2018 International Atmospheric Rivers Conference : Multi‐disciplinary studies and high‐impact applications of atmospheric rivers

Atmospheric rivers (ARs) play a vital role in shaping the hydroclimate of many regions globally, and can substantially impact water resource management, emergency response planning, and other socioeconomic entities. The second International Atmospheric Rivers Conference took place at the Scripps Institution of Oceanography, University of California, San Diego, during 25–28 June, 2018, in La Jolla, California, USA. It was sponsored by the Center for Western Weather and Water Extremes (CW3E). A total of 120 people attended the Conference with 94 abstracts submitted and 30 participating students. In addition to the conference, the Student Forecasting Workshop was organised in the same week. During this workshop, students were exposed to AR forecasting tools, and learned examples of how these tools could be used to make decisions for various applications. The main goals of this conference were to bring together experts from across the fields of hydrology, atmospheric, oceanic, and polar sciences, as well as water management, civil engineering, and ecology to advance the state of AR science and to explore the future directions for the field. The conference was organised into traditional oral and poster presentations, along with panel discussions and Breakout Groups. This format allowed enhanced interaction between participants, driving progress within the scientific community and the enhanced communication of societal needs by various stakeholders. Several emerging topics of research were highlighted, including subseasonal‐to‐seasonal (S2S) prediction of ARs and an overview of the AR Reconnaissance campaign. In addition to providing a forum to disseminate and debate new results from scientific talks and posters, the conference was equally effective and useful in linking scientists to users and decision‐makers that require improved knowledge on ARs to manage resources and prepare for hazards. The third International Atmospheric Rivers Conference will be held in Chile in 2020, and hosted by the University of Chile, Santiago

Evaluation of current and projected Antarctic precipitation in CMIP5 models

International audienceOn average, the models in the Fifth Climate Model Intercomparison Project archive predict an increase in Antarctic precipitation from 5.5 to 24.5 % between 1986-2005 and 2080-2099, depending on greenhouse gas emissions scenarios. This translates into a moderation of future sea level rise ranging from -19 to -71 mm between 2006 and 2099. However, comparison with CloudSat and ERA-Interim data show that almost all the models overestimate current Antarctic precipitation, some by more than 100 %. If only the models that agree with CloudSat data within 20 % of error are considered, larger precipitation changes (from 7.4 to 29.3 %) and impact on sea level (from -25 to -85 mm) are predicted. A common practice of averaging all models to evaluate climate projections thus leads to a significant underestimation of the contribution of Antarctic precipitation to future sea level. Models simulate, on average, a 7.4 %/°C precipitation change with surface temperature warming. The models in better agreement with CloudSat observations for Antarctic snowfall predict, on average, larger temperature and Antarctic sea ice cover changes, which could explain the larger changes in Antarctic precipitation simulated by these models. The agreement between the models, CloudSat data and ERA-Interim is generally less in the interior of Antarctica than at the peripheries, but the interior is also where climate change will induce the smallest absolute change in precipitation. About three-quarters of the impact on sea level will result from precipitation change over the half most peripheral and lowest elevation part of the surface of Antarctica

Record warming at the South Pole during the past three decades

Over the last three decades, the South Pole has experienced a record-high statistically significant warming of 0.61 ± 0.34 °C per decade, more than three times the global average. Here, we use an ensemble of climate model experiments to show this recent warming lies within the upper bounds of the simulated range of natural variability. The warming resulted from a strong cyclonic anomaly in the Weddell Sea caused by increasing sea surface temperatures in the western tropical Pacific. This circulation, coupled with a positive polarity of the Southern Annular Mode, advected warm and moist air from the South Atlantic into the Antarctic interior. These results underscore the intimate linkage of interior Antarctic climate to tropical variability. Further, this study shows that atmospheric internal variability can induce extreme regional climate change over the Antarctic interior, which has masked any anthropogenic warming signal there during the twenty-first century

Effects of Atmospheric Rivers

This book is intended to summarize the state of the science of atmospheric rivers (ARs) and itsapplication to practical decision-making and broader policy topics. It is the first book on thesubject and is intended to be a learning resource for professionals, students, and indeed anyonenew to the field, as well as a reference source for all.We first envisioned the book during the heady days of 2013 when the Center for WesternWeather and Water Extremes was being planned and established. However, right from the start,we recognized that the effort required would exceed that of any single or couple of authors, andthat the book would surely benefit from a broad range of perspectives and knowledge from avariety of leaders of atmospheric-river science from around the world. Consequently, the firststep toward this book was to organize workshops addressing various aspects of AR science thatwe were able to co-opt, in part, for recruitment of, and discussions among, possible contributingauthors. This led to the diverse authorship team that ultimately wrote this book, as well asour engagement of an experienced publication and book editing team. Among the strategiesagreed to by the contributing authors, one key decision was that the book would focus mostlyon results that have already been published and would emphasize figures and references fromthose formal publications. Where vital, new information has been developed and incorporated.Each chapter was led by a few expert lead authors recruited by the four of us, and those chapterleads recruited contributions from other experts on the chapter topic. Each chapter wasreviewed by other specialists who were not part of its authorship team, generally including onehighly technical expert and one reviewer intended to represent members of a broader audience.This helped ensure the accuracy of interpretations as well as high standards and accessibilityof presentation. We, the editors of the book, reviewed all chapters at various stages of compositionand layout.Given currently high levels of interest in ARs in the scientific community as well as by thepublic, we hope that the book will be a useful starting place for many readers. Writing a bookabout a topic that is as new and that is advancing as quickly as AR science is today (in 2018)poses many difficult challenges but, with the help of the large team of expert authors who havecontributed, we believe that, with this book, we are providing a firm foundation for futureexpansion and advances in this important field.Fil: Dettinger, Michael D.. United States Geological Survey; Estados UnidosFil: Lavers, David A.. No especifíca;Fil: Compo, Gilbert P.. State University of Colorado at Boulder; Estados UnidosFil: Gorodetskaya, Irina V.. Universidade de Aveiro; PortugalFil: Neff, William. State University of Colorado at Boulder; Estados UnidosFil: Neiman, Paul J.. National Oceanic And Atmospheric Administration; Estados UnidosFil: Ramos, Alexandre M.. Universidade Nova de Lisboa; PortugalFil: Rutz, Jonathan J.. National Weather Service; Estados UnidosFil: Viale, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Wade, Andrew J.. University of Reading; Reino UnidoFil: White, Allen B.. National Oceanic And Atmospheric Administration; Estados Unido