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Kerry H. Cook and Edward K. Vizy

the observed Indian Ocean warming trend is enhanced subsidence near southern Somalia, eastern Ethiopia, and northern Kenya as well as regional suppression of convection over central Ethiopia and eastern Sudan. Lyon and DeWitt (2012) relate the observed decline in East African long rains to large-scale SSTA forcing from the tropical Pacific that recurs during boreal spring. Cook and Vizy (2012) simulate severe reductions in growing-season days in East Africa during growing seasons of both the

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Elinor R. Martin and Chris Thorncroft

selected models are identified in Table 1 . 3. Simulation of AEWs and rainfall Biases between the AMIP multimodel mean, multireanalysis JJAS EKE, and multiobservation JJAS rainfall are shown in Figs. 2a–c . The models produce too much EKE at both levels in the central and southern portion of West Africa (south of 20°N) and too little EKE to the north, with the largest biases over land at low levels and over the ocean at midlevels. A secondary region of underestimation by the AMIP models at midlevels

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Wassila M. Thiaw and Vadlamani B. Kumar

in agricultural production and river flow. The National Oceanic and Atmospheric Administration (NOAA)’s Climate Prediction Center (CPC) began to provide USAID FEWS with real-time gauge-based 10-day weather summaries to enable operational monitoring of crop conditions. However, given the difficulty to access rain gauge measurements from Africa, CPC also began to provide USAID FEWS with access to real-time satellite rainfall estimates to improve the weather summaries and to enable effective

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Abdou L. Dieng, Saidou M. Sall, Laurence Eymard, Marion Leduc-Leballeur, and Alban Lazar

and Reiner 2003 ; Kiladis et al. 2006 ). They have a 3–5-day period and a mean wavelength of 2500 km and develop along two axes north and south of the AEJ. The north wave primarily grows in association with dry baroclinic energy conversions at the southern margin of the Sahara, while southern-track AEWs mainly result from barotropic instability and interaction with deep convection ( Burpee 1972 ; Thorncroft and Hoskins 1994 ; Thorncroft and Blackburn 1999 ; Pytharoulis and Thorncroft 1999

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M. Issa Lélé, Lance M. Leslie, and Peter J. Lamb

South Atlantic Ocean. f. Ocean-to-land moisture transport variations during dry and wet years The breakdown of the ocean–land moisture transport into its zonal and meridional components was evaluated for four very WET years (1988, 1994, 1998, and 1999) and four very DRY years (1982, 1983, 1984, and 1987) across WAM boundaries. The selection of these years is based exclusively on the Lamb index, where they appear as pronounced wet and dry years. While the meridional flux is evaluated along southern

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

agreement and a clear local minimum in radiation over the stratus belt (identical averages over the study region of 294 W m −2 ; Figs. 8a,b ), however with some underestimation of radiation over the tropical Atlantic Ocean in MRI-AGCM3. In the afternoon, ERA-I maintains a west–east-oriented minimum across SWA with the area average decreasing to 276 W m −2 , particularly due to decreased solar radiation over southern Nigeria and Benin ( Fig. 8c ). This behavior disagrees with the tendency for afternoon

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

correlation patterns continue in the zonal wind at pressure levels greater than 250 hPa. The positive correlation indicates a likelihood of enhanced Kiremt rainfall with increased Tu100 over southern Europe. Another potential predictor involving the mass field was found over the western equatorial Indian Ocean in association with the meridional flux of geopotential height at 500 hPa (ϕv500) during March ( Fig. 2 , middle). The main correlation signal was linked to the meridional wind (v500), but including

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

grassland in bright green, between the 200- and 500-mm isohyets. In the West African area of interest, it covers northern Senegal and southern Mauritania, central Mali, northern Burkina Faso, and the southern tier of Niger. However, in this paper we are interested in environmental change in the broader region of gradation from shrubland/grassland in the north, through cropland, to savanna in the south, encompassing the latitudinal range between 12° and 18°N, between the 200- and 800-mm isohyets. Annual

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Rahul S. Todmal

). Additionally, the difference between class-wise NDVI values in wet and drought years was verified with the use of the Student’s t test. To understand the connection between observed droughts over the present study area (basins) with the Southern Oscillation index (SOI), monthly SOI data were collected from the National Oceanic and Atmospheric Administration (NOAA) website ( www.noaa.gov ). As it is based on the methodology given by Ropelewski and Jones (1987) , the lower index values (negative values

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Irenea L. Corporal-Lodangco, Lance M. Leslie, and Peter J. Lamb

. El Niño–Southern Oscillation (ENSO) is a tropical atmosphere–ocean interaction that modifies the thermodynamic and dynamic states that influence the weather and climate system ( Bjerknes 1969 ). Kim et al. (2008) consider it to be the most important planetary-scale phenomenon affecting interannual variations in TC activity in the WNP. The relationship between ENSO and TC activity in the WNP has been explored extensively in previous studies (e.g., Chan 1985 , 2000 ; Dong 1988 ; Lander 1993

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