text:
Proinsulin
From Wikipedia, the free encyclopedia
Jump to: navigation, search
insulin
Insulin undergoes extensive posttranslational modification along the production pathway. Production and secretion are largely independent; prepared insulin is stored awaiting secretion. Both C-peptide and mature insulin are biologically active. Cell components and proteins in this image are not to scale.
Identifiers
Symbol
INS
Entrez
3630
HUGO
6081
OMIM
176730
RefSeq
NM_000207
UniProt
P01308
Other data
Locus
Chr. 11 p15.5
Proinsulin is the prohormone precursor to insulin made in the beta cells of the islets of Langerhans, specialized regions of the pancreas. In humans, proinsulin is encoded by the INS gene.[1][2] The islets of Langerhans only secrete between 1% and 3% of proinsulin intact.[3] However, because proinsulin has a longer half life than insulin, it can account for anywhere from 5–30% of the insulin-like structures circulating in the blood.[3] There are higher concentrations of proinsulin after meals and lower levels when a person is fasting.[3] Additionally, while proinsulin and insulin have structural differences, proinsulin does demonstrate some affinity for the insulin receptor. Due to the relative similarities in structure, proinsulin can produce between 5% and 10% of the metabolic activity similarly induced by insulin.[3]
Proinsulin is the final single chain protein structure secreted by cells before cleavage into mature insulin.[4] Proinsulin was discovered by Professor Donald F. Steiner of the University of Chicago in 1967.[5]
Contents
[hide]
1 Structure
2 Synthesis and Post-translational Modification
3 Immunogenicity
4 Medical Relevance
4.1 Diabetes Mellitus
4.2 Neonatal Diabetes Mellitus
5 See also
6 References
Structure[edit]
Proinsulin is made up of 81 residues and formed by three distinct chains.[6] The A chain, B, chain, and the area connecting the two named the C peptide.[6] The correct structure of proinsulin is crucial for the correct folding of mature insulin, as the placement of the C peptide sets the molecule up to create correctly positioned disulfide bonds in and between the A and B chains.[6][7] There are three disulfide bonds that are necessary for mature insulin to be the correct structure. Two of these disulfide bonds are between the A and B chains, and one is an intra-A chain bond.[6] The disulfide bonds occur between the seventh residues of the A and B chain, the 19th residue of the A chain and the 20th residue of the B chain, and the 6th and 11th residues of the A chain.[8]
The C peptide is between the A and B chains of proinsulin.[6] The connection between the A chain and C peptide is much more stable than the junction between the C peptide and B chain, with alpha helical features being exhibited near the C peptide-A chain connection.[9] The C peptide-A chain junction occurs between residues 64 and 65 of proinsulin. These are lysine and arginine molecules, respectively.[9] The C peptide-B chain connection is between two arginine residues at positions 31 and 32 of proinsulin.[9]
There is conservation of much of the structure of proinsulin among mammalian species, with much of the residue changes seen from one species to another present in the C peptide.[7][10] That said, the residues of the C peptide that are conserved across species interact with similarly conserved residues on the A and B chains.[7] Thus, it is hypothesized that these conserved residues are important for the functionality of mature insulin.[7]
Synthesis and Post-translational Modification[edit]
Proinsulin is synthesized on membrane associated ribosomes found on the rough endoplasmic reticulum, where it is folded and its disulfide bonds are oxidized. It is then transported to the Golgi apparatus where it is packaged into secretory vesicles, and where it is processed by a series of proteases to form mature insulin. Mature insulin has 35 fewer amino acids; 4 are removed altogether, and the remaining 31 form the C-peptide. The C-peptide is abstracted from the center of the proinsulin sequence; the two other ends (the B chain and A chain) remain connected by disulfide bonds.
The post translational modification of proinsulin to mature insulin only occurs in the beta cells of the islets of Langerhans.[11] When proinsulin is transported through the Golgi apparatus the C-peptide is cleaved.[8] This cleavage occurs with the aid of two endoproteases.[12] Type I endoproteases, PC1 and PC3, disrupt the C peptide-B chain connection.[12] PC2, a type II endoprotease, cleaves the C peptide-A chain bond.[12] The resulting molecule, now mature insulin, is stored as a hexamer in secretory vesicles and is stabilized with Z n 2 + {\displaystyle Zn^{2+}} molecules until it is secreted.[8]
Immunogenicity[edit]
When insulin was originally purified from bovine or porcine pancreata, all the proinsulin was not fully removed.[13][14] When some people used these insulins, the proinsulin may have caused the body to react with a rash, to resist the insulin, or even to make dents or lumps in the skin at the place where the insulin was injected. This can be described as an iatrogenic injury due to slight differences between the proinsulin of different species. Since the late 1970s, when highly purified porcine insulin was introduced, and the level of insulin purity reached 99%, this ceased to be a significant clinical issue.[15] It should also be noted that in respect of their influence on insulin pharmacokinetics, moderate concentrations of certain insulin antibodies may, in fact, be of positive advantage to all diabetics without endogenous insulin secretion (e.g. people with type 1 diabetes) because insulin binding antibodies effectively increase the insulin's clearance rate and distribution space and therefore helps to prolong its pharmacological and biological half lives.[16][clarification needed]
Medical Relevance[edit]
Historically, the focus of many insulin related metabolic diseases has focused on mature insulin. However, in recent years the importance of studying the structure and function of proinsulin in relation to these diseases has become increasingly clear.
Diabetes Mellitus[edit]
Increased levels of proinsulin in the circulatory system relative to mature insulin concentrations can indicate impending insulin resistance and the development of type 2 diabetes.[17] Additional problems with proinsulin that can lead to diabetes include mutations in the number of cysteines present, which could affect correct folding.[8] If the mutation causes only a mild change it could simply stress the endoplasmic reticulum’s ability to properly fold the protein.[8] This stress, after a while, would lead to a decrease in the number of β-cells producing mature insulin, and would then lead to diabetes mellitus.[8]
Neonatal Diabetes Mellitus[edit]
Postnatal proinsulin is crucial for metabolic regulation. However, proinsulin in neonates is important for normal development of the nerves of the eye, development of the heart, and general survival of embryonic cells.[18] Regulation of the concentration of proinsulin during embryonic development is crucial, as too much or too little of the peptide can cause defects and death of the fetus.[18] Thus far in the study of neonatal diabetes mellitus, only amino acid change mutations found in the B domain lead to the disease.[8]
See also[edit]
insulin
preproinsulin
signal peptide
signal peptide peptidase
proprotein convertase 1 (PC1)
proprotein convertase 2 (PC2)
References[edit]
Jump up ^ "Entrez Gene: INS insulin".
Jump up ^ Bell GI, Pictet RL, Rutter WJ, Cordell B, Tischer E, Goodman HM (March 1980). "Sequence of the human insulin gene". Nature. 284 (5751): 26–32. doi:10.1038/284026a0. PMID 6243748.
^ Jump up to: a b c d "Interpretation for 80908 Proinsulin, Plasma". www.mayomedicallaboratories.com. Retrieved 2017-03-09.
Jump up ^ Hernandez-Sanchez, Catalina; et al. (1995). "Autocrine/paracrine role of insulin-related growth factors in neurogenesis: Local expression and effects on cell proliferation and differentiation in retina". Physiology. 92: 9834–9838. doi:10.1073/pnas.92.21.9834 – via PNAS. CS1 maint: Explicit use of et al. (link)
Jump up ^ Philipson, Louis; et al. (2015). "Donald F. Steiner MD, 1930–2014: Discoverer of proinsulin" (PDF). Retrospective. 112: 940–941. doi:10.1073/pnas.1423774112 – via PNAS. CS1 maint: Explicit use of et al. (link)
^ Jump up to: a b c d e Nolan, Chris; Margoliash, E.; Peterson, James D.; Steiner, Donald F. (1971-05-10). "The Structure of Bovine Proinsulin". Journal of Biological Chemistry. 246 (9): 2780–2795. ISSN 0021-9258. PMID 4928892.
^ Jump up to: a b c d Snell, C. R.; Smyth, D. G. (1975-08-25). "Proinsulin: a proposed three-dimensional structure". Journal of Biological Chemistry. 250 (16): 6291–6295. ISSN 0021-9258. PMID 808541.
^ Jump up to: a b c d e f g Weiss, Michael A. (2009-07-17). "Proinsulin and the Genetics of Diabetes Mellitus". Journal of Biological Chemistry. 284 (29): 19159–19163. doi:10.1074/jbc.R109.009936. ISSN 0021-9258. PMC 2740536  . PMID 19395706.
^ Jump up to: a b c Yang, Yanwu; et al. (2010). "Solution Structure of Proinsulin: Connecting domain flexibility and prohormone processing" (PDF). The Journal of Biological Chemistry. 285: 7847–7851. doi:10.1074/jbc.c109.084921 – via JBC. CS1 maint: Explicit use of et al. (link)
Jump up ^ Bell, G.I.; et al. (1980). "Sequence of the human insulin gene". Nature. 284: 26. doi:10.1038/284026a0. PMID 6243748. CS1 maint: Explicit use of et al. (link)
Jump up ^ Groskreutz, Debyra (1993). "Genetically Engineered Proinsulin Constitutively Processed and Secreted as Mature, Active Insulin" (PDF). The Journal of Biological Chemistry. 8: 6241–6245 – via JBC.
^ Jump up to: a b c Kaufmann, Jocelyn; et al. (1995). "Sequence requirements for proinsulin processing at the B-chain/C-peptide junction" (PDF). Biochemistry. 310: 869–874. doi:10.1042/bj3100869. PMC 1135976  . PMID 7575420. CS1 maint: Explicit use of et al. (link)
Jump up ^ Wilson RM, Douglas CA, Tattersall RB, Reeves WG (September 1985). "Immunogenicity of highly purified bovine insulin: a comparison with conventional bovine and highly purified human insulins". Diabetologia. 28 (9): 667–70. doi:10.1007/BF00291973. PMID 3905477.
Jump up ^ Tanyolac S, Goldfine ID, Kroon L. "Insulin Pharmacology, Type of Regimens and Adjustments". Endotext.com. Retrieved 2011-03-18.
Jump up ^ Home PD, Alberti KG (November 1982). "The new insulins. Their characteristics and clinical indications". Drugs. 24 (5): 401–13. doi:10.2165/00003495-198224050-00003. PMID 6756879.
Jump up ^ Gray RS, Cowan P, di Mario U, Elton RA, Clarke BF, Duncan LJ (June 1985). "Influence of insulin antibodies on pharmacokinetics and bioavailability of recombinant human and highly purified beef insulins in insulin dependent diabetics". Br Med J (Clin Res Ed). 290 (6483): 1687–91. doi:10.1136/bmj.290.6483.1687. PMC 1416075  . PMID 3924216.
Jump up ^ Mykkänen, Leena; Haffner, Steven M.; Hales, C. Nick; Rönnemaa, Tapani; Laakso, Markku (1997-12-01). "The Relation of Proinsulin, Insulin, and Proinsulin-to-Insulin Ratio to Insulin Sensitivity and Acute Insulin Response in Normoglycemic Subjects". Diabetes. 46 (12): 1990–1995. doi:10.2337/diab.46.12.1990. ISSN 0012-1797. PMID 9392485.
^ Jump up to: a b Hernández-Sánchez, C.; Mansilla, A.; de la Rosa, E. J.; de Pablo, F. (2006-06-01). "Proinsulin in development: New roles for an ancient prohormone". Diabetologia. 49 (6): 1142–1150. doi:10.1007/s00125-006-0232-5. ISSN 0012-186X. PMID 16596360.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Proinsulin&oldid=830182359"
Categories:
Genes on human chromosome 11
Peptides
Diabetes
Hidden categories:
CS1 maint: Explicit use of et al.
Wikipedia articles needing clarification from August 2009
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
Languages
Deutsch
Español
Italiano
עברית
Polski
Русский
Українська
Edit links
This page was last edited on 13 March 2018, at 07:46.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

values: mw-page-base noprint

values: mw-head-base noprint

values: firstHeading firstHeading en

values: siteSub noprint

values: jump-to-nav mw-jump

attrs: scope style

values:
row
background-color: #e7dcc3

attrs: rel class href

values:
nofollow
external text
https://www.omim.org/176730

values: National Center for Biotechnology Information

values:
nofollow
external text
https://www.uniprot.org/uniprot/P01308

values:
/wiki/Chromosome_11_(human)
mw-redirect
Chromosome 11 (human)

values:
/wiki/Islets_of_Langerhans
mw-redirect
Islets of Langerhans

values:
/wiki/Residue_(amino_acid)
mw-redirect
Residue (amino acid)

values:
/wiki/Disulfide_bonds
mw-redirect
Disulfide bonds

values: Edit section: Synthesis and Post-translational Modification

values:
/wiki/Rough_endoplasmic_reticulum
mw-redirect
Rough endoplasmic reticulum

values:
/wiki/Disulfide_bond
mw-redirect
Disulfide bond

values:
/wiki/Secretory_vesicles
mw-redirect
Secretory vesicles

values: vertical-align: -0.338ex; width:5.408ex; height:2.676ex;

values:
/wiki/Type_1_diabetes
mw-redirect
Type 1 diabetes

values: The text near this tag may need clarification or removal of jargon. (August 2009)

values:
noprint Inline-Template
margin-left:0.1em; white-space:nowrap;

values:
/wiki/Type_2_diabetes
mw-redirect
Type 2 diabetes

values: Edit section: Neonatal Diabetes Mellitus

values:
nofollow
external text
//doi.org/10.1038%2F284026a0

values:
/wiki/PubMed_Identifier
mw-redirect
PubMed Identifier

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/6243748

values:
nofollow
external text
//doi.org/10.1073%2Fpnas.92.21.9834

values: Category:CS1 maint: Explicit use of et al.

values:
nofollow
external text
//doi.org/10.1073%2Fpnas.1423774112

values:
nofollow
external text
http://www.jbc.org/content/246/9/2780

values:
nofollow
external text
//www.worldcat.org/issn/0021-9258

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/4928892

values:
nofollow
external text
http://www.jbc.org/content/250/16/6291

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/808541

values:
nofollow
external text
http://www.jbc.org/content/284/29/19159

values:
nofollow
external text
//doi.org/10.1074%2Fjbc.R109.009936

attrs: alt src title width height srcset data-file-width data-file-height

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/19395706

values:
nofollow
external text
//doi.org/10.1074%2Fjbc.c109.084921

values:
nofollow
external text
//doi.org/10.1042%2Fbj3100869

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/7575420

values:
nofollow
external text
//doi.org/10.1007%2FBF00291973

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/3905477

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/6756879

values:
nofollow
external text
//doi.org/10.1136%2Fbmj.290.6483.1687

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/3924216

values:
nofollow
external text
//doi.org/10.2337%2Fdiab.46.12.1990

values:
nofollow
external text
//www.worldcat.org/issn/0012-1797

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/9392485

values:
nofollow
external text
//www.worldcat.org/issn/0012-186X

values:
nofollow
external text
//www.ncbi.nlm.nih.gov/pubmed/16596360

values: Category:Wikipedia articles needing clarification from August 2009

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Proinsulin
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-navigation p-navigation-label

values: Guidance on how to use and edit Wikipedia

values: About the project, what you can do, where to find things

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-interaction p-interaction-label

values: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

values: Recent changes in pages linked from this page [ctrl-alt-k]

values:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

values: A list of all special pages [ctrl-alt-q]

values: פרואינסולין – Hebrew

values: Проинсулин – Russian

values: Проінсулін – Ukrainian

values: /static/images/wikimedia-button-1.5x.png 1.5x, /static/images/wikimedia-button-2x.png 2x

values: /static/images/poweredby_mediawiki_132x47.png 1.5x, /static/images/poweredby_mediawiki_176x62.png 2x

values:
suggestions
display: none; font-size: 13px;

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Proinsulin rootpage-Proinsulin skin-vector action-view


text:
Climate of Africa
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Climate zones of Africa, showing the ecological break between the hot desert climate of the Sahara Desert (red), the hot semi-arid climate of the Sahel (orange) and the tropical climate of Central and Western Africa (blue). Southern Africa has a transition to semi-tropical or temperate climates (green), and more desert or semi-arid regions, centered on Namibia, Botswana, and South Africa.
A map of Africa showing the ecological break around the Sahara Desert
Owing to Africa's position across equatorial and subtropical latitudes in both the northern and southern hemisphere, several different climate types can be found within it. The continent mainly lies within the intertropical zone between the Tropic of Cancer and the Tropic of Capricorn. Hence, it’s interesting density of humidity intensity is always high, and it is a hot continent. Warm and hot climates prevail all over Africa, but the northern part is that most marked by aridity and high temperatures. Only the northernmost and the southernmost fringes of the continent have a Mediterranean climate.The equator runs through the middle of Africa, as do the Tropic of Cancer and the Tropic of Capricorn, making Africa the most tropical continent.
The climate of Africa is a range of climates such as the equatorial climate, the tropical wet and dry climate, the tropical monsoon climate, the semi-desert climate (semi-arid), the desert climate (hyper-arid and arid), the subtropical highland climate etc. Temperate climates are rare across the continent except at very high elevations and along the fringes. In fact, the climate of Africa is more variable by rainfall amount than by temperatures, which are consistently high. African deserts are the sunniest and the driest parts of the continent, owing to the prevailing presence of the subtropical ridge with subsiding, hot, dry air masses. Africa holds many heat-related records: the continent has the hottest extended region year-round, the areas with the hottest summer climate, the highest sunshine duration etc.
Contents
[hide]
1 Temperatures
2 Wind
3 Precipitation
4 Snow and glaciers
5 See also
6 References
Temperatures[edit]
See also: Subtropical ridge
Monthly mean and minimum outdoor and indoor temperatures throughout Africa
Globally, heating of the earth near the equator leads to large amounts of upward motion and convection along the monsoon trough or Intertropical Convergence Zone. The divergence over the near-equatorial trough leads to air rising and moving away from the equator aloft. As it moves towards the Mid-Latitudes, the air cools and sinks, which leads to subsidence near the 30th parallel of both hemispheres. This circulation is known as the Hadley cell and leads to the formation of the subtropical ridge.[1] Many of the world's deserts are caused by these climatological high-pressure areas,[2] including the Sahara Desert.
Temperatures are hottest within the Sahara regions of Algeria and Mali,[3] and coolest across the south and at elevation within the topography across the eastern and northwest sections of the continent. The hottest average temperature on Earth is at Dallol, Ethiopia, which averages a temperature of 33.9 °C (93.0 °F) throughout the year.[4] The hottest temperature recorded within Africa, which was also the world record, was 57.8 °C (136.0 °F) at 'Aziziya, Libya on September 13, 1922. This was later proven to be false, and to derive from an inaccurate reading of a thermometer. The world's hottest place is in fact Death Valley, in California.[5][6][7] Apparent temperatures, combining the effect of the temperature and humidity, along the Red Sea coast of Eritrea and Gulf of Aden coast of Somalia range between 57 °C (135 °F) and 63 °C (145 °F) during the afternoon hours.[3] The lowest temperature measured within Africa was −24 °C (−11 °F) at Ifrane, Morocco on February 11, 1935.[5] Nevertheless, the major part of Africa experiences extreme heat during much of the year, especially the deserts, steppes and savannas. The African deserts are arguably the hottest places on Earth, especially the Sahara Desert and the Danakil Desert, located in the Horn of Africa.
Wind[edit]
Main article: African easterly jet
The low-level easterly African jet stream is considered to play a crucial role in the southwest monsoon of Africa,[8] and helps form the tropical waves which march across the tropical Atlantic and eastern Pacific oceans during the warm season.[9] The jet exhibits both barotropic and baroclinic instability, which produces synoptic-scale, westward-propagating disturbances in the jet known as African easterly waves, or tropical waves. A small number of mesoscale storm systems embedded in these waves develop into tropical cyclones after they move from west Africa into the tropical Atlantic, mainly during August and September. When the jet lies south of normal during the peak months of the Atlantic hurricane season, tropical cyclone formation is suppressed.[10]
Precipitation[edit]
Mean precipitation map
See also: Wet season
Great parts of North Africa and Southern Africa as well as the whole Horn of Africa mainly have a hot desert climate, or a hot semi-arid climate for the wetter locations. The Sahara Desert in North Africa is the largest hot desert in the world and is one of the hottest, driest and sunniest places on Earth. Located just south of the Sahara is a narrow steppe (a semi-arid region) called the Sahel, while Africa's most southern areas contain both savanna plains, and its central portion contains very dense jungle (rainforest) regions. The equatorial region near the Intertropical Convergence Zone is the wettest portion of the continent. Annually, the rain belt across the country moves northward into Sub-Saharan Africa by August, then passes back southward into south-central Africa by March.[11] Areas with a savannah climate in Sub-Saharan Africa, such as Ghana, Burkina Faso,[12][13] Darfur,[14] Eritrea,[15] Ethiopia,[16] and Botswana have a distinct rainy season.[17] El Nino results in drier-than-normal conditions in Southern Africa from December to February, and wetter-than-normal conditions in equatorial East Africa over the same period.[18]
In Madagascar, trade winds bring moisture up the eastern slopes of the island, which is deposited as rainfall, and bring drier downsloped winds to areas south and west, leaving the western sections of the island in a rain shadow. This leads to significantly more rainfall over northeast sections of Madagascar than its southwestern portions.[19] Southern Africa receives most of its rainfall from summer convective storms and with extratropical cyclones moving through the Westerlies. Once a decade, tropical cyclones lead to excessive rainfall across the region.[20]
Snow and glaciers[edit]
Snow in the Atlas Mountains in Morocco
Snow is an almost annual occurrence on some of the mountains of South Africa, including those of the Cedarberg and around Ceres in the South-Western Cape, and on the Drakensberg in Natal and Lesotho. Tiffendell Resort in the Drakensberg is the only commercial skiing that takes place in South Africa, and has "advanced snow-making capability" allowing skiing for three months of the year.[21] The Mountain Club of South Africa (MCSA) and the Mountain and Ski Club (MSC) [22] of the University of Cape Town both have equipped ski huts in the Hex River mountains. Skiing including snowboarding in the Cape is a hit-and-miss affair, both in terms of timing of snowfalls, and whether there is sufficient snow to cover the rocks.
Table Mountain gets a light dusting of snow on the Front Table and also at Devil's Peak every few years. Snowfalls on Table Mountain took place on 20 September 2013;[23] 30 Aug 2013;[24] 5 August 2011;[25] and on 15 June 2010.[26]
Snow is a rare occurrence in Johannesburg; it fell in May 1956, August 1962, June 1964, September 1981, August 2006, and on 27 June 2007,[27] accumulating up to 10 centimetres (3.9 in) in the southern suburbs.
Additionally, snow regularly falls in the Atlas Mountains in the Maghreb. Snowfall is also a regular occurrence at Mount Kilimanjaro in Tanzania.
There have been permanent glaciers on the Rwenzori Mountains, on the border of Uganda and the Democratic Republic of the Congo. However, by the 2010s, the glaciers were in retreat, and they are under threat of disappearing through rising temperatures.[28]
See also[edit]
Effects of global warming on Africa
Climate of South Africa
Earth rainfall climatology
References[edit]
Jump up ^ Dr. Owen E. Thompson (1996). Hadley Circulation Cell. Archived 2009-03-05 at the Wayback Machine. Channel Video Productions. Retrieved on 2007-02-11.
Jump up ^ ThinkQuest team 26634 (1999). The Formation of Deserts. Archived 2012-10-17 at the Wayback Machine. Oracle ThinkQuest Education Foundation. Retrieved on 2009-02-16.
^ Jump up to: a b Christopher C. Burt (2004). Extreme Weather: a guide & record book. W. W. Norton & Company, Inc. pp. 24–28. ISBN 0-393-32658-6.
Jump up ^ Ronald L. Wagner; Bill Adler, Jr. (1997). The Weather Sourcebook. Adler & Robin Books, Inc. p. 91. ISBN 0-76270-080-7.
^ Jump up to: a b Global Measured Extremes of Temperature and Precipitation. National Climatic Data Center. Retrieved on 2007-06-21.
Jump up ^ El Fadli, KI; et al. (September 2012). "World Meteorological Organization Assessment of the Purported World Record 58°C Temperature Extreme at El Azizia, Libya (13 September 1922)". Bulletin of the American Meteorological Society. 94 (2): 199. Bibcode:2013BAMS...94..199E. doi:10.1175/BAMS-D-12-00093.1. (The 136 °F (57.8 °C), claimed by 'Aziziya, Libya, on September 13, 1922, has been officially deemed invalid by the World Meteorological Organization.)
Jump up ^ "World Meteorological Organization World Weather / Climate Extremes Archive". Archived from the original on 4 January 2013. Retrieved 10 January 2013.
Jump up ^ Kerry H. Cook. Generation of the African Easterly Jet and Its Role in Determining West African Precipitation. Retrieved on 2008-05-08.
Jump up ^ Chris Landsea. AOML Frequently Asked Questions. Subject: A4) What is an easterly wave ? Retrieved on 2008-05-08.
Jump up ^ Climate Prediction Center (November 1997). "Figure 7". National Oceanic and Atmospheric Administration. Retrieved 2011-02-05.
Jump up ^ Todd Mitchell (October 2001). "Africa Rainfall Climatology". University of Washington. Retrieved 2010-01-02.
Jump up ^ Patrick Laux et al. (2008): Predicting the regional onset of the rainy season in West Africa. International Journal of Climatology, 28 (3), 329-342.
Jump up ^ Patrick Laux et al. (2009): Modelling daily precipitation features in the Volta Basin of West Africa. International Journal of Climatology, 29 (7), 937-954.,
Jump up ^ David Vandervort (2009). Darfur: getting ready for the rainy season. International Committee of the Red Cross. Retrieved on 2009-02-06.
Jump up ^ Mehari Tesfazgi Mebrhatu, M. Tsubo, and Sue Walker (2004). A Statistical Model for Seasonal Rainfall Forecasting over the Highlands of Eritrea. New directions for a diverse planet: Proceedings of the 4th International Crop Science Congress. Retrieved on 2009-02-08.
Jump up ^ Alex Wynter (2009). Ethiopia: March rainy season "critical" for southern pastoralists. Thomson Reuters Foundation. Retrieved on 2009-02-06.
Jump up ^ The Voice (2009). Botswana: Rainy Season Fills Up Dams. allAfrica.com. Retrieved on 2009-02-06.
Jump up ^ http://www.scoop.co.nz/stories/WO1010/S00173/la-nina-weather-likely-to-last-for-months.htm
Jump up ^ T. Andry Arivelo; Professeur A. Ratiarison; Professeur M.Bessafi; Rodolphe Ramiharijafy (2007-12-19). "Madagascar rainfall climatology: Extreme Phenomena" (PDF). Stanford University. Retrieved 2010-01-02.
Jump up ^ Pearl Mngadi; Petrus JM Visser; Elizabeth Ebert (October 2006). "Southern Africa Satellite Derived Rainfall Estimates Validation" (PDF). International Precipitation Working Group. p. 1. Retrieved 2010-01-05. [permanent dead link]
Jump up ^ "Skiing and Snowboarding". Tiffendell. Retrieved 16 February 2014.
Jump up ^ "UCT Mountain and Ski Club". Retrieved 16 February 2014.
Jump up ^ "Snow on Table Mountain". Retrieved 16 February 2014.
Jump up ^ "Snow Doubt…There's Snow on Table Mountain Today". Retrieved 16 February 2014.
Jump up ^ "Snow on Table Mountain: August Chill Sets In". Retrieved 16 February 2014.
Jump up ^ "Icy Weather Brings Snow to Table Mountain". Retrieved 16 February 2014.
Jump up ^ SABCnews.com. "Joburg covered by snow as temperature drops". Archived from the original on 2007-06-29. Retrieved 2007-07-16.
Jump up ^ Dalsy Carrington, CNN, April,3, 2014 "Last chance to see: Disappearing glaciers in the 'Mountains of the Moon'" http://www.cnn.com/2014/04/03/world/africa/last-chance-disappearing-glaciers/
[hide]
v
t
e
Climate of Africa
Sovereign states
Algeria
Angola
Benin
Botswana
Burkina Faso
Burundi
Cameroon
Cape Verde (Cabo Verde)
Central African Republic
Chad
Comoros
Democratic Republic of the Congo
Republic of the Congo
Djibouti
Egypt
Equatorial Guinea
Eritrea
Ethiopia
Gabon
The Gambia
Ghana
Guinea
Guinea-Bissau
Ivory Coast (Côte d'Ivoire)
Kenya
Lesotho
Liberia
Libya
Madagascar
Malawi
Mali
Mauritania
Mauritius
Morocco
Mozambique
Namibia
Niger
Nigeria
Rwanda
São Tomé and Príncipe
Senegal
Seychelles
Sierra Leone
Somalia
South Africa
South Sudan
Sudan
Swaziland
Tanzania
Togo
Tunisia
Uganda
Zambia
Zimbabwe
States with limited
recognition
Sahrawi Arab Democratic Republic
Somaliland
Dependencies and
other territories
Canary Islands / Ceuta / Melilla (Spain)
Madeira (Portugal)
Mayotte / Réunion (France)
Saint Helena / Ascension Island / Tristan da Cunha (United Kingdom)
Western Sahara
Retrieved from "https://en.wikipedia.org/w/index.php?title=Climate_of_Africa&oldid=836247976"
Categories:
Climate of Africa
Hidden categories:
Webarchive template wayback links
All articles with dead external links
Articles with dead external links from May 2017
Articles with permanently dead external links
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Languages
한국어
Norsk
Norsk nynorsk
Polski
Română
Slovenščina
Српски / srpski
Srpskohrvatski / српскохрватски
Svenska
Українська
3 more
Edit links
This page was last edited on 13 April 2018, at 15:55.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

key: html

type: local

value: div

attrs: id class

values: mw-page-base noprint

values: mw-head-base noprint

value: a

attrs: id class lang

values: firstHeading firstHeading en

values: siteSub noprint

values: jump-to-nav mw-jump

value: img

attrs: alt src width height class srcset data-file-width data-file-height

attrs: href class

attrs: href class title

values:
/wiki/Climate_zone
mw-redirect
Climate zone

values:
/wiki/Hot_desert_climate
mw-redirect
Hot desert climate

values:
/wiki/Sahara_Desert
mw-redirect
Sahara Desert

values:
/wiki/Hot_semi-arid_climate
mw-redirect
Hot semi-arid climate

attrs: href title

attrs: class style

values:
/wiki/Tropical_climate_zone
mw-redirect
Tropical climate zone

values:
/wiki/Equatorial_climate
mw-redirect
Equatorial climate

values:
/wiki/Tropical_wet_and_dry_climate
mw-redirect
Tropical wet and dry climate

values:
/wiki/Semi-desert_climate
mw-redirect
Semi-desert climate

values:
/wiki/Subtropical_highland_climate
mw-redirect
Subtropical highland climate

values:
/wiki/Natal_(region)
mw-redirect
Natal (region)

values:
nofollow
external text
//doi.org/10.1175%2FBAMS-D-12-00093.1

values:
/wiki/Chris_Landsea
mw-redirect
Chris Landsea

values: National Oceanic and Atmospheric Administration

values:
nofollow
http://www.mountainandski.com/
external text

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;

values:
/wiki/Climate_of_Algeria
mw-redirect
Climate of Algeria

values:
/wiki/Climate_of_Angola
mw-redirect
Climate of Angola

values:
/wiki/Climate_of_Benin
mw-redirect
Climate of Benin

values:
/wiki/Climate_of_Botswana
mw-redirect
Climate of Botswana

values:
/wiki/Climate_of_Burkina_Faso
mw-redirect
Climate of Burkina Faso

values:
/wiki/Climate_of_Burundi
mw-redirect
Climate of Burundi

values:
/wiki/Climate_of_Cameroon
mw-redirect
Climate of Cameroon

values:
/wiki/Climate_of_Cape_Verde
mw-redirect
Climate of Cape Verde

values:
/wiki/Climate_of_Chad
mw-redirect
Climate of Chad

values:
/wiki/Climate_of_the_Comoros
mw-redirect
Climate of the Comoros

values: Climate of the Democratic Republic of the Congo

values:
/wiki/Climate_of_Djibouti
mw-redirect
Climate of Djibouti

values:
/wiki/Climate_of_Equatorial_Guinea
mw-redirect
Climate of Equatorial Guinea

values:
/wiki/Climate_of_Eritrea
mw-redirect
Climate of Eritrea

values:
/wiki/Climate_of_Ethiopia
mw-redirect
Climate of Ethiopia

values:
/wiki/Climate_of_Gabon
mw-redirect
Climate of Gabon

values:
/wiki/Climate_of_the_Gambia
mw-redirect
Climate of the Gambia

values:
/wiki/Climate_of_Guinea
mw-redirect
Climate of Guinea

values:
/wiki/Climate_of_Guinea-Bissau
mw-redirect
Climate of Guinea-Bissau

values:
/wiki/Climate_of_Ivory_Coast
mw-redirect
Climate of Ivory Coast

values:
/wiki/Climate_of_Kenya
mw-redirect
Climate of Kenya

values:
/wiki/Climate_of_Lesotho
mw-redirect
Climate of Lesotho

values:
/wiki/Climate_of_Liberia
mw-redirect
Climate of Liberia

values:
/wiki/Climate_of_Libya
mw-redirect
Climate of Libya

values:
/wiki/Climate_of_Madagascar
mw-redirect
Climate of Madagascar

values:
/wiki/Climate_of_Malawi
mw-redirect
Climate of Malawi

values:
/wiki/Climate_of_Mali
mw-redirect
Climate of Mali

values:
/wiki/Climate_of_Mauritania
mw-redirect
Climate of Mauritania

values:
/wiki/Climate_of_Mauritius
mw-redirect
Climate of Mauritius

values:
/wiki/Climate_of_Morocco
mw-redirect
Climate of Morocco

values:
/wiki/Climate_of_Mozambique
mw-redirect
Climate of Mozambique

values:
/wiki/Climate_of_Namibia
mw-redirect
Climate of Namibia

values:
/wiki/Climate_of_Niger
mw-redirect
Climate of Niger

values:
/wiki/Climate_of_Nigeria
mw-redirect
Climate of Nigeria

values:
/wiki/Climate_of_Rwanda
mw-redirect
Climate of Rwanda

values:
/wiki/Climate_of_Senegal
mw-redirect
Climate of Senegal

values:
/wiki/Climate_of_Seychelles
mw-redirect
Climate of Seychelles

values:
/wiki/Climate_of_Sierra_Leone
mw-redirect
Climate of Sierra Leone

values:
/wiki/Climate_of_Somalia
mw-redirect
Climate of Somalia

values:
/wiki/Climate_of_South_Sudan
mw-redirect
Climate of South Sudan

values:
/wiki/Climate_of_Sudan
mw-redirect
Climate of Sudan

values:
/wiki/Climate_of_Swaziland
mw-redirect
Climate of Swaziland

values:
/wiki/Climate_of_Tanzania
mw-redirect
Climate of Tanzania

values:
/wiki/Climate_of_Togo
mw-redirect
Climate of Togo

values:
/wiki/Climate_of_Tunisia
mw-redirect
Climate of Tunisia

values:
/wiki/Climate_of_Uganda
mw-redirect
Climate of Uganda

values:
/wiki/Climate_of_Zimbabwe
mw-redirect
Climate of Zimbabwe

values: Climate of the Sahrawi Arab Democratic Republic

values:
/wiki/Climate_of_Somaliland
mw-redirect
Climate of Somaliland

values:
/wiki/Climate_of_the_Canary_Islands
mw-redirect
Climate of the Canary Islands

values:
/wiki/Climate_of_Ceuta
mw-redirect
Climate of Ceuta

values:
/wiki/Climate_of_Melilla
mw-redirect
Climate of Melilla

values:
/wiki/Climate_of_Madeira
mw-redirect
Climate of Madeira

values:
/wiki/Climate_of_Mayotte
mw-redirect
Climate of Mayotte

values:
/wiki/Climate_of_R%C3%A9union
mw-redirect
Climate of Réunion

values:
/wiki/Climate_of_Saint_Helena
mw-redirect
Climate of Saint Helena

values:
/wiki/Climate_of_Ascension_Island
mw-redirect
Climate of Ascension Island

values:
/wiki/Climate_of_Tristan_da_Cunha
mw-redirect
Climate of Tristan da Cunha

values:
/wiki/Climate_of_Western_Sahara
mw-redirect
Climate of Western Sahara

values: nowraplinks collapsible autocollapse navbox-inner

values: Category:Webarchive template wayback links

values: Category:All articles with dead external links

values: Category:Articles with dead external links from May 2017

values: Category:Articles with permanently dead external links

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Climate_of_Africa
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values: Find background information on current events

values: Permanent link to this revision of the page

values: Link to connected data repository item [ctrl-alt-g]

values: Printable version of this page [ctrl-alt-p]

values: portal navigation p-wikibase-otherprojects p-wikibase-otherprojects-label

values: 아프리카의 기후 – Korean

values:
interlanguage-link interwiki-sl
display: none;

values: Клима Африке – Serbian

values: interlanguage-link interwiki-sr badge-Q17437796 badge-featuredarticle

values:
interlanguage-link interwiki-sh
display: none;

values: Клімат Африки – Ukrainian

values:
interlanguage-link interwiki-uk
display: none;

values: All languages (initial selection from common choices by you and others)

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Climate_of_Africa rootpage-Climate_of_Africa skin-vector action-view