variation of upper tropospheric humidity and its relations to convective activities over tropical Africa. Abstract Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion EGU Abstract Diurnal variations of upper tropospheric humidity (UTH) as well as middle tropospheric humidity (MTH) were examined in conjunction with the diurnal cycle of convection over tropical Africa and the adjacent tropical Atlantic Ocean using

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... Meteosat-8 measurements. Cloud and humidity features were also tracked to document the diurnal varia-5 tions of humidity and clouds in the Lagrangian framework. A distinct diurnal variation of UTH (and MTH) is noted over regions where tropical deep convective cloud systems are commonly observed. The amplitude of the UTH diurnal variation is larger over land, while its variations over convectively inactive subtropical regions are much smaller. The diurnal variation of UTH tends to peak during 10 nighttime over land, lagging deep convection and high cloud whose maxima occurred in the late afternoon and the evening, respectively. The time lag between the maximum UTH and deep convection/high cloud maxima over the ocean appears to be longer in comparison to that found over land. It was also indicated that both the UTH (and MTH) and the cirrus anvil cloud show a variation which is in phase, implying that moistening 15 of the upper troposphere is closely linked to process of development and dissipation of deep convective clouds.