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Gabriel T. Bromley, Tobias Gerken, Andreas F. Prein, and Paul C. Stoy

difficult to understand the mechanisms causing regional cooling in the combined CP and NGP [called herein the northern North American Great Plains (NNAGP)] without first characterizing regional climate observations. Here, we describe changes in observed near-surface (2 m) air temperature T air , vapor pressure deficit (VPD), and precipitation P in the NNAGP at annual, seasonal, and monthly time scales from 1970 to 2015 by analyzing global climatic databases. Changes in T air and P are commonly

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Yaheng Tan, Francis Zwiers, Song Yang, Chao Li, and Kaiqiang Deng

global spatial distribution of AR frequency and showed that the west coast of North America is one of the areas where ARs make landfall most frequently, especially in winter ( Mundhenk et al. 2016a ). Indeed, most of the winter precipitation over coastal western North America is contributed by ARs ( Gershunov et al. 2017 ). ARs making landfall over western North America on different time scales in the current climate have recently been studied extensively, with many studies considering dynamical

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Robbie A. Hember and Peter M. Lafleur

North American ecosystems. To achieve this, we used linear regression to identify the presence of significant relationships between estimates of GEP and ER at 14 EC stations and modes of Northern Hemisphere tropospheric circulation variability, identified herein as the North Atlantic Oscillation (NAO) and the North Pacific Oscillation (NPO). Although such relationships may be prevalent over a range of temporal scales, we limited the current study to the analysis of seasonal connections by

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Anthony M. DeAngelis, Anthony J. Broccoli, and Steven G. Decker

-twentieth-century simulations of daily precipitation statistics and the physical mechanisms that generate extreme precipitation over North America. The use of 17 climate models, emphasis on the spatial patterns of precipitation statistics, and analysis of the atmospheric dynamic and thermodynamic structure associated with extreme daily precipitation provides a more comprehensive evaluation of CMIP3 simulated precipitation over North America than is currently available. In the subsequent section, the observations and

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Sloan Coats, Jason E. Smerdon, Richard Seager, Benjamin I. Cook, and J. F. González-Rouco

1. Introduction A particularly stark feature of proxy-estimated multidecadal hydroclimate variability in the North American southwest (NASW: 25°–42.5°N, 125°–105°W) is the occurrence of so called megadroughts [for a review, see Cook et al. (2007) ]. Although drought definitions vary, a megadrought can be defined as a persistent period of drought conditions lasting decades to centuries. Proxy records indicate the presence of two century-scale megadroughts during the last millennium in the

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M. A. Ben Alaya, F. Zwiers, and X. Zhang

). Nevertheless, only few studies have considered the uncertainty of PMP estimates ( Salas et al. 2014 ; Micovic et al. 2015 ; Salas and Salas 2016 ). The main objective of this paper is to compare and assess PMP estimates based on the output of two Canadian regional climate models, CanRCM4 and CRCM5, over North America. To this end, a probabilistic extension of the usual moisture maximization method proposed by Ben Alaya et al. (2018) is adopted to provide a probabilistic description of the operational

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Richard Seager and Naomi Henderson

1. Introduction California experienced four consecutive drier than normal winters from 2011/12 to 2014/15 that pushed the state into a record multiyear drought that has had serious social, economic, environmental, and agricultural consequences ( Howitt et al. 2014 ). Although intensified by long-term warming and coincident high temperatures ( Williams et al. 2015 ), the root cause of the drought has been higher than normal pressure at the west coast of North America, which has gone along with

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Ngar-Cheung Lau, Ants Leetmaa, and Mary Jo Nath

1. Introduction El Niño–Southern Oscillation (ENSO) is one of most significant modes of climate variability on interannual time scales. Its impacts on the atmospheric environment in different regions of the globe have been documented in detail by many investigators (e.g., Ropelewski and Halpert 1987 ; Halpert and Ropelewski 1992 ). The changes in atmospheric circulation and surface climate (such as air temperature and precipitation) in the North Pacific–North America sector during the warm

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Tereza Cavazos and Sarahí Arriaga-Ramírez

not only for Baja California (BCC in Fig. 1a ), but also for the North American monsoon (NAM) region and the southwestern United States (SW-U.S.) to assess the extension of the future changes of this semiarid region. Fig . 1. Mean annual precipitation (mm day −1 ) and mean annual temperature (°C) during 1961–90 for (a),(d) observed data from the CRU monthly gridded dataset (0.5° × 0.5° resolution), (b),(e) median ensemble of the GCM (2° × 2° resolution), and (c),(f) median ensemble of the BCSD (⅛

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Franco Biondi

received some attention ( Gray and McCabe 2010 ; Prairie et al. 2008 ), but requires additional studies, as suggested in a joint report by the Bureau of Reclamation and the U.S. Army Corps of Engineers ( Brekke 2011 ). In the Great Basin of North America, dendroclimatic reconstructions of moisture parameters have a long and productive history, starting with pioneering work in the 1930s ( Antevs 1938 ; Hardman and Reil 1936 ), continuing with isolated efforts into the 1980s ( Nichols 1989 ; Smith

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