Matching Pairs Climate: relating termsOnline version Link the geographical term with its definition to practice the geography glossary. National Geographic Insitute of Spain. by Instituto Geográfico Nacional (IGNSpain) 1 Low-pressure area 2 Isohyet 3 Climate 4 Climate change 5 Atmospheric weather 6 Anticyclone 7 Atmospheric pressure 8 Isobar Variation in the elements of the Earth's climate that can be due to natural and human causes. Activity region with atmospheric pressure greater than 1013 millibars, which is the average pressure at sea level. In anticyclones, the air masses descend and, in the northern hemisphere, they circulate clockwise. Imaginary line on a map connecting all points with the same pressure. An imaginary line drawn on a map that connects all the points with the same precipitation over a period of time. Activity region with atmospheric pressure below 1013 millibars, which is the average pressure at sea level. In low-pressure areas, air rises and, in the northern hemisphere, it circulates counter-clockwise. The usual sequence of atmospheric conditions or types of weather in a given place or region over an extended period of time. The physical state of the atmosphere at a given time and place. The force that atmospheric air exerts per unit area on the Earth's surface.