The representation of dry-season low-level clouds over Western Equatorial Africa in reanalyses and historical CMIP6 simulations

Camberlin, Pierre; Togbedji, Christian F; Pergaud, Julien; Berger, Aaron M.; Aellig, R.; Fink, Andreas H.; Knippertz, Peter; Moron, Vincent; Philippon, Nathalie

doi:10.1007/s00382-023-06714-w

Cited by 2 publications

(3 citation statements)

References 80 publications

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“…Finally, Figure 15 offers a view on the relationships between six atmospheric indices associated with interannual variations of the stratiform cloud cover over WEA (Figures 13 and 14) and SAT-N34 SST indices, matching some of the analyses for CMIP6 simulations by Camberlin et al (2023). Note that the correlation values shown in Figure 15 are not very sensitive to the choice of the spatial windows.…”

Section: Atmospheric and Oceanic Controls On The Low-level Cloud Cove...mentioning

confidence: 66%

“…Both mechanisms are strongly related to SST variations over the coastal and equatorial Atlantic, which were shown to be negatively correlated to stratiform cloud cover over WEA. Note that this relationship is not adequately reproduced by many coupled climate models from CMIP6 (Camberlin et al, 2023).…”

Section: Discussionmentioning

confidence: 96%

“…In this subsection, we analyse the space–time interannual variations of low‐level cloud cover during the core of the cloudy season of JJAS (Figures 3 and 7), as in Champagne et al (2023) and Camberlin et al (2023). Classical EOF analysis is applied to the frequencies of the three DTs.…”

Section: Space–time Variations Of the Stratiform Cloud Deckmentioning

confidence: 99%

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Diurnal to interannual variability of low‐level cloud cover over western equatorial Africa in May–October

Moron

Camberlin

Aellig

et al. 2023

Intl Journal of Climatology

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This study examines the diurnal to interannual variations of the stratiform cloud cover in May–October (1971–2019) from a 3‐hourly station database and from ERA5 reanalyses over western equatorial Africa (WEA). The main diurnal variations of the local‐scale fraction and genus of stratiform clouds are synthesized into three canonical diurnal types (i.e., “clear,” “clear afternoon,” “cloudy” days). The interannual variations of frequencies of the three diurnal types during the cloudiest months (JJAS) are mostly associated with two main mechanisms: a meridional shallow overturning cell associating more “cloudy” and less “clear” and “clear afternoon” days to anomalous southerlies below 900 hPa over and around WEA, anomalous ascent around 5°–7°N, anomalous northerlies between 875 and 700 hPa, and anomalous subsidence over the equatorial Atlantic. This circulation is strongly related to interannual variations of the equatorial Atlantic upwelling (i.e., more clouds when the upwelling is strong) associated with a meridional shift of the Intertropical Convergence Zone over the Tropical Atlantic and adjacent continents. The second mechanism operates mostly in the zonal direction and involves again the coupled ocean–atmosphere system over the equatorial Atlantic, but also the remote El Niño–Southern Oscillation (ENSO). An anomalously cold equatorial Atlantic drives increased low‐level westerlies toward the Congo Basin. Warm ENSO events promote broad warm and easterly anomalies in the middle and upper troposphere, which increase the local static stability, and thus the local stratiform cloud cover over WEA. The present study suggests new mechanisms responsible for interannual variations of stratiform clouds in WEA, thus providing avenues of future research regarding the stability of the stratiform cloud deck under the ongoing differential warming of tropical ocean and land masses.

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Section: Atmospheric and Oceanic Controls On The Low-level Cloud Cove...mentioning

confidence: 66%

Section: Discussionmentioning

confidence: 96%

See 1 more Smart Citation

Diurnal to interannual variability of low‐level cloud cover over western equatorial Africa in May–October

Moron

Camberlin

Aellig

et al. 2023

Intl Journal of Climatology

Self Cite

View full text Add to dashboard Cite

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The seasonal cycle of cloud radiative effects over Congo Basin based on CERES observation and comparison to CMIP6 models

Dommo

Klutse

Fiedler

et al. 2023

Atmospheric Research

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The representation of dry-season low-level clouds over Western Equatorial Africa in reanalyses and historical CMIP6 simulations

Cited by 2 publications

References 80 publications

Diurnal to interannual variability of low‐level cloud cover over western equatorial Africa in May–October

Diurnal to interannual variability of low‐level cloud cover over western equatorial Africa in May–October

The seasonal cycle of cloud radiative effects over Congo Basin based on CERES observation and comparison to CMIP6 models

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