Noaa wind chill chart4/30/2024 ![]() ![]() Jet streams vary in height of four to eight miles and can reach speeds of more than 275 mph (239 kts / 442 km/h). The subtropical jet is located around the 30° latitude line. The polar jet is located between the 50°-60° latitude lines in both the northern and southern hemispheres. There are several different jet streams, or jets, around the globe. Therefore, the regions around 30° N/S and 50°-60° N/S are also regions where the wind in the upper atmosphere is the strongest. In addition, with the three-cell circulations mentioned previously, the regions around 30° N/S and 50°-60° N/S are areas where changes in temperature at any one point are the greatest.Īs the difference in temperature increases between the two locations, the strength of the wind increases. The result is that the farther the air moves from the equator, the faster and faster east it moves relative to the Earth's surface below. The Earth below the air, however, moves slower toward the poles. The momentum the air has as it travels around the Earth is conserved, which means that as the air over the equator starts moving toward one of the poles, it keeps its eastward motion constant. ![]() As a result, air moving away from the equator does not move directly north and south because it retains this rotational momentum, causing it to rotate faster than the surface below as it moves toward the poles. Therefore, the Earth’s rotational speed is fastest at its widest point, the equator. Since the entire Earth makes one rotation in 24 hours, locations along the longer latitudes are rotating at a faster speed than the shorter ones because they are traveling more distance in the same amount of time. The rotational speed of the Earth’s surface, and thus the air above it, is relative to its latitude. We saw that the Earth's rotation divided this circulation into three cells, and it is responsible for the existence of the jet stream as well. Why do the jet stream winds blow from west to east? Recall from the previous section what the global wind patterns would be like if the Earth was not rotating – the warm air rising at the equator would move directly toward both poles.) Since these hot and cold air boundaries are most pronounced in winter, jet streams are the strongest during both the northern and southern hemisphere winters. Within jet streams, the winds blow from west to east, but the band often shifts north and south because jet streams follow the boundaries between hot and cold air. Jet streams are relatively narrow bands of strong wind in the upper levels of the atmosphere, typically occurring around 30,000 feet (9,100 meters) in elevation.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |