The benefits of homogenising snow depth series – Impacts on decadal trends and extremes for Switzerland
Our current knowledge of spatial and temporal snow depth trends is based almost exclusively on time series of non-homogenised observational data. However, like other long-term series from observations, they are prone to inhomogeneities that can influence and even change trends if not taken into acco...
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ftdoajarticles:oai:doaj.org/article:750c7ea7a3bf444bad0b4d17c1459421 2023-05-15T18:32:29+02:00 The benefits of homogenising snow depth series – Impacts on decadal trends and extremes for Switzerland M. Buchmann G. Resch M. Begert S. Brönnimann B. Chimani W. Schöner C. Marty 2023-02-01T00:00:00Z https://doi.org/10.5194/tc-17-653-2023 https://doaj.org/article/750c7ea7a3bf444bad0b4d17c1459421 EN eng Copernicus Publications https://tc.copernicus.org/articles/17/653/2023/tc-17-653-2023.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-17-653-2023 1994-0416 1994-0424 https://doaj.org/article/750c7ea7a3bf444bad0b4d17c1459421 The Cryosphere, Vol 17, Pp 653-671 (2023) Environmental sciences GE1-350 Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.5194/tc-17-653-2023 2023-02-12T01:29:51Z Our current knowledge of spatial and temporal snow depth trends is based almost exclusively on time series of non-homogenised observational data. However, like other long-term series from observations, they are prone to inhomogeneities that can influence and even change trends if not taken into account. In order to assess the relevance of homogenisation for time-series analysis of daily snow depths, we investigated the effects of adjusting inhomogeneities in the extensive network of Swiss snow depth observations for trends and changes in extreme values of commonly used snow indices, such as snow days, seasonal averages or maximum snow depths in the period 1961–2021. Three homogenisation methods were compared for this task: Climatol and HOMER, which apply median-based adjustments, and the quantile-based interpQM. All three were run using the same input data with identical break points. We found that they agree well on trends of seasonal average snow depth, while differences are detectable for seasonal maxima and the corresponding extreme values. Differences between homogenised and non-homogenised series result mainly from the approach for generating reference series. The comparison of homogenised and original values for the 50-year return level of seasonal maximum snow depth showed that the quantile-based method had the smallest number of stations outside the 95 % confidence interval. Using a multiple-criteria approach, e.g. thresholds for series correlation ( >0.7 ) as well as for vertical ( <300 m) and horizontal ( <100 km) distances, proved to be better suited than using correlation or distances alone. Overall, the homogenisation of snow depth series changed all positive trends for derived series of snow days to either no trend or negative trends and amplifying the negative mean trend, especially for stations >1500 m. The number of stations with a significant negative trend increased between 7 % and 21 % depending on the method, with the strongest changes occurring at high snow depths. The ... Article in Journal/Newspaper The Cryosphere Directory of Open Access Journals: DOAJ Articles The Cryosphere 17 2 653 671 |
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Directory of Open Access Journals: DOAJ Articles |
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English |
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Environmental sciences GE1-350 Geology QE1-996.5 |
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Environmental sciences GE1-350 Geology QE1-996.5 M. Buchmann G. Resch M. Begert S. Brönnimann B. Chimani W. Schöner C. Marty The benefits of homogenising snow depth series – Impacts on decadal trends and extremes for Switzerland |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Our current knowledge of spatial and temporal snow depth trends is based almost exclusively on time series of non-homogenised observational data. However, like other long-term series from observations, they are prone to inhomogeneities that can influence and even change trends if not taken into account. In order to assess the relevance of homogenisation for time-series analysis of daily snow depths, we investigated the effects of adjusting inhomogeneities in the extensive network of Swiss snow depth observations for trends and changes in extreme values of commonly used snow indices, such as snow days, seasonal averages or maximum snow depths in the period 1961–2021. Three homogenisation methods were compared for this task: Climatol and HOMER, which apply median-based adjustments, and the quantile-based interpQM. All three were run using the same input data with identical break points. We found that they agree well on trends of seasonal average snow depth, while differences are detectable for seasonal maxima and the corresponding extreme values. Differences between homogenised and non-homogenised series result mainly from the approach for generating reference series. The comparison of homogenised and original values for the 50-year return level of seasonal maximum snow depth showed that the quantile-based method had the smallest number of stations outside the 95 % confidence interval. Using a multiple-criteria approach, e.g. thresholds for series correlation ( >0.7 ) as well as for vertical ( <300 m) and horizontal ( <100 km) distances, proved to be better suited than using correlation or distances alone. Overall, the homogenisation of snow depth series changed all positive trends for derived series of snow days to either no trend or negative trends and amplifying the negative mean trend, especially for stations >1500 m. The number of stations with a significant negative trend increased between 7 % and 21 % depending on the method, with the strongest changes occurring at high snow depths. The ... |
format |
Article in Journal/Newspaper |
author |
M. Buchmann G. Resch M. Begert S. Brönnimann B. Chimani W. Schöner C. Marty |
author_facet |
M. Buchmann G. Resch M. Begert S. Brönnimann B. Chimani W. Schöner C. Marty |
author_sort |
M. Buchmann |
title |
The benefits of homogenising snow depth series – Impacts on decadal trends and extremes for Switzerland |
title_short |
The benefits of homogenising snow depth series – Impacts on decadal trends and extremes for Switzerland |
title_full |
The benefits of homogenising snow depth series – Impacts on decadal trends and extremes for Switzerland |
title_fullStr |
The benefits of homogenising snow depth series – Impacts on decadal trends and extremes for Switzerland |
title_full_unstemmed |
The benefits of homogenising snow depth series – Impacts on decadal trends and extremes for Switzerland |
title_sort |
benefits of homogenising snow depth series – impacts on decadal trends and extremes for switzerland |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/tc-17-653-2023 https://doaj.org/article/750c7ea7a3bf444bad0b4d17c1459421 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 17, Pp 653-671 (2023) |
op_relation |
https://tc.copernicus.org/articles/17/653/2023/tc-17-653-2023.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-17-653-2023 1994-0416 1994-0424 https://doaj.org/article/750c7ea7a3bf444bad0b4d17c1459421 |
op_doi |
https://doi.org/10.5194/tc-17-653-2023 |
container_title |
The Cryosphere |
container_volume |
17 |
container_issue |
2 |
container_start_page |
653 |
op_container_end_page |
671 |
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