Primary Atmospheric Drivers of Pluvial Years in the United States Great Plains

Precipitation variability has increased in recent decades across the Great Plains (GP) of the United States. Drought and its associated drivers have been studied in the GP region; however, periods of excessive precipitation (pluvials) at seasonal to interannual scales have received less attention. This study narrows this knowledge gap with the overall goal of understanding GP precipitation variability during pluvial periods. Through composites of relevant atmospheric variables from the ECMWF twentieth-century reanalysis (ERA-20C), key differences between southern Great Plains (SGP) and northern Great Plains (NGP) pluvial periods are highlighted. The SGP pluvial pattern shows an area of negative height anomalies over the southwestern United States with wind anomalies consistent with frequent synoptic wave passages along a southward-shifted North Pacific jet. TheNGPpattern during pluvial periods, by contrast, depicts anomalously low heights in the northwestern United States and an anomalously extended Pacific jet. Analysis of daily heavy precipitation events reveals the key drivers for these pluvial events, namely, an east–west height gradient and associated stronger poleward moisture fluxes. Therefore, the results show that pluvial years over the GP are likely driven by synoptic-scale processes rather than by anomalous seasonal precipitation driven by longer time-scale features. Overall, the results present a possible pathway to predicting the occurrence of pluvial years over the GP and understanding the causes of GP precipitation variability, potentially mitigating the threats of water scarcity and excesses for the public and agricultural sectors

Primary Atmospheric Drivers of Dry and Wet Periods over the U.S. Great Plains within CMIP5 Models

Precipitation variability is critical to the economic and ecosystem health of the United States Great Plains (GP). Whether from wet or dry extremes, changes in annual precipitation can lead to impacts on the health of the ecosystem and overall crop yield in a given year. To this end, wet and dry extremes have been investigated using the ERA-20C and CMIP5 dataset on an annual timescale to determine the ability of climate-scale simulations to resolve atmospheric drivers of precipitation variability. Results from the ERA-20C analysis show that specific atmospheric circulation anomalies can be detected which relate eddy geopotential height (EGH) anomalies to dry or wet annual precipitation anomalies in the GP domain. Using a similar method of defining dry and wet years, CMIP5 model simulations were examined to determine their ability to resolve these drivers and the associated precipitation variability in the GP. After filtering the different models based on their depiction of GP precipitation variability, the model simulations were categorized as Tier 1 and Tier 2 models, where Tier 1 yielded overall strong similarities and Tier 2 with overall weaker similarities. Both the Tier 1 and Tier 2 models were subsequently analyzed using the same atmospheric fields investigated within the ERA-20C dataset. The results demonstrated that both the Tier 1 and Tier 2 model ensembles were able to resolve the atmospheric anomalies associated with dry and wet years over the GP. However, specific differences exist between the Tier 1 and Tier 2 ensembles, namely that the Tier 2 model composites show larger magnitude anomalies. This result likely means that the Tier 2 model composites produce too many years in which the atmospheric anomalies are the primary cause of the precipitation anomalies when compared with known observational cases of GP dry or wet years. Overall, however, the CMIP5 models were able to satisfactorily reproduce GP precipitation variability, while the root of the variability appears to be forced by processes that are not widely evident in reanalysis datasets

Role of Sea Surface Temperatures in Forcing Circulation Anomalies Driving U.S. Great Plains Pluvial Years

In the U.S. Great Plains (GP), diagnosing precipitation variability is key in developing an understanding of the present and future availability of water in the region. Building on previous work investigating U.S. GP pluvial years, this study usesERAtwentieth century (ERA-20C) reanalysis data to investigate key circulation anomalies driving GP precipitation anomalies during a subset of GP pluvial years (called in this paper Pattern pluvial years). With previous research showing links between tropical Pacific sea surface temperature (SST) anomalies and GP climate variability, this study diagnoses the key circulation anomalies through an analysis of SSTs and their influence on the atmosphere. Results show that during Pattern southern Great Plains (SGP) pluvial years, central tropical Pacific SST anomalies are coincident with key atmospheric anomalies across the Pacific basin and North America. During northern Great Plains (NGP) Pattern pluvial years, no specific pattern of oceanic anomalies emerges that forces the circulation anomaly feature inherent in specific NGP pluvial years. Utilizing the results for SGP pluvial years, a conceptual model is developed detailing the identified pathway for the occurrence of circulation patterns that are favorable for pluvial years over the SGP. Overall, results from this study show the importance of the identified SGP atmospheric anomaly signal and the potential for predictability of such events

Global projections of flash drought show increased risk in a warming climate

Flash drought, characterized by unusually rapid drying, can have substantial impact on many socioeconomic sectors, particularly agriculture. However, potential changes to flash drought risk in a warming climate remain unknown. In this study, projected changes in flash drought frequency and cropland risk from flash drought are quantified using global climate model simulations. We find that flash drought occurrence is expected to increase globally among all scenarios, with the sharpest increases seen in scenarios with higher radiative forcing and greater fossil fuel usage. Flash drought risk over cropland is expected to increase globally, with the largest increases projected across North America (change in annual risk from 32% in 2015 to 49% in 2100) and Europe (32% to 53%) in the most extreme emissions scenario. Following low-end and medium scenarios compared to high-end scenarios indicates a notable reduction in annual flash drought risk over cropland

The “polar vortex” winter of 2013/14

The term “polar vortex” remained largely a technical term until early January 2014 when the United States (US) media used it to describe an historical cold air outbreak in eastern North America. Since then, “polar vortex” has been used more frequently by the media and the public, often conflating circulation features and temperatures near the surface with only partially related features at the tropopause and in the stratosphere. The polar vortex in its most common scientific usage refers to a hemispheric-scale stratospheric circulation over the Arctic that is present during the Northern Hemisphere cold season. Reversal of the zonal mean zonal winds circumnavigating the stratospheric polar vortex (SPV), termed major sudden stratospheric warmings, can be linked to mid-latitude cold air outbreaks. However, this mechanism does not explain the cold US winter of 2013/2014. This study revisits the winter of 2013/2014 to understand how SPV variability may still have played a role in the severe winter weather. Observations indicate that anomalously strong vertical wave propagation occurred throughout the winter and disrupted, but did not fully break, the SPV. Instead, vertically propagating waves were reflected back downward, amplifying a blocking high near Alaska and downstream troughing across central North America, a classic signature for extreme cold air outbreaks across central and eastern North America. Thus, the association of the term “polar vortex” with winter 2013/2014, while not justified by the most common usage of the term, serves as a case study of the wave-reflection mechanism of SPV influence on mid-latitude weather

Recent Arctic amplification and extreme mid-latitude weather

This is the author accepted manuscript. The final version is available from Nature via the DOI in this record.The Arctic region has warmed more than twice as fast as the global average — a phenomenon known as Arctic amplification. The rapid Arctic warming has contributed to dramatic melting of Arctic sea ice and spring snow cover, at a pace greater than that simulated by climate models. These profound changes to the Arctic system have coincided with a period of ostensibly more frequent extreme weather events across the Northern Hemisphere mid-latitudes, including severe winters. The possibility of a link between Arctic change and mid-latitude weather has spurred research activities that reveal three potential dynamical pathways linking Arctic amplification to mid-latitude weather: changes in storm tracks, the jet stream, and planetary waves and their associated energy propagation. Through changes in these key atmospheric features, it is possible, in principle, for sea ice and snow cover to jointly influence mid-latitude weather. However, because of incomplete knowledge of how high-latitude climate change influences these phenomena, combined with sparse and short data records, and imperfect models, large uncertainties regarding the magnitude of such an influence remain. We conclude that improved process understanding, sustained and additional Arctic observations, and better coordinated modelling studies will be needed to advance our understanding of the influences on mid-latitude weather and extreme events

Representation of the Scandinavia-Greenland pattern and its relationship with the polar vortex in S2S forecast models

The strength of the stratospheric polar vortex is a key contributor to subseasonal prediction during boreal winter. Anomalously weak polar vortex events can be induced by enhanced vertically propagating Rossby waves from the troposphere, driven by blocking and wave breaking. Here, we analyse a tropospheric pattern – the Scandinavia-Greenland (S-G) pattern – associated with both processes. The S-G pattern is defined as the second empirical orthogonal function (EOF) of mean sea-level pressure in the northeast Atlantic. The first EOF is a zonal pattern resembling the North Atlantic Oscillation. We show that the S-G pattern is associated with a transient amplification of planetary wavenumber2 and meridional eddy heat flux, followed by the onset of a weakened polar vortex which persists for the next 2 months. We then analyse 10 different models from the S2S database, finding that while all models represent the structure of the S-G pattern well, some models have a zonal bias with more than the observed variability in their first EOF, and accordingly less in their second EOF. This bias is largest in models with the lowest resolution. Skill in predicting the S-G pattern is not high beyond week 2 in any model, in contrast to the zonal pattern. We find that the relationship between the S-G pattern and enhanced eddy heat flux and a weakened polar vortex is initially well-represented but significantly decays with lead time in most S2S models. Our results motivate improved representation of the S-G pattern and its stratospheric response at longer lead-times for improved subseasonal prediction of the stratospheric polar vortex

On the tropospheric response to anomalous stratospheric wave drag and radiative heating

Observational and numerical evidence suggest that variability in the extratropical stratospheric circulation has a demonstrable impact on tropospheric variability on intraseasonal time scales. In this study, it is demonstrated that the amplitude of the observed tropospheric response to vacillations in the stratospheric flow is quantitatively similar to the zonal-mean balanced response to the anomalous wave forcing at stratospheric levels. It is further demonstrated that the persistence of the tropospheric response is consistent with the impact of anomalous diabatic heating in the polar stratosphere as stratospheric temperatures relax to climatology. The results contradict previous studies that suggest that variations in stratospheric wave drag are too weak to account for the attendant changes in the tropospheric flow. However, the results also reveal that stratospheric processes alone cannot account for the observed meridional redistribution of momentum within the troposphere

Myopathy associated BAG3 mutations lead to protein aggregation by stalling Hsp70 networks

BAG3 is a multi-domain hub that connects two classes of chaperones, small heat shock proteins (sHSPs) via two isoleucine-proline-valine (IPV) motifs and Hsp70 via a BAG domain.\ua0Mutations in either the IPV or BAG domain of BAG3 cause a dominant form of myopathy, characterized by protein aggregation in both skeletal and cardiac muscle tissues. Surprisingly, for both disease mutants, impaired chaperone binding is not sufficient to explain disease phenotypes. Recombinant mutants are correctly folded, show unaffected Hsp70 binding but are impaired in stimulating Hsp70-dependent client processing. As a consequence, the mutant BAG3 proteins become the node for a dominant gain of function causing aggregation of itself, Hsp70, Hsp70 clients and tiered interactors within the BAG3 interactome. Importantly, genetic and pharmaceutical interference with Hsp70 binding completely reverses stress-induced protein aggregation for both BAG3 mutations. Thus, the gain of function effects of BAG3 mutants act as Achilles heel of the HSP70 machinery

Randomized Trial of Anticoagulation Strategies for Noncritically Ill Patients Hospitalized With COVID-19.

BACKGROUND Prior studies of therapeutic-dose anticoagulation in patients with COVID-19 have reported conflicting results. OBJECTIVES We sought to determine the safety and effectiveness of therapeutic-dose anticoagulation in noncritically ill patients with COVID-19. METHODS Patients hospitalized with COVID-19 not requiring intensive care unit treatment were randomized to prophylactic-dose enoxaparin, therapeutic-dose enoxaparin, or therapeutic-dose apixaban. The primary outcome was the 30-day composite of all-cause mortality, requirement for intensive care unit-level of care, systemic thromboembolism, or ischemic stroke assessed in the combined therapeutic-dose groups compared with the prophylactic-dose group. RESULTS Between August 26, 2020, and September 19, 2022, 3,398 noncritically ill patients hospitalized with COVID-19 were randomized to prophylactic-dose enoxaparin (n = 1,141), therapeutic-dose enoxaparin (n = 1,136), or therapeutic-dose apixaban (n = 1,121) at 76 centers in 10 countries. The 30-day primary outcome occurred in 13.2% of patients in the prophylactic-dose group and 11.3% of patients in the combined therapeutic-dose groups (HR: 0.85; 95% CI: 0.69-1.04; P = 0.11). All-cause mortality occurred in 7.0% of patients treated with prophylactic-dose enoxaparin and 4.9% of patients treated with therapeutic-dose anticoagulation (HR: 0.70; 95% CI: 0.52-0.93; P = 0.01), and intubation was required in 8.4% vs 6.4% of patients, respectively (HR: 0.75; 95% CI: 0.58-0.98; P = 0.03). Results were similar in the 2 therapeutic-dose groups, and major bleeding in all 3 groups was infrequent. CONCLUSIONS Among noncritically ill patients hospitalized with COVID-19, the 30-day primary composite outcome was not significantly reduced with therapeutic-dose anticoagulation compared with prophylactic-dose anticoagulation. However, fewer patients who were treated with therapeutic-dose anticoagulation required intubation and fewer died (FREEDOM COVID [FREEDOM COVID Anticoagulation Strategy]; NCT04512079).Dr Stone has received speaker honoraria from Medtronic, Pulnovo, Infraredx, Abiomed, and Abbott; has served as a consultant to Daiichi-Sankyo, Valfix, TherOx, Robocath, HeartFlow, Ablative Solutions, Vectorious, Miracor, Neovasc, Ancora, Elucid Bio, Occlutech, CorFlow, Apollo Therapeutics, Impulse Dynamics, Cardiomech, Gore, Amgen, Adona Medical, and Millennia Biopharma; and has equity/ options from Ancora, Cagent, Applied Therapeutics, Biostar family of funds, SpectraWave, Orchestra Biomed, Aria, Cardiac Success, Valfix, and Xenter; his daughter is an employee at IQVIA; and his employer, Mount Sinai Hospital, receives research support from Abbott, Abiomed, Bioventrix, Cardiovascular Systems Inc, Phillips, BiosenseWebster, Shockwave, Vascular Dynamics, Pulnovo, and V-wave. Dr Farkouh has received institutional research grants from Amgen, AstraZeneca, Novo Nordisk, and Novartis; has received consulting fees from Otitopic; and has received honoraria from Novo Nordisk. Dr Lala has received consulting fees from Merck and Bioventrix; has received honoraria from Zoll Medical and Novartis; has served on an advisory board for Sequana Medical; and is the Deputy Editor for the Journal of Cardiac Failure. Dr Moreno has received honoraria from Amgen, Cuquerela Medical, and Gafney; has received payment for expert testimony from Koskoff, Koskoff & Dominus, Dallas W. Hartman, and Riscassi & Davis PC; and has stock options in Provisio. Dr Goodman has received institutional research grants from Bristol Myers Squibb/Pfizer Alliance, Bayer, and Boehringer Ingelheim; has received consulting fees from Amgen, Anthos Therapeutics, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, CSL Behring, Ferring Pharmaceuticals, HLS Therapeutics, Novartis, Pendopharm/Pharmascience, Pfizer, Regeneron, and Sanofi; has received honoraria from Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, Eli Lilly, Ferring Pharmaceuticals, HLS Therapeutics, JAMP Pharma, Merck, Novartis, Pendopharm/Pharmascience, Pfizer, Regeneron, Sanofi, and Servier; has served on Data Safety and Monitoring boards for Daiichi-Sankyo/American Regent and Novo Nordisk A/C; has served on advisory boards for Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, CSL Behring, Eli Lilly, Ferring Pharmaceuticals, HLS Therapeutics, JAMP Pharma, Merck, Novartis, Pendopharm/Pharmascience, Pfizer, Regeneron, Sanofi, Servier, and Tolmar Pharmaceuticals; has a leadership role in the Novartis Council for Heart Health (unpaid); and otherwise has received salary support or honoraria from the Heart and Stroke Foundation of Ontario/University of Toronto (Polo) Chair, Canadian Heart Failure Society, Canadian Heart Research Centre and MD Primer, Canadian VIGOUR Centre, Cleveland Clinic Coordinating Centre for Clinical Research, Duke Clinical Research Institute, New York University Clinical Coordinating Centre, PERFUSE Research Institute, and the TIMI Study Group (Brigham Health). Dr Ricalde has received consulting fees from Medtronic, Servier, and Boston Scientific; has received honoraria from Medtronic, Pfizer, Merck, Boston Scientific, Biosensors, and Bayer; has served on an advisory board for Medtronic; and has leadership roles in SOLACI and Kardiologen. Dr Payro has received consulting fees from Bayer Mexico; has received honoraria from Bayer, Merck, AstraZeneca, Medtronic, and Viatris; has received payments for expert testimony from Bayer; has received travel support from AstraZeneca; has served on an advisory board for Bayer; and his institution has received equipment donated from AstraZeneca. Dr Castellano has received consulting fees and honoraria from Ferrer International, Servier, and Daiichi-Sankyo; and has received travel support from Ferrer International. Dr Hung has served as an advisory board member for Pfizer, Merck, AstraZeneca, Fosun, and Gilead. Dr Nadkarni has received consulting fees from Renalytix, Variant Bio, Qiming Capital, Menarini Health, Daiichi-Sankyo, BioVie, and Cambridge Health; has received honoraria from Daiichi-Sankyo and Menarini Health; has patents for automatic disease diagnoses using longitudinal medical record data, methods, and apparatus for diagnosis of progressive kidney function decline using a machine learning model, electronic phenotyping technique for diagnosing chronic kidney disease, deep learning to identify biventricular structure and function, fusion models for identification of pulmonary embolism, and SparTeN: a novel spatio-temporal deep learning model; has served on a Data Safety and Monitoring Board for CRIC OSMB; has leadership roles for Renalytix scientific advisory board, Pensive Health scientific advisory board, and ASN Augmented Intelligence and Digital Health Committee; has ownership interests in Renalytix, Data2Wisdom LLC, Verici Dx, Nexus I Connect, and Pensieve Health; and his institution receives royalties from Renalytix. Dr Goday has received the Frederick Banting and Charles Best Canada Graduate Scholarship (Doctoral Research Award) from the Canadian Institutes of Health Research. Dr Furtado has received institutional research grants from AstraZeneca, CytoDin, Pfizer, Servier, Amgen, Alliar Diagnostics, and the Brazilian Ministry of Health; has received consulting fees from Biomm and Bayer; has received honoraria from AstraZeneca, Bayer, Servier, and Pfizer; and has received travel support from Servier, AstraZeneca, and Bayer. Dr Granada has received consulting fees, travel support, and stock from Cogent Technologies Corp; and has received stock from Kutai. Dr Contreras has served as a consultant for Merck, CVRx, Novodisk, and Boehringer Ingelheim; and has received educational grants from Alnylam Pharmaceuticals and AstraZeneca. Dr Bhatt has received research funding from Abbott, Acesion Pharma, Afimmune, Aker Biomarine, Amarin, Amgen, AstraZeneca, Bayer, Beren, Boehringer Ingelheim, Boston Scientific, Bristol Myers Squibb, Cardax, CellProthera, Cereno Scientific, Chiesi, Cincor, CSL Behring, Eisai, Ethicon, Faraday Pharmaceuticals, Ferring Pharmaceuticals, Forest Laboratories, Fractyl, Garmin, HLS Therapeutics, Idorsia, Ironwood, Ischemix, Janssen, Javelin, Lexicon, Lilly, Medtronic, Merck, Moderna, MyoKardia, NirvaMed, Novartis, Novo Nordisk, Owkin, Pfizer Inc, PhaseBio, PLx Pharma, Recardio, Regeneron, Reid Hoffman Foundation, Roche, Sanofi, Stasys, Synaptic, The Medicines Company, Youngene, and 89bio; has received royalties from Elsevier; has received consultant fees from Broadview Ventures and McKinsey; has received honoraria from the American College of Cardiology, Baim Institute for Clinical Research, Belvoir Publications, Boston Scientific, Cleveland Clinic, Duke Clinical Research Institute, Mayo Clinic, Mount Sinai School of Medicine, Novartis, Population Health Research Institute, Rutgers University, Canadian Medical and Surgical Knowledge Translation Research Group, Cowen and Company, HMP Global, Journal of the American College of Cardiology, K2P, Level Ex, Medtelligence/ReachMD, MJH Life Sciences, Oakstone CME, Piper Sandler, Population Health Research Institute, Slack Publications, WebMD, Wiley, Society of Cardiovascular Patient Care; has received fees from expert testimony from the Arnold and Porter law firm; has received travel support from the American College of Cardiology, Society of Cardiovascular Patient Care, American Heart Association; has a patent for otagliflozin assigned to Brigham and Women’s Hospital who assigned to Lexicon; has participated on a data safety monitoring board or advisory board for Acesion Pharma, Assistance Publique-Hôpitaux de Paris, AngioWave, Baim Institute, Bayer, Boehringer Ingelheim, Boston Scientific, Cardax, CellProthera, Cereno Scientific, Cleveland Clinic, Contego Medical, Duke Clinical Research Institute, Elsevier Practice Update Cardiology, Janssen, Level Ex, Mayo Clinic, Medscape Cardiology, Merck, Mount Sinai School of Medicine, MyoKardia, NirvaMed, Novartis, Novo Nordisk, PhaseBio, PLx Pharma, Regado Biosciences, Population Health Research Institute, and Stasys; serves as a trustee or director for American College of Cardiology, AngioWave, Boston VA Research Institute, Bristol Myers Squibb, DRS.LINQ, High Enroll, Society of Cardiovascular Patient Care, and TobeSoft; has ownership interests in AngioWave, Bristol Myers Squibb, DRS.LINQ, and High Enroll; has other interests in Clinical Cardiology, the NCDR-ACTION Registry Steering Committee; has conducted unfunded research with FlowCo and Takeda, Contego Medical, American Heart Association Quality Oversight Committee, Inaugural Chair, VA CART Research and Publications Committee; and has been a site co-investigator for Abbott, Biotronik, Boston Scientific, CSI, St Jude Medical (now Abbott), Phillips SpectraWAVE, Svelte, and Vascular Solutions. Dr Fuster declares that he raised $7 million from patients for this study granted to Mount Sinai Heart, unrelated to industry. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.S