Atlantic Meridional Overturning Circulation: Observed Transport and Variability

The Atlantic Meridional Overturning Circulation (AMOC) extends from the Southern Ocean to the northern North Atlantic, transporting heat northwards throughout the South and North Atlantic, and sinking carbon and nutrients into the deep ocean. Climate models indicate that changes to the AMOC both herald and drive climate shifts. Intensive trans-basin AMOC observational systems have been put in place to continuously monitor meridional volume transport variability, and in some cases, heat, freshwater and carbon transport. These observational programs have been used to diagnose the magnitude and origins of transport variability, and to investigate impacts of variability on essential climate variables such as sea surface temperature, ocean heat content and coastal sea level. AMOC observing approaches vary between the different systems, ranging from trans-basin arrays (OSNAP, RAPID 26°N, 11°S, SAMBA 34.5°S) to arrays concentrating on western boundaries (e.g., RAPID WAVE, MOVE 16°N). In this paper, we outline the different approaches (aims, strengths and limitations) and summarize the key results to date. We also discuss alternate approaches for capturing AMOC variability including direct estimates (e.g., using sea level, bottom pressure, and hydrography from autonomous profiling floats), indirect estimates applying budgetary approaches, state estimates or ocean reanalyses, and proxies. Based on the existing observations and their results, and the potential of new observational and formal synthesis approaches, we make suggestions as to how to evaluate a comprehensive, future-proof observational network of the AMOC to deepen our understanding of the AMOC and its role in global climate

The accuracy of estimates of the overturning circulation from basin-wide mooring arrays

Previous modeling and observational studies have established that it is possible to accurately monitor the Atlantic Meridional Overturning Circulation (AMOC) at 26.5°N using a coast-to-coast array of instrumented moorings supplemented by direct transport measurements in key boundary regions (the RAPID/MOCHA/WBTS Array). The main sources of observational and structural errors have been identified in a variety of individual studies. Here a unified framework for identifying and quantifying structural errors associated with the RAPID array-based AMOC estimates is established using a high-resolution (eddy resolving at low-mid latitudes, eddy permitting elsewhere) ocean general circulation model, which simulates the ocean state between 1978 and 2010. We define a virtual RAPID array in the model in close analogy to the real RAPID array and compare the AMOC estimate from the virtual array with the true model AMOC. The model analysis suggests that the RAPID method underestimates the mean AMOC by ∼1.5 Sv (1 Sv = 106 m3 s−1) at ∼900 m depth, however it captures the variability to high accuracy. We examine three major contributions to the streamfunction bias: (i) due to the assumption of a single fixed reference level for calculation of geostrophic transports, (ii) due to regions not sampled by the array and (iii) due to ageostrophic transport. A key element in (i) and (iii) is use of the model sea surface height to establish the true (or absolute) geostrophic transport. In the upper 2000 m, we find that the reference level bias is strongest and most variable in time, whereas the bias due to unsampled regions is largest below 3000 m. The ageostrophic transport is significant in the upper 1000 m but shows very little variability. The results establish, for the first time, the uncertainty of the AMOC estimate due to the combined structural errors in the measurement design and suggest ways in which the error could be reduced. Our work has applications to basin-wide circulation measurement arrays at other latitudes and in other basins as well as quantifying systematic errors in ocean model estimates of the AMOC at 26.5°N

Nursing diagnostics and nursing diagnoses in Pediatrics

Children´s nursing has its particularities, whether in differences between child care during individual development stages or in the range of illnesses and their clinical manifestations. Nurses taking care of a child patient should observe all particularities of pediatric nursing which surely makes the nursing diagnostics diffucult and demanding. The theoretical part of the bachelor{\crq}s thesis {\clqq}Nursing diagnostics and nursing diagnoses in pediatrics`` opens with a description of pediatrics alongside with an outline of history and development in pediatric nursing. The following part of the thesis describes the current state of child care. The main operating method used by nurses who take care of hospitalized children complies with the Section 4 (1) of the decree No. 424/2004 concerning the nursing procedure. Nursing diagnostics is one of the stages described in the nursing procedure. The following parts of the thesis include detailed accounts of the theory of nursing diagnostics, taxonomy of nursing diagnoses, and particularities of the nursing diagnoses in pediatrics. The survey was based on quantitative method by way of questinnaires. Also, the data content analysis was utilized in order to complete the data acquired. The aim of the bachelor{\crq}s thesis was to find out whether the nurses addressed knew the nursing diagnoses used in pediatrics, if they use such diagnoses in practice, and what is the biggest obstacle when performing nursing diagnostics in pediatrics. The outcome from the data collected proves all three hypotheses correct. Hypothesis 1 is: Nurses have a good command of nursing diagnostics in pediatrics. Hypothesis 2 is: Nurses utilize individually the nursing diagnoses in pediatrics. Hypothesis 3 is: Lack of time is considered to be the biggest obstacle while using the nursing diagnostics in pediatrics by nurses. The survey has also found out that there are utilized different taxonomies for nursing diagnoses with respect to differences at various age and other particularities, which certainly respects the child as an individual human being but makes the diagnostics more time demanding. Therefore it is suggested to unify the used terminology within individual departments with respect to a number of published books on nursing diagnostics in pediatrics and make otherwise time demanding nursing work a little easier

Supplement to physical exchanges at the air-sea interface: UK-SOLAS Field Measurements

Author Posting. © American Meteorological Society, 2009. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 90 (2009): ES9-ES16, doi:10.1175/2008BAMS2578.2

Physical exchanges at the air-sea interface: UK-SOLAS Field Measurements

As part of the U.K. contribution to the international Surface Ocean–Lower Atmosphere Study, a series of three related projects—DOGEE, SEASAW, and HiWASE—undertook experimental studies of the processes controlling the physical exchange of gases and sea spray aerosol at the sea surface. The studies share a common goal: to reduce the high degree of uncertainty in current parameterization schemes. The wide variety of measurements made during the studies, which incorporated tracer and surfactant release experiments, included direct eddy correlation fluxes, detailed wave spectra, wind history, photographic retrievals of whitecap fraction, aerosol-size spectra and composition, surfactant concentration, and bubble populations in the ocean mixed layer. Measurements were made during three cruises in the northeast Atlantic on the RRS Discovery during 2006 and 2007; a fourth campaign has been making continuous measurements on the Norwegian weather ship Polarfront since September 2006. This paper provides an overview of the three projects and some of the highlights of the measurement campaigns