Unit 19
HIGHER LATITUDE (D AND E) AND HIGH-ALTITUDE (H) CLIMATES
Unit OverviewThis unit examines the "cool" climates, which occur either in the upper-middle to higher latitudes, or at high-elevation locales, or both. The main sections are:
- The major humid microthermal (D) climates
- The polar (E) climates
- High-altitude (H) climates
The D climates are located in the middle latitudes, predominantly in the interior portions of Northern Hemisphere continents. The E climates are located poleward of the D climates and receive little precipitation because of the lack of water vapour in the air. The H climates are located at high elevations, and as a result are relatively cold compared to surrounding climates. H climates can be considered anomalies when viewed from the regional perspective. Finally, owing to the location of pollutant-emitting facilities in the D climates and the prevalent westerly winds, acid precipitation is an important geographically displaced environmental problem in this zone.
Unit Objectives
- To expand the discussion of typical D, E, and H climates and to interpret representative climographs for those zone
- To highlight a major environmental-climatic problem of many climate regions: acid precipitation
- To characterize the general influence of altitude on climatic conditions
Glossary of Key Terms
Acid precipitation | Abnormally acidic rain, snow, or fog resulting from high levels of the oxides of sulfurs and nitrogen that exist as industrial pollutants in the air. |
Highland climate | Climate of high-elevation areas that exhibit characteristics of climates located poleward of those found at the base of those highlands; the higher one climbs, the colder the climate becomes - even in the low latitudes. Thus H climate areas are marked by the vertical zonation of climates. |
Humid microthermal climate | The weakly heated continental climates of the Northern Hemisphere's upper midlatitudes, where the seasonal rhythms swing from short, decidedly warm summers to long, often harsh winters; mostly confined to the vast interior expanses of North America and Eurasia poleward of 45 degrees N. |
Permafrost | The permanently frozen layer of subsoil that is characteristic of the colder portions of the D-climate zone as well as the entire E-climate zone; can exceed 300 m (1000 ft) in depth. |
pH scale | Used to measure acidity and alkalinity of substances on a scale ranging from 0 to 14, with 7 being neutral; below 7 increasing acidity is observed as 0 is approached, while above 7 increasing alkalinity is observed as 14 is approached. |
Polar climate | Climate in which the mean temperature of the warmest month is less than 10° C (50° F); the tundra (ET) subtype exhibits warmest-month temperatures between 0° C (32° F) and 10° C (50° F), while in the (coldest) icecap (EF) subtype the average temperature of the warmest month does not reach 0° C (32° F). |
Vertical zonation | Characteristic of H climates, the distinct arrangement of climate zones according to altitudinal position; the higher one climbs, the colder and harsher the climate becomes. |
Unit Outline
- The major humid microthermal (D) climates
- Located poleward of meso thermal climates in Northern Hemisphere
- Harsh winters and warm summers
- Period longer than a month when temperature is below O°C (32°F)
- Humid continental (Dfa/Dwa/,Dtb/Dwb) and taiga (Dfc/Dwc, Dfd, Dwd) climates
- humid continental climates in upper-midlatitudes
- taiga climate is subarctic
- both humid continental and taiga are moist year round (Dt)
- on interiors of large landmasses, dry-winter climates occur (Dw)
- permafrost is a permanently frozen layer of topsoil
- environmental problem of acid precipitation in D climate zones
- The polar (E) climates
- Located beyond the Arctic and Antarctic Circles (66 degrees N & S)
- Six months of light in summer, six months of darkness in winter
- extensive ice fields in winter months
- Average temperature for warmest month is less than 10° C (50° F)
- The tundra (ET) climate
- warmest average monthly temperature between 0° C (32° F) and 10° C (50° F)
- stunted trees, mosses, lichens
- The ice cap (EF) climate
- lowest annual temperatures on Earth
- warmest monthly average temperatures are not above freezing
- High-altitude (H) climates
- Vertical zonation with altitude
- climates become progressively colder with increasing altitude, mimic the pattern as climates progress from the equator to higher latitudes
- tropical or desert climate, surface - 1200m [4,000 feet])
- subtropical climate, 1200m [4,000 feet] - 2400m [8,000 feet]
- mesothermal climate, 2400m [8,000feet] - 3600m [12,000 feet]
- microthermal climate, 3600m [12,000feet] - 4800m [16,000 feet]
- permanent ice and snow, above 4800m [16,000 feet]
- Vertical zonation with altitude
Review Questions
- Compare and contrast the tundra (ET) and icecap (EF) climates.
- Describe the vertical zonation scheme of H climates.