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Humphreys Peak
Humphreys Peak (, "its summit never melts") is the highest mountain and the second most prominent peak after Mount Graham in the U.S. state of Arizona. With an elevation of , it is located within the Kachina Peaks Wilderness in the Coconino National Forest, about north of Flagstaff, Arizona. Humphreys Peak is the highest of a group of dormant volcanic peaks known as the San Francisco Peaks. Humphreys Peak was named in about 1870 for General Andrew A. Humphreys, a U.S. Army officer who was a Union general during the American Civil War, and who later became Chief of Engineers of the United States Army Corps of Engineers. However, a United States General Land Office map from 1903 showed the name ''San Francisco Peak'' applied to this feature (apparently borrowed from San Francisco Mountain on which the peak stands). Thus the United States Board on Geographic Names approved the variant name in 1911. In 1933, the application of the names was rectified. Geology Humphreys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sierra Nevada (U
The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley (California), Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily in Nevada. The Sierra Nevada is part of the American Cordillera, an almost continuous chain of mountain ranges that forms the western "backbone" of the Americas. The Sierra runs north-south, and its width ranges from to across east–west. Notable features include the General Sherman Tree, the largest tree in the world by volume; Lake Tahoe, the largest alpine lake in North America; Mount Whitney at , the highest point in the contiguous United States; and Yosemite Valley sculpted by glaciers from one-hundred-million-year-old granite, containing List of waterfalls in Yosemite National Park, high waterfalls. The Sierra is home to three national parks, twenty-six wilderness areas, ten national forests, and two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Civil War
The American Civil War (April 12, 1861May 26, 1865; also known by Names of the American Civil War, other names) was a civil war in the United States between the Union (American Civil War), Union ("the North") and the Confederate States of America, Confederacy ("the South"), which was formed in 1861 by U.S. state, states that had Secession in the United States, seceded from the Union. The Origins of the American Civil War, central conflict leading to war was a dispute over whether Slavery in the United States, slavery should be permitted to expand into the western territories, leading to more slave states, or be prohibited from doing so, which many believed would place slavery on a course of ultimate extinction. Timeline of events leading to the American Civil War, Decades of controversy over slavery came to a head when Abraham Lincoln, who opposed slavery's expansion, won the 1860 presidential election. Seven Southern slave states responded to Lincoln's victory by seceding f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dew Point
The dew point is the temperature the air needs to be cooled to (at constant pressure) in order to produce a relative humidity of 100%. This temperature depends on the pressure and water content of the air. When the air at a temperature above the dewpoint is cooled, its moisture capacity is reduced and airborne water vapor will Condensation, condense to form liquid water known as dew. When this occurs through the air's contact with a colder surface, dew will form on that surface. The dew point is affected by the air's humidity. The more moisture the air contains, the higher its dew point. When the temperature is below the freezing point of water, the dew point is called the frost point, as frost is formed via deposition (phase transition), deposition rather than condensation. In liquids, the analog to the dew point is the cloud point. Humidity If all the other factors influencing humidity remain constant, at ground level the relative humidity rises as the temperature falls; this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mediterranean Climate
A Mediterranean climate ( ), also called a dry summer climate, described by Köppen and Trewartha as ''Cs'', is a temperate climate type that occurs in the lower mid-latitudes (normally 30 to 44 north and south latitude). Such climates typically have dry summers and wet winters, with summer conditions being hot and winter conditions typically being mild. These weather conditions are typically experienced in the majority of Mediterranean-climate regions and countries, but remain highly dependent on proximity to the ocean, altitude and geographical location. The dry summer climate is found throughout the warmer middle latitudes, affecting almost exclusively the western portions of continents in relative proximity to the coast. The climate type's name is in reference to the coastal regions of the Mediterranean Sea, which mostly share this type of climate, but it can also be found in the Atlantic portions of Iberia and Northwest Africa, the Pacific portions of the United States ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humid Continental Climate
A humid continental climate is a climatic region defined by Russo-German climatologist Wladimir Köppen in 1900, typified by four distinct seasons and large seasonal temperature differences, with warm to hot (and often humid) summers, and cold (sometimes severely cold in the northern areas) and snowy winters. Precipitation is usually distributed throughout the year, but often these regions do have dry seasons. The definition of this climate in terms of temperature is as follows: the mean temperature of the coldest month must be below or depending on the isotherm, and there must be at least four months whose mean temperatures are at or above . In addition, the location in question must not be semi-arid or arid. The cooler ''Dfb'', ''Dwb'', and ''Dsb'' subtypes are also known as hemiboreal climates. Although amount of snowfall is not a factor used in defining the humid continental climate, snow during the winter in this type of climate is almost a guarantee, either intermitte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tundra Climate
The tundra climate is a polar climate sub-type located in high latitudes and high mountains. It is classified as ET according to the Köppen climate classification. It is a climate which at least one month has an average temperature high enough to melt snow (), but no month with an average temperature in excess of . If the climate occurs at high elevations, it is known as alpine climate. Despite the potential diversity of climates in the ''ET'' category involving precipitation, extreme temperatures, and relative wet and dry seasons, this category is rarely subdivided. Rainfall and snowfall are generally slight due to the low vapor pressure of water in the chilly atmosphere, but as a rule potential evapotranspiration is extremely low, allowing soggy terrain of swamps and bogs even in places that get precipitation typical of deserts of lower and middle latitudes. The amount of native tundra biomass depends more on the local temperature than the amount of precipitation. Tundra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Köppen Climate Classification
The Köppen climate classification divides Earth climates into five main climate groups, with each group being divided based on patterns of seasonal precipitation and temperature. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (temperate), ''D'' (continental), and ''E'' (polar). Each group and subgroup is represented by a letter. All climates are assigned a main group (the first letter). All climates except for those in the ''E'' group are assigned a seasonal precipitation subgroup (the second letter). For example, ''Af'' indicates a tropical rainforest climate. The system assigns a temperature subgroup for all groups other than those in the ''A'' group, indicated by the third letter for climates in ''B'', ''C'', ''D'', and the second letter for climates in ''E''. Other examples include: ''Cfb'' indicating an oceanic climate with warm summers as indicated by the ending ''b.'', while ''Dwb'' indicates a semi-Monsoon continental climate, monsoonal continental climate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subarctic Climate
The subarctic climate (also called subpolar climate, or boreal climate) is a continental climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of an ocean, generally at latitudes from 50°N to 70°N, poleward of the humid continental climates. Like other Class D climates, they are rare in the Southern Hemisphere, only found at some isolated highland elevations. Subarctic or boreal climates are the source regions for the cold air that affects temperate latitudes to the south in winter. These climates represent Köppen climate classification ''Dfc'', ''Dwc'', ''Dsc'', ''Dfd'', ''Dwd'' and ''Dsd''. Description This type of climate offers some of the most extreme seasonal temperature variations found on the planet: in winter, temperatures can drop to below and in summer, the temperature may exceed . However, the summers are short; no more than three months of the year (but at least on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trachyte
Trachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanite, aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava (or shallow intrusions) enriched with silica and alkali metals. It is the volcanic equivalent of syenite. Trachyte is common wherever alkali magma is erupted, including in late stages of ocean island volcanismMacDonald 1983, pp. 51–52 and in continental rift valleys, above mantle plumes,Philpotts and Ague 2009, pp. 390–394 and in areas of back-arc extension. Trachyte has also been found in Gale crater on Mars. Trachyte has been used as decorative building stone and was extensively used as dimension stone in the Roman Empire and the Republic of Venice. Chemical composition Trachyte has a silica content of 60 to 65% and an alkali oxide content of over 7%. This gives it less SiO2 than rhyolite and more (Na2O plus K2O) than dacite. These chemical differe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek () 'most' and (; Latinized as ) 'new'. The aridification and cooling trends of the preceding Neogene were continued in the Pleistocene. The climate was strongly variable depending on the glacial cycle, oscillating between cold Glacial period, glacial periods and warmer Interglacial, int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1980 Eruption Of Mount St
__NOTOC__ Year 198 (CXCVIII) was a common year starting on Sunday of the Julian calendar. At the time, it was known as the Year of the Consulship of Sergius and Gallus (or, less frequently, year 951 ''Ab urbe condita''). The denomination 198 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire *January 28 **Publius Septimius Geta, son of Septimius Severus, receives the title of Caesar. **Caracalla, son of Septimius Severus, is given the title of Augustus. China *Winter – Battle of Xiapi: The allied armies led by Cao Cao and Liu Bei defeat Lü Bu; afterward Cao Cao has him executed. By topic Religion * Marcus I succeeds Olympianus as Patriarch of Constantinople (until 211). Births * Lu Kai, Chinese official and general (d. 269) * Quan Cong, Chinese general and advisor (d. 249) Deaths * Li Jue, Chinese warlord and reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Board On Geographic Names
The United States Board on Geographic Names (BGN) is a Federal government of the United States, federal body operating under the United States Secretary of the Interior. The purpose of the board is to establish and maintain uniform usage of geography, geographic names throughout the federal government of the United States. History Following the American Civil War, more and more American pioneer, American settlers began moving westward, prompting the Federal government of the United States, U.S. federal government to pursue some sort of consistency for referencing landmarks on maps and in official documents. As such, on January 8, 1890, Thomas Corwin Mendenhall, superintendent of the United States Coast and Geodetic Survey Office, wrote to 10 noted geographers "to suggest the organization of a Board made up of representatives from the different Government services interested, to which may be referred any disputed question of geographical orthography." President Benjamin Harrison si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
