The coordinates refer to the angles, which are measured in degrees: minutes of arc and seconds of arc.
1 minute = 60 seconds of arc
What is Latitude?
The angular distance, north or south of the equator. Latitude measurements range from 90 degrees north, to zero at the equator, to 90 degrees south.
The latitude, sometimes called a parallel because each line is equally spaced, signifies the location north or south, relative to the equator. Latitude is expressed as degrees north or degrees south. The equator, which divides the earth into the Northern Hemisphere and the Southern Hemisphere, has a latitude of zero. The North Pole has the latitude of 90 degrees north, while the South Pole's latitude is around 90 degrees south.
On a world map that shows latitude and longitude, the imaginary lines of latitude appear horizontally from east to west. Though these lines may appear to have varying curvature, the lines are actually circular in nature with different radii, and are parallel to one another.
Though equator is the most important of all latitudes, four other latitudes play a pivotal role in the geometric relationship between the Sun and the Earth.
Arctic Circle: 66° 33' 39" N
Tropic of Cancer: 23° 26' 21" N
Tropic of Capricorn: 23° 26' 21" S
Antarctic Circle: 66° 33' 39" S
All of the above latitude lines lie in the Earth's axial tilt with respect to the sun (23° 26' 21.41").
The Sun remains at the zenith only at latitudes between the Tropics. Midnight sun is possible only in the north of Arctic Circle or south of Antarctic Circle.
The Arctic Circle and Tropic of Cancer are colatitudes, meaning that the summation of their angles is 90 degrees. Similarly, Antarctic Circle and Tropic of Capricorn are also colatitudes.
Effects of Latitude
Latitude plays a major role in the weather and climate around the world, affecting the prevailing winds, polar auroras and other physical characteristics. Temperature is one of the major effects of latitude, as places with latitudes farther from the equator receive less sunlight and are much cooler as a result.
Types of Latitude
There can be various types of latitude, which can be listed as below:
- Common Latitude
- Reduced Latitude
- Authalic Latitude
- Rectifying Latitude
- Conformal Latitude
- Geocentric Latitude
- Astronomical Latitude
What is Longitude?
The angular distance of a specific place, measured east or west from the zero meridian. It expressed in degrees, minutes and seconds.
Longitude is the geographic coordinate used to express the distance of a point east or west, relative to the Greenwich meridian or Prime meridian. Greenwich median has a longitude of 0 degrees, and places located to the east of the Greenwich median may have longitude angles up to 180 degrees east. Similarly, the places located to the west of Greenwich would have longitudes up to 180 degrees west. Longitudes form an integral part of cartography, and they are also used in global navigation for measuring east-west directions.
The Earth rotates about 15 degrees per hour around its axis As a result, when some parts of the world see the sun right at mid-sky, it is midnight in another part of the world at the same time. With differences in longitude, the relative position of sun changes. For this reason, different time zones are necessary.
Longitudes range from 0 degrees to 180 degrees east on one side and 180 degrees west on the other. Every degree of change of longitude calls for four minutes of time adjustment. Movement towards the east requires the addition of the time. Similarly, time will be subtract from the starting time with westward movement. Large countries usually have more than one time zone.
Daylight Saving Time
During Daylight Saving Time (DST), time is adjusted one hour forward, to make use of earlier sunrises, usually between April and October each year. Daylight Saving Time is observed in many countries around the world.
The Date Line
Since longitude determines only the hour of the day and not the time, it is necessary to adjust the date when passing across the 180th meridian. For this, the concept of an International Date Line was formulated. The date advances one day when crossing the line from east to west, and goes back one day when the movement is on the opposite direction.
Effect on Climate
Latitudes play a pivotal role in determining the climate of a region. As the axis of the Earth is tilted 23° 26' 21.41" from perpendicular, specific latitudes receive varied amount of sunlight with the changing of seasons. From April through September, the Northern Hemisphere receives more sunlight, because it is tilted toward the Sun. The Southern Hemisphere is tilted toward the Sun from October to March. For this reason, the Northern Hemisphere has summer at the same time the Southern Hemisphere has winter, and vice versa.
Because of differences in latitudes, there are three different climate zones in general:
Arctic Climate Zone:
This climate zone remains under the snow throughout the year, covering from 66.5°N to the North Pole and 66.5°S to the South Pole. These places are extremely dry and receive very little precipitation. The amount of snowfall is also low, but melting is lower still because of the cold temperatures. As a result, the amount of ice and snow cover builds up. The activity of the Sun is also different in the Arctic Climate Zone. During the summer, it is known as the midnight sun, hovering over the horizon throughout the night during the summer. During parts of the winter, the Sun doesn't rise at all.
Temperate Climate Zone
The temperate climate zone lies between the Arctic and Tropic zones. This zone sees distinct variations across four seasons. The climate in this region is also affected by the wind flow that it receives.
Tropical Climate Zone
This zone lies from 23.5°N to 23.5°S. This is the region that receives the highest amount of sunlight, but is not necessarily the hottest zone, with mostly moderate temperatures in this region.
Last Updated on: Feb 2, 2015