Abstract: Ocean tides have been observed to be changing worldwide for nonastronomical reasons, which can combine with rising mean sea level (MSL) to increase the long-term impact to coastal regions. Tides can also exhibit variability at shorter timescales, which may be correlated with short-term variability in MSL. This short-term coupling may yield higher peak water levels and increased impacts of exceedance events that may be equally significant as long-term sea level rise. Previous studies employed the tidal anomaly correlation (TAC) method to quantify the sensitivity of tides to MSL fluctuations at long-period (>20 years) tide gauges in basin-scale surveys of the Pacific and Atlantic Ocean, finding that TACs exist at most locations. The Indian Ocean also experiences significant sea level rise and tidal variability yet has been less studied due to a sparse network of tide gauges. However, since the beginning of the 21st century, more tide gauges have been established in a wider geographical range, bringing the possibility of better estimates of tidal and MSL variability. Here, we improve the TAC approach, using the ensemble empirical mode decomposition (EEMD) method to analyze tidal amplitudes and sea level at multiple frequency bands, allowing a more effective use of shorter record tide gauges and better understanding of multiple timescales of tidal variability. We apply this approach to 73 tide gauges in the Indian Ocean to better quantify tidal variability in these under-studied regions, finding that the majority of locations exhibit significant correlations of tides and MSL.

Abstract: The H2020 project Integrated Arctic Observation System (INTAROS) aspires to increase the temporal and geographic coverage of in situ observations and add new key geophysical and biogeochemical variables in selected regions of the Arctic. By using a combination of mature and new instruments and sensors in integration with existing observatories, INTAROS aims to fill selected gaps in the present-day system and build additional capacity of the Arctic monitoring networks for ocean and sea ice. Three reference sites have been selected as key locations for monitoring ongoing Arctic changes: Costal Greenland, paramount for freshwater output from the Greenland ice sheet; North of Svalbard (covering the region from shelf to deep basin) – the hot-spot for ocean-air-sea ice interactions, and heat and biological energy input to the European Arctic; and Fram Strait – the critical gateway for exchanges between the Arctic and the World oceans. The existing observatories in the reference sites have been extended with new moorings and novel autonomous instrumentation, in particular for biogeochemical measurements and sea ice observations. Bottom-mounted instruments have been also implemented for seismic observations. A distributed observatory for ocean and sea ice in the Arctic Ocean and sub-Arctic seas includes non-stationary components such as ice-tethered observing platforms, float, gliders, and ships of opportunities, collecting multidisciplinary observations, still missing from the Arctic regions. New sensors, integrated platforms and experimental set-ups are currently under implementation during a two-year long deployment phase (2018-2020) with an aim to evaluate their sustained use in a future iAOS. New observations will be used for integration of new data products, demonstration studies and stakeholder consultations, contributing also to ongoing and future long-term initiatives (e.g. SAON).

Abstract: Camera traps for motion-triggered or continuous time-lapse recordings are readily available on the market. For demanding applications in ecology and environmental sciences, however, commercial systems often lack flexibility to freely adjust recording time intervals, suffer from mechanical component wear, and can be difficult to combine with auxiliary sensors such as GPS, weather stations, or light sensors. We present a robust time-lapse camera system that has been operating continuously since 2013 under the harsh climatic conditions of the Antarctic and Subantarctic regions. Thus far, we have recorded over one million images with individual cameras. The system consumes 122 mW of power in standby mode and captures up to 200,000 high-resolution (16 MPix) images without maintenance such as battery or image memory replacement. It offers time-lapse intervals between 2 s and 1 h, low-light or night-time power saving, and data logging capabilities for additional inputs such as GPS and weather data.