14.7 pounds per square inch
At sea level, the average air pressure is about 1 bar. As you increase in altitude, the air pressure decreases. On average, the air pressure decreases by about 12% for every 1000 meters of elevation gain. Therefore, at an altitude of 1200 meters, the air pressure would be approximately 0.88 bar.
The average air pressure at sea level is about 14.7 pounds per square inch (psi), or 101.3 kilopascals. This pressure is caused by the weight of the air in the Earth's atmosphere above us. It decreases as altitude increases.
Normal air pressure is greatest at sea level, where it is typically around 1013 millibars or 29.92 inches of mercury. As you go higher in elevation, air pressure decreases.
The higher the elevation the lower the air pressure. Sea level is considered the standard for air pressure measurement.
Air has a weight of about 14.7 pounds per square inch at sea level.
Below sea level atmospheric pressure increases with depth. Air pressure at sea level is about 14.7 psia. Air pressure below sea level would be slightly higher.
1013 mb
Sea level pressure, sometimes as mean sea level pressure.
1.5 Kilos is the heaviest, but typically the ball would weigh around 800 grams
The air pressure is greatest at sea level.
At sea level, the average air pressure is about 1 bar. As you increase in altitude, the air pressure decreases. On average, the air pressure decreases by about 12% for every 1000 meters of elevation gain. Therefore, at an altitude of 1200 meters, the air pressure would be approximately 0.88 bar.
Assuming you are talking about air pressure, atmospheric pressure is created by the weight of the air resting against the earth. the higher up you go, the less air stacked on top of itself, and the pressure is less, until there is no more air at all (space). The pressure of air at sea level is relatively the same around the world because of all the water flows to the same level. this obviously changes with storms and hurricanes - as those move some of the air out of the way. So if you were to go below sea level, there would be more air on top of you, and the pressure would be higher. In death valley (well below sea level) the atmospheric pressure is much higher than at sea level. To answer the question, No, pressure is not negative below sea level. It is greater than at sea level.
Air pressure is greatest at ground level because the weight of the air above compresses the air molecules closer together, creating higher pressure. As altitude increases, there is less air above, resulting in lower air pressure.
Sea level pressure.
Air pressure depends mainly on altitude - how high you are above sea level. The lattitude doesn't make much difference.
The highest altitudes have the lowest air pressure. Air pressure increases as altitude decreases. Above sea level is lower pressure; below sea level is higher pressure.
Air pressure is greater at sea level because there is more air above that is pressing down. Any atmosphere is more dense at the surface of the planet than at locations higher in altitude. (Areas that are lower than sea level will generally have still higher atmospheric pressure.)