22 The Monsoon Rains Commence In April And Continue Until October. During

22 The monsoon rains commence in April and continue until October. During this period up to 200cm of precipitation can fall and the Brahmaputra is 'swollen by June or July.'23 Such a high influx of water explains why discharge increases rapidly. Non-equatorial tropical river systems experience higher rates of precipitation during the summer months and a considerable reduction in winter.24 Indeed, only 9.54% of total annual discharge flows through the Brahmaputra from December to March.
The flow regime of the Congo River is unique amongst the six river regimes as it is of a bi-modal nature, ebbing and flowing twice annually. Precipitation levels are bi-modal25 and peak at the time of the equinoxes in March and April.26 This is due to the tropical equatorial location of the river, and discharge rate exhibits a marked increase after these months. Indeed, rainfall is continuous throughout the year and the annual level in Kasangani, Democratic Republic of Congo, is approximately 170cm. This factor highlights why the monthly discharge rate never drops below 4.7% of the total annual volume. Temperature remains practically constant at 25(C along the route of the Congo throughout the year due to the absence of seasonality in this biome.27
Conclusion
The discharge levels of the Suir, Thames and Vinalopo rivers all correspond with increased levels of precipitation in the winter and reduced precipitation in the summer. The range of discharge in the Thames and Suir is much less than that of the Vinalopo. This is due to the fact that they are situated in a temperate climate and do not experience the extremes of high temperature, altitude and rainfall which exist in the Mediterranean environment. Increased autumn and winter precipitation rates on the Alicante mountains, and the dry hot summers, are responsible for a flow discharge rate which ranges from 410m( /sec in January to only 25m( /sec in August.
Mountain ranges also influence the discharge rates of the Brahmaputra and Yennisey Rivers profoundly. Snow melt and glacial ablation at high altitudes cause a surge in discharge during the spring months in both rivers. However, discharge reduces to 6,000 m( /sec on the Yennisey by November and this is due to the onset of the severely cold continental winter. Precipitation in the Siberian mountains is now frozen, and overland and through flow to the river channel is severely reduced. The monsoon climate of south east Asia ensures that the discharge of the Brahmaputra remains high for a longer period of time. In November average discharge is still 11,735 m( /sec; almost double that of the Yennisey. Thus, total annual flow is dissipated over a longer time period than the more extreme 'freeze/thaw' trend of the Yennisey regime.
The Congo has a very different annual discharge trend to the other rivers due to its situation in equatorial Africa.