Intraseasonal variability in the southwestern and central tropical Atlantic Ocean

Various kinds of intraseasonal variability (ISV) exist in the oceans which have recently been observed in many locations surrounding the tropical Atlantic Ocean. In this study, current measurements from mooring sites close to the western boundary in the southern hemisphere and at the equator in the central basin are analyzed which reveal signals at intraseasonal periods. Basinwide altimeter measurements as well as results from two numerical model simulations with varying surface wind forcing are applied in order to clarify the dynamic processes essential for the observed intraseasonal signals. It is shown that in the tropical Atlantic two key processes lead to the generation of fluctuative energy at intraseasonal periods: barotropic and baroclinic instability

The warring gods of sustainability : approaches to sustainability within capitalism

There is no answer to the question “Are sustainability challenges solvable within capitalism?” which is not already taking sides in a debate about values, perceptions and motivations. There are several different approaches to sustainability, based on assumed feasibilities and expected agents of change. By disclosing one’s own stand in the debate while being aware and acknowledging other possible approaches and their rationale would not only be constructive but essential if we are to find solutions to the pressing challenges ahead in the short time frame we have. The aim of this thesis is to enable the reader to grasp and acknowledge the differences between ap-proaches to sustainability with in capitalism, while taking an informed decision for him-/herself as a prerequisite for meaningful dissonance and deliberation. I distinguish between four approaches to sustainability within capitalism based on the type of envisaged change mechanism, i.e. formal institutions – laws, constitutions, regulations – and informal in-stitutions – norms, values, perceptions. Each approach is elaborated and presented in detail: neoliberal sustainability, based on the neoliberal rationale and without any considerable demand for institutional change; neoliberal deep sustainability, advocating informal, i.e. value and perception, change within neoliberalism; Keynesian sustainability, which favours stricter regulation and does not focus too much on informal institutional advance; and republican sustainability, which suggests a revival of civic values in combination with stronger regulation. The selection of approaches is based on an extensive literature review across disciplines and schemes are pooled according to common characteristics. After presenting the four approaches, each is extensively critiqued with arguments of proponents of other approaches including arguments from Eco-Socialist/Marxist and De-/Post-Growth, which serve to critique capitalism as such. This thesis is intended to be a thought-provoking presentation of the plurality of sustainability, pro-posed to facilitate deliberative processes in our daily encounters as well as political debates which have the potential to render clashes of worldviews and interests more constructive

Earth's Energy Imbalance and Implications

Improving observations of ocean heat content show that Earth is absorbing more energy from the sun than it is radiating to space as heat, even during the recent solar minimum. The inferred planetary energy imbalance, 0.59 \pm 0.15 W/m2 during the 6-year period 2005-2010, confirms the dominant role of the human-made greenhouse effect in driving global climate change. Observed surface temperature change and ocean heat gain together constrain the net climate forcing and ocean mixing rates. We conclude that most climate models mix heat too efficiently into the deep ocean and as a result underestimate the negative forcing by human-made aerosols. Aerosol climate forcing today is inferred to be 1.6 \pm 0.3 W/m2, implying substantial aerosol indirect climate forcing via cloud changes. Continued failure to quantify the specific origins of this large forcing is untenable, as knowledge of changing aerosol effects is needed to understand future climate change. We conclude that recent slowdown of ocean heat uptake was caused by a delayed rebound effect from Mount Pinatubo aerosols and a deep prolonged solar minimum. Observed sea level rise during the Argo float era is readily accounted for by ice melt and ocean thermal expansion, but the ascendency of ice melt leads us to anticipate acceleration of the rate of sea level rise this decade.Comment: 39 pages, 18 figures; revised version submitted to Atmos. Chem. Phy

Generation of tropical instability waves in the Atlantic Ocean

The spatial and temporal distributions of tropical instability waves (TIWs) in the Atlantic Ocean are investigated using a combination of current observations with moored instruments deployed at the equator at 23°W and a realistic eddy-resolving (1/12°) general circulation model of the Atlantic Ocean. The meridional and vertical shears of the zonal current system contribute to the eddy production rates and thus to the generation of TIWs in the central tropical Atlantic Ocean. In the Southern Hemisphere, TIWs are forced only by baroclinic instability associated with the vertical shear of the central part of the South Equatorial Current (SEC). In the Northern Hemisphere, baroclinic instability due to the vertical shear of the northern SEC (nSEC) as well as barotropic instabilities due to horizontal shears of the Equatorial Undercurrent (EUC)/nSEC and nSEC/North Equatorial Countercurrent (NECC) contribute to the generation of the TIWs. Since seasonal changes of the instability production rates related to the EUC/nSEC are comparable low while the rates related to the nSEC/NECC are high, we suggest that the seasonality of the NECC dominates the seasonal modulation of the TIWs

Blood pressure from the optical Aktiia Bracelet: a 1-month validation study using an extended ISO81060-2 protocol adapted for a cuffless wrist device.

The objective of this study (NCT04027777) was to assess the accuracy and precision of the Aktiia Bracelet, a CE-marked noninvasive optical blood pressure (BP) monitor worn at the wrist, over a period of 1 month. In this study, participants aged between 21 and 65 years were recruited. The clinical investigation extended the ISO81060-2:2013 standard to the specificities of cuffless devices. Each BP assessment consisted of the simultaneous recording of optical signals with Aktiia Bracelet and double-blinded auscultation by two trained observers in the standard sitting position. The algorithms of Aktiia Bracelet further processed the recorded optical signals to perform a signal quality check and to calculate uncalibrated estimates of systolic BP (SBP) and diastolic BP (DBP). These estimates were transformed into mmHg using a subject-dependent calibration parameter, which was calculated using the first two available reference measurements per subject. Eighty-six participants were included in the analysis. The mean and SD of the differences between Aktiia Bracelet estimates and the reference (ISO81060-2 criterion 1) were 0.46 ± 7.75 mmHg for SBP and 0.39 ± 6.86 mmHg for DBP. The SD of the averaged paired difference per subject (ISO81060-2 criterion 2) were 3.9 mmHg for SBP and 3.6 mmHg for DBP. After initialization and during 1 month, the overall accuracy of Aktiia Bracelet satisfied validation criteria 1 and 2 of ISO81060-2 in the sitting position. The Aktiia Bracelet can be recommended for BP measurement in the adult population

The use of Copernicus Marine Service products to describe the state of the Tropical Western Pacific Ocean around the Islands: a case study

Fiji served as President of the UN General Assembly in 2017, linking climate (SDG13) and ocean (SDG14) as the foundation of blue economies for island and coastal states around the world. The resulting United Nations Oceans outcome statement stressed “the importance of enhancing understanding of the health and role of our ocean and the stressors on its ecosystems, including through assessments on the state of the ocean, based on science and on traditional knowledge systems. We also stress the need to further increase marine scientific research to inform and support decision-making, and to promote knowledge hubs and networks to enhance the sharing of scientific data, best practices and ‘know-how.’” (UN, 2017). The Copernicus Marine Service Atlas for the Pacific Ocean States goes beyond the unique compilation of CMIP3 climate model projections and data tools compiled by the Pacific Climate Change Science Program (PCCSP, 2011, 2014). A complete overview of tropical Pacific observing network is available in the WMO publication library (GCOS, 2014a, 2014b). Our study focuses on the application of the available CMEMS products to the Pacific domain defined by PCCSP. As president of COP23, Prime Minister Frank Bainimarama has emphasized the importance of the climate and ocean connection and the need to protect ocean health to protect the planet: ‘We are all in the same canoe’ (https://cop23.com.fj/fijian-prime-minister-cop23-president-remarks-assuming-presidency-cop23/). The Copernicus Marine Service Atlas for Pacific Ocean States compiled by the author team responds directly to Fiji’s requests at the 2017 United Nation Oceans for SDG 14, life below water and the 2017 COP23 for SDG13, climate action which goes beyond the Pacific

Ocean science, data, and services for the UN 2030 Sustainable Development Goals

Relating the Sustainable Development Goal (SDG) 14 for Ocean and Life Below Water to the 16 remaining SDGs in the UN 2030 sustainable development agenda. A holistic approach that embraces sustainable Ocean stewardship informed by best available science, data and services to support society and the economy is required to create the ‘Future We Want’. The UN Decade of Ocean Science for Sustainable Development is an essential foundation to achieve this objective

Uncertainties in steric sea level change estimation during the satellite altimeter era: concepts and practices

This article presents a review of current practice in estimating steric sea level change, focussed on the treatment of uncertainty. Steric sea level change is the contribution to the change in sea level arising from the dependence of density on temperature and salinity. It is a significant component of sea level rise and a reflection of changing ocean heat content. However tracking these steric changes remains still a significant challenge for the scientific community. We review the importance of understanding the uncertainty in estimates of steric sea level change. Relevant concepts of uncertainty are discussed and illustrated with the example of observational uncertainty propagation from a single profile of temperature and salinity measurements to steric height. We summarise and discuss the recent literature on methodologies and techniques used to estimate steric sea level in the context of the treatment of uncertainty. Our conclusions are that progress in quantifying steric sea level uncertainty will benefit from: greater clarity and transparency in published discussions of uncertainty, including exploitation of international standards for quantifying and expressing uncertainty in measurement; and the development of community ‘recipes’ for quantifying the error covariances in observations and from sparse sampling, and for estimating and propagating uncertainty across spatio-temporal scales

The ICES Working Group on Oceanic Hydrography:A bridge from in-situ sampling to the remote autonomous observation era

The ICES (International Council for the Exploration of the Sea) Working Group on Oceanic Hydrography (WGOH) was established in the late 1970's with the aim of gathering experts in physical oceanography to provide regular science-based assessments of the North Atlantic hydrographical condition (basically termohaline fields). From the beginning, the WGOH has relied on repeated long-term in-situ sampling at key sites around the North Atlantic, the Nordic Seas and adjacent shelf seas. An annual Report on Ocean Climate (IROC), produced by the WGOH since the late 1990's, summarizes trends in regional hydrography and identifies patterns linking these changes across the North Atlantic. Regional analyses are prepared by local experts who are directly involved in the monitoring programs responsible for collecting data presented in the report. An interactive webpage created in 2013 allows users to browse and download data that inform the IROC. Within the last two decades the physical oceanography community has evolved quickly incorporating technological advances such as autonomous devices into classical in-situ sampling programs. The WGOH has embraced such technological developments without diverting focus from ongoing in-situ long-term monitoring programs. Having longstanding experience synthesizing data and expertise from a large number of operational programs spanning an extensive international footprint, the WGOH has a unique perspective to offer the global ocean observing community. Here we discuss how we might foster connections with ICES to benefit the GOOS (Global Ocean Observing System) community