For over a decade, several research groups have been developing air-sea heat flux information over the global ocean, including latent (LHF) and sensible (SHF) heat fluxes over the global ocean. This paper aims to provide new insight into the quality and error characteristics of turbulent heat flux estimates at various spatial and temporal scales (from daily upwards). The study is performed within the European Space Agency (ESA) Ocean Heat Flux (OHF) project. One of the main objectives of the OHF project is to meet the recommendations and requirements expressed by various international programs such as the World Research Climate Program (WCRP) and Climate and Ocean Variability, Predictability, and Change (CLIVAR), recognizing the need for better characterization of existing flux errors with respect to the input bulk variables (e.g. surface wind, air and sea surface temperatures, air and surface specific humidities), and to the atmospheric and oceanic conditions (e.g. wind conditions and sea state). The analysis is based on the use of daily averaged LHF and SHF and the associated bulk variables derived from major satellite-based and atmospheric reanalysis products. Inter-comparisons of heat flux products indicate that all of them exhibit similar space and time patterns. However, they also reveal significant differences in magnitude in some specific regions such as the western ocean boundaries during the Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. Northern Hemisphere winter season, and the high southern latitudes. The differences tend to be closely related to large differences in surface wind speed and/or specific air humidity (for LHF) and to air and sea temperature differences (for SHF). Further quality investigations are performed through comprehensive comparisons with daily-averaged LHF and SHF estimated from moorings. The resulting statistics are used to assess the error of each OHF product. Consideration of error correlation between products and observations (e.g., by their assimilation) is also given. This reveals generally high noise variance in all products and a weak signal in common with in situ observations, with some products only slightly better than others. The OHF LHF and SHF products, and their associated error characteristics, are used to compute daily OHF multiproduct-ensemble (OHF/MPE) estimates of LHF and SHF over the ice-free global ocean on a 0.25° × 0.25° grid. The accuracy of this heat multiproduct, determined from comparisons with mooring data, is greater than for any individual product. It is used as a reference for the anomaly characterization of each individual OHF product. Highlights ► Establishing reference input dataset maximizing the use of remotely sensed data ► Performing a cross-comparison of different heat flux algorithms and approaches ► Generating an ensemble of turbulent fluxes, including multiple approaches ► Evaluating the q...
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Objective. Patients with type 2 diabetes are encouraged to lose weight, but excessive weight loss in older adults may be a marker of poor health and subsequent mortality. We examined weight changes during the post-intervention period of Look AHEAD, a randomized trial comparing intensive lifestyle intervention (ILI) and diabetes support and education (DSE; control) in individuals with overweight/obesity and type 2 diabetes and sought to identify predictors of excessive post-intervention weight loss and its association with mortality. <p>Research Design and Methods. These secondary analyses compared post-intervention weight change (year-8 to final visit [median 16 years]) in ILI and DSE in 3999 Look AHEAD participants. Using empirically derived trajectory categories, we compared four subgroups: Weight Gainers (N= 307), Weight Stable (N=1561), Steady Losers (N=1731) and Steep Losers (N=380) on post-intervention mortality, demographic variables and health status at randomization and year-8.</p> <p>Results. Post-intervention weight change averaged -3.7 ±9.5%, with greater weight loss in DSE than ILI. The steep weight loss trajectory subgroup lost on average 17.7 + 6.6%.; 30% of Steep Losers died during post-intervention follow-up vs 10-18% in other trajectories (p<. 0001). The following variables distinguished Steep Losers from Weight Stable: <i>Baseline </i>- older; longer diabetes duration; higher BMI; greater multimorbidity; <i>Intervention </i>– randomization to control group; less weight loss in years 1-8; <i>Year 8 </i>- higher prevalence of frailty, multimorbidity and depressive symptoms; lower use of weight control strategies. </p> <p>Conclusion. Steep weight losses post-intervention were associated with increased risk of mortality. Older individuals with longer duration diabetes and multi-morbidity should be monitored for excessive, unintentional weight loss. </p>
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