of leaf and canopy properties derived from airborne spectroscopy, ground-based measurements of plant productivity, phenology, and physiology, and atmospheric profiles of wind, water vapor, and temperature using radar, sodar, lidar, microwave radiometers, infrared interferometers, and radiosondes. These observations are being used with large eddy simulation and scaling experiments to better understand sub-mesoscale processes and improve formulations of sub-grid scale processes in numerical weather and climate models.