Windy Weather II: The Correlation Between Barometric Pressure and Wind Velocity

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Author: Leigh, Grade 7


The purpose of this science project was to find the correlation between barometric pressure and wind velocity. I did this by recording the wind velocity in rotations per minute by using an anemometer. I used barometer readings, which I got off an Internet site. The readings measured air pressure in inches. I did this procedure daily starting on October 27, 2003 and ending December 1, 2003. I took the readings at 6:30 am, 11:30 am, 6:00 pm, and 9:30 pm. I converted the wind velocity from rotations per minute to miles per hour using an algebraic formula. I graphed my data on a scatter plot to find the correlation between barometric pressure and wind velocity. I used a scatter plot because it shows the correlation between two variables.

I found out that I had a negative correlation between barometric pressure and wind velocity. I knew this because the x-axis (barometric pressure) increased as the y-axis (wind velocity) decreased. I calculated the correlation and found that it was -0.45, not a perfect negative correlation of -1. This showed that there was a relationship between barometric pressure and wind velocity. The data proved that my hypothesis was correct. I hypothesized that as the barometric pressure increased the wind velocity would decrease which my plot showed.

My background information also stated that when air currents are rising in a low-pressure zone, the upper atmosphere rotates faster than the lower atmosphere’s high pressure sinking currents. This causes wind to move faster in low pressure than in high pressure because of the faster rotation of air in a low pressure system.


What is the correlation between barometric pressure and wind velocity? I wanted to research this as a continuation of my last year’s science project. Last year I tested how much wind speeds varied from October to December. This year I hope to find out how barometric pressure affects wind velocity based on comparing the readings of each variable on a scatter plot.

Background Reading Summary

Wind is the movement of air. It is caused when warm and cold air mix or upper and lower air mix causing the air to rotate.

Air moves in a horizontal fashion but also rotates due to pressure currents. In low pressure air rises and rotates fast in the high atmosphere forming fast winds. In high pressure the air sinks instead of rising forming slow moving air currents or slow wind. A low pressure system brings rain, snow, and high winds, while a high pressure system brings cold air. Warm highs bring warm maritime air. Winds travel in curved patterns because of the Coriolis affect or the Earth’s rotation. Wind is also controlled by pressure gradients or pressure differences developed between two air masses. Pressure gradients are caused by the varied heating of the Earth and the Coriolis Effect. This controls the wind speed of a wind that moves from a high to a low because of diffusion. Diffusion is the need to equalize the air pressure. For example, when you pour water in a cup there isn’t more water on one side of the cup than the other it levels out to fill the cup. This happens between high and low pressure systems, the result is wind. The air passes to the systems making an equal amount of air in each system. In a low the faster the air in the center rises the faster it rotates so the faster the wind speed is.

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