Surface Flux Measurements during the 21 August 2017 Total Solar Eclipse

The total solar eclipse of 21 August 2017 spurred a wide range of projects aimed at examining the response of various components of the Earth system to the eclipse. Among these was Project ARTSE, which focused on the surface layer effects of the total solar eclipse. Previous experiments have recorded drops in temperature, reduced turbulence, and changes in fluxes of sensible heat and latent heat associated with partial and annular eclipses in the United States. Further studies have described similar results from total eclipses in Europe. The goal of Project ARTSE was to build upon these previous results through collection and comparison of near-surface meteorological data during the solar eclipse from two locations: one in the path of totality and one in partial eclipse (72% obscurity). This presentation will provide an overview and initial analysis of these two different eclipse-centered meteorological datasets.

The first dataset was collected through the deployment of two Integrated Surface Flux System (ISFS) stations, provided by NCAR through an educational deployment loan, to the path of totality in Grand Island, Nebraska. This general location was chosen to reduce the chances of cloud cover contamination and increase the opportunity for deployment locations with open exposure. The ISFS stations recorded changes in solar radiation and surface layer fluxes during the eclipse that can be used to characterize the boundary layer response to the total eclipse. Each flux station incorporates a high resolution sonic anemometer mounted at 3 m, a gas analyzer to measure changes in carbon dioxide and water vapor near the sonic anemometer, an additional sonic anemometer at 10 m, a radiation sensor to measure incoming shortwave and outgoing longwave radiation, temperature and relative humidity sensors at 2 m, and soil temperature sensors. For this project, stations were deployed for three days (centered on the eclipse) in order for the evolution of the surface layer fluxes during the event to be compared to those of a typical diurnal cycle.

In addition to flux data collected in the path of totality, data collected at the Texas Tech University National Wind Institute (NWI) Field Site near Lubbock, Texas (obscuration 72%) will also be analyzed. The NWI field site boasts multiple meteorological platforms, including a 200 m instrumented tower, a pair of mobile Ka-band Doppler radars, and a high power X-band radar. The 200 m tower is equipped with high resolution sonic anemometers at 10 different levels that support the computation of sensible heat and momentum flux as well as standard stability parameters through the depth of the tower. Data from these different platforms can then be compared to evaluate the response of the lower atmosphere to the eclipse from both a volumetric and point measurement perspective.