Editing Microclimate (section)

==Sources and influences on microclimate==
Two main parameters to define a microclimate within a certain area are temperature and [[humidity]]. A source of a drop in temperature and/or humidity can be attributed to different sources or influences.
Often a microclimate is shaped by a conglomerate of different influences and is a subject of [[microscale meteorology]].

===Cold air pool===
Examples of the [[Cold-air pool|cold air pool]] (CAP) effect are Gstettneralm Sinkhole in Austria (lowest recorded temperature {{convert|-53|C|abbr=on}})<ref>{{cite web|url=http://www.wetter-freizeit.com/mikroklima.html|title=Mikroklima – Definition – Wissenswertes|website= wetter-freizeit.com}}</ref> and [[Peter Sinks]] in the US.
The main criterion on the wind speed <math>v</math> in order to create a warm air flow penetration into a CAP is the following:
:<math>
\mathrm{Fr} = \frac{v}{Nh} \geq \mathrm{Fr}_c,
</math>

where <math>\mathrm{Fr}</math> is the [[Froude number]], <math>N</math> — the [[Brunt–Väisälä frequency]], <math>h</math> — depth of the valley, and <math>\mathrm{Fr}_c</math> — Froude number at the threshold wind speed.<ref>J. Racovec et al. Turbulent dissipation of the cold-air pool in a basin: comparison of observed and simulated development. Meteorol. Atmos. Phys. 79, 195–213 (2002).</ref>

===Craters===
The presence of [[permafrost]] close to the surface in a [[volcanic crater|crater]] creates a unique microclimate environment.<ref>{{cite web|url=http://astrobiology.nasa.gov/nai/reports/annual-reports/2010/uh/permafrost-in-hawaii/|title=Permafrost in Hawaii |website=NASA Astrobiology Institute |date=2010|url-status=dead|archive-url=https://web.archive.org/web/20141217143746/http://astrobiology.nasa.gov/nai/reports/annual-reports/2010/uh/permafrost-in-hawaii/|archive-date=2014-12-17}}</ref>

===Caves===
[[Caves]] are important geologic formations that can house unique and delicate geologic/biological environments. The vast majority of caves found are made of calcium carbonates such as [[limestone]]. In these dissolution environments, many species of flora and fauna find home. The mixture of water content within the cave atmosphere, air pressure, geochemistry of the cave rock as well as the waste product from these species can combine to make unique microclimates within cave systems.<ref name="Dredge, Jonathan 2013">Dredge, Jonathan & Fairchild, Ian & Harrison, Roy & Fernandez-Cortes, Angel &  Sanchez-Moral, S. & Jurado, Valme & Gunn, John & Smith, Andrew & Spötl, Christoph  & Mattey, David & Wynn, Peter & Grassineau, Nathalie. (2013). Cave aerosols:  Distribution and contribution to speleothem geochemistry. Quaternary Science Reviews.  63. 23–41. 10.1016/j.quascirev.2012.11.016</ref> 
 
The speleogenetic effect is an observed and studied process of air circulation within cave environments brought on by convection. In [[Phreatic zone|phreatic]] conditions the cave surfaces are exposed to the enclosed air (as opposed to submerged and interacting with water from the water table in [[vadose]] conditions). This air circulates water particles that condense on cave walls and formations such as [[speleothems]]. This condensing water has been found to contribute to cave wall erosion and the formation of morphological features. Some examples of this can be found in the limestone walls of [[Monsummano Terme#Main sights|Grotta Giusti]]; a thermal cave near [[Monsummano Terme|Monsummano]], Lucca, Italy. Any process that leads to an increase or decrease in chemical/physical processes will subsequently impact the environment within that system. Air density within caves, which directly relates to the convection processes, is determined by the air temperature, humidity, and pressure. In enclosed cave environments, the introduction of bacteria, algae, plants, animals, or human interference can change any one of these factors therefore altering the microenvironment within the cave.<ref name="Dredge, Jonathan 2013"/> There are over 750 caves worldwide that are available for people to visit. The constant human traffic through these cave environments can have a negative effect on the microclimates as well as on the geological and archeological findings. Factors that play into the deterioration of these environments include nearby deforestation, agriculture operations, water exploitation, mining, and tourist operations.<ref>Hoyos, M., Soler, V., Cañaveras, J. et al. Microclimatic characterization of a karstic cave human impact on microenvironmental parameters of a prehistoric rock art cave (Candamo Cave, northern Spain). Environmental Geology 33, 231–242 (1998). https://doi.org/10.1007/s002540050242</ref>

The speleogenetic effect of normal caves tends to show a slow circulation of air. In unique conditions where acids are present, the effects of erosion and changes to the microenvironment can be drastically enhanced. One example is the effect of the presence of hydro[[sulfuric acid]]({{chem2|H2S}}). When the oxidized hydrosulfuric acid chemically alters to sulfuric acid({{chem2|H2SO4}}), this acid starts to react with the calcium [[carbonate rock]] at much higher rates. The water involved in this reaction tends to have a high pH of 3 which renders the water almost unlivable for many bacteria and algae. An example of this can be found in the [[Frasassi Caves#Chambers|Grotta Grande del Vento cave]] in [[Province of Ancona|Ancona, Italy]].<ref name="Dredge, Jonathan 2013"/>

===Plant microclimate===
As pointed out by meteorologist [[Rudolf Geiger]],<ref>R. Geiger. The climate near the ground. Harvard University Press, 1957.</ref> not only does climate influence the living plant, but the opposite effect of the interaction of plants on their environment can also take place, which is ultimately known as ''plant climate''. This effect has important consequences for forests in the midst of a continent; indeed, if forests were not creating their own clouds and [[Water cycle management|water cycle]] with their efficient [[evapotranspiration]] activity, there would be no forest far away from coasts,<ref>{{Cite journal|last1=Sheil|first1=Douglas|last2=Murdiyarso|first2=Daniel|date=2009-04-01|title=How Forests Attract Rain: An Examination of a New Hypothesis|url=https://academic.oup.com/bioscience/article/59/4/341/346941 |doi-access=free |s2cid-access=free |journal=BioScience|language=en|volume=59|issue=4|pages=341–347|doi=10.1525/bio.2009.59.4.12|s2cid=85905766|issn=0006-3568 |via=Oxford Academic |url-status=live |archive-url=https://web.archive.org/web/20240324085021/https://academic.oup.com/bioscience/article/59/4/341/346941 |archive-date= Mar 24, 2024 |url-access=subscription}}</ref> as statistically, without any other influence, rainfall occurrence would decrease from the coast towards inland. Planting trees to fight drought has also been proposed in the context of [[afforestation]].<ref>{{Cite web|url=https://forestsnews.cifor.org/10316/make-it-rain-planting-forests-to-help-drought-stricken-regions?fnl=en |first1=Kate |last1=Evans |title=Make it rain: Planting forests could help drought-stricken regions|date=2012-07-23|website=CIFOR-ICRAF Forests News |access-date=2020-02-09}}</ref>

===Dams===
{{Main|Environmental impact of reservoirs}}
Artificial reservoirs as well as natural ones create microclimates and often influence the macroscopic climate as well.

=== Slopes ===
Another contributing factor of microclimate is the slope or [[aspect (geography)|aspect]] of an area. South-facing slopes in the [[Northern Hemisphere]] and north-facing slopes in the [[Southern Hemisphere]] are exposed to [[effect of Sun angle on climate|more direct sunlight]] than opposite slopes and are therefore warmer for longer periods of time, giving the slope a warmer microclimate than the areas around the slope. The lowest area of a [[glen]] may sometimes [[frost]] sooner or harder than a nearby spot uphill, because cold air sinks, a drying breeze may not reach the lowest bottom, and [[dew point|humidity lingers and precipitates]], then [[freezing|freezes]].

===Soil types===
The type of soil found in an area can also affect microclimates. For example, soils heavy in clay can act like pavement, moderating the near ground temperature. On the other hand, if soil has many air pockets, then the heat could be trapped underneath the topsoil, resulting in the increased possibility of frost at ground level.<ref>{{Cite web |title=Microclimates |url=http://www.gardening.cornell.edu/weather/microcli.html |url-status=dead |archive-url=https://web.archive.org/web/20160802083235/http://www.gardening.cornell.edu:80/weather/microcli.html |archive-date=Aug 2, 2016 |website=Gardening Resources, Cornell University}}</ref>