In late June 2021, western North America, and in particular the Pacific Northwest experienced a heatwave with temperatures usually only encountered in hot desert climates. Using a blend of reanalysis ...data and Earth System Model (ESM) simulations, we disentangle the physical drivers underlying this exceptional event. Our analysis highlights the role of the anticyclonic circulation aloft, which converted previously gained potential energy—some of which by intense latent heating thousands of kilometers upwind over the North Pacific—back into sensible heat through subsidence. We demonstrate that this upwind latent heat release did not only result in a hot troposphere above the heatwave region, but also contributed directly to escalating near‐surface temperatures. Facilitated by the mountainous terrain and dry soils in the region, deep atmospheric boundary layers were established over the course of several days, connecting the air close to Earth's surface to a massive heat reservoir many kilometers above. Anomalous soil moisture acted to raise the heatwave temperatures by 3°C in a large region during the peak of the event, with local anomalies exceeding 5°C. Overall, we conclude that this heatwave was the outcome of an intricate interplay between dynamic and thermodynamic processes. ESM experiments suggest that the same large‐scale atmospheric circulation fueled by enhanced thermodynamic drivers, such as more available moisture for condensation upwind, could enable even more extreme near‐surface temperatures, in particular in a warmer climate.
Plain Language Summary
In late June 2021, western North America, and in particular the Pacific Northwest, experienced temperatures normally encountered in hot deserts. Our analysis highlights the role of the anticyclonic circulation aloft, whose downward spiraling air masses converted previously gained potential energy back into sensible heat. We show that in addition to heating through sinking, the air was previously heated by condensation in ascending air streams thousands of kilometers upwind, over the North Pacific. Together, these processes fostered a massive heat reservoir above the heatwave region, which contributed to escalating near‐surface temperatures through strong vertical mixing. Dry soils in the region intensified surface heating, boosting maximum temperatures in excess of 5°C. Overall, we conclude that this heatwave was the outcome of an intricate interplay of the atmospheric flow and processes such as condensational and surface heating, further exacerbated by human‐induced background warming. Our experiments suggest that if fueled by more available moisture for condensation upwind, the same large‐scale atmospheric circulation could enable even more extreme near‐surface temperatures.
Key Points
A strong “Omega Block” enabled the heatwave, yet near‐surface air temperatures were more extreme than suggested by the large‐scale flow
Sinking air aloft previously experienced strong latent heating over the North Pacific, contributing to the high near‐surface temperatures
Deep atmospheric boundary layers brought the extreme heat down to the surface, with local soil moisture effects in excess of 5°C
Summary
Many racial and ethnic minority groups (minorities) are disproportionately affected by overweight and obesity; however, minorities are often under‐represented in clinical trials of ...behavioural weight loss (BWL) treatment, potentially limiting the generalizability of these trials' conclusions. Interventions involving technology may be particularly well suited to overcoming the barriers to minority enrollment in BWL trials, such as demanding or unpredictable work schedules, caregiving responsibilities and travel burdens. Thus, this systematic review aimed to describe minority enrollment in trials utilizing technology in interventions, as well as to identify which form(s) of technology yield the highest minority enrollment. Results indicated relatively low enrollment of minorities. Trials integrating smartphone use exhibited significantly greater racial minority enrollment than trials that did not; trials with both smartphone and in‐person components exhibited the highest racial minority enrollment. This review is the first to explore how the inclusion of technology in BWL trials relates to minority enrollment and can help address the need to improve minority enrollment in weight loss research.
Non-alcoholic steatohepatitis (NASH) is a form of non-alcoholic fatty liver disease (NAFLD) characterized by steatosis, inflammation, and fibrosis often associated with metabolic syndrome. Fibroblast ...growth factor 15 (FGF15), an endocrine factor mainly produced in the distal part of small intestine, has emerged to be a critical factor in regulating bile acid homeostasis, energy metabolism, and liver regeneration. We hypothesized that FGF15 alters the development of each of the listed features of NASH. To test this hypothesis, four-week old male Fgf15−/− and their corresponding wild-type (WT) mice were fed either a high fat diet (HFD) or a control chow diet for six months. The results confirmed that HFD feeding for six months in WT mice recapitulated human NASH phenotype, including macrovesicular steatosis, inflammation, and fibrosis. Whereas FGF15 deficiency had no effect on the severity of liver steatosis or inflammation, it was associated with decreased liver fibrosis. Furthermore, FGF15 deficiency resulted in abnormal bile acid homeostasis, increased insulin resistance, increased HFD-induced serum triglycerides, decreased inductions of hepatic cholesterol content by HFD, and altered gene expression of lipid metabolic enzymes. These data suggest that FGF15 improves lipid homeostasis and reduces bile acid synthesis, but promotes fibrosis during the development of NASH.
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•Deficiency of FGF15 had both beneficial and detrimental effects on the development of HFD-induced NASH.•FGF15 deficiency did not affect the severity of hepatic steatosis or inflammation in HFD-fed mice.•FGF15 deficiency protected against HFD induced hepatic fibrosis.•FGF15 deficient mice fed the HFD had increased insulin resistance and higher levels of serum triglycerides.
Genetically encoded libraries of peptides and oligonucleotides are well suited for the identification of ligands for many macromolecules. A major drawback of these techniques is that the resultant ...ligands are subject to degradation by naturally occurring enzymes. Here, a method is described that uses a bioloically encoded library for the identification of D-peptide ligands, which should be resistant to proteolytic degradation. In this approach, a protein is synthesized in the D-amino acid configuration and used to select peptides from a phage display library expressing random L-amino acid peptides. For reasons of symmetry, the mirror images of these phage-displayed peptides interact with the target protein of the natural handedness. The value of this approach was demonstrated by the identification of a cyclic D-peptide that interacts with the Src homology 3 domain of c-Src. Nuclear magnetic resonance studies indicate that the binding site for this D-peptide partially overlaps the site for the physiologically ligands of this domain.
The size of the Fontan population with end-stage heart failure is growing. In this population, heart transplantation has been the only option. This study sought to investigate the efficacy of ...ventricular assist device (VAD) support in Fontan patients.
We conducted a retrospective study of Fontan patients in the Advanced Cardiac Therapies Improving Outcomes Network. We evaluated patient characteristics, and the clinical and physiologic outcomes after VAD implantation.
We identified 45 Fontan patients implanted with VAD. The average age of patients was 10 years (interquartile range: 4.5-18) and 30% were female. The majority had a morphologic right ventricle (69%), moderate or greater ventricular dysfunction (83%), and moderate or greater atrioventricular valve regurgitation (65%). The majority of implants were as a bridge to transplantation (76%), and the majority of patients were Interagency Registry for Mechanically Assisted Circulatory Support Profile 2 (56%). The most commonly employed device was the Medtronic HeartWare HVAD (56%). A total of 13 patients were discharged on device support, and 67% of patients experienced adverse events, the most common of which were neurologic (25%). At 1 year after device implantation, the rate of transplantation was 69.5%, 9.2% of patients continued to be VAD supported, and 21.3% of patients had died. Hemodynamically, VAD was effective in decreasing both Fontan and ventricular end-diastolic pressures in some individuals.
VAD is effective in supporting patients with end-stage Fontan failure awaiting heart transplantation. Future research should focus on identifying clinical and physiologic characteristics predictive of a favorable response to VAD support.
The volume of Earth system observations has grown massively in recent decades. However, multivariate or multisource analyses at the interface of atmosphere and land are still hampered by the sparsity ...of ground measurements and the abundance of missing values in satellite observations. This can hinder robust multivariate analysis and introduce biases in trends. Nevertheless, gap‐filling is often done univariately, which can obscure physical dependencies. Here, we apply the new multivariate gap‐filling framework CLIMate data gapFILL (CLIMFILL). CLIMFILL combines state‐of‐the‐art spatial interpolation with an iterative approach accounting for dependencies across multiple incomplete variables. CLIMFILL is applied to a set of remotely sensed and in situ observations over land that are central to observing land–atmosphere interactions and extreme events. The resulting gridded monthly time series covers 1995–2020 globally with gap‐free maps of nine variables: surface layer soil moisture from European Space Agency (ESA)‐Climate Change Initiative (CCI), land surface temperature and diurnal temperature range from Moderate‐resolution Imaging Spectroradiometer, precipitation from GPM, terrestrial water storage from GRACE, ESA‐CCI burned area, and snow cover fraction as well as 2‐m temperature and precipitation from CRU. Time series of anomalies are reconstructed better compared to state‐of‐the‐art interpolation. The gap‐filled data set shows high correlations with ERA5‐Land, and soil moisture estimates compare favorably to in situ observations from the International Soil Moisture Network. Soil moisture drying trends in ESA‐CCI only agree with the reanalysis product ERA5‐Land trends after gap‐filling. We furthermore showcase that key features of droughts and heatwaves in major fire seasons are well represented. The data set can serve as a step toward the fusion of multivariate multisource observations.
Plain Language Summary
The Earth has been increasingly observed by satellites and ground stations in the last decades. However, those observations have many missing values. Multivariate analysis of events or climate interactions or the observation of trends can be biased by missing values. Those missing values are often not gap‐filled, or gap‐filled for each variable separately, which can obscure physical dependencies between the variables. Here, we apply CLIMate data gapFILL, a new multivariate gap‐filling framework, to fill gaps in a range of freely available observational data sets. It can consider information dependencies across multiple incomplete variables to fill the gaps. It is applied to nine observational variables that describe land–climate interactions and dynamics of extreme events. The result is gap‐free maps from 1995 to 2020 globally for surface layer soil moisture, land surface temperature, diurnal temperature range, precipitation (from satellite), terrestrial water storage, burned area, snow cover fraction, 2‐m temperature, and precipitation (from ground). The gap‐filled data set produces better estimates than univariate interpolation and has a high correlation with ERA5‐Land and soil moisture observations from the International Soil Moisture Network data set. Soil moisture drying trends in European Space Agency‐Climate Change Initiative only agree with ERA5‐Land after gap‐filling. Major fire seasons are well represented. The data set can is a step toward fusion of multi‐source multivariate observational data sets.
Key Points
Large fractions of missing values in Earth observations can bias multisource multivariate analysis of land–climate interactions and extremes
We apply a multivariate gap‐filling framework to nine variables relevant to observing land–climate interactions centering on soil moisture
Regional aggregated averages and soil moisture trends agree well with independent observational data sets and reanalysis after gap‐filling
Climate reanalyses provide a plethora of global atmospheric and surface parameters in a consistent
manner over multi-decadal timescales. Hence, they are widely used in many fields, and an in-depth
...evaluation of the different variables provided by reanalyses is a necessary means to provide
feedback on the quality to their users and the operational centres producing these data sets, and
to help guide their development. Recently, the European Centre for Medium-Range Weather Forecasts
(ECMWF) released the new state-of-the-art climate reanalysis ERA5, following up on its popular
predecessor ERA-Interim. Different sets of variables from ERA5 were already evaluated in a handful
of studies, but so far, the quality of land-surface energy partitioning has not been assessed.
Here, we evaluate the surface energy partitioning over land in ERA5 and concentrate on the
appraisal of the surface latent heat flux, surface sensible heat flux, and Bowen ratio against
different reference data sets and using different modelling tools. Most of our analyses point
towards a better quality of surface energy partitioning in ERA5 than in ERA-Interim, which may be
attributed to a better representation of land-surface processes in ERA5 and certainly to the
better quality of near-surface meteorological variables. One of the key shortcomings of the
reanalyses identified in our study is the overestimation of the surface latent heat flux over
land, which – although substantially lower than in ERA-Interim – still remains in ERA5. Overall,
our results indicate the high quality of the surface turbulent fluxes from ERA5 and the general
improvement upon ERA-Interim, thereby endorsing the efforts of ECMWF to improve their climate
reanalysis and to provide useful data to many scientific and operational fields.
Towards the end of June 2021, temperature records were broken by several degrees Celsius in several cities in the Pacific Northwest areas of the US and Canada, leading to spikes in sudden deaths and ...sharp increases in emergency calls and hospital visits for heat-related illnesses. Here we present a multi-model, multi-method attribution analysis to investigate the extent to which human-induced climate change has influenced the probability and intensity of extreme heat waves in this region. Based on observations, modelling and a classical statistical approach, the occurrence of a heat wave defined as the maximum daily temperature (TXx) observed in the area 45–52∘ N, 119–123∘ W, was found to be virtually impossible without human-caused climate change. The observed temperatures were so extreme that they lay far outside the range of historical temperature observations. This makes it hard to state with confidence how rare the event was. Using a statistical analysis that assumes that the heat wave is part of the same distribution as previous heat waves in this region led to a first-order estimation of the event frequency of the order of once in 1000 years under current climate conditions. Using this assumption and combining the results from the analysis of climate models and weather observations, we found that such a heat wave event would be at least 150 times less common without human-induced climate change. Also, this heat wave was about 2 ∘C hotter than a 1-in-1000-year heat wave would have been in 1850–1900, when global mean temperatures were 1.2 ∘C cooler than today. Looking into the future, in a world with 2 ∘C of global warming (0.8 ∘C warmer than today), a 1000-year event would be another degree hotter. Our results provide a strong warning: our rapidly warming climate is bringing us into uncharted territory with significant consequences for health, well-being and livelihoods. Adaptation and mitigation are urgently needed to prepare societies for a very different future.
Despite the existing myriad of tools and models to assess
atmospheric source–receptor relationships, their uncertainties remain
largely unexplored and arguably stem from the scarcity of observations
...available for validation. Yet, Lagrangian models are increasingly used to
determine the origin of precipitation and atmospheric heat by scrutinizing the
changes in moisture and temperature along air parcel trajectories. Here, we
present a unified framework for the process-based evaluation of atmospheric
trajectories to infer source–receptor relationships of both moisture and
heat. The framework comprises three steps: (i) diagnosing precipitation,
surface evaporation, and sensible heat from the Lagrangian simulations and
identifying the accuracy and reliability of flux detection criteria; (ii) establishing source–receptor relationships through the attribution of
sources along multi-day backward trajectories; and (iii) performing a bias
correction of source–receptor relationships. Applying this framework to
simulations from the Lagrangian model FLEXPART, driven with ERA-Interim
reanalysis data, allows us to quantify the errors and uncertainties
associated with the resulting source–receptor relationships for three
cities in different climates (Beijing, Denver, and Windhoek). Our results
reveal large uncertainties inherent in the estimation of heat and
precipitation origin with Lagrangian models, but they also demonstrate that
a source and sink bias correction acts to reduce this uncertainty. The
proposed framework paves the way for a cohesive assessment of the
dependencies in source–receptor relationships.
The application of site-specific conservation practices requires knowledge of spatial patterns in fields. This study evaluated two methods of delineating soil erosion patterns in a central Iowa ...field. First, soil erosion rates of individual grid based samples were estimated using soil displacement of cesium-137 (137Cs). Second, tillage and water erosion were estimated using the topography-driven Water and Tillage Erosion Model (WATEM). The tillage erosion map showed soil loss in convex shoulder positions and soil accumulation in concave footslope and toeslope landscape positions. Alternately, water erosion was associated with slope severity and slope length on backslopes. When the tillage and water erosion map patterns were combined a good correlation with the 137Cs soil erosion pattern was graphically and statistically exhibited. Study results suggest that tillage erosion be included with water and wind erosion estimates when developing spatial maps that reflect a field's erosion history. Spatial maps depicting a field's erosion history and the primary processes affecting erosion could be used for site-specific implementation of conservation practices such as cover crops, organic matter additions, and no-till, which could be targeted at specific erosion processes.
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