Fig. 7

Diurnal pattern of rainfall frequency for each region N, S, M, and C as the date–hour cross-section in 2011. The percentage of the number of “rainy” stations against the total number of stations in each region is shown with a blue shade. At region C, there is only one gauge, and thus the percentage is either 0 or 100. The horizontal red lines indicate 1 March, the onset and withdrawal dates of the summer monsoon season, and 30 November. The vertical yellow shades indicate hours with peak rainfall frequency in each season in each region, whereas the horizontal orange broken lines indicate days with prominent rainfall with no diurnal cycle or in different hours. The geopotential height (Φ) at 850 hPa and zonal winds (u) at 700 hPa (gray line) and 850 hPa (black line) as the areal averages over Cambodia (102–108°E and 10–15°N) at 7:00 LT (0:00 UTC) from JRA-55 are also shown for each day in the left panels