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1. Introduction This is the second part of a three-part paper on phase 5 of the Coupled Model Intercomparison Project (CMIP5; Taylor et al. 2012 ) model simulations for North America. This second part evaluates the CMIP5 models in their ability to replicate the observed variability of North American continental and regional climate, and related climate processes. Sheffield et al. (2013 , hereafter Part I) evaluate the representation of the climatology of continental and regional climate
1. Introduction This is the second part of a three-part paper on phase 5 of the Coupled Model Intercomparison Project (CMIP5; Taylor et al. 2012 ) model simulations for North America. This second part evaluates the CMIP5 models in their ability to replicate the observed variability of North American continental and regional climate, and related climate processes. Sheffield et al. (2013 , hereafter Part I) evaluate the representation of the climatology of continental and regional climate
1. Introduction This is the first part of a three-part paper on the phase 5 of the Coupled Model Intercomparison Project (CMIP5; Taylor et al. 2012 ) model simulations for North America. The first two papers evaluate the CMIP5 models in their ability to replicate the observed features of North American continental and regional climate and related climate processes for the recent past. This first part evaluates the models in terms of continental and regional climatology, and Sheffield et al
1. Introduction This is the first part of a three-part paper on the phase 5 of the Coupled Model Intercomparison Project (CMIP5; Taylor et al. 2012 ) model simulations for North America. The first two papers evaluate the CMIP5 models in their ability to replicate the observed features of North American continental and regional climate and related climate processes for the recent past. This first part evaluates the models in terms of continental and regional climatology, and Sheffield et al
.1, respectively. The lack of relationship between subtropical jet changes and equatorial Pacific SST is consistent with Lu et al. (2008) , who contrasted jet changes under global warming with those under El Niño. Given the large zonal scale of the jet changes in Fig. 7 (and Fig. A3 ), it is likely that the jet changes arise from the global-scale mechanisms discussed below, and it is simply the regional precipitation impacts that follow a local physical pathway akin to the jet-related effects active during
.1, respectively. The lack of relationship between subtropical jet changes and equatorial Pacific SST is consistent with Lu et al. (2008) , who contrasted jet changes under global warming with those under El Niño. Given the large zonal scale of the jet changes in Fig. 7 (and Fig. A3 ), it is likely that the jet changes arise from the global-scale mechanisms discussed below, and it is simply the regional precipitation impacts that follow a local physical pathway akin to the jet-related effects active during
), related changes in the tropical tropospheric stability ( Chou et al. 2001 ; Neelin et al. 2003 ), and the regional effects of aerosols and black carbon ( Lau et al. 2006 ; Meehl et al. 2008 ). Despite the weakening of tropical circulations, the World Climate Research Programme (WCRP) phase 3 of the Coupled Model Intercomparison Project (CMIP3) multimodel climate projections suggested a tendency toward increased monsoon precipitation and increased low-level moisture convergence ( Christensen et al
), related changes in the tropical tropospheric stability ( Chou et al. 2001 ; Neelin et al. 2003 ), and the regional effects of aerosols and black carbon ( Lau et al. 2006 ; Meehl et al. 2008 ). Despite the weakening of tropical circulations, the World Climate Research Programme (WCRP) phase 3 of the Coupled Model Intercomparison Project (CMIP3) multimodel climate projections suggested a tendency toward increased monsoon precipitation and increased low-level moisture convergence ( Christensen et al
1. Introduction El Niño–Southern Oscillation (ENSO) is a leading mode of interannual climate variability originating in the tropical Pacific. ENSO teleconnections are a reflection of the strong coupling between the tropical ocean and global atmosphere, and SST anomalies in the equatorial Pacific can have substantial remote effects on climate ( Horel and Wallace 1981 ; Ropelewski and Halpert 1987 ; Trenberth et al. 1998 ; Wallace et al. 1998 ; Dai and Wigley 2000 ). In recent decades
1. Introduction El Niño–Southern Oscillation (ENSO) is a leading mode of interannual climate variability originating in the tropical Pacific. ENSO teleconnections are a reflection of the strong coupling between the tropical ocean and global atmosphere, and SST anomalies in the equatorial Pacific can have substantial remote effects on climate ( Horel and Wallace 1981 ; Ropelewski and Halpert 1987 ; Trenberth et al. 1998 ; Wallace et al. 1998 ; Dai and Wigley 2000 ). In recent decades
that the nighttime temperature rose more than the daytime temperature because of cloud cover and other feedback processes ( Karl et al. 1993 ). Furthermore, high mountain regions warmed more than low-lying regions ( Liu and Chen 2000 ). On regional scales, temperature changes often deviate from the above discussed general warming patterns. There are some special geographical regions where a lack of warming or even a cooling has occurred. The central and southeastern United States (CSE) actually
that the nighttime temperature rose more than the daytime temperature because of cloud cover and other feedback processes ( Karl et al. 1993 ). Furthermore, high mountain regions warmed more than low-lying regions ( Liu and Chen 2000 ). On regional scales, temperature changes often deviate from the above discussed general warming patterns. There are some special geographical regions where a lack of warming or even a cooling has occurred. The central and southeastern United States (CSE) actually
are some chances (10%–20%) that the warming hole may reappear in the second half of the twenty-first century (RCP4.5). However, if we follow the highest emission pathway (RCP8.5), the warming hole would disappear in the twenty-first century. Many theories for the warming hole have been proposed, including internally generated climate variability, multidecadal climate variability, land–atmosphere interactions, regional-scale hydrologic processes, and aerosol effects ( Robinson et al. 2002 ; Pan et
are some chances (10%–20%) that the warming hole may reappear in the second half of the twenty-first century (RCP4.5). However, if we follow the highest emission pathway (RCP8.5), the warming hole would disappear in the twenty-first century. Many theories for the warming hole have been proposed, including internally generated climate variability, multidecadal climate variability, land–atmosphere interactions, regional-scale hydrologic processes, and aerosol effects ( Robinson et al. 2002 ; Pan et
:10.1029/2007JD008972 . Gutzler , D. S. , and T. O. Robbins , 2011 : Climate variability and projected change in the western United States: Regional downscaling and drought statistics . Climate Dyn. , 37 , 835 – 849 . Hamlet , A. F. , and D. P. Lettenmaier , 2007 : Effects of 20th century warming and climate variability on flood risk in the western U.S . Water Resour. Res. , 43 , W06427 , doi:10.1029/2006WR00509 . Hay , L. E. , S. L. Markstrom , and C. Ward
:10.1029/2007JD008972 . Gutzler , D. S. , and T. O. Robbins , 2011 : Climate variability and projected change in the western United States: Regional downscaling and drought statistics . Climate Dyn. , 37 , 835 – 849 . Hamlet , A. F. , and D. P. Lettenmaier , 2007 : Effects of 20th century warming and climate variability on flood risk in the western U.S . Water Resour. Res. , 43 , W06427 , doi:10.1029/2006WR00509 . Hay , L. E. , S. L. Markstrom , and C. Ward
agricultural land. Precipitation amounts are moderate and consistent throughout the annual cycle ( Sabbagh and Bryson 1962 ; Leathers et al. 2000 ). Perhaps because precipitation is generally reliable, relatively little research has been done to examine northeast-region warm-season precipitation at the regional scale. Yet, the northeast region is sensitive to variations in water quality and availability and is known to experience periods of flooding and drought ( Leathers et al. 2000 ; Hayhoe et al. 2007
agricultural land. Precipitation amounts are moderate and consistent throughout the annual cycle ( Sabbagh and Bryson 1962 ; Leathers et al. 2000 ). Perhaps because precipitation is generally reliable, relatively little research has been done to examine northeast-region warm-season precipitation at the regional scale. Yet, the northeast region is sensitive to variations in water quality and availability and is known to experience periods of flooding and drought ( Leathers et al. 2000 ; Hayhoe et al. 2007
1. Introduction During boreal summer, convective activity over the eastern North Pacific Ocean (ENP) along the intertropical convergence zone (ITCZ) exhibits significant intraseasonal variability (ISV). Through its associated large-scale circulation and thermodynamical variations, the ISV exerts broad impacts on regional weather and climate systems, including the North American monsoon (NAM), midsummer drought over Central America, and Caribbean rainfall and low-level jet, as well as tropical
1. Introduction During boreal summer, convective activity over the eastern North Pacific Ocean (ENP) along the intertropical convergence zone (ITCZ) exhibits significant intraseasonal variability (ISV). Through its associated large-scale circulation and thermodynamical variations, the ISV exerts broad impacts on regional weather and climate systems, including the North American monsoon (NAM), midsummer drought over Central America, and Caribbean rainfall and low-level jet, as well as tropical
