The Lower Stratosphere Passage is a huge air pocket at the top of the atmosphere, and the upper level air tends to move eastwards when latitudes reach 30deg poleward. This is due to the stratosphere’s constraint on air movement upward. As air descends, compressional warming occurs, creating vast regions of subtropical high pressure centred over the oceans. This area is characterized by strong thermodynamic stability and sparse precipitation with technolookup.com
The Lower Stratosphere Passage is a region in the stratosphere that consists of air molecules. It has a temperature and pressure equilibrium and allows the absorption of light and heat from Earth. The absorption of water vapor is influenced by the density and composition of air molecules.
Water vapor is a greenhouse gas that traps heat. When the air temperature drops below a certain level, the water vapor is converted to ice particles and must fall out. The coldest stratosphere is found in the equator, due to the rising currents of the troposphere. The average temperature of the stratosphere is 190 degrees Abs, but it can dip as low as 182 degrees.
The presence of chemicals in the atmosphere is a cause for concern. Chemicals like HO and Cl exist in the lower atmosphere but were not recognized as atmospheric components until the second half of the twentieth century. The presence of these substances is attributed to the fact that the stratosphere is only accessible to air masses that are rising in deep convection in the tropics. In order to enter the stratosphere, these air masses must first pass through the tropical troposphere, a temperature minimum that separates the stratosphere from the troposphere.
The chemical composition of the stratosphere is largely determined by photo chemical reactions. High-energy UV rays from the sun stimulate the formation of Cl and NO in the stratosphere. This process causes a significant diminution in the stratosphere’s ozone content. This decrease in ozone causes more solar ultraviolet-B radiation to reach the earth’s surface. The effects of this process are felt in temperate zones and during all seasons.
An increase in the level of lower stratospheric ozone may account for the hiatus in tropospheric temperature over the tropical Pacific since 1997. Nevertheless, climate models that include observed changes in SSTs do not fully explain this hiatus.
Ozone is formed locally in the atmosphere, including thunderstorms and cumulo-nimbus clouds. However, when ozone levels are high, these conditions are unlikely to be associated with thunderstorms. In such cases, ozone formation is likely to be due to local electrical causes.
High pressure systems
The stratosphere has long fascinated scientists. At first, its formation was a mystery, and many scientists doubted whether it even existed. However, the stratosphere exists and the transition from the troposphere to the stratosphere is accompanied by a change in the weather. This lecture aims to give an overview of the conditions found at these high levels of the atmosphere.
The stratosphere is located at an altitude of about 50 km (30 miles) above the troposphere. The temperature rises with altitude, reaching 0 degC near the top of the stratosphere. This warm climate leads to almost no clouds in this region. Nevertheless, there are some rare cloud formations, such as nacreous clouds, which are named after their striking iridescence. These clouds form in the stratosphere at about 30 km (19 miles) high.
Wave disturbances in the Lower Stratosphere have been observed for many years. The main types of disturbances are Rossby-gravity waves and Kelvin waves. Both types of waves are responsible for the day-to-day variability in the lower stratosphere. The first observations of these waves were made in 1968 by Wallace and Kousky. Since then, many studies have been conducted to quantify and characterize these waves. These studies include observations made from ultra-long duration balloons and ground-based observations.
Several studies have investigated the extent to which GCM simulations of SEWs reproduce the observed phenomena. The results have shown that SEW amplitudes depend on the convective parameterize and the vertical resolution of the stratosphere.
Temperature fluctuations in the Lower Stratosphere are driven by variations in wave frequencies. These waves are associated with negative vertical temperature gradients. In the eastern and western Pacific, the frequency of the waves is not different and the difference may be due to different mean relative humanities in the equatorial regions.
Temperature fluctuations in the Lower Stratosphere reflect seasonal cycles in atmospheric circulation. The NAM SLP index is one indicator of how quickly stratospheric temperatures change over a period of time. The number of days that major stratospheric warming occur is a function of the daily values of the NAM index. The NAM index may influence the surface climate during these periods.
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