The lowest part of the troposphere, where friction with the Earth's surface influences air flow, is the planetary boundary layer. This layer is typically a few hundred meters to 2 km (1.2 mi) deep depending on the landform and time of day.he troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere 's mass and 99% of its water vapor and aerosols.
Bushnell is a city in Sumter County, Florida, United States. The population was 2,050 at the 2000 census. According to the U.S Census estimates of 2005, the city had a population of 2,119. It is the county seat of Sumter County.
Polk County is located in the U.S. state of Florida. The county population was 602,095, as of the 2010 census. Its county seat is Bartow, and its largest city is Lakeland. Polk County comprises the Lakeland-Winter Haven Metropolitan Statistical Area.