Köppen climate classification

The '''Köppen climate classification''' is one of the most widely used Free ringtones climate classification systems. It was developed by Majo Mills Wladimir Köppen, a Mosquito ringtone Germany/German climatologist, around Sabrina Martins 1900 (with several further modifications by himself, notably in Nextel ringtones 1918 and Abbey Diaz 1936). It is based on the concept that native vegetation is the best expression of climate, thus climate zone boundaries have been selected with vegetation distribution in mind. It combines average annual and monthly Free ringtones temperatures and Majo Mills precipitation (meteorology)/precipitation, and the seasonality of precipitation.

The scheme

Köppen climate classification scheme divides the climates into five main groups and several types and subtypes. Each particular climate type is represented by a 2 to 4 letter symbol:

=GROUP A: Mosquito ringtone Tropical climate/Tropical/Megathermal climates=

Tropical climates (see Sabrina Martins tropics) are characterized by constant high temperature (at sea level and low elevations) — all twelve months of the year have average temperatures of 18 °C (64.4 °F) or higher. They are subdivided as follows:

* '''Tropical Cingular Ringtones rain forest climate''' (''Af''): All twelve months have average precipitation of at least 60 mm (2.36 inches). These climates, usually occurring within 5° latitude of the equator, are dominated by the sacks reasons Doldrums Low Pressure System all year round, and thus have no real seasons.Examples: companies adjust Singaporeindispensable home Belém, cabin older Brazil.Some of the places that have this climate are indeed uniformly and monotonously wet throughout the year (e.g., the northwest old percent Pacific Ocean/Pacific coast of suffrage planks South America/South and friendlier climate Central America, from cover expenses Ecuador to new on Costa Rica, see for instance, labels out Andagoya, maternal resources Colombia), but in many cases the period of higher sun and longer days is distinctly wettest (as at up shows Palembang, sounds items Indonesia) or the time of lower sun and shorter days may have more rain (as at libertarianism and Sitiawan, once taken Malaysia).A few places with this climate are found at the outer edge of the tropics, almost exclusively in the Southern Hemisphere; one example is up opinion Santos, pictures mediocre Brazil. '''Note'''. The term speculated upon seasons/aseasonal refers to the lack in the tropical zone of large differences in day light hours and mean monthly (or daily) temperature throughout the year. There are annual cyclic changes in the tropics, not as predictable as thosse in the temperate zone, albeit unrelated to temperature but to water availability whether as rain, mist, soil, or ground water. Plant response (e. g., less risk phenology), animal (feeding, migration, reproduction, et cetera), and human activities (plant sowing, harvesting, hunting, fishing, et cetera) are tuned to this ''seasonality''. Indeed, in tropical South America and Central America, the ''rainy season'' (and the ''high water season'') is called noble president rainy season/''Invierno'', even though it could occur in the northern hemisphere summer; likewise, the ''dry season'' (and ''low water season'') is called dry season/''Verano'' and can occur in the northern hemisphere winter.
* '''Tropical monsoon climate''' (''Am''): This type of climate, most common in southern Asia and West Africa, results from the monsoon winds which change direction according to the seasons. This climate has a driest month (which nearly always occurs at or soon after the "winter" solstice for that side of the equator) with rainfall less than 60 mm, but more than (100 − [total annual precipitation /25]): Examples: Bangalore, IndiaVeracruz, MexicoTownsville, Queensland/Townsville, Australia.Most places that have this climate are found at the outer margins of the tropical zone, but occasionally an inner-tropical location (e.g., San Marcos, Colombia) also qualifies. Actually, the Caribbean sea/Caribbean coast, eastward from Urabá gulf on the Colombia–Panamá border to the Orinoco river delta, on the Atlantic ocean/Atlantic ocean (ca. 4,000 km), have long dry periods (the extreme is the ''BSh'' climate (see below), characterised by very low, unreliable precipitation, present, for instance, in extensive areas in the :es:Guajira Península/Guajira, and Coro, western Venezuela, the northernmost peninsulas in South America, which receive Sometimes ''As'' is used in place of ''Aw'' if the dry season occurs during the time of higher sun and longer days. This is the case in parts of Hawaii (Honolulu), East Africa (Mombasa, Kenya) and Sri Lanka (Trincomalee), for instance. In most places that have tropical wet and dry climates, however, the dry season occurs during the time of lower sun and shorter days.

=GROUP B: Dry (Arid and semiarid) climates=

These climates are characterized by the fact that precipitation is less than potential evaporation and transpiration. The threshold is determined as follows:
* To find the precipitation threshold (in millimeters), multiply the average annual temperature in °C by 20, then add 280 if 70% or more of the total precipitation is in the high-sun half of the year (April through September in the Northern Hemisphere, or October through March in the Southern), or 140 if 30%-70% of the total precipitation is received during the applicable period, or 0 if less than 30% of the total precipitation is so received.
* If the annual precipitation is less than half the threshold for Group B, it is classified as ''BW'' (desert climate); if it is less than the threshold but more than half the threshold, it is classified as ''BS'' (steppe climate).
* A third letter can be included to indicate temperature. Originally, ''h'' signified low latitude climate (average annual temperature above 18 °C) while ''k'' signified middle latitude climate (average annual temperature below 18 °C), but the more common practice today (especially in the United States) is to use ''h'' to mean that the coldest month has an average temperature that is above 0 °C (32 °F), with ''k'' denoting that at least one month averages below 0 °C.
* Examples: Yuma, Arizona/Yuma, Arizona (''BWh'')Turpan, China (''BWk'')Cobar, Australia (''BSh'')Medicine Hat, Alberta (''BSk'').Some desert areas, situated along the west coasts of continents at tropical or near-tropical locations, are characterized by cooler temperatures than encountered elsewhere at comparable latitudes (due to the nearby presence of cold ocean currents) and frequent fog and low clouds, despite the fact that these places rank among the driest on earth in terms of actual precipitation received. This climate is sometimes labelled ''BWn'' and examples can be found at Lima, Peru/Lima, Peru and Walvis Bay, Namibia.
* On occasion, a fourth letter is added to indicate if either the winter or summer is "wetter" than the other half of the year. To qualify, the wettest month must have at least 60 mm of average precipitation if all twelve months are above 18 °C, or 30 mm (1.18 inches) if not; plus at least 70% of the total precipitation must be in the same half of the year as the wettest month — but the letter used indicates when the ''dry'' season occurs, not the "wet" one. This would result in Khartoum, Sudan being reckoned as ''BWhw'', Niamey, Niger as ''BShw'', El Arish, Egypt as ''BWhs'', Asbi'ah, Libya as ''BShs'', Umnugobi, Mongolia as ''BWkw'', and Xining, China as ''BSkw'' (''BWks'' and ''BSks'' do not exist if 0°C in the coldest month is recognized as the ''h''/''k'' boundary). If the standards for neither ''w'' nor ''s'' are met, no fourth letter is added.

=GROUP C: temperate climate/Temperate/mesothermal climates=

These climates have an average temperature above 10 °C (50 °F) in their warmest months, and a coldest month average between −3 °C and 18 °C. (Some climatologists, particularly in the United States, however, prefer to observe 0 °C rather than −3 °C in the coldest month as the boundary between this group and Group D; this is done to prevent certain headland locations in New England — principally Cape Cod — and such nearby islands as Nantucket and Martha's Vineyard, from fitting into the Maritime Temperate category noted below; this category is alternately known as the ''Marine West Coast'' climate, and eliminating the aforementioned locations indeed confines it exclusively to places found along the western margins of the continents, at least in the Northern Hemisphere).
* The second letter indicates the precipitation pattern — ''w'' indicates dry winters (driest winter month average precipitation less than one-tenth wettest summer month average precipitation; one variation also requires that the driest winter month have less than 30 mm average precipitation), ''s'' inidicates dry summers (driest summer month less than 30 mm average precipitation and less than one-third wettest winter month precipitation) and ''f'' means significant precipitation in all seasons (neither above mentioned set of conditions fulfilled).
* The third letter indicates the degree of summer heat — ''a'' indicates warmest month average temperature above 22 °C (71.6 °F), ''b'' indicates warmest month average temperature below 22 °C, with at least 4 months averaging above 10 °C, while ''c'' means 3 or fewer months with mean temperatures above 10 °C.
* The order of these two letters is sometimes reversed, especially by climatologists in the United States.
* Group C climates are subdivided as follows:
** '''Mediterranean climates''' (''Csa'', ''Csb''): These climates usually occur on the western sides of continents between the latitudes of 30° and 45° (higher in North America, where it extends to 50°). These climates are in the polar front region in winter, and thus have moderate temperatures and changeable weather. Summers are hot and dry, due to the domination of the subtropical high pressure systems, except in the immediate coastal areas, where summers are cooler due to the nearby presence of cold ocean currents.Examples: Palermo, Sicily (''Csa'')Gaziantep, Turkey (''Csa'')Santiago,_Chile/Santiago, Chile (''Csb'')Portland, Oregon (''Csb'').
** '''Humid Subtropical climates''' (''Cfa'', ''Cwa''): These climates usually occur in the interiors of continents, or on their east coasts, between the latitudes of 25° and 40°. Unlike the Mediterranean climates, the summers are humid due to unstable tropical air masses, or onshore Trade Winds. In eastern Asia, winters can be dry (and colder than other places at a corresponding latitude) because of the Siberian high pressure system, and summers very wet due to monsoonal influence. Examples: Houston, Texas (''Cfa — uniform precipitation distribution'')Brisbane, Australia (''Cfa — summer wetter than winter'')Yalta, Ukraine (''Cfa — summer drier than winter'')Luodian, China (''Cwa'').
** '''Maritime Temperate climates''' (''Cfb'', ''Cwb''): ''Cfb'' climates usually occur on the western sides of continents between the latitudes of 45° and 55°; they are typically situated immediately poleward of the Mediterranean climates, although in Australia this climate is found immediately poleward of the Humid Subtropical climate, and at a somewhat lower latitude. These climates are dominated all year round by the polar front, leading to changeable, often overcast weather. Summers are cool due to cloud cover, but winters are milder than other climates in similar latitudes.Examples: Limoges, France (''uniform precipitation distribution'')Langebaanweg, South Africa (''summer wetter than winter'')Prince Rupert, British Columbia/Prince Rupert, British Columbia (''summer drier than winter'').''Cfb'' climates are also encountered at high elevations in certain tropical areas, where the climate would be that of a tropical rain forest if not for the altitude. Bogotá, Colombia is perhaps the best example.''Cwb'' is found only at higher altitudes, without which the climate would be tropical wet and dry; examples include Addis Ababa, Ethiopia and Mexico City.
** '''Maritime Subarctic climates''' (''Cfc''): These climates occur poleward of the Maritime Temperate climates, and are confined either to narrow coastal strips on the western poleward margins of the continents, or, especially in the Northern Hemisphere, to islands off such coasts.Examples: Punta Arenas, Chile (''uniform precipitation distribution'')Monte Dinero, Argentina (''summer wetter than winter'')Tórshavn, Faroe Islands (''summer drier than winter'').

=GROUP D: Continental climate/Continental/microthermal climate=

These climates have an average temperature above 10 °C in their warmest months, and a coldest month average below −3 °C (or 0 °C in some versions, as noted previously). These usually occur in the interiors of continents, or on their east coasts, north of 40° North latitude. Group D climates do not exist at all in the Southern hemisphere due to the smaller land masses here.
* The second and third letters are used as for Group C climates, while a third letter of ''d'' indicates 3 or fewer months with mean temperatures above 10 °C ''and'' a coldest month temperature below −38 °C (−36.4 °F).
* Group D climates are subdivided as follows:
** '''Hot Summer Continental climates''' (''Dfa'', ''Dwa'', ''Dsa'') — ''Dfa'' climates usually occur in the forties latitudes, and in eastern Asia ''Dwa'' climates extend further south due to the influence of the Siberian high pressure system, which also causes winters here to be dry, and summers can be very wet because of monsoon circulation. Examples: Lowell, Massachusetts (''Dfa — uniform precipitation distribution'')Peoria, Illinois (''Dfa — summer wetter than winter'')Santaquin, Utah (''Dfa — summer drier than winter'')Beijing, China (''Dwa'').''Dsa'' exists only at higher elevations adjacent to areas with Mediterranean climates, such as Cambridge, Idaho and Saqqez in Iranian Kurdistan.
** '''Warm Summer Continental or Hemiboreal climates''' (''Dfb'', ''Dwb'', ''Dsb'') — ''Dfb'' and ''Dwb'' climates are immediately north of Hot Summer Continental climates, and also in central and eastern Europe, between the Maritime Temperate and Continental Subarctic climates.Examples: Moncton, New Brunswick (''Dfb — uniform precipitation distribution'')Minsk, Belarus (''Dfb — summer wetter than winter'')Revelstoke, British Columbia (''Dfb — summer drier than winter'')Rudnaya Pristan, Russia (''Dwb'').''Dsb'' arises from the same scenario as ''Dsa'', but at even higher altitudes, and chiefly in North America since here the Mediterranean climates extend further poleward than in Eurasia; Mazama, Washington is one such location.
** '''Continental Subarctic or Boreal (taiga) climates''' (''Dfc'', ''Dwc'', ''Dsc'') — ''Dfc'' and ''Dwc'' climates occur poleward of the other Group D climates, mostly north of 50° North latitude.Examples: Sept-Îles, Quebec (''Dfc — uniform precipitation distribution'')Anchorage, Alaska/Anchorage, Alaska (''Dfc — summer wetter than winter'')Mount Robson, British Columbia (''Dfc — summer drier than winter'')Irkutsk, Russia (''Dwc'').''Dsc'', like ''Dsa'' and ''Dsb'', is confined exclusively to highland locations near areas that have Mediterranean climates, and is the rarest of the three as a still higher altitude is needed to produce this climate. Example: Galena Summit, Idaho.
** '''Continental Subarctic climates with extremely severe winters''' (''Dfd'', ''Dwd''): These climates occur only in eastern Siberia. The names of some of the places that have this climate — most notably Verkhoyansk and Oymyakon — have become veritable synonyms for extreme, severe winter cold.

=GROUP E: Polar climates=

These climates are characterized by average temperatures below 10 °C in all twelve months of the year:
* '''Tundra climate''' (''ET''): Warmest month has an average temperature between 0 °C and 10 °C. These climates occur on the northern edges of the North American and Eurasian landmasses, and on nearby islands; they also exist along the outer fringes of Antarctica (especially the Palmer Peninsula) and on nearby islands.Examples: Iqaluit, NunavutProvideniya, RussiaDeception Island, Antarctica.''ET'' is also found at high elevations outside the polar regions, above the timber line — as at Mount Washington (New Hampshire)/Mount Washington, New Hampshire.
* '''Ice Cap climate''' (''EF''): All twelve months have average temperatures below 0 °C. This climate is dominant in Antarctica (e.g., Scott Base) and in inner Greenland (e.g., Eismitte).
* Occasionally, a third, lower-case letter is added to ''ET'' climates if either the summer or winter is clearly drier than the other half of the year; thus Qikiqtaruk, or Herschel Island, off the coast of Canada's Yukon Territory, becomes ''ETw'', with Pic du Midi de Bigorre in the French Pyrenees acquiring an ''ETs'' designation. If the precipitation is more or less evenly spread throughout the year, ''ETf'' may be used, such as for Hebron, Labrador. When the option to include this letter is exercised, the same standards that are used for Groups C and D apply, with the additional requirement that the wettest month must have an average of at least 30 mm precipitation (Group E climates can be as dry or even drier than Group B climates based on actual precipitation received, but their rate of evaporation is much lower). Seasonal precipitation letters are almost never attached to ''EF'' climates, mainly due to the difficulty in distinguishing between falling and blowing snow, as snow is the sole source of moisture in these climates.

Trewartha climate classification scheme

The Trewartha climate classification scheme is a modified version of the Köppen system. It attempts to redefine the broad climatic groups in such a way as to be closer to vegetational zoning.

* '''Group A:''' This the tropical climate group, defined the same as in Köppen's scheme (i.e., all 12 months average 18 °C or above). Climates with no more than two dry months (defined as having less than 60mm average precipitation, same as per Köppen) are classified ''Ar'' (instead of Köppen's ''Af''), while others are classified ''Aw'' if the dry season is at the time of low sun/short days or ''As'' if the dry season is at the time of high sun/long days. There was no specific monsoon climate identifier in the original scheme, but ''Am'' was added later, with the same parameters as Köppen's (except that at least three months, rather than one, must have less than 60mm average precipitation).
* '''Group B:''' ''BW'' and ''BS'' mean the same as in the Köppen scheme, with the Köppen ''BWn'' climate sometimes being designated ''BM'' (the ''M'' standing for "marine"). However, a different formula is used to quantify the aridity threshold: 10 X (''T'' − 10) + 3''P'', with ''T'' equalling the mean annual temperature in degrees Celsius and ''P'' denoting the percentage of total precipitation received in the six high-sun months (April through September in the Northern Hemisphere and October through March in the Southern). If the precipition for a given location is less than the above formula, its climate is said to be that of a desert (''BW''); if it is equal to or greater than the above formula but less than twice that amount, the climate is classified as steppe (''BS''); and if the precipitation is more than double the value of the formula the climate is not in Group B. Unlike in Köppen's scheme, no thermal subsets exist within this group in Trewartha's, unless the Universal Thermal Scale (see below) is used.
* '''Group C:''' In the Trewartha scheme this category encompasses subtropical climates only (8 or more months above 10 °C). ''Cs'' and ''Cw'' have the same meanings as they do in Köppen's scheme, but the subtropical climate with no distinct dry season is designated ''Cr'' instead of Köppen's ''Cf'' (and for ''Cs'' the average annual precipitation must be less than 890mm [35 inches] in addition to the driest summer month having less than 30mm precipitation and being less than one-third as wet as the wettest winter month).
* '''Group D:''' This group represents temperate climates (4 to 7 months above 10 °C). Maritime temperate climates (most of Köppen's ''Cfb'' and ''Cwb'' climates, though some of these would fit into Trewartha's ''Cr'' and ''Cw'' respectively) are denoted ''DO'' in the Trewartha classification (although some places near the east coasts of both North America and Asia actually qualify as ''DO'' climates in Trewartha's scheme when they fit into ''Cfa/Cwa'' rather than ''Cfb/Cwb'' in Köppen's), while continental climates are represented as ''DCa'' (Köppen ''Dfa'', ''Dwa'', ''Dsa'') and ''DCb'' (Köppen ''Dfb'', ''Dwb'', ''Dsb''). For the continental climates, sometimes the third letter (''a'' or ''b'') is omitted and ''DC'' is simply used instead, and occasionally a precipitational seasonality letter is added to both the maritime and continental climates (''r'', ''w'', or ''s'', as applicable). The dividing point between the maritime and continental climates is 0 °C in the coldest month, rather than the Köppen value of −3 °C (as noted in the section on the Köppen scheme, however, some climatologists — particularly in the United States — now observe 0 °C in the coldest month as the equatorward limit of the continental climates in that scheme as well).
* '''Group E:''' This represents subarctic climates, defined the same as in Köppen's scheme (1 to 3 months with average temperatures of 10 °C or above; Köppen ''Cfc'', ''Dfc'', ''Dwc'', ''Dsc'', ''Dfd'', ''Dwd''). In the original scheme, this group was not further divided; later, the designations ''EO'' and ''EC'' were created, with ''EO'' (maritime subarctic) signifying that the coldest month averages above −10 °C, while ''EC'' (continental subartctic or "boreal") means that at least one month has an average temperature of −10 °C or below. As in Group D, a third letter can be added to indicate seasonality of precipitation. There is no separate counterpart to the Köppen ''Dfd/Dwd'' climate in Trewartha's scheme.
* '''Group F:''' This is the polar climate group, split into ''FT'' (Köppen ''ET'') and ''FI'' (Köppen ''EF'').
* '''Group H:''' Highland climates, in which altitude plays a role in determining climate classification. Specifically, this would apply if correcting the average temperature of each month to a sea-level value using the formula of adding 5.6°C for each 1,000 meters of elevation would result in the climate fitting into a different thermal group than that into which the actual monthly temperatures place it. Sometimes ''G'' is used instead of ''H'' if the above is true and the altitude is 500 meters or higher but lower than 2,500 meters; but the ''G'' or ''H'' is placed in front of the applicable thermal letter rather than replacing it — and the second letter used reflects the ''corrected'' monthly temperatures, not the actual monthly temperatures.
* '''Universal Thermal Scale:''' An option exists to include information on both the warmest and coldest months for every climate by adding a third and fourth letter, respectively. The letters used conform to the following scale:''i'' — severely hot: Mean monthly temperature 35 °C or higher''h'' — very hot: 28 to 34.9°C''a'' — hot: 23 to 27.9°C''b'' — warm: 18 to 22.9°C''l'' — mild: 10 to 17.9°C''k'' — cool: 0.1 to 9.9°C''o'' — cold: −9.9 to 0 °C''c'' — very cold: −24.9 to −10 °C''d'' — severely cold: −39.9 to −25 °C''e'' — excessively cold: −40 °C or below.Examples of the resulting designations include ''Afaa'' for Kuala Lumpur, Malaysia, ''BWhl'' for Aswan, Egypt, ''Crhk'' for Dallas, Texas, ''DOlk'' for London, ''EClc'' for Arkhangelsk, Russia, and ''FTkd'' for Barrow, Alaska.

Criticisms of the Köppen scheme

Some climatologists have argued that Köppen's system could be improved upon. One of the most frequently-raised objections concerns the temperate Group C category, regarded by many as overbroad (it includes both Tampa, Florida/Tampa, Florida and Cape May, New Jersey, for example). In ''Applied Climatology'' (first edition published in 1966), John Griffiths proposed a new Subtropical climate/subtropical zone, encompassing those areas with a coldest month of between 6 °C (42.8 °F) and 18 °C, effectively subdividing Group C into two nearly equal parts (his scheme assigns the letter ''B'' to the new zone, and identifies dry climates with an additional letter immediately following the temperature-based letter).

Another point of contention involves the dry ''B'' climates; the argument here is that their separation by Köppen into only two thermal subsets is inadequate. Those who hold this view (including Griffiths) have suggested that the dry climates be placed on the same temperature continuum as other climates, with the thermal letter being followed by an additional capital letter — ''S'' for steppe or ''W'' (or ''D'') for desert — as applicable (Griffiths also advances an alternate formula for use as an aridity threshold: ''R'' = 160 + 9''T'', with ''R'' equalling the threshold, in millimeters of mean annual precipitation, and ''T'' denoting the mean annual temperature in degrees Celsius).

A third idea is to create a ''maritime polar'' or ''EM'' zone within Group E to separate relatively mild marine locations (such as Ushuaia, Argentina and the outer Aleutian Islands) from the colder, continental tundra climates. Specific proposals vary; some advocate setting a coldest-month parameter, such as −7 °C (19.4 °F), while others support assigning the new designation to areas with an average annual temperature of above 0 °C.

The accuracy of the 10 °C warmest-month line as the start of the polar climates has also been questioned; Otto Nordenskiöld, for example, devised an alternate formula: ''W'' = 9 − 0.1 ''C'', with ''W'' representing the average temperature of the warmest month and ''C'' that of the coldest month, both in degrees Celsius (for instance, if the coldest month averaged −20 ° C, a warmest-month average of 11 °C or higher would be necessary to prevent the climate from being polar). This boundary does appear to more closely follow the tree line, or the latitude poleward of which trees cannot grow, than the 10 °C warmest-month isotherm; the former tends to run poleward of the latter near the western margins of the continents, but at a lower latitide in the landmass interiors, the two lines crossing at or near the east coasts of both Asia and North America.

External links

* http://www.atm.dal.ca/~glesins/climatechangecourse/koeppen.jpg - world map

* http://snow.ag.uidaho.edu/Clim_map/koppen_usa_map.htm - United States

* '''Climate records'''

* http://www.worldclimate.com
* http://www.weatherbase.com

et:Köppeni kliimaklassifikatsioon
ja:ケッペンの気候区分
pt:Temperado
sv:Köppens system

Tag: Climate