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Matthias Zahn and Richard P. Allan

1. Introduction Future changes in the tropical hydrological cycle ( Trenberth et al. 2007 ; Bengtsson 2010 ) may alter the distribution of available freshwater regionally through altered moisture transport properties and precipitation minus evaporation patterns ( Allen and Ingram 2002 ; Trenberth et al. 2003 ). The atmospheric part of the hydrological cycle is to a large extent determined by the large-scale circulation patterns. In the tropics these consist of convective regions of upward

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Isaac M. Held and Brian J. Soden

larger spread in the temperature responses in this figure is in part a consequence of a larger contribution from noise as compared to the smaller forced response. The fact that the correlation is nearly as tight as in the twenty-first-century integrations suggests that temperature fluctuations generated internally are also accompanied by CC scaled water vapor fluctuations, consistent with the GFDL AM2/LM2 results in Fig. 1 on shorter time scales. 3. The global-mean hydrological cycle It is

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Olga Zolina, Ambroise Dufour, Sergey K. Gulev, and Georgiy Stenchikov

1. Introduction The Red Sea is a unique basin characterized by extremely high evaporation, which amounts to 1.6–1.9 m yr −1 for the whole sea ( Tragou et al. 1999 ) and may increase to more than 3 m yr −1 in the northern part (e.g., Papadopoulos et al. 2013 ). Upon rising into the atmosphere, this moisture participates in the regional hydrological cycle, influencing water content and precipitation over the adjacent continents. Over the Arabian Peninsula, precipitation, while very rare, has

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Mohamed S. Siam, Marie-Estelle Demory, and Elfatih A. B. Eltahir

, model outputs are often statistically or dynamically downscaled for impact studies on water resources, floods and droughts, and agriculture. However, many uncertainties lie behind the choice of a downscaling method, which may amplify inherent errors in GCM outputs and increase uncertainties associated with climate change predictions of the hydrological cycle at smaller scale, such as over river basins ( Boé et al. 2009 ). These errors are reflected in the disagreement between GCM predictions on the

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Ramiro I. Saurral

forecasts before using the data as a forcing to the hydrology model, as GCMs tend to commonly have large biases in both variables. In this paper, the impacts of the GCMs’ misrepresentations in precipitation and temperature on the hydrological cycle of the LPB are determined by forcing a hydrological model with observed precipitation and temperature data from the period 1990–99 and also using input data from five different GCMs for the same time period. Results show that the GCMs are unable to capture

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Ken Takahashi

1. Introduction Comprehensive climate models predict that the global hydrological cycle [or, equivalently, the global mean surface latent heat flux (LH) and precipitation] will increase at a significantly smaller (fractional) rate than atmospheric water vapor content with global warming ( Mitchell et al. 1989 ; Allen and Ingram 2002 ; Held and Soden 2006 ). It has been argued that this smaller rate is set by energetic (i.e., radiative) considerations rather than by moist processes ( Mitchell

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Jianhua Lu and Ming Cai

propose a mechanism responsible for the muted increase in the hydrological cycle in climate models from the perspective of the surface energy balance. We also wish to discuss the physical consistency among the proposed mechanism and the existing mechanisms—that is, the reduction in convective mass flux and the atmospheric energy constraint. 2. Data and method The data used in this study are derived from outputs of the control (1 × CO 2 ) and 2 × CO 2 equilibrium experiments made with 11 Coupled Model

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Hansi K. A. Singh, Cecilia M. Bitz, Aaron Donohoe, and Philip J. Rasch

1. Introduction A thorough understanding of the polar hydrologic cycle response to CO 2 -induced warming is essential for advancing study of both the global hydrologic cycle and the climate of the polar regions. The polar regions are tightly coupled to the extrapolar regions through the meridional transfer of heat, moisture, and momentum. As a result, it is not surprising that the polar climate response to greenhouse gas forcing is, at least in part, dependent on changes in meridional transport

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Biljana Music and Daniel Caya

1. Introduction The hydrological cycle controls and regulates climate in a fundamental way through many complex interactions ( Peixoto and Oort 1992 ). Inadequate understanding of the hydrological cycle and limited ability to model and predict the various hydrological cycle processes and their associated feedbacks contribute to many of the uncertainties associated with our understanding of long-term changes in the climate system ( Watson et al. 2001 ). An international effort focusing on the

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Robert C. Wills and Tapio Schneider

1. Introduction The tendency for wet latitude bands to get wetter and for dry latitude bands to get drier has been highlighted as a robust response of the zonal-mean hydrological cycle to global warming ( Mitchell et al. 1987 ; Chou and Neelin 2004 ; Held and Soden 2006 ). As Held and Soden (2006) point out, this wet gets wetter, dry gets drier response relies on the assumption of fixed relative humidity and circulation. These assumptions are expected to break down for variations about

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