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mixing ratio

The mixing ratio is a measure of humidity in terms of the mass of water vapor for a given mass of dry air. Its units are typically grams of water vapor per kilogram of dry air. Notice the difference between mixing ratio and specific humidity: the latter includes the water vapor in the air in the denominator, while mixing ratio measures water vapor per mass of dry air. Since water vapor comprises only a few percent of the mass of air, the values for specific humidity and mixing ratio are very close for a given parcel of air. Mixing ratio is not affected by changes in pressure and temperature and is a measure commonly used by meteorologists.

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