Regions of the magnetosphere roughly 1.2 to 6 Earth radii above the equator in which charged particles are stably trapped by closed geomagnetic field lines. There are two belts. The inner belt is part
of the plasmasphere and corotates with the Earth; its maximum proton density lies near 5000 km. Inner belt protons are mostly high energy (10-50 MeV range) and originate from the decay of secondary neutrons created during collisions between cosmic rays and upper atmospheric particles. The outer belt extends on to the magnetopause on the sunward side. The altitude of maximum proton density is near 16,000-20,000 km. Outer belt protons are lower energy (about 200 eV to 1 MeV) and come from the solar wind. The outer belt is also characterized by highly variable fluxes of energetic electrons. The radiation belts are often called the ”Van Allen radiation belts” because they were discovered in 1968 by a research group at the University of Iowa led by Professor J. A. Van Allen.
Two belts of radiation that surround Earth, also known as the Van Allen Belts. These two concentric donut-shaped regions are filled with high-energy particles from the sun and Earth's ionosphere that
gyrate, bounce and drift, sometimes shooting down into Earth's atmosphere, sometimes escaping out into space. The inner belt is fairly stable; however, the outer belt can swell and shrink over time, sometimes inflating so much that the belts appear as one.
Fog caused by nocturnal radiational cooling of the Earth's surface, which in turn cools the adjacent air to a degree sufficient to cause condensation of the water vapour within the air.
Frost caused by nocturnal radiational cooling of the Earth's surface, usually under conditions of clear skies and little or no wind. Surface temperatures must fall to 0 degrees C or below.
Freezing conditions that typically occur on clear nights with little or no wind, when the outgoing is greater than the incoming radiation and cooling air temperature near the surface creates a stable
temperature inversion near the ground.