WordNet

elevation especially above sea level or above the earths surface; "the altitude gave her a headache" (同)height
the perpendicular distance from the base of a geometric figure to the opposite vertex (or side if parallel)
in or to a high position, amount, or degree; "prices have gone up far too high"
a state of altered consciousness induced by alcohol or narcotics; "they took drugs to get a high on"
a state of sustained elation; "Im on a permanent high these days"
an air mass of higher than normal pressure; "the east coast benefits from a Bermuda high"
a lofty level or position or degree; "summer temperatures reached an all-time high"
a high place; "they stood on high and observed the countryside"; "he doesnt like heights" (同)heights
at a great altitude; "he climbed high on the ladder" (同)high up
used of sounds and voices; high in pitch or frequency (同)high-pitched
happy and excited and energetic (同)in high spirits
slightly and pleasantly intoxicated from alcohol or a drug (especially marijuana) (同)mellow
in a rich manner; "he lives high" (同)richly, luxuriously
(literal meaning) being at or having a relatively great or specific elevation or upward extension (sometimes used in combinations like `knee-high'
far up toward the source; "he lives high up the river"
greater than normal in degree or intensity or amount; "a high temperature"; "a high price"; "the high point of his career"; "high risks"; "has high hopes"; "the river is high"; "he has a high opinion of himself"
farther along in physical or mental development; "the childs skeletal age was classified as `advanced"; "children in the advanced classes in elementary school read far above grade average"
ahead of the times; "the advanced teaching methods"; "had advanced views on the subject"; "a forward-looking corporation"; "is British industry innovative enough?" (同)forward-looking, innovative, modern
far along in time; "a man of advanced age"; "advanced in years"; "a ripe old age"; "the ripe age of 90" (同)ripe
ahead in development; complex or intricate; "advanced technology"; "a sophisticated electronic control system" (同)sophisticated
(of societies) highly developed especially in technology or industry; "advanced societies"; "an advanced country technologically"
at a higher level in training or knowledge or skill; "an advanced degree"; "an advanced text in physics"; "special seminars for small groups of advanced students at the University"
comparatively late in a course of development; "the illness had reached an advanced stage"; "an advanced state of exhaustion"
in a high position or level or rank; "details known by only a few highly placed persons"
to a high degree or extent; favorably or with much respect; "highly successful"; "He spoke highly of her"; "does not think highly of his writing"; "extremely interesting" (同)extremely
at a high rate or wage; "highly paid workers"
surpassing in quality; "top-grade ore" (同)top-quality, top-grade

PrepTutorEJDIC

〈U〉『高さ』(height) / 〈C〉標高,海抜(かいばつ) / 《しばしば複数形で》高所;高い地位 / 〈U〉〈C〉(三角形などの底辺からの)高さ;(天体の)高度,高角
『高い』,高い所にある / 《数の後に置いて》高さが…ある / (数量・程度などが標準より)『高い』,大きい,激しい / (身分・地位が)『高い』,高貴な / 『気高い』,高潔な / (声の調子が)『高い』,鋭い / 値段の高い,金の掛かる,ぜいたくな / 楽しい,陽気な,上得意の / (時・季節が)盛りの,たけなわの / (色が)濃い,赤い / 《話》(酒・麻薬などに)酔って / 『高く』,高い所に / (価値・程度などが)高く,高度に,激しく / 〈C〉《話》高水準,高値 / 〈U〉(自動車の)高速ギア / 〈C〉《話》(麻薬などによる)酔った状態
進出した,前進した / 進歩した / 上級の,高等の / (時が)進んだ,進行した
『高度に』,『非常に』,大いに / 高い位に,高貴に / 高価で(に),高給で(に)
上等の,高級の

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/01 18:51:10」(JST)

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Altitude or height (sometimes known as depth ) is defined based on the context in which it is used (aviation, geometry, geographical survey, sport, and more). As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context. Although the term altitude is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage.

Vertical distance measurements in the "down" direction are commonly referred to as depth.

Altitude in aviation

Vertical distance comparison

In aviation, the term altitude can have several meanings, and is always qualified by either explicitly adding a modifier (e.g. "true altitude"), or implicitly through the context of the communication. Parties exchanging altitude information must be clear which definition is being used.^[1]

Aviation altitude is measured using either mean sea level (MSL) or local ground level (above ground level, or AGL) as the reference datum.

Pressure altitude divided by 100 feet (30 m) as the flight level, and is used above the transition altitude (18,000 feet (5,500 m) in the US, but may be as low as 3,000 feet (910 m) in other jurisdictions); so when the altimeter reads 18,000 ft on the standard pressure setting the aircraft is said to be at "Flight level 180". When flying at a flight level, the altimeter is always set to standard pressure (29.92 inHg or 1013.25 hPa).

On the flight deck, the definitive instrument for measuring altitude is the pressure altimeter, which is an aneroid barometer with a front face indicating distance (feet or metres) instead of atmospheric pressure.

There are several types of aviation altitude:

Indicated altitude is the reading on the altimeter when the altimeter is set to the local barometric pressure at mean sea level.
Absolute altitude is the height of the aircraft above the terrain over which it is flying. Also referred to feet/metres above ground level (AGL).
True altitude is the actual elevation above mean sea level. It is indicated altitude corrected for non-standard temperature and pressure. In UK aviation radiotelephony usage, the vertical distance of a level, a point or an object considered as a point, measured from mean sea level; this is referred to over the radio as altitude.(see QNH)^[2]
Cruising altitude is the height at which an aircraft usually flies when it has risen into the sky.^[3]
Height is the elevation above a ground reference point, commonly the terrain elevation. In UK aviation radiotelephony usage, the vertical distance of a level, a point or an object considered as a point, measured from a specified datum; this is referred to over the radio as height, where the specified datum is the airfield elevation (see QFE)^[2]
Pressure altitude is the elevation above a standard datum air-pressure plane (typically, 1013.25 millibars or 29.92" Hg). Pressure altitude and indicated altitude are the same when the altimeter setting is 29.92" Hg or 1013.25 millibars.
Density altitude is the altitude corrected for non-ISA International Standard Atmosphere atmospheric conditions. Aircraft performance depends on density altitude, which is affected by barometric pressure, humidity and temperature. On a very hot day, density altitude at an airport (especially one at a high elevation) may be so high as to preclude takeoff, particularly for helicopters or a heavily loaded aircraft.

These types of altitude can be explained more simply as various ways of measuring the altitude:

Indicated altitude – the altimeter reading
Absolute altitude – altitude in terms of the distance above the ground directly below
True altitude – altitude in terms of elevation above sea level
Height – altitude in terms of the distance above a certain point
Pressure altitude – the air pressure in terms of altitude in the International Standard Atmosphere
Density altitude – the density of the air in terms of altitude in the International Standard Atmosphere

Altitude regions

The Earth's atmosphere is divided into several altitude regions. These regions start and finish at varying heights depending on season and distance from the poles. The altitudes stated below are averages:^[4]

Troposphere — surface to 8,000 metres (5.0 mi) at the poles – 18,000 metres (11 mi) at the equator, ending at the Tropopause.
Stratosphere — Troposphere to 50 kilometres (31 mi)
Mesosphere — Stratosphere to 85 kilometres (53 mi)
Thermosphere — Mesosphere to 675 kilometres (419 mi)
Exosphere — Thermosphere to 10,000 kilometres (6,200 mi)

High altitude and low pressure

Regions on the Earth's surface (or in its atmosphere) that are high above mean sea level are referred to as high altitude. High altitude is sometimes defined to begin at 2,400 metres (8,000 ft) above sea level.^[5]^[6]^[7]

At high altitude, atmospheric pressure is lower than that at sea level. This is due to two competing physical effects: gravity, which causes the air to be as close as possible to the ground; and the heat content of the air, which causes the molecules to bounce off each other and expand.^[8]

Because of the lower pressure, the air expands as it rises, which causes it to cool.^[9]^[10] Thus, high altitude air is cold, which causes a characteristic alpine climate. This climate dramatically affects the ecology at high altitude.

Relation between temperature and altitude in Earth's atmosphere

The environmental lapse rate (ELR), is the rate of decrease of temperature with altitude in the stationary atmosphere at a given time and location. As an average, the International Civil Aviation Organization (ICAO) defines an international standard atmosphere (ISA) with a temperature lapse rate of 6.49 K(°C)/1,000 m (3.56 °F or 1.98 K(°C)/1,000 Ft) from sea level to 11 kilometres (36,000 ft). From 11 to 20 kilometres (36,000 to 66,000 ft), the constant temperature is −56.5 °C (−69.7 °F), which is the lowest assumed temperature in the ISA. The standard atmosphere contains no moisture. Unlike the idealized ISA, the temperature of the actual atmosphere does not always fall at a uniform rate with height. For example, there can be an inversion layer in which the temperature increases with height.

Effects of high altitude on humans

Medicine recognizes that altitudes above 1,500 metres (4,900 ft) start to affect humans,^[11] and there is no record of humans living at extreme altitudes above 5,500–6,000 metres (18,000–19,700 ft) for more than two years.^[12] As the altitude increases, atmospheric pressure decreases, which affects humans by reducing the partial pressure of oxygen.^[13] The lack of oxygen above 2,400 metres (8,000 ft) can cause serious illnesses such as altitude sickness, high altitude pulmonary edema, and high altitude cerebral edema.^[7] The higher the altitude, the more likely are serious effects.^[7] The human body can adapt to high altitude by breathing faster, having a higher heart rate, and adjusting its blood chemistry.^[14]^[15] It can take days or weeks to adapt to high altitude. However, above 8,000 metres (26,000 ft), (in the "death zone"), altitude acclimatization becomes impossible.^[16]

There is a significantly lower overall mortality rate for permanent residents at higher altitudes.^[17] Additionally, there is a dose response relationship between increasing elevation and decreasing obesity prevalence in the United States.^[18] In addition, the recent hypothesis suggests that high altitude could be protective against Alzheimer's disease via action of erythropoietin, a hormone released by kindney in response to hypoxia.^[19] However, people living at higher elevations have a statistically significant higher rate of suicide.^[20] The cause for the increased suicide risk is unknown so far.^[20]

Athletes

For athletes, high altitude produces two contradictory effects on performance. For explosive events (sprints up to 400 metres, long jump, triple jump) the reduction in atmospheric pressure signifies less atmospheric resistance, which generally results in improved athletic performance.^[21] For endurance events (races of 5,000 metres or more) the predominant effect is the reduction in oxygen which generally reduces the athlete's performance at high altitude. Sports organizations acknowledge the effects of altitude on performance: the International Association of Athletic Federations (IAAF), for example, marks record performances achieved at an altitude greater than 1,000 metres (3,300 ft) with the letter "A".^[22]

Athletes also can take advantage of altitude acclimatization to increase their performance. The same changes that help the body cope with high altitude increase performance back at sea level.^[23]^[24] These changes are the basis of altitude training which forms an integral part of the training of athletes in a number of endurance sports including track and field, distance running, triathlon, cycling and swimming.

Effect of high altitude on animals

Decreased oxygen availability and decreased temperature make life at high altitude challenging. Despite these environmental conditions, many species have been successfully adapted at high altitudes. Animals have developed physiological adaptations to enhance oxygen uptake and delivery to tissues which can be used to sustain metabolism. The strategies used by animals to adapt to high altitude depend on their morphology and phylogeny. For example, small mammals face the challenge of maintaining body heat in cold temperatures, due to their large volume to surface area ratio. As oxygen is used as a source of metabolic heat production, the hypobaric hypoxia at high altitudes is problematic.

There is also a general trend of smaller body sizes and lower species richness at high altitudes, likely due to lower oxygen partial pressures.^[25] These factors may decrease productivity in high altitude habitats, meaning there will be less energy available for consumption, growth, and activity.^[26]

However, some species, such as birds, thrive at high altitude.^[27] Birds thrive because of physiological features that are advantageous for high-altitude flight.

References

^ Air Navigation. Department of the Air Force. 1 December 1989. AFM 51-40.
^ ^a ^b Radiotelephony Manual. UK Civil Aviation Authority. 1 January 1995. ISBN 0-86039-601-0. CAP413.
^ "Cruising altitude". Macmillan English Dictionary. Retrieved 9 April 2015.
^ "Layers of the Atmosphere". JetStream, the National Weather Service Online Weather School. National Weather Service. Archived from the original on 19 December 2005. Retrieved 22 December 2005.
^ Webster's New World Medical Dictionary. Wiley. 2008. ISBN 978-0-470-18928-3.
^ "An Altitude Tutorial". International Society for Mountain Medicine. Archived from the original on 19 July 2011. Retrieved 2011-06-22.
^ ^a ^b ^c Cymerman, A; Rock, PB (1994). "Medical Problems in High Mountain Environments. A Handbook for Medical Officers". USARIEM-TN94-2. U.S. Army Research Inst. of Environmental Medicine Thermal and Mountain Medicine Division Technical Report. Retrieved 2009-03-05.
^ "Atmospheric pressure". NOVA Online Everest. Public Broadcasting Service. Archived from the original on 25 January 2009. Retrieved 23 January 2009.
^ Jacobson, Mark Zachary (2005). Fundamentals of Atmospheric Modelling (2nd ed.). Cambridge University Press. ISBN 0-521-83970-X.
^ Ahrens, C. Donald (2006). Meteorology Today (8th ed.). Brooks/Cole Publishing. ISBN 0-495-01162-2.
^ "Non-Physician Altitude Tutorial". International Society for Mountain Medicine. Archived from the original on 23 December 2005. Retrieved 22 December 2005.
^ West, JB (2002). "Highest permanent human habitation". High Altitude Medical Biology 3 (4): 401–407. doi:10.1089/15270290260512882. PMID 12631426.
^ Peacock, Andrew J (17 October 1998). "Oxygen at high altitude". British Medical Journal 317 (7165): 1063–1066. doi:10.1136/bmj.317.7165.1063. PMC 1114067. PMID 9774298.
^ Young, Andrew J.; Reeves, John T. (2002). "21". Human Adaptation to High Terrestrial Altitude. In: Medical Aspects of Harsh Environments 2. Borden Institute, Washington, DC. Archived from the original on 11 January 2009. Retrieved 2009-01-05.
^ Muza, SR; Fulco, CS; Cymerman, A (2004). "Altitude Acclimatization Guide". U.S. Army Research Inst. of Environmental Medicine Thermal and Mountain Medicine Division Technical Report (USARIEM–TN–04–05). Retrieved 2009-03-05.
^ "Everest:The Death Zone". Nova. PBS. 1998-02-24.
^ West, John B. (January 2011). "Exciting Times in the Study of Permanent Residents of High Altitude". High Altitude Medicine & Biology 12 (1): 1. doi:10.1089/ham.2011.12101.
^ Voss, JD; Masuoka, P; Webber, BJ; Scher, AI; Atkinson, RL (2013). "Association of Elevation, Urbanization and Ambient Temperature with Obesity Prevalence in the United States". International Journal of Obesity 37 (10): 1407–1412. doi:10.1038/ijo.2013.5. PMID 23357956.
^ Ismailov, RM (Jul–Sep 2013). "Erythropoietin and epidemiology of Alzheimer disease". Alzheimer Dis. Assoc. Disord. 27 (3): 204–6. doi:10.1097/WAD.0b013e31827b61b8. PMID 23314061.
^ ^a ^b Brenner, Barry; Cheng, David; Clark, Sunday; Camargo, Carlos A., Jr (Spring 2011). "Positive Association between Altitude and Suicide in 2584 U.S. Counties". High Altitude Medicine & Biology 12 (1): 31–5. doi:10.1089/ham.2010.1058. PMC 3114154. PMID 21214344.
^ Ward-Smith, AJ (1983). "The influence of aerodynamic and biomechanical factors on long jump performance". Journal of Biomechanics 16 (8): 655–658. doi:10.1016/0021-9290(83)90116-1. PMID 6643537.
^ "IAAF World Indoor Lists 2012" (PDF). IAAF Statistics Office. 2012-03-09.
^ Wehrlin, JP; Zuest, P; Hallén, J; Marti, B (June 2006). "Live high—train low for 24 days increases hemoglobin mass and red cell volume in elite endurance athletes". J. Appl. Physiol. 100 (6): 1938–45. doi:10.1152/japplphysiol.01284.2005. PMID 16497842. Retrieved 2009-03-05.
^ Gore, CJ; Clark, SA; Saunders, PU (September 2007). "Nonhematological mechanisms of improved sea-level performance after hypoxic exposure". Med Sci Sports Exerc 39 (9): 1600–9. doi:10.1249/mss.0b013e3180de49d3. PMID 17805094. Retrieved 2009-03-05.
^ Jacobsen, Dean (24 September 2007). "Low oxygen pressure as a driving factor for the altitudinal decline in taxon richness of stream macroinvertebrates". Oceologia 154 (4): 795–807. doi:10.1007/s00442-007-0877-x. PMID 17960424.
^ Rasmussen, Joseph B.; Robinson, Michael D.; Hontela, Alice; Heath, Daniel D. (8 July 2011). "Metabolic traits of westslope cutthroat trout, introduced rainbow trout and their hybrids in an ecotonal hybrid zone along an elevation gradient". Biological Journal of the Linnean Society 105: 56–72. doi:10.1111/j.1095-8312.2011.01768.x.
^ McCracken, K. G.; Barger, CP; Bulgarella, M; Johnson, KP et al. (October 2009). "Parallel evolution in the major haemoglobin genes of eight species of Andean waterfowl". Molecular Evolution 18 (19): 3992–4005. doi:10.1111/j.1365-294X.2009.04352.x. PMID 19754505.

External links

"Altitude pressure calculator". Apex (altitude physiology expeditions). Retrieved 2006-08-08.
"The Race to the Stratosphere". U.S. Centennial of Flight Commission. Archived from the original on 9 March 2006. Retrieved 25 January 2006.
Downloadable ETOPO2 Raw Data Database (2 minute grid)
Downloadable ETOPO5 Raw Data Database (5 minute grid)
Calculate true altitude with these JavaScript applications
Find the altitude of any place

UpToDate Contents

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1. 高山病：生理学、危険因子、および一般的な予防法 high altitude illness physiology risk factors and general prevention
2. 急性高山病および高地脳浮腫 acute mountain sickness and high altitude cerebral edema
3. 高地と心疾患 high altitude and heart disease
4. 高山病：小児特有の懸念事項 high altitude disease unique pediatric considerations
5. 高地肺水腫 high altitude pulmonary edema

English Journal

Association of polymorphisms in FLT3, EGFR, ALOX5, and NEIL3 with glioblastoma in the Han Chinese population.

Jin TB, Li XL, Yang H, Jiri M, Shi XG, Yuan DY, Kang LL, Li SQ.SourceKey Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region, School of Medicine, Tibet University for Nationalities, #6 East Wenhui Road, Xianyang, 712082, Shaanxi, China.
Medical oncology (Northwood, London, England).Med Oncol.2013 Dec;30(4):718. doi: 10.1007/s12032-013-0718-1. Epub 2013 Sep 5.
Glioblastoma (GBM) is the highest-grade glioma in astrocytoma. Patients often have poor prognosis due to therapeutic resistance and tumor recurrence. Identification of the genetic factors of GBM could be important contribution to early prevention of this disease. We genotyped 17 tag single-nucleotid
PMID 24005813

Effect of normobaric hypoxia on the testis in a murine model.

Madrid E, Reyes JG, Hernández B, García JM, San Martín S, Olivero P, Crespo PV, Párraga M.SourceCentro de Investigaciones Biomédicas Escuela de Medicina, Universidad de Valparaíso, Valparaíso, Chile.
Andrologia.Andrologia.2013 Oct;45(5):332-8. doi: 10.1111/and.12019. Epub 2012 Sep 11.
High-altitude hypoxia generates spermiogram impairment due to germinal epithelium, Leydig cells, sperm and seminal plasma alterations, but precise mechanisms involved are unknown. The objective of this work was to analyse the effect of normobaric hypoxia on the morphology of testicular interstitium
PMID 22967372

Myocardial ER chaperone activation and protein degradation occurs due to synergistic, not individual, cold and hypoxic stress.

Jain K, Suryakumar G, Prasad R, Singh SN, Ganju L.SourceCellular Biochemistry Group, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi 110054, India.
Biochimie.Biochimie.2013 Oct;95(10):1897-908. doi: 10.1016/j.biochi.2013.06.018. Epub 2013 Jun 29.
Environmental stress at high altitude affects the myocardium at the physiological and molecular level. Characterized by hypobaric hypoxia and low temperatures, the cumulative impact of these stressors on the protein folding homeostasis in the heart is yet unexplored. The present study evaluates the
PMID 23816873

Nrf2 activation: A potential strategy for the prevention of acute mountain sickness.

Lisk C, McCord J, Bose S, Sullivan T, Loomis Z, Nozik-Grayck E, Schroeder T, Hamilton K, Irwin DC.SourceDivision of Cardiology, Cardiovascular Pulmonary Research Group, School of Medicine, Aurora, CO 80045, USA.
Free radical biology & medicine.Free Radic Biol Med.2013 Oct;63:264-73. doi: 10.1016/j.freeradbiomed.2013.05.024. Epub 2013 May 27.
Reactive oxygen species (ROS) formed during acute high altitude exposure contribute to cerebral vascular leak and development of acute mountain sickness (AMS). Nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2) is a transcription factor that regulates expression of greater than 90% of anti
PMID 23722164