A Newly Found Jet in North Kenya (Turkana Channel)

Kinuthia, J. H.; Asnani, G. C.

doi:10.1175/1520-0493(1982)110<1722:anfjin>2.0.co;2

Cited by 53 publications

(47 citation statements)

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“…It persists throughout the year, and is formed by orographic channeling of the flow (Kinuthia and Asnani 1982;Kinuthia 1992). A negative correlation between the strength of the Turkana jet and the Somali jet is found in regional model simulations (Vizy and Cook 2003), although the authors note that the Turkana jet should be investigated further with higher resolution simulations.…”

Section: Climate Variability: East Africamentioning

confidence: 98%

Sub-Saharan Northern African climate at the end of the twenty-first century: forcing factors and climate change processes

Patricola

Cook

2010

Clim Dyn

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A regional climate model, the Weather Research and Forecasting (WRF) Model, is forced with increased atmospheric CO 2 and anomalous SSTs and lateral boundary conditions derived from nine coupled atmosphere-ocean general circulation models to produce an ensemble set of nine future climate simulations for northern Africa at the end of the twenty-first century. A well validated control simulation, agreement among ensemble members, and a physical understanding of the future climate change enhance confidence in the predictions. The regional model ensembles produce consistent precipitation projections over much of northern tropical Africa. A moisture budget analysis is used to identify the circulation changes that support future precipitation anomalies. The projected midsummer drought over the Guinean Coast region is related partly to weakened monsoon flow. Since the rainfall maximum demonstrates a southward bias in the control simulation in July-August, this may be indicative of future summer drying over the Sahel. Wetter conditions in late summer over the Sahel are associated with enhanced moisture transport by the West African westerly jet, a strengthening of the jet itself, and moisture transport from the Mediterranean. Severe drought in East Africa during August and September is accompanied by a weakened Indian monsoon and Somali jet. Simulations with projected and idealized SST forcing suggest that overall SST warming in part supports this regional model ensemble agreement, although changes in SST gradients are important over West Africa in spring and fall. Simulations which isolate the role of individual climate forcings suggest that the spatial distribution of the rainfall predictions is controlled by the anomalous SST and lateral boundary conditions, while CO 2 forcing within the regional model domain plays an important secondary role and generally produces wetter conditions.

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Section: Climate Variability: East Africamentioning

confidence: 98%

Sub-Saharan Northern African climate at the end of the twenty-first century: forcing factors and climate change processes

Patricola

Cook

2010

Clim Dyn

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“…Figure 1, the Turkana channel is -700 km long, and it is oriented from southeast to northwest. Kinuthia and Asnani [1982] The CB region usually experiences its yearly peak rainfall in October and November when the soil moisture is expected to increase as well. The model simulated a soil moisture gain in October and November.…”

Section: Precipitationmentioning

confidence: 99%

Application of the NCAR regional climate model to eastern Africa: 1. Simulation of the short rains of 1988

Sun¹,

Semazzi²,

Giorgi³

et al. 1999

J. Geophys. Res.

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Abstract. The National Center for Atmospheric Research (NCAR) Regional Climate Model (RegCM2) is employed to investigate the physical mechanisms that govern the October-December rains over eastern Africa. The model employs the Mercator conformal projection, with a domain of 5580 km x 5040 km centered at 31øE, 4øS, and a horizontal grid point spacing of 60 km. The simulation period is October-December 1988, and the model initial and lateral boundary conditions are taken from ECMWF reanalysis. A number of month-long simulations have been conducted to optimize various parameterizations of the model which include the following factors: cumulus convection, moisture parameterization, radiative transfer formulation, surface processes, boundary layer physics, and the lateral boundary conditions. The model was successfully customized over eastern Africa. The model simulates the large-scale circulation characteristics over the region as well as local features such as the dominant precipitation maxima, the Turkana low-level jet, and the diurnal reversal in the lake/land breeze circulation over Lake Victoria. Several model deficiencies are also identified. They include a negative rainfall bias over the western portions of the domain and the Kenya Highlands and a temperature bias over the tropical forest regions. Systematic analysis of surface water budget reveals that evapotranspiration is a major sink in the water budget over the regions where precipitation is moderate or small, while the role of runoff and drainage becomes important over the regions where precipitation is abundant. The model simulations also suggest that during the short-rains season, the large-scale circulation anomalies play the most important role in shaping the precipitation anomalies. IntroductionOver eastern Africa the large-scale tropical climate regimes, which include several major convergence zones, are superimposed upon regional factors asso'ciated with complex terrain, extreme contrasts in vegetation type, the existence of large inland lakes, and the proximity of the Indian Ocean. As a result, the climate patterns over eastern Africa are extraordinarily complex and require relatively high resolution to be adequately resolved.Recently, a collaborative effort among the North Carolina State University, the National Center for Atmospheric Research (NCAR), the University of Nairobi, and the Drought Monitor Center (DMC) in Kenya has been initiated aimed at the development of a Seasonal Climate Prediction System (SCPS) for eastern Africa. The SCPS is based on the use of the NCAR Regional Climate Model (RegCM) driven by initial and lateral boundary conditions obtained from general circulation model (GCM) simulations. The nesting technique has been extensively used for long-term regional simulations and has been shown to capture regional patterns of precipitation, Model DescriptionThe model used in this study is the NCAR secondgeneration regional climate model (hereinafter referred to as NCAR RegCM2), which is described in detail by Giorgi ½t al. Des...

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“…Kulal (2300 m ASL) and the Mt Nyiru Range (2750 m ASL). Both Kinuthia and Asnani [21,22] observed that, throughout the year, the NE and SE monsoon near the equator branches off from the Indian Ocean, enters the Turkana channel and intensifies (Fig. 1).…”

Section: Area Of Studymentioning

confidence: 56%

“…The jet stream is created by the much bigger East African low-level jet. The Turkana Channel jet blows lasting through the year from the South East through the valley between the East African and the Ethiopian Highlands extending from the Ocean to the deserts in Sudan [21]. The wind is enhanced locally between Mt.…”

Section: Area Of Studymentioning

confidence: 99%

WAsP model performance verification using lidar data

Indasi

Lynch

McGann

et al. 2015

Int J Energy Environ Eng

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This study describes the verification of Wind Atlas Analysis and Application program (WAsP) modelled average wind speeds in a complex terrain. WAsP model was run using data collected at 3 masts: Kalkumpei, Nyiru and Sirima using cup anemometers and wind vanes for the entire 2009 calendar year and verified using data collected by WindTracer LIDAR (light detection and ranging) for 2 weeks from 11th to 24th July 2009. Evaluating WAsP mean wind speed map using LIDAR data showed that Nyiru station provides the best data to model mean wind speed over the wind farm domain with a mean difference of 0.16 m/s, root mean square error of 0.85 m/s and Index of Agreement of 0.61. Construction of a 310 MW windfarm has commenced at this site. Once completed, the windfarm will be operating 365 vestas V52-850kW turbines.

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A Newly Found Jet in North Kenya (Turkana Channel)

Cited by 53 publications

References 0 publications

Sub-Saharan Northern African climate at the end of the twenty-first century: forcing factors and climate change processes

Sub-Saharan Northern African climate at the end of the twenty-first century: forcing factors and climate change processes

Application of the NCAR regional climate model to eastern Africa: 1. Simulation of the short rains of 1988

WAsP model performance verification using lidar data

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