The jet stream is a fast moving current of air found in the upper atmospheric levels between 10 to 15 kilometers above the surface of the earth. The stream can be thousands of kilometers in length while its width can stretch for hundreds of kilometers. However, the thickness of the jet stream is only few kilometers in height. In general, the upper level of the jet stream whas the strongest surface temperature contrast and in effect, the temperature contrast controls the intensity and the speed of a particular jet stream.
Overview of the functioning of a jet stream
During the winter months, the jet stream is at its strongest as the Arctic and the tropical air masses create the strongest temperature contrast. However, during the summer months, the surface temperature contrast is not that dramatic and therefore the jet stream remains weak. Thus, the temperature experienced by various regions on earth affects the flow of the jet stream and any dramatic deviations can shift the jet stream significantly in addition to affecting its usual intensity.
Global warming, climate change and its effect on the jet stream
In recent times, scientists debated the effects of global warming on the world’s weather pattern and a recent study adds fuel to these debates because it reveals how climate change affects the Northern jet stream in a significant manner. According to the study, the Arctic autumn temperatures have moved up by about 5 degrees Celsius, which reduces the temperature gradient between the Arctic and temperature latitudes in higher levels of the atmosphere. Because of these climate changes, the jet stream appears to be moving northwards, while its wind speed remains lower than usual. Such movements and slowing down of the jet stream means that the westward progression of waves in the jet stream also slows down and therefore the weather variations seen in its path will also become less dramatic and almost still.
Altered jet streams and its influence on the changing weather patterns
Therefore, it is argued that heat waves and cold snaps that manifest from time to time can remain static for a prolonged period as the jet stream does not alter the weather pattern as promptly as it did earlier. These effects can also translate into less rain in the already dry South and Southwest while there are more storms in the North. Furthermore, as the jet stream slows down, its ability to suppress hurricanes is lost and therefore regions experiencing hurricanes could now experience more and stronger hurricanes than ever.
Jet stream changes expected in the future
However, according to the study, the jet stream movement towards the North is not a sudden event because it has been moving gradually for many decades. Similarly, the two other jet streams seen in the Southern hemisphere are also moving towards the pole and therefore would inflict similar effects on the weather patterns in its path. However, given the complex nature of the weather patterns and the continued effects of global warming, the degree of shift and slowing down of jet streams and its influence on the weather patterns needs to be studied continuously while collecting more and more data using more sophisticated methods.