Ozone layer stratospheric wind patterns. In the northern hemisphere these patterns, known as the Brewer-Dobson circulation, make the ozone layer thickest in the spring and thinnest in the fall. When ozone in produced by solar UV radiation in the tropics, it is done so by circulation lifting ozone-poor air out of the troposphere and into the stratosphere where the sun photolyzes oxygen molecules and turns them into ozone. Then, the ozone-rich air is carried to higher latitudes and drops into lower layers of the atmosphere. Research has found that the ozone levels in the United States are highest in the spring months
Layer 8 been referenced to physical (real-world) controllers containing an external hardware device which interacts with an OSI model network. An example of this is ALI in Profibus. A network guru T-shirt from the 1980s shows Layer 8 as the "financial" layer, and Layer 9 as the "political" layer. The design was credited to Evi Nemeth. In the TCP/IP model, the 4-layer model of the Internet, the 5th layer is analogously sometimes described as the "political layer" (and the 6th as the "religious layer"). This appears in RFC 2321, which is a humorous April Fools' Day RFC published in 1998. Layer 8