Ocean and land forcing of the record-breaking Dust Bowl heat waves across central United States

International audienceThe severe drought of the 1930s Dust Bowl decade coincided with record-breaking summer heatwaves that contributed to the socioeconomic and ecological disaster over North America's Great Plains. It remains unresolved to what extent these exceptional heatwaves, hotter than in historically forced coupled climate model simulations, were forced by sea surface temperatures (SSTs) and exacerbated through human-induced deterioration of land cover. Here we show, using an atmospheric-only model, that anomalously warm North Atlantic SSTs enhance heatwave activity through an association with drier spring conditions resulting from weaker moisture transport. Model devegetation simulations, that represent the widespread exposure of bare soil in the 1930s, suggest human activity fueled stronger and more frequent heatwaves through greater evaporative drying in the warmer months. This study highlights the potential for the amplification of naturally occurring extreme events like droughts by vegetation feedbacks to create more extreme heatwaves in a warmer world

Afternoon rain more likely over drier soils

Land surface properties, such as vegetation cover and soil moisture, influence the partitioning of radiative energy between latent and sensible heat fluxes in daytime hours. During dry periods, a soil-water deficit can limit evapotranspiration, leading to increased surface heating ofwarmer and drier conditions in the lower atmosphere and affecting the climate. Soil moisture can influence the development of convective storms through such modifications of low-level atmospheric temperature and humidity, which in turn feeds back on soil moisture. Yet there is considerable uncertainty in how soil moisture affects convective storms across the world, owing to a lack of observational evidence and uncertainty in large-scale models. Here we present a global-scale observational analysis of the coupling between soil moisture and precipitation. We show that across all six continents studied, afternoon rain falls preferentially over soils that are relatively dry compared to the surrounding area. The signal emerges most clearly in the observations over semi-arid regions, where surface fluxes are sensitive to soil moisture, and convective events are frequent. Mechanistically, our results are consistent with enhanced afternoon moist convection driven by increased sensible heat flux over drier soils, and/or mesoscale variability in soil moisture. We find no evidence in our analysis of a positive feedback—that is, a preference for rain over wetter soils—at the spatial scale (50–100 kilometres) studied. In contrast, we find that a positive feedback of soil moisture on simulated precipitation does dominate in six state-of-the-art global weather and climate models—a difference that may contribute to excessive simulated droughts in large-scale models

Avaliação médica: o consumo na medicina e a mercantilização da saúde

INTRODUÇÃO: A Saúde vem sendo ameaçada pela colonização empresarial do médico que, iniciada dentro da Universidade, prolonga-se no ambiente de trabalho. Essa ação tem origem no ensino defasado da realidade científica e na asserção de tendências individualistas que expressam opiniões isoladas e não abalizadas, em geral induzidas pelas propagandas e investigações encomendadas para agitar o mercado no uso de aparelhos e produtos médico-farmacêuticos. OBJETIVO: Usar o ponto de vista do Cirurgião Geral e do Coloproctologista para comentar a mercantilização da saúde e a maneira como a Instituição Industrial, usando a empresa médica, age e modifica a ação do médico, contribuindo para o alto custo da Medicina. MATERIAL E MÉTODO: As bases serão os exames laboratoriais e as avaliações cardiovasculares pré-operatórias de rotina, usados para operações não cardíacas em pacientes cardiopatas. O material e o conteúdo para discussão foram extraídos do livro de Ivan Illich¹, do artigo de atualização de Coelho e col. ², do modelo proposto na Cleveland Clinic³ sobre avaliação pré-operatória e das normas estabelecidas pelo American College of Cardiology e pela American Heart Association4 para a orientação de avaliação médica mínima, necessária e suficiente, de pacientes cardiopatas, quando candidatos a tratamento cirúrgico de doenças em outros órgãos.<br>BACKGROUND: The Health has been threatened by the physician's managerial colonization that, begun inside of the University, continues in the work environment. That action has origin of the teaching in disagreement with the scientific reality and in the assertion of individualistic tendencies expressing isolated and not-distinguished opinions, in general induced by the investigations requested to give rise to the market of drugs and devices disposable for physician and pharmacists. PURPOSE: The aim of this report is to use the General Surgeon's point of view to comment on the commercialization of the health and on the way as the Industrial Institution, using the medical company, acts and modifies the physician's action contributing to the high cost of the medicine. MATERIAL AND METHODS: The bases will be the laboratory exams and the preoperative cardiovascular routine evaluation used for noncardiac surgery on patients with cardiomyopathies. The material and the content for discussion were extracted from Ivan Illich's¹ book, Coelho and col.² article, from the model proposed in Cleveland Clinic³ on preoperative tests, and from the established norms of ACC1 and of the AHA* about the orientation on minimum medical evaluation and exam of patient with cardiac disease, when they are candidates to a noncardiac surgery4