Cloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, Sweden
In this study, four and a half months of ceilometer data from Östergarnsholm are used to analyze cloud related to processes in the boundary layer. Measurements are divided into two categories, which are defined by wind direction: a continental and a marine sector. The results show that there are sig...
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Uppsala universitet, Luft-, vatten och landskapslära
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ndltd-UPSALLA1-oai-DiVA.org-uu-3808632019-04-02T03:08:18ZCloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, SwedenengMolnobservationer vid en kustnära plats – en analys av ceilometermätningar från ÖstergarnsholmStenlid, AronUppsala universitet, Luft-, vatten och landskapslära2019CeilometerStratocumuluscloud base heightLCLDLSupwellingcloud coverMeteorology and Atmospheric SciencesMeteorologi och atmosfärforskningIn this study, four and a half months of ceilometer data from Östergarnsholm are used to analyze cloud related to processes in the boundary layer. Measurements are divided into two categories, which are defined by wind direction: a continental and a marine sector. The results show that there are significant differences in the height of the lowest cloud bases detected for the two sectors, where cloud base heights are lower for the marine wind sector during unstable and neutral conditions. The ceilometer’s ability to detect several cloud base heights simultaneously is utilized to test whether a double layer structure (DLS) can be detected. The results of this particular analysis are inconclusive as to whether a DLS has been observed or not. Detected cloud base heights differ greatly from heights suggested by the lifting condensation level (LCL). A new empirical formula for lowest cloud base height is then derived using the measurements. The Ceilometer’s estimations of sky cover are assessed to be of reasonable quality. This is suggested by computed high correlation with incoming shortwave radiation at noon for three months. However, histograms of cloud cover measurements suggest that the ceilometer tends to probably either overestimate or underestimate cloud cover. Large differences in cloud cover were observed for the two wind sectors during unstable conditions. For the months of July and August, a diurnal cycle in cloud cover for the continental wind sector was observed which suggest the presence of Stratocumulus. Measurements performed during upwelling conditions closely resemble those of the marine wind sector performed during stable conditions. Student thesisinfo:eu-repo/semantics/bachelorThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-380863Examensarbete vid Institutionen för geovetenskaper, 1650-6553 ; 454application/pdfinfo:eu-repo/semantics/openAccess |
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English |
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Others
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Ceilometer Stratocumulus cloud base height LCL DLS upwelling cloud cover Meteorology and Atmospheric Sciences Meteorologi och atmosfärforskning |
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Ceilometer Stratocumulus cloud base height LCL DLS upwelling cloud cover Meteorology and Atmospheric Sciences Meteorologi och atmosfärforskning Stenlid, Aron Cloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, Sweden |
description |
In this study, four and a half months of ceilometer data from Östergarnsholm are used to analyze cloud related to processes in the boundary layer. Measurements are divided into two categories, which are defined by wind direction: a continental and a marine sector. The results show that there are significant differences in the height of the lowest cloud bases detected for the two sectors, where cloud base heights are lower for the marine wind sector during unstable and neutral conditions. The ceilometer’s ability to detect several cloud base heights simultaneously is utilized to test whether a double layer structure (DLS) can be detected. The results of this particular analysis are inconclusive as to whether a DLS has been observed or not. Detected cloud base heights differ greatly from heights suggested by the lifting condensation level (LCL). A new empirical formula for lowest cloud base height is then derived using the measurements. The Ceilometer’s estimations of sky cover are assessed to be of reasonable quality. This is suggested by computed high correlation with incoming shortwave radiation at noon for three months. However, histograms of cloud cover measurements suggest that the ceilometer tends to probably either overestimate or underestimate cloud cover. Large differences in cloud cover were observed for the two wind sectors during unstable conditions. For the months of July and August, a diurnal cycle in cloud cover for the continental wind sector was observed which suggest the presence of Stratocumulus. Measurements performed during upwelling conditions closely resemble those of the marine wind sector performed during stable conditions. |
author |
Stenlid, Aron |
author_facet |
Stenlid, Aron |
author_sort |
Stenlid, Aron |
title |
Cloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, Sweden |
title_short |
Cloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, Sweden |
title_full |
Cloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, Sweden |
title_fullStr |
Cloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, Sweden |
title_full_unstemmed |
Cloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, Sweden |
title_sort |
cloud observations at a coastal site – analysis of ceilometer measurements from östergarnsholm, sweden |
publisher |
Uppsala universitet, Luft-, vatten och landskapslära |
publishDate |
2019 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-380863 |
work_keys_str_mv |
AT stenlidaron cloudobservationsatacoastalsiteanalysisofceilometermeasurementsfromostergarnsholmsweden AT stenlidaron molnobservationervidenkustnaraplatsenanalysavceilometermatningarfranostergarnsholm |
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1719008886630907904 |