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| Atmospheric Icing is icing happening in the air, when water droplets freeze on objects. The water droplets can be in form of [[Mist]], [[Fog]], [[Cloud]] or rain. Sometimes also water vapour can cause icing directly without the presence of liquid water.
| | [[File:Parameters.jpg|thumb|677x677px|Meteorological parameters of atmospheric icing. <ref>S. Fikke, G. Ronsten, A. Heimo, S. Kunz, M. Ostrozlik, P.-E. Persson, J. Sabata, B. Wareing, B. Wichura, J. Chum, T. Laakso, K. Säntti, Lasse Makkonen, COAT 727: Atmospheric Icing on Strutures Measurements and data collection on icing: State of the Art, MeteoSwiss No. 75, 2007.</ref>]] |
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| The ice is often classified as follows:
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| * [[Clear ice]]
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| * [[Hard Rime]] ice
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| * [[Soft Rime]] ice
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| * [[Frost]]<ref name="Makkonen">{{Cite journal| doi = 10.1002/we.517| title = Production of the Finnish Wind Atlas| accessdate = 2021-08-09| url = https://onlinelibrary.wiley.com/doi/10.1002/we.517}}</ref>
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| [[Freezing rain]] causes [[Clear ice]] or [[Hard Rime]] ice. Freezing [[Fog]], clouds or [[Mist]] cause [[Soft Rime]] and cold water vapour may cause [[Frost]].<ref>{{Cite journal| doi = 10.1016/S0169-8095(97)00056-2| issn = 0169-8095| volume = 46| issue = 1| pages = 131–142| last = Makkonen| first = Lasse| title = Modeling power line icing in freezing precipitation| journal = Atmospheric Research| accessdate = 2021-06-24| date = 1998-04-01| url = https://www.sciencedirect.com/science/article/pii/S0169809597000562}}</ref>
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| The international ISO standard Atmospheric Icing on Structures (ISO, E 2017) is based on Makkonen icing model. The icing model calculates the amount of ice accumulated over a 1m high vertically oriented, freely rotating cylinder with a diameter of 3 cm. A threshold value of 10 g/h for the modelled icing intensity is often used (Hämäläinen and Niemelä 2017; Kjeller Vindteknikk 2020) to distinguish between icing and non-icing conditions. Production of a Numerical Icing Atlas for Finland<ref name="Makkonen">{{Cite journal| doi = 10.1002/we.517| title = Production of the Finnish Wind Atlas| accessdate = 2021-08-09| url = https://onlinelibrary.wiley.com/doi/10.1002/we.517}}</ref>
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| The equation 3.1 describes the rime ice rate [g/h] over the standard cylinder, taking into account also melting<ref>{{Cite_web|last=Testi|first=Mies|date=2021-11-26|title=Testailuja|url=https://www.google.com|url-status=live|archive-date=2021-11-26|access-date=2021-11-26}}</ref>
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| <math>\frac{\mathrm{d} M}{\mathrm{d} t}=\alpha_1 \cdot \alpha_2 \cdot \alpha_3 \cdot \rho_{LW} \cdot A \cdot v -Q_m,</math>
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| where dM/dt is the rate of accretion [g/s], The collision (α1), sticking (α2 ) and accretion (α3) are unitless coefficients and they describe the interactions between the cylinder and cloud water droplets. The ρLW is the liquid water content [g/m3], A is the surface area of the cylinder [m2] and v is the wind speed [m/s]. Liquid water content, ρLW depends on cloud type. In clean air ρLW=0, and in different kinds of clouds it varies ρLW = [0.03-3.0] g/cm3. The only relevant cloud type in our case is fog, when ρLW = 0.06 g/cm3. Another
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| {{Cite journal| doi = 10.1016/S0169-8095(97)00056-2| issn = 0169-8095| volume = 46| issue = 1| pages = 131–142| last = Makkonen| first = Lasse| title = Modeling power line icing in freezing precipitation| journal = Atmospheric Research| accessdate = 2021-06-24| date = 1998-04-01| url = https://www.sciencedirect.com/science/article/pii/S0169809597000562}}
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| {{Cite journal| doi = 10.1002/met.1964| issn = 1469-8080| volume = 27| issue = 6| pages = –1964| last1 = Hämäläinen| first1 = Karoliina| last2 = Hirsikko| first2 = Anne| last3 = Leskinen| first3 = Ari| last4 = Komppula| first4 = Mika| last5 = O'Connor| first5 = Ewan J.| last6 = Niemelä| first6 = Sami| title = Evaluating atmospheric icing forecasts with ground-based ceilometer profiles| journal = Meteorological Applications| accessdate = 2021-08-05| date = 2020| url = https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/met.1964}}
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| {{Cite journal| doi = 10.1002/we.517| title = Production of the Finnish Wind Atlas| accessdate = 2021-08-09| url = https://onlinelibrary.wiley.com/doi/10.1002/we.517}}
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| {{Cite journal| doi = 10.1002/we.1998| issn = 1099-1824| volume = 20| issue = 1| pages = 171–189| last1 = Hämäläinen| first1 = Karoliina| last2 = Niemelä| first2 = Sami| title = Production of a Numerical Icing Atlas for Finland| journal = Wind Energy| accessdate = 2021-08-09| date = 2017| url = https://onlinelibrary.wiley.com/doi/abs/10.1002/we.1998}}
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| {{Cite journal| doi = 10.1098/rsta.2000.0690| volume = 358| issue = 1776| pages = 2913–2939| last1 = Poots| first1 = G.| last2 = Makkonen| first2 = Lasse| title = Models for the growth of rime, glaze, icicles and wet snow on structures| journal = Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences| accessdate = 2021-08-12| date = 2000-11-15| url = https://royalsocietypublishing.org/doi/10.1098/rsta.2000.0690}}
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| {{Cite journal| doi = 10.1175/JTECH-D-14-00151.1| issn = 0739-0572, 1520-0426| volume = 32| issue = 8| pages = 1447–1463| last1 = Gregow| first1 = E.| last2 = Bernstein| first2 = B.| last3 = Wittmeyer| first3 = I.| last4 = Hirvonen| first4 = J.| title = LAPS–LOWICE: A Real-Time System for the Assessment of Low-Level Icing Conditions and Their Effect on Wind Power| journal = Journal of Atmospheric and Oceanic Technology| accessdate = 2021-08-20| date = 2015-08-01| url = https://journals.ametsoc.org/view/journals/atot/32/8/jtech-d-14-00151_1.xml}}
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| ==References== | | ==References== |
| <references /> | | <references /> |
