{"id":15027,"date":"2026-09-16T11:32:17","date_gmt":"2026-09-16T09:32:17","guid":{"rendered":"https:\/\/wp.unil.ch\/geoblog\/2026\/09\/exploring-the-potential-of-streamflow-observations-for-snow-mass-reanalysis-from-synthetic-to-real-world-experiments\/"},"modified":"2026-10-07T11:15:15","modified_gmt":"2026-10-07T09:15:15","slug":"exploring-the-potential-of-streamflow-observations-for-snow-mass-reanalysis-from-synthetic-to-real-world-experiments","status":"publish","type":"post","link":"https:\/\/wp.unil.ch\/geoblog\/en\/2026\/09\/exploring-the-potential-of-streamflow-observations-for-snow-mass-reanalysis-from-synthetic-to-real-world-experiments\/","title":{"rendered":"Exploring the potential of streamflow observations for snow mass reanalysis: from synthetic to real-world experiments"},"content":{"rendered":"
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Thesis defended by Pau Wiersma, October 16, 2026 – Institute of Earth Surface Dynamics<\/em><\/p>\n<\/div>\n\n\n\n

Snow that accumulates in mountains each winter is much more than a scenic feature of the landscape. It acts as a natural water reservoir, supplying rivers during spring and summer and supporting agriculture, hydropower production, drinking water supplies, and many ecosystems. In the context of climate change, it is essential to understand how snow amounts have changed over past decades and how they may evolve in the future. <\/p>\n\n\n\n

To answer this question, scientists use so-called snow water equivalent (SWE) reanalyses<\/em>, which reconstruct the amount of snow present in mountain regions through time. These reconstructions combine meteorological data with snow observations collected either on the ground or from satellites. However, such observations are not available everywhere and rarely extend back before the 1980s, which limits our ability to study long-term changes. Moreover, they do not always allow us to verify whether model estimates of snow storage are accurate at the scale of entire catchments, or whether snowmelt processes are represented correctly. <\/p>\n\n\n\n

This thesis explores a complementary source of information: streamflow observations. When snow melts, the resulting water eventually reaches rivers and streams. Measurements of streamflow, which are often available over many decades and across large parts of the world, may therefore provide valuable information about how much snow is present in a catchment and how quickly it melts. <\/p>\n\n\n\n

To investigate this potential, I first conducted numerical experiments in an idealized environment. These experiments showed that streamflow indeed contains information about snowmelt at the catchment scale. In particular, day-to-day variations in streamflow reflect melt rates, while the total volume of water flowing through rivers during the melt season provides information about the total amount of snow that has melted. However, the usefulness of this information depends on catchment characteristics. It is easier to extract in catchments where meltwater reaches streams quickly and where rainfall does not strongly obscure the snowmelt signal. <\/p>\n\n\n\n

I then tested these findings under real-world conditions using a large dataset covering 160 snow-influenced catchments across the western United States, Switzerland, and Chile. Using artificial intelligence methods, I showed that snowmelt dynamics can be reconstructed remarkably well using streamflow observations alone. This confirms that rivers retain a strong signature of snow-related processes. Nevertheless, meteorological variables such as temperature and precipitation remain the strongest predictors of snowmelt, and adding streamflow observations provides only a moderate additional improvement. <\/p>\n\n\n\n

In conclusion, this thesis demonstrates that streamflow observations are a valuable but largely underused source of information for snow research. When properly combined with existing methods, they could help improve historical snow reconstructions, particularly in regions and periods where direct snow observations are sparse. These findings open new opportunities to better monitor mountain water resources and their response to a changing climate.<\/p>\n","protected":false},"excerpt":{"rendered":"

Th\u00e8se en sciences de la Terre<\/p>\n","protected":false},"author":47,"featured_media":14976,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"footnotes":"","_links_to":"","_links_to_target":""},"categories":[67055],"tags":[],"class_list":["post-15027","post","type-post","status-publish","format-standard","has-post-thumbnail","category-thesis-defended"],"_links":{"self":[{"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/posts\/15027","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/users\/47"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/comments?post=15027"}],"version-history":[{"count":1,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/posts\/15027\/revisions"}],"predecessor-version":[{"id":15029,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/posts\/15027\/revisions\/15029"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/media\/14976"}],"wp:attachment":[{"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/media?parent=15027"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/categories?post=15027"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/tags?post=15027"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}