# Spatio-Temporal Distribution of Deep Convection Observed along the Trans-Mexican Volcanic Belt
## 5 Conclusions  
The Trans-Mexican Volcanic Belt is a complex orography zone in central Mexico in which a large number of manifestations of severe weather has been documented. This area concentrates a large population exposed to severe weather events such as tornadoes and heavy precipitation with accompanying flash floods, making the improved forecasting, detection and monitoring of deep convective cloud systems and associated severe weather of great importance. Due to the lack of a dense ground-based observational network for the extensive detection and monitoring of severe weather phenomena in the country, satellite observations of cloud and precipitation events provide a suitable and affordable alternative to characterize and improve our understanding of deep convective events in Mexico. This work contributes to an improved understanding of the occurrence and natural variability of deep convective events in the TMVB region by performing a first estimation and assessment of satellite-observed spatio-temporal distribution of deep convective clouds using well-established MODIS cloud products. The study area exhibits large variations in elevations, including mountainous areas with heights of up to 5000 m along the TMVB. It serves as a transition zone between a drier (north) and more humid (south) climate, leading to a large variety of land surface characteristics [33], and is known to be subject to the differential influence of the Gulf of Mexico (east) and the Pacific Ocean (west) [58; 66] with corresponding moisture fluxes and large-scale dynamics [67]. The substantial climatic and environmental regional differences within the study area allow, by studying geographical variations, first indications of the impact of local conditions, such as terrain features, to be considered, as well as the impacts of large-scale conditions on the observed distinct spatio-temporal variabilities of DCCs. Monthly climatology data for 10 years (2008 to 2017) of the cloud fraction and the frequency of deep convective clouds along the TMVB in Mexico on a 0.1 degree resolution have been produced using a combination of MODIS Coll. 6 cloud products. The analysis of 10 years of satellite observations shows the clear establishment of wet and dry phases characterized by cloud abundance, and more specifically, deep convective cloud frequency, preceded by transition phases. The first peak observed in the deep convective cloud frequency in July can be related to the change in the wind patterns that increase the moisture advection from both the Pacific Ocean and the Gulf of Mexico [66; 68]. The second observed DCC frequency peak in September is related to the frequent passage of easterly waves and tropical cyclones during that time of year [60]. The spatial variability within the study area is greatest for the summertime period, though large, persistent cloud fields can be found in the eastern part throughout the entire year. The spatio-temporal patterns of deep convective cloud frequency have been related to extreme weather events; i.e., extreme rain episodes obtained from precipitation data from the CHIRPS in-situ and satellite-based dataset. A very similar pattern of the spatio-temporal distribution of extreme precipitation days and deep convective clouds was found. For both, the highest frequencies align just over the higher elevations of the TMVB, indicating the important role of orography in the development of convective systems. Calculations of the 90 th percentile of precipitation show extremely high variations in a relatively small geographical area. Again, higher values are related to the higher regions with a complex orography. For domain-averaged seasonal patterns, a strong correlation was found between observed DCC frequency and precipitation (with a correlation coefficient of 0.84). The frequencies of the DCCs and precipitation events show a clear decrease in August, which corresponds well with the description of the midsummer drought phenomena in Mexico--the so-called \"canicula\"--provided by others [49; 63].