MCR LTER: Coral Reef: In Situ Light Data, ongoing since 2021

This time series describes light (PAR, 400-700 nm) recorded in the air, on the surface, and at depth (17.1 m depth) at the LTER2 fore reef site. Surface data originate from twin cosine collectors (Hobo/Onset brand, model S-LIA-M003) attached to USB micro weather stations (Hobo/Onset brand, model H21-USB). Sensors are attached to the roof of the waterfront building at the UCB Gump station (-17.490598, -149.826208) with the sensors ~ 6 m above sea level. In situ light is recorded with a single PME miniPAR logger fitted with a Li-COR LI-192 cosine correct PAR sensor attached to a PME miniWiper. The sensor is mounted underwater with the top of the sensor at 17.1 m depth. The objective is to measure KdPAR, the diffuse attenuation coefficient for PAR wavelengths, over long periods. The technique relies on the assumption that ~96% of surface PAR is transmitted through the air-sea interface when sun altitudes are > 46° and wind speeds are < 5 m s-1 (Gregg and Carder 1990). Departures from this assumption degrade the estimation of subsurface PAR from surface PAR, which is required to calculate KdPAR. This material is based upon work supported by the U.S. National Science Foundation under Grant No. OCE 16-37396 (and earlier awards) as well as a generous gift from the Gordon and Betty Moore Foundation. Research was completed under permits issued by the French Polynesian Government (Délégation à la Recherche) and the Haut-commissariat de la République en Polynésie Francaise (DTRT) (Protocole d'Accueil 2005-2023). This work represents a contribution of the Moorea Coral Reef (MCR) LTER Site.