Diurnal variations due to atmosphere-ocean-land interactions and their climatological significance

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Observations over the Indonesian "maritime continent" have shown striking diurnal variations with horizontal scales of about a thousand kilometers, which are different from known sea-land breeze and local circulations and from global atmospheric tides. Similar phenomena are also seen in Tibet-Himalaya and North-American continent. Furthermore, in other planets (Venus and Mars) there are several types of diurnal variations.Those diurnal variations have been investigated on the basis of atmospheric dynamics and cloud physics. Their effects on intraseasonal, seasonal (annual) and interannual variations have been studied. Since the diurnal periodicity is originated from solar radiation dependent on the planetary rotation and revolution, the significance of such astronomical conditions in determination of the planetary climate has been also studied.Over the maritime continent, the diurnal variations in rainy season are dominant rather than those in clear days or in dry season expected in classical sea-land breeze theories. The diurnal variations in rainy seasons are enhanced by themselves ; active convective clouds and rainfall in the afternoon and nighttime "reset" the atmospheric instability and turbidity before sunrise, and the maximum solar radiation (close to the solar constant) heats the land surface before the noontime which generates convective clouds again in the afternoon.Migrations of clouds with diurnal cycles, response of large-scale atmosphere for diurnal variations, geographical variations among the maritime continent and neighborhood (Indian and Pacific) oceans have been studied. The planetary climate with various astronomical conditions and cloud condensation constituents has been also studied.