Using Radiative Flux Measurements from Climate Networks to Improve our Understanding of Radiative Energy Available for Plant Growth

The NOAA Global Monitoring Laboratory makes high-quality surface radiation measurements at long-term and field-campaign based stations in a variety of climate regimes in the Continental United States. The SURFRAD network contains long-term records of upwelling and downwelling shortwave and longwave broadband radiative fluxes, diffuse and direct shortwave fluxes, downwelling photosynthetically active irradiance, and upwelling and downwelling (total and diffuse) spectral filter-based fluxes at seven shortwave channels in seven unique climate regimes, including agricultural areas like Bondville, IL and State College, PA. Additionally, we have built portable Radiation Systems (RADSYS) that we have deployed in unique terrain, such as a heterogeneous forested area of northern Wisconsin during the CHEESEHEAD field campaign. These RADSYS platforms are designed to be more flexibly deployed but still take good quality broadband measurements, and measure the total and diffuse shortwave flux with SPN1 radiometers from which direct flux may be inferred. Our measurement systems have primarily been designed to be of sufficient quality to detect climate trends and understand cloud, aerosol, and land surface processes impacting climate and weather prediction models. However, the commitment to diffuse measurements, and the long-term, high-quality nature of the measurements also give rich records for understanding how atmospheric and land-surface changes impact the availability of shortwave radiation for plant growth. In this presentation, we will describe current work in two areas. First, the potential to analyze our historical records for the impact of aerosol events (such as volcanic eruptions, wildfire smoke, or dust events) on the diffuse partitioning of SW radiation which impacts the depth of penetration of SW radiation into a forest canopy. Second, we will describe efforts underway to install RADSYS platforms above and below the forest canopy at a new Department of Energy site in the Southeastern United States, which will allow for better quantification of the impact of forest canopies on solar radiative fluxes.