Lahaina groundwater tracer study -- Lahaina, Maui, Hawaii

The studies presented in this report provide the positive establishment of hydrologic connections between the municipal wastewater injection from the LWRF and the nearshore region of the Kaanapali coast on the Island of Maui, Hawaii, and provide the results from the study’s principal objectives, which have been to: (1) implement a tracer dye study from the LWRF (Section 3), (2) conduct continuous monitoring for the emergence of the injected tracer dyes at the most probable points of emergence at nearshore sites within the coastal reaches of the LWRF (Section 2), (3) conduct an airborne infrared sea surface temperature mapping survey of coastal zone fronting the LWRF in an effort to detect cool and/or warm temperature anomalies that may be indicative of cool submarine groundwater discharge and warm wastewater effluent (Section 4), (4) complete radon and radium radiochemical surveys to detect the emergence points and flow rates of the naturally occurring submarine groundwater along the coastal zone (Section 5), (5) complete geochemical and stable isotopic analyses of LWRF effluent, upland well waters, terrestrial surface waters, marine waters, and submarine groundwater discharge in an effort to help partition the relative contribution of effluent waters to the ocean (Section 6), and (6) combine complete dye emergence breakthrough curves with which to develop groundwater models to determine the LWRFs effluent flow paths and rates of emergence to the coastal zone (Section 7).U.S. Environmental Protection AgencyDepartment of Health, State of HawaiiU.S. Army Engineer Research and Development Cente

An Autonomous Vehicle Approach for Quantifying Bioluminescence in Ports and Harbors

Bioluminescence emitted from marine organisms upon mechanical stimulation is an obvious military interest, as it provides a low-tech method of identifying surface and subsurface vehicles and swimmer tracks. Clearly, the development of a passive method of identifying hostile ships, submarines, and swimmers, as well as the development of strategies to reduce the risk of detection by hostile forces is relevant to Naval operations and homeland security. The measurement of bioluminescence in coastal waters has only recently received attention as the platforms and sensors were not scaled for the inherent small-scale nature of nearshore environments. In addition to marine forcing, many ports and harbors are influenced by freshwater inputs, differential density layering and higher turbidity. The spatial and temporal fluctuations of these optical water types overlaid on changes in the bioluminescence potential make these areas uniquely complex. The development of an autonomous underwater vehicle with a bioluminescence capability allows measurements on sub-centimeter horizontal and vertical scales in shallow waters and provides the means to map the potential for detection of moving surface or subsurface objects. A deployment in San Diego Bay shows the influence of tides on the distribution of optical water types and the distribution of bioluminescent organisms. Here, these data are combined to comment on the potential for threat reduction in ports and harbors

Impacts of urban carbon dioxide emissions on sea-air flux and ocean acidification in nearshore waters.

Greatly enhanced atmospheric carbon dioxide (CO2) levels relative to well-mixed marine air are observed during periods of offshore winds at coastal sensor platforms in Monterey Bay, California, USA. The highest concentrations originate from urban and agricultural areas, are driven by diurnal winds, and peak in the early morning. These enhanced atmospheric levels can be detected across a ~100km wide nearshore area and represent a significant addition to total oceanic CO2 uptake. A global estimate puts the added sea-air flux of CO2 from these greatly enhanced atmospheric CO2 levels at 25 million tonnes, roughly 1% of the ocean's annual CO2 uptake. The increased uptake over the 100 km coastal swath is of order 20%, indicating a potentially large impact on ocean acidification in productive coastal waters

The NASA EPIC/DSCOVR Ocean PAR Product

The EPIC/DSCOVR observations of the Earth’s surface lit by the Sun made from the first Lagrange point several times during the day in spectral bands centered on 443, 551, and 680 nm are used to estimate daily mean photosynthetically available radiation (PAR) at the ice-free ocean surface. The PAR algorithm uses a budget approach, in which the solar irradiance reaching the surface is obtained by subtracting from the irradiance arriving at the top of the atmosphere (known), the irradiance reflected to space (estimated from the EPIC Level 1b radiance data), taking account of atmospheric transmission and surface albedo (modeled). Clear and cloudy regions within a pixel do not need to be distinguished, which dismisses the need for often-arbitrary assumptions about cloudiness distribution within a pixel and is therefore adapted to the relatively large EPIC pixels. A daily mean PAR is estimated on the source grid for each EPIC instantaneous daytime observation, assuming no cloudiness changes during the day, and the individual estimates are remapped and weight-averaged using the cosine of the Sun zenith angle. In the computations, wind speed, surface pressure, and water vapor amount are extracted from NCEP Reanalysis 2 data, aerosol optical thickness and Angström coefficient from MERRA-2 data, and ozone amount from EPIC Level 2 data. Areas contaminated by Sun glint are excluded using a threshold on Sun glint reflectance calculated using wind data. Ice masking is based on NSIDC near-real-time ice fraction data. The product is evaluated against in situ measurements at various locations and compared with estimates from sensors in polar and geostationary orbits (MODIS, AHI). Unlike with MODIS, the EPIC PAR product does not exhibit gaps at low and middle latitudes. Accuracy is satisfactory for long-term studies of aquatic photosynthesis, especially given the much larger uncertainties on the fraction of PAR absorbed by live algae and the quantum yield of carbon fixation. The EPIC daily mean PAR product is generated operationally on a Plate Carrée (equal-angle) grid with 18.4 km resolution at the equator and on an 18.4 km equal-area grid, i.e., it is fully compatible with the NASA Greenbelt OBPG ocean-color products. Data are available since the beginning of the DSCOVR mission (i.e., June 2015) from the NASA Langley ASDC website