Digital illustration of bare deciduous tree branches. In the Northern Hemisphere, deciduous trees grow new leaves each Spring and lose their leaves each Autumn. Many trees have bare branches during the Winter months.
The continent of North America is located in the northern hemisphere and includes Canada, the United States, Mexico, the nations of Central America, Greenland, and the Caribbean Islands.
In a first-ever study using ozone data from commercial aircraft, researchers found that levels of the pollutant in the lowest part of Earth's atmosphere have increased across the Northern Hemisphere over the past 20 years. ...
Science Daily. Fri, 21 Aug 2020 14:13:11 EDT.