| Summary: | <p>Quantifying the variability of convective cloud is of fundamental importance in order to understand and accurately model global weather and climate systems. While broad features of the diurnal and lifecycles of convective cloud are understood, the spatial and temporal variability of convective properties are not well characterised on the global scale, particularly over large areas of Africa. Due to the complexity of the processes involved, models also struggle to realistically simulate the spatial and temporal variability of convective cloud.</p> <p>Observations provide insight into the properties of convective cloud and valuable information about avenues for model development. Due to the wide range of spatial and temporal scales involved in convection, the continuous nature of observations from geostationary satellites makes them ideal for investigating convection. This study uses high temporal resolution data from the geostationary Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument to quantify seasonal and diurnal cycles of cloud top temperature (CTT) and the lifecycle of individually tracked convective clouds over a large area and period of time.</p> <p>This study demonstrates that biases in SEVIRI CTT retrievals vary from less than 5 K over the southeast Atlantic Ocean, up to 30 K over central Africa at night, while biases can also differ by up to 30 K between night and daytime retrievals. This highlights the importance of considering spatial and diurnal variations in retrieval errors. Keeping these biases in mind, it is shown that the diurnal cycle of cloud tops is measured accurately in regions of stratiform cloud, while quantifying the diurnal cycle over the tropics and regions of desert is more difficult.</p> <p>SEVIRI observations are used to track individual convective cloud cores and anvils across sub-Saharan Africa. The distributions, diurnal cycles, lifecycles and spatial and seasonal cycles of a number of properties are quantified. Horizontal core and anvil areas are shown to increase with longer cloud lifetimes, while minimum core CTTs are shown to decrease with cloud lifetime. The diurnal cycle in convective activity is shown to have both a morning and an evening peak, while the total anvil coverage peaks in the late afternoon. Seasonal and spatial variations in core and anvil area, CTT, time of convective initiation and dissipation are also quantified.</p> <p>These results will be of interest to those in the observation and modelling communities, particularly for studies considering the diurnal cycle of convection, or developing new convective cloud process models and parameterisations.</p>
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