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Kerry H. Cook and Edward K. Vizy

topography as resolved. A large domain is used to minimize the effects of lateral boundary constraints over East Africa and to allow the development of subtropical anticyclones over the oceans. Over the Ethiopian plateau, the model topography reaches about 2500 m. Mt. Kilimanjaro, near the Kenya–Tanzania border and separated from the Ethiopia topography by the Turkana Channel, extends above 1500 m at this resolution. Fig . 2. Regional climate model domain with topography (shaded; m) as resolved at 90-km

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Zewdu T. Segele, Michael B. Richman, Lance M. Leslie, and Peter J. Lamb

Barnston 2007 ). Also, because the effects of slowly evolving global SST variations on Ethiopian rainfall must be transmitted through changes in local and regional atmospheric circulations and SST patterns, development of monthly-to-seasonal Ethiopian rainfall predictions can be enhanced by identifying local and regional predictors and aggregating their effects into ensemble-based statistical prediction schemes. The present Kiremt predictability investigation involves 2–3-month lead time forecasts of

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Peter J. Lamb, Diane H. Portis, and Abraham Zangvil

) the relationships between cumulus clouds and the soil–plant–atmosphere exchange of heat, carbon, and water at the SGP ACRF site; (iii) how land cover changes (including the winter wheat harvest) impact surface heat, carbon, and water fluxes, and whether those changes affect local and regional cumulus cloud formation at the SGP ACRF; (iv) how SGP land surface processes affect atmospheric aerosol loading and chemistry, and the resulting effects on cumulus cloud microphysics and macrophysics; and (v

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Gang Zhang, Kerry H. Cook, and Edward K. Vizy

1. Introduction This paper is the second part of a study that aims to improve our understanding of the diurnal cycle of warm season rainfall over West Africa. Here, we follow an observational study ( Zhang et al. 2016 , hereafter Part I ) with an analysis of high-resolution simulations. Atmospheric models, including both general circulation models (GCMs) and regional climate models (RCMs), are primary tools for predicting rainfall from subsynoptic to multidecadal time scales. The diurnal cycle

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John G. Dwyer, Michela Biasutti, and Adam H. Sobel

timing have large regional implications due to the dependence of many agricultural and pastoral communities on rainfall. Nearly all of the models in the World Climate Research Programme’s (WCRP’s) Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset ( Meehl et al. 2007 ) project consistent changes to the annual cycle of tropical SST and precipitation in simulations with increased greenhouse gases: a phase delay and an amplification ( Chou et al. 2007 ; Tan et al. 2008 ; Biasutti

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Gang Zhang, Kerry H. Cook, and Edward K. Vizy

of rainfall is represented in regional climate models without using cumulus convection parameterization, convection-permitting simulations over West Africa are analyzed in Zhang et al. (2016 , hereinafter Part II) . 2. Background The diurnal cycle of rainfall over West Africa is discussed in several studies that have a global perspective. Dai (2001) examines 3-hourly reports from weather stations around the globe to find that the Sahel region (defined as 10°W–20°E and 10°–15°N) exhibits a

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Lisa Hannak, Peter Knippertz, Andreas H. Fink, Anke Kniffka, and Gregor Pante

associated with the radiative imbalance in the SHL ( Milton et al. 2008 ), air–sea interactions over the tropical eastern Atlantic Ocean ( Brandt et al. 2011 ), and the representation of deep convection in the Sahel and its effects on the WAM ( Garcia-Carreras et al. 2013 ; Marsham et al. 2013 ; Birch et al. 2014 ). Particularly, biases in sea surface temperatures (SSTs) have a large effect on precipitation and the WAM circulation ( Biasutti et al. 2008 ; Hourdin et al. 2010 ; Roehrig et al. 2013

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Elinor R. Martin and Chris Thorncroft

, there is a strong need to investigate the simulation of AEW structures and characteristics in global and regional (e.g., Crétat et al. 2015 ) climate models to further understand the role biases in AEW properties and characteristics may play in influencing future projections of TC activity and rainfall in the Sahel. Acknowledgments The authors thank three anonymous reviewers for thoughtful comments and suggestions that greatly strengthened the manuscript. The research was supported by NOAA Grant NA

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Mimi Stith, Alessandra Giannini, John del Corral, Susana Adamo, and Alex de Sherbinin

formation of many regional and global institutions, most notably the Comité permanent Inter-États de Lutte contre la Sécheresse au Sahel (CILSS; Permanent Interstate Committee to Combat Drought in the Sahel); the Club du Sahel of the Organization for Economic Co-Operation and Development (OECD, later renamed the Sahel and West Africa Club); the United Nations (UN) International Fund for Agricultural Development (IFAD); and the UN Convention to Combat Desertification (UN CCD), one of three environmental

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Rahul S. Todmal

assessed, criticized, and modified for several reasons during the last 50 years. The standardized precipitation index (SPI), introduced by McKee et al. (1993) , overcomes the limitations of the PDSI, as it is simple to calculate and requires minimum data. As the SPI has the advantage of applicability for all types of climatic regions, thereby allowing spatial comparison of drought, it has been extensively used to assess regional droughts in all parts of the world, particularly during the last two

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