Evaluating Where and Why Drifters Die*

Abstract

NOAA's Global Drifter Program (GDP) manages a global array of ;1250 active satellite-tracked surface drifting buoys (''drifters'') in collaboration with numerous national and international partners. To better manage the drifter array and to assess the performance of various drifter manufacturers, it is important to discriminate between drifters that cease transmitting because of internal failure and those that cease because of external factors such as running aground or being picked up. An accurate assessment of where drifters run aground would also allow the observations to be used to more accurately simulate the evolution of floating marine debris and to quantify globally which shores are most prone to the deposit of marine debris. While the drifter Data Assembly Center of the GDP provides a metadata file that includes cause of death, the identified cause for most drifters is simply ''quit transmitting.'' In this study it is shown that a significant fraction of these drifters likely ran aground or were picked up, and a statistical estimate that each drifter ran aground or was picked up is derived.

Threat of plastic pollution to seabirds is global, pervasive, and increasing

“…Although evidence of population level impacts from plastic pollution is still emerging, our results suggest that this threat is geographically widespread, pervasive, and rapidly increasing. predictions covered 90% of the species' range on average (interquartile range, 89-100%), with the only notable areas of poor coverage being in the North Sea and the Indonesian archipelago (18). Average exposure to plastic was 0.064 (range, 0-0.36; dimensionless scale) (Methods) but was right skewed, with most seabirds having low relative plastic exposure levels.…”

Lateral Heat Transport in the Lofoten Basin: Near‐Surface Pathways and Subsurface Exchange

“…The drifter population experiences a nearly exponential decay in time after deployment (Koszalka et al, ). The subset of drifters selected in this study has an e ‐folding time scale of 190 days, less than half the value given in Lumpkin et al (). A typical drifter propagating northward from areas around Iceland travels a distance of approximately 900 km to reach the center of the LB, in more than 100 days with an average speed of 10 cm/s.…”

A Call for New Approaches to Quantifying Biases in Observations of Sea Surface Temperature

“…Drifting buoys presently provide measurements of SST that are near-globally distributed and have better accuracy than from ships (Kennedy et al 2012), since problems with early drifters were resolved (Bitterman and Hansen 1993). Careful quality control is still required to identify spurious spikes in reported position or SST measurements from when the buoy is out of the water (due to predeployment data transmission, beaching, or human interference) and instrument failure or other causes of erroneous data (Lumpkin et al 2012;Atkinson et al 2013 and air-sea temperature difference) that control the thermodynamic forcing. The construction of the bucket is important: different materials will insulate the water sample from the external thermal forcing to varying extents; the volume and water level affect the heat capacity; a lid may reduce heat exchange from the top.…”