38th_parallel_north
The 38th parallel north is a circle of latitude located 38 degrees north of the Earth's equator, extending eastward from the Prime Meridian across the Atlantic Ocean, Europe (including the Azores), the Mediterranean Sea, North Africa, Asia (through Algeria, China, Japan, and the Korean Peninsula), the Pacific Ocean, and North America (from the U.S. West Coast through states including California, Nevada, Utah, Colorado, Kansas, Missouri, Kentucky, and Virginia to the Atlantic).[1] Its most prominent historical role emerged in 1945, when U.S. and Soviet military planners arbitrarily selected it as the temporary dividing line for administering Japan's surrender in Korea, with Soviet forces occupying the north and U.S. forces the south, despite the line ignoring natural geographic features like rivers or mountains and cutting through populated areas, roads, and rail lines.[2][3] This division, intended as provisional, solidified into a de facto ideological frontier amid emerging Cold War tensions, with the Soviet Union establishing a communist regime in the north and the United States supporting a non-communist government in the south by 1948.[2] On June 25, 1950, North Korean forces, equipped with Soviet-supplied tanks and artillery, launched a coordinated invasion across the parallel, overrunning South Korean defenses and advancing deep into the south, which prompted U.S.-led United Nations intervention and escalated into the Korean War.[4][5] The conflict ended in an armistice on July 27, 1953, establishing the Korean Demilitarized Zone (DMZ) along a military demarcation line that approximates but deviates from the original 38th parallel in places, leaving the peninsula technically at war without a peace treaty.[6] Beyond Korea, the parallel holds lesser geographic note for traversing diverse terrains and urban centers, such as Lisbon in Portugal and Sacramento in California, but its Korean association underscores arbitrary partitions' potential for prolonged geopolitical instability.[1][3]Geography
Global extent and coordinates
The 38th parallel north constitutes a circle of latitude situated precisely at 38 degrees north of the Earth's equatorial plane, denoted in geographic coordinates as 38°00′00″ N, with longitude spanning the full 360 degrees from the Prime Meridian eastward and westward. This parallel lies approximately 4,218 kilometers north of the equator, based on the standard metric where one degree of latitude equates to about 111 kilometers. Its east-west extent forms a complete circumnavigation of the globe, with a total length of roughly 31,600 kilometers, computed from the equatorial circumference of 40,075 kilometers multiplied by the cosine of 38 degrees (approximately 0.788).[7][8] The parallel traverses diverse terrestrial and marine environments, intersecting the Atlantic Ocean off Portugal's western coast, the Mediterranean Sea, the Pacific Ocean east of Japan, and the Atlantic Ocean again east of the United States. In continental landmasses, it extends across portions of Europe, Asia, and North America, avoiding Africa and South America entirely. This global path reflects the parallel's position in the Northern Hemisphere's temperate zone, influencing local climates through variations in solar insolation and prevailing winds.[9] Specific land crossings include Portugal and Spain in western Europe; southern Italy, Greece, and Turkey in southern Europe and western Asia; the Korean Peninsula (dividing North and South Korea along much of its length prior to wartime adjustments); Japan; China along its eastern coastal regions near the Yellow River Delta; and the United States, from the Pacific coastline near San Francisco northward through inland states to the Atlantic vicinity of Washington, D.C. These intersections span approximately 15-20% land coverage amid predominantly oceanic segments.[10][11][12]Notable passages and landmarks
The 38th parallel north traverses diverse terrains and intersects several notable landmarks globally. In southeastern Spain, it meets the European continent at Torrevieja (38°00′N, 00°42′W), a coastal town distinguished by its vast salt flats and lagoons, which have supported salt extraction since antiquity and remain a key economic feature through evaporation-based production yielding over 600,000 tons annually as of recent records.[11] In eastern Asia, the parallel cuts across the Korean Peninsula, where it delineates the approximate alignment of the Korean Demilitarized Zone (DMZ), a 250-kilometer buffer strip fortified since the 1953 armistice ending active hostilities in the Korean War, rendering this segment one of the world's most heavily guarded land borders despite no formal peace treaty.[13] Nearby, in Yangyang County, South Korea, the line reaches the Sea of Japan at 38th Parallel Beach, a coastal site evoking the division's enduring geopolitical tensions through its position just beyond former frontline areas.[14] Across the Pacific in North America, the parallel spans the United States from coastal California eastward, passing through Stockton (37°57′N, adjusted proximally within the latitude band) and Charlottesville, Virginia (38°02′N), amid varied physiographic regions including the Central Valley's agricultural expanses and the Appalachian foothills.[7]Astronomical and physical characteristics
Day length and solar phenomena
At latitude 38° N, daylight duration varies annually from approximately 9 hours 22 minutes on the winter solstice (December 21) to 14 hours 38 minutes on the summer solstice (June 21), based on geometric calculations accounting for Earth's 23.44° axial tilt.[15] These extremes arise because the sun's declination reaches +23.44° at summer solstice, maximizing the sun's path above the horizon, and -23.44° at winter solstice, minimizing it.[16] Atmospheric refraction extends actual observed daylight by 5–10 minutes beyond geometric values, as the sun appears above the horizon when its true position is slightly below due to light bending.[17]| Date | Approximate Geometric Day Length | Notes |
|---|---|---|
| March/September Equinox | 12 hours | Observed ~12 hours 7 minutes with refraction; sun's declination ≈0° yields equal geometric day/night everywhere on Earth.[17] |
| June Solstice | 14 hours 38 minutes | Longest day; no midnight sun, as latitude is below 66.56° N (90° - 23.44°).[18] |
| December Solstice | 9 hours 22 minutes | Shortest day; sun never exceeds low altitudes.[15] |