Atmospheric Pressure & Wind lecture for additional information and watch the video below for a visual illustration. Explain what primary force influences low and high pressure upon the surface of the earth. Then explain which imagery tool can be used to display differences in pressure on maps. Also, explain which measurement type is used to measure air pressure typically in the United States. Lastly, explain why it is common for air pressure to decrease in higher altitudes and increase in lower altitudes. Write your response in two-three full paragraph below