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River Science: Barometric Pressure

Barometric pressure is also known as air pressure or atmospheric pressure. Simply put, it represents the weight of the air above us. Just as water pressure increases as you dive deeper beneath the surface, barometric pressure drops as you rise in altitude (and thus have less air above you). Of more immediate importance, barometric pressure is a valuable indicator of weather conditions; rapidly dropping barometric pressure typically means that stormy weather is on its way.

Captain Hudson would have loved to possess a barometer in 1609; although the connection between air pressure and the weather was intuitively understood in his day, the first instrument to measure it would not be invented until 1643.

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