El Nino is a climatic condition that occurs along the Tropical Pacific Ocean and is characterized by a rise in oceanic temperatures of up to 0.5 °C. This condition leads to an increase in air pressure along the western part of the Pacific Ocean. On the other hand, La Nina refers to a climatic condition that is characterized by a decrease in oceanic temperatures of up to 0.5 °C. This leads to a decrease in air pressure along the western part of the Pacific Ocean. The two conditions occur after every five years for up to nine months though, longer episodes have also been witnessed.
The Southern Oscillation is the atmospheric condition associated with El Nino. It refers to the surface air pressure in the eastern and western pacific waters during El Nino. During El Nino years, the tropical Pacific Ocean waters are normally warmer and coupled with the rise in air pressure as compared to non - El Nino years. El Nino events in Northern America are associated with warmer winters and reduced snow fall. The reverse is true for La Nina which is currently happening in the Equatorial Pacific and is anticipated to persist up to the end of the year.
The Koppen Climate Classification System uses vegetation distribution data, annual and monthly temperature, and precipitation records to determine the climate of a particular region or location. The Koppen Climate Classification System has come up with six climatic groups which include: Group A (Tropical/megathermal climates) which is characterized by high temperatures throughout the year. This group is further subdivided into Tropical rainforest climate (Af) characterized by rainfall all year, Tropical monsoon climate (Am) characterized by a dry month after winter and Tropical wet and dry or savanna climate (Aw) which has long dry seasons.
Group B (Dry arid and semiarid climates) is characterized by high temperatures and minimal or no precipitation. This group is subdivided into desert climate (Bw) and steppe climate (Bs) depending on the amount of precipitation. Further, Group C (Temperate/mesothermal climates) is characterized by moderate temperatures that are neither too warm nor too cold. Subgroups of C include Dry-summer subtropical (Csa), humid subtropical climates (Cfa) and temperate climate with dry winters (Cwb).
Group D (Continental/microthermal climate) is a very rare climate that occurs in the continent interiors with average temperatures of 10°C and -3°C during the warm and cold seasons respectively. The group is subdivided into Ds at high areas, Df between 30 and 40 latitudes and, Dw characterized by dry winters. Finally, group E (Polar climates) with an annual average temperatures of less than 10 °C is subdivided into Ice Cap climate (EF) and Tundra climate (ET) which is the climatic condition for one of my favorite tourist destination Alaska.