Asian monsoon's range of devastation

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The Asian monsoon has brought unusually high levels of rain to the region, with catastrophic consequences in countries from Pakistan and India to North Korea and China.

Nasa has used satellite images from 1 to 9 August to show the intensity of rainfall compared to average rates for the same period in previous years.

The darker blue shows where rain was much more intense than usual; brown indicates less intense rainfall. Some regions have had as much as 24 millimetres of rain per day above normal.

In Khanpur, in Pakistan's Sindh district, for example, the average rainfall is 17.4mm for the whole month of August. So far, 255mm has fallen in 12 days.

The annual monsoon season, typically from June to September, is caused by the difference in temperature between the land and the sea.

As the Tibetan plateau warms up, heated air rises, drawing in moist air from the sea to replace it. This also warms, rises and the water condenses into rain.

The BBC Weather Centre says a kink in the jet stream of fast-moving air in the upper atmosphere has exacerbated conditions this year. More spiralling air in the upper atmosphere sucks in more moist air, causing larger clouds and more intense rainfall.

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