Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions
A global climate change may have large impacts on water resources on regional and global scales. General circulation models (GCMs) are the most used tools to evaluate climate-change scenarios on a global scale. They are, however, insufficiently describing the effects at the local scale. This thesis...
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ftuppsalauniv:oai:DiVA.org:uu-5937 2023-05-15T17:45:06+02:00 Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions Statistisk nedskalning av nederbörd från storskalig atmosfärscirkulation : Jämförelse mellan metoder och klimatregioner Wetterhall, Fredrik 2005 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5937 eng eng Institutionen för geovetenskaper Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 93 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5937 urn:isbn:91-554-6344-4 info:eu-repo/semantics/openAccess Hydrology Statistical Downscaling Precipitation Large-scale circulation PCA TWS Weather pattern Regression Weather generator Hydrologi Oceanography Hydrology and Water Resources Oceanografi hydrologi och vattenresurser Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2005 ftuppsalauniv 2023-02-23T21:58:36Z A global climate change may have large impacts on water resources on regional and global scales. General circulation models (GCMs) are the most used tools to evaluate climate-change scenarios on a global scale. They are, however, insufficiently describing the effects at the local scale. This thesis evaluates different approaches of statistical downscaling of precipitation from large-scale circulation variables, both concerning the method performance and the optimum choice of predictor variables. The analogue downscaling method (AM) was found to work well as “benchmark” method in comparison to more complicated methods. AM was implemented using principal component analysis (PCA) and Teweles-Wobus Scores (TWS). Statistical properties of daily and monthly precipitation on a catchment in south-central Sweden, as well as daily precipitation in three catchments in China were acceptably downscaled. A regression method conditioning a weather generator (SDSM) as well as a fuzzy-rule based circulation-pattern classification method conditioning a stochastical precipitation model (MOFRBC) gave good results when applied on Swedish and Chinese catchments. Statistical downscaling with MOFRBC from GMC (HADAM3P) output improved the statistical properties as well as the intra-annual variation of precipitation. The studies show that temporal and areal settings of the predictor are important factors concerning the success of precipitation modelling. The MOFRCB and SDSM are generally performing better than the AM, and the best choice of method is depending on the purpose of the study. MOFRBC applied on output from a GCM future scenario indicates that the large-scale circulation will not be significantly affected. Adding humidity flux as predictor indicated an increased intensity both in extreme events and daily amounts in central and northern Sweden. Doctoral or Postdoctoral Thesis Northern Sweden Uppsala University: Publications (DiVA) |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Hydrology Statistical Downscaling Precipitation Large-scale circulation PCA TWS Weather pattern Regression Weather generator Hydrologi Oceanography Hydrology and Water Resources Oceanografi hydrologi och vattenresurser |
spellingShingle |
Hydrology Statistical Downscaling Precipitation Large-scale circulation PCA TWS Weather pattern Regression Weather generator Hydrologi Oceanography Hydrology and Water Resources Oceanografi hydrologi och vattenresurser Wetterhall, Fredrik Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions |
topic_facet |
Hydrology Statistical Downscaling Precipitation Large-scale circulation PCA TWS Weather pattern Regression Weather generator Hydrologi Oceanography Hydrology and Water Resources Oceanografi hydrologi och vattenresurser |
description |
A global climate change may have large impacts on water resources on regional and global scales. General circulation models (GCMs) are the most used tools to evaluate climate-change scenarios on a global scale. They are, however, insufficiently describing the effects at the local scale. This thesis evaluates different approaches of statistical downscaling of precipitation from large-scale circulation variables, both concerning the method performance and the optimum choice of predictor variables. The analogue downscaling method (AM) was found to work well as “benchmark” method in comparison to more complicated methods. AM was implemented using principal component analysis (PCA) and Teweles-Wobus Scores (TWS). Statistical properties of daily and monthly precipitation on a catchment in south-central Sweden, as well as daily precipitation in three catchments in China were acceptably downscaled. A regression method conditioning a weather generator (SDSM) as well as a fuzzy-rule based circulation-pattern classification method conditioning a stochastical precipitation model (MOFRBC) gave good results when applied on Swedish and Chinese catchments. Statistical downscaling with MOFRBC from GMC (HADAM3P) output improved the statistical properties as well as the intra-annual variation of precipitation. The studies show that temporal and areal settings of the predictor are important factors concerning the success of precipitation modelling. The MOFRCB and SDSM are generally performing better than the AM, and the best choice of method is depending on the purpose of the study. MOFRBC applied on output from a GCM future scenario indicates that the large-scale circulation will not be significantly affected. Adding humidity flux as predictor indicated an increased intensity both in extreme events and daily amounts in central and northern Sweden. |
format |
Doctoral or Postdoctoral Thesis |
author |
Wetterhall, Fredrik |
author_facet |
Wetterhall, Fredrik |
author_sort |
Wetterhall, Fredrik |
title |
Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions |
title_short |
Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions |
title_full |
Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions |
title_fullStr |
Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions |
title_full_unstemmed |
Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions |
title_sort |
statistical downscaling of precipitation from large-scale atmospheric circulation : comparison of methods and climate regions |
publisher |
Institutionen för geovetenskaper |
publishDate |
2005 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5937 |
genre |
Northern Sweden |
genre_facet |
Northern Sweden |
op_relation |
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 93 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5937 urn:isbn:91-554-6344-4 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766147846467223552 |