Seasonal variations in the diurnal patterns of convection in Cameroon–Nigeria and their neighboring areas

Vondou, Derbetini A.; Nzeukou, Armand; Lenouo, André; Kamga, F. Mkankam

doi:10.1002/asl.297

Cited by 33 publications

(11 citation statements)

References 32 publications

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“…McCollum et al, 2003;Dinku et al, 2007;Ruiz et al, 2010). While the 1DD GPCP rainfall data is available over a rather short period, this product seems to be essential over Central Africa where topography and surface conditions force high rain spatial variability (Thomas et al, 2009;Vondou et al, 2010;Tchakoutio et al, 2012) and where OLR values may not be always highly correlated with rainfall quantities.…”

Section: Gpcp Precipitation Datamentioning

confidence: 97%

Synoptic Kelvin type perturbation waves over Congo basin over the period 1979–2010

Zebaze

Lenouo

Tchawoua

et al. 2015

Journal of Atmospheric and Solar-Terrestrial Physics

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Section: Gpcp Precipitation Datamentioning

confidence: 97%

Synoptic Kelvin type perturbation waves over Congo basin over the period 1979–2010

Zebaze

Lenouo

Tchawoua

et al. 2015

Journal of Atmospheric and Solar-Terrestrial Physics

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“…This product has been validated regionally and globally by McCollum et al (2003); Dinku et al (2007) and Ruiz et al (2010). While the 1DD GPCP rainfall data is available over a rather short period, this product seems to be essential over Africa where topography and surface conditions force high rain spatial variability (Thomas et al, 2009;Vondou et al, 2010;Tchakoutio et al, 2012) and where OLR values may not be always highly correlated with rainfall quantities.…”

Section: Datamentioning

confidence: 99%

Interannual Variability of Rainfall over the West Africa Sahel

Dia-Diop¹,

Zebaze²,

Wade³

et al. 2020

GEP

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Interannual variability of the precipitation over West Africa Sahel is analyzed based on 32 years (1979-2010) from monthly and daily database of the Global Precipitation Climatology Project (GPCP). In this region, we found that there is a link between the West Africa Monsoon (WAM) and the daily means of the precipitation in the summer, unseasonal rains can occur in the transition seasons and even in the heart of the dry season. Rainfall is the most important element for agro-pastoral activities in this region. The 850-hPa wind and wind divergence structure show a maximum convection over Mountain region (Fouta-Djalon and Mont-Cameroon) which corresponds to the high precipitation and OLR observed in these regions. The trend and empirical orthogonal function (EOF) of the precipitation are presented, including the mid-July variability of the precipitation. The dominant EOF of GPCP precipitation accounts for around 25.3% of the variance with slightly large amplitude in the north while relatively small in the equatorial band respectively. The second and third EOF which accounts for 20.5% and 14%, describes a longitudinal contrast with a zonal gradient.

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“…Discussing the effect of coastline curvature on diurnally modulated frequency of convection over the Bay of Biafra, Vondou et al [32] have noted enhancements in coastal concavities in satellite datasets, with geometric land-breeze convergence speculated to be the cause. Further north, this gradient of convective activity is decreasing northward due to the reduction of moisture.…”

Section: South Ofmentioning

confidence: 99%

Spatio-Temporal Variability of Western Central African Convection from Infrared Observations

Vondou

2012

Atmosphere

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The present study has used Meteosat infrared brightness temperature images to investigate the regional and interannual variability of Central African cloudiness. Spatial and temporal variability were investigated using half-hourly data from the Meteosat-7 during June-July-August (JJA) of 1998-2002. The full domain of study (1.5• E-17was divided into six regions and statistics in each region were derived. Analysis of the dependence of cloud fraction to the brightness temperature threshold is explored both over land and ocean. Three diurnal cycle regimes (continental, oceanic, and coastal) are depicted according to the amplitude and peak time. Over regions of relatively flat terrain, results indicate enhancement of deep convection in the afternoon followed by a gradual decrease in the night. The diurnal cycle of convection is characterised by afternoon and early evening (around 15:00-18:00 LST) maxima located mainly downwind of the major mountain chains, and a more rapid nighttime decay. In terms of the harmonic amplitude, the diurnal signal shows significant regional contrast with the strongest manifestation over the Adamaoua Plateau and the weakest near the South Cameroon Plateau. This remarkable spatial dependence is clear evidence of orographic and heterogeneous land-surface impacts on convective development. Oceanic region exhibits weak activity of convective cloudiness with a maximum at noon. It is suggested that daytime heating of the land surface and moist environment may play a role in determining the spatial distribution of cloud fraction. This study further demonstrates the importance of the Cameroon coastline concavity and coastal mountains in regulating regional frequencies of convection and their initialization. The strength of the diurnal cycle of convective activity depends on mountain height, mean flow, coastal geometry.

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Seasonal variations in the diurnal patterns of convection in Cameroon–Nigeria and their neighboring areas

Cited by 33 publications

References 32 publications

Synoptic Kelvin type perturbation waves over Congo basin over the period 1979–2010

Synoptic Kelvin type perturbation waves over Congo basin over the period 1979–2010

Interannual Variability of Rainfall over the West Africa Sahel

Spatio-Temporal Variability of Western Central African Convection from Infrared Observations

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