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instruments:ceilo:ceilometer

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instruments:ceilo:ceilometer [2014/01/17 12:13]
jan [Specifications]
instruments:ceilo:ceilometer [2020/02/06 09:09] (current)
jan [Principle]
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 ====== Ceilometer CT25K ====== ====== Ceilometer CT25K ======
-//​Mentor: ​SSteinke.//+ 
 +//​Mentor: ​[[http://​www.geomet.uni-koeln.de/​das-institut/​mitarbeiter/​schween/​|J.HSchween]]//
  
 ===== Principle ===== ===== Principle =====
-A ceilometer measures the cloud base height, ​i.e. the //ceiling// in aviation. It is based on the light detecting and ranging (LIDAR) principle, i.e. it sends laser pulses and measures the backscattered light. From travel time the distance of the back scattering object can be determined. From strength and attenuation of the backscattered signal the backscatter coefficient is determined. The instrument identifies cloud bases by the strong increase of the backscatter coefficient. If the lower clouds are transparent it can detect up to three distinct cloud layers. ​We use the backscatter profile for an estimate of boundary layer height.+A ceilometer measures the cloud base height, ​called ​//ceiling// in aviation. It is based on the light detecting and ranging (LIDAR) principle, i.e. it sends laser pulses and measures the backscattered light. From travel time the distance of the back scattering object can be determined. From strength and attenuation of the backscattered signal the backscatter coefficient is determined. The instrument identifies cloud bases by caluclating visibility from the backscatter coefficient ​and identifying the height from which on you cant see the ground any more. If the lower clouds are transparent it can detect up to three distinct cloud layers. ​In clud free cases we can use the backscatter profile for an estimate of boundary layer height.
  
 ===== Instrument ===== ===== Instrument =====
-{{:​instruments:​ceilo:​ceilo_tophat.jpg?300}}\\ +{{:​instruments:​ceilo:​img_2776_1.jpg?200|}}\\ 
-Current setup at [[http://​www.fz-juelich.de/​|Research Center Jülich]] on the roof of IEK-8: on the left hand side the [[http://​www.radiometer-physics.de/​rpg/​html/​Home.html|RPG]] HATPRO-TOPHAT,​ on the right hand side the [[http://​www.vaisala.com/​en/​meteorology/​Pages/​default.aspx|Vaisala]] CT25K ceilometer.+Current setup at [[http://​www.fz-juelich.de/​|Research Center Jülich]] on the roof of IEK-8.
  
 ===== Data ===== ===== Data =====
 +  * If you are interested in receiving data please contact the instrument mentor: // [[http://​www.geomet.uni-koeln.de/​das-institut/​mitarbeiter/​schween/​|J.H. Schween]]//
  
-[[http://​gop.meteo.uni-koeln.de/​~hatpro/​dataBrowser/​dataBrowser2.html?​site=JOYCE&​date=-1&​UpperLeft=Ceilometer_Backscatter&​UpperRight=Ceilometer_Instrument-status|Quicklook archive]]+  * [[http://​gop.meteo.uni-koeln.de/​~hatpro/​dataBrowser/​dataBrowser2.html?​site=JOYCE&​date=-1&​UpperLeft=Ceilo_ct25k_Backscatter&​UpperRight=Ceilo_ct25k_Instrument-status|Quicklook archive]]
  
  
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 ^  Period ​ ^  Place  ^  Project ​ ^ ^  Period ​ ^  Place  ^  Project ​ ^
 | 10/2010 - today | [[http://​www.fz-juelich.de/​|Research Center Jülich]], Germany |  | | 10/2010 - today | [[http://​www.fz-juelich.de/​|Research Center Jülich]], Germany |  |
-summer months ​2007-2010 | [[http://​www.fz-juelich.de/​icg/​icg-4/​index.php?​index=500|Selhausen]],​ Germany | [[http://​www.tr32.de|TR32]] | +09/2007 - 10/2010 | [[http://​www.fz-juelich.de/​icg/​icg-4/​index.php?​index=500|Selhausen]],​ Germany | [[http://​www.tr32.de|TR32]] | 
-| winter months ​2007 - 2010 | [[http://​www.schneefernerhaus.de/​|UFS]],​ Zugspitze, Germany | [[http://​gop.meteo.uni-koeln.de/​tosca/​| TOSCA]] |+| winter months ​2008/​2009 ​| [[http://​www.schneefernerhaus.de/​|UFS]],​ Zugspitze, Germany | [[http://​gop.meteo.uni-koeln.de/​tosca/​| TOSCA]] |
 | 2006 - 2007 | Nangatchori,​ Benin | [[http://​amma-international.org/​|AMMA]] | | 2006 - 2007 | Nangatchori,​ Benin | [[http://​amma-international.org/​|AMMA]] |
  
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 | Average Power | 8.9 mW | | Average Power | 8.9 mW |
 | Pulse Width | 100 ns | | Pulse Width | 100 ns |
-| Repetition Rate: | 5.57 kHz | +Pulse Repetition Rate (PRR): | 5.57 kHz | 
-| Number of pulses: | 65,​536((65,​536=2^16)) |+| Number of pulses ​(PQTY): | 65,​536((65,​536=2^16=64*1024=4^(7+1) the 7 contained in the last is what you find in the status message)) | 
 +| Averaging time: | 11.7sec (=PQTY/PRR) | 
 +| Time resolution | 15sec ((=> 3.3sec for processing and data transmission)) |
 | Range resolution | 50ft = 30m (see [[internal:​instruments:​ceilometer:​ceilo_readme#​resolution_height_and_range|here]]) | | Range resolution | 50ft = 30m (see [[internal:​instruments:​ceilometer:​ceilo_readme#​resolution_height_and_range|here]]) |
-| Time resolution | 15sec | +| Range | 200...25,000 ft. (60...7500 m) |
-| Range | 0...25,000 ft. (0...7.5 km) |+
 | Laser Divergence | ± 0.53×0.75 mrad (edge×diagonal((the laser is a diode with square shape. The beam thus a pyramid with different opening angles for neighbouring and opposite edges))) |  | Laser Divergence | ± 0.53×0.75 mrad (edge×diagonal((the laser is a diode with square shape. The beam thus a pyramid with different opening angles for neighbouring and opposite edges))) | 
 | Field-of-View Divergence | ± 0.66 mrad |  | Field-of-View Divergence | ± 0.66 mrad | 
 | Telescope diameter | 145mm | | Telescope diameter | 145mm |
 +| Tilting angle | 2.5° as of Aug 21 2015 (7° before...) ​ |
 | Size | 760 x 280 x 245 mm | | Size | 760 x 280 x 245 mm |
 | Power Consumption | 365 W | | Power Consumption | 365 W |
 | Weight ​   | 40 kg | | Weight ​   | 40 kg |
-  ​+| Manufacturer |[[http://​www.vaisala.com/​en/​meteorology/​Pages/​default.aspx|Vaisala]] | 
instruments/ceilo/ceilometer.1389957212.txt.gz · Last modified: 2016/04/07 19:53 (external edit)