class: center, middle, inverse, title-slide .title[ # Snow in the European Alps ] .subtitle[ ## Environmental Meteorology seminar series UniTN ] .author[ ### Michael Matiu ] .institute[ ### DICAM, Uni Trento ] .date[ ### 2022/11/17 ] --- ## Outline 1. Snow: what is it and why is it important? 2. How is snow measured 3. Snow climatology in the European Alps 4. Past and future trends of snow cover --- class: center, middle, inverse # What is snow? --- background-image: url("fig/snowfall2.jpg") background-size: cover .footnote[Photo <a href="https://pixabay.com/users/cocoparisienne-127419/?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=1861704">Anja</a> from <a href="https://pixabay.com//?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=1861704">Pixabay</a>] --- background-image: url("fig/snow-shoveling.jpg") background-size: cover .footnote[Image by <a href="https://pixabay.com/users/alehandra13-1817807/?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=3146420">Alehandra13</a> from <a href="https://pixabay.com//?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=3146420">Pixabay</a>] --- background-image: url("fig/snow-fun.jpg") background-size: cover .footnote[Image by <a href="https://pixabay.com/users/cdporter-4278988/?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=1984387">Charles Porter</a> from <a href="https://pixabay.com//?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=1984387">Pixabay</a>] --- background-image: url("fig/snow-avalanche.jpg") background-size: cover .footnote[<a href="https://www.rainews.it/tgr/tagesschau/articoli/2019/11/tag-Martell-Lahn-Lawine-Suedtirol-Unwetter-Christian-Gurschler-de137fd1-b796-4070-a8a4-058c80353f43.html">Avalanche 2019 in Martell/Martello, Alto Adige</a>] --- background-image: url("fig/snow-grains.png") background-size: contain .footnote[https://cryosphericsciences.org/publications/snow-classification/] --- background-image: url("fig/snow-layer-wind.jpg") background-size: cover .footnote[Image by <a href="https://pixabay.com/users/natalia_kollegova-5226803/?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=3173001">Наталья Коллегова</a> from <a href="https://pixabay.com//?utm_source=link-attribution&amp;utm_medium=referral&amp;utm_campaign=image&amp;utm_content=3173001">Pixabay</a>] --- class: center, middle, inverse # Why is snow important? --- # Albedo .pull-left[ <img height="500" alt="Albedo explanation" src="fig/albedo2-examples.png"> ] .pull-right[ <img alt="Albedo explanation" src="fig/albedo1-explanation.png"> .footnote[Source: [here](https://www.essearth.com/why-albedo-is-important-for-our-melting-ice-caps/) and [here](https://en.wikipedia.org/wiki/Albedo)] ] --- class: middle .pull-left[<img src="fig/nh_map_2018_2022_biweekly.gif">] .pull-right[<img src="fig/nh-seasonal-clim.png">] .footnote[Source: [Global Snow Lab](http://climate.rutgers.edu/snowcover/index.php)] --- class: middle .pull-left[<img src="fig/nh_map_2018_2022_biweekly.gif">] .pull-right[<img src="fig/nh-interannual-feb.png">] .footnote[Source: [Global Snow Lab](http://climate.rutgers.edu/snowcover/index.php)] --- class: middle .pull-left[<img src="fig/nh_map_2018_2022_biweekly.gif">] .pull-right[<img src="fig/nh-interannual-jun.png">] .footnote[Source: [Global Snow Lab](http://climate.rutgers.edu/snowcover/index.php)] --- # Snow = Water Globally, **mountain water towers** affect a quarter of humanity ([Immerzeel et al., 2020](https://doi.org/10.1038/s41586-019-1822-y)) .pull-left[<img height="450" alt="Immerzeel et al. 2020, Fig 2a" src="fig/immerzeel1.png">] .pull-right[<img height="450" alt="Immerzeel et al. 2020, Fig 2b" src="fig/immerzeel2.png">] --- # The 2022 Italian snow drought <a href="https://blogs.egu.eu/divisions/cr/2022/09/16/why-the-2022-italian-snow-drought-matters-to-you/"><img height="500" alt="SWE of the Italian Alps 2022 compared to last decade" src="https://blogs.egu.eu/divisions/cr/files/2022/09/Fig2.png"></a> .footnote[Source: https://blogs.egu.eu/divisions/cr/2022/09/16/why-the-2022-italian-snow-drought-matters-to-you/] --- # The 2022 Italian snow drought .leftcol-21[ <a href="https://www.theguardian.com/world/2022/jun/17/italy-drought-po-river-climate-crisis"><img alt="Screenshot of guardian article on 2022 Italian snow drought" src="fig/guardian1.png"></a> ] .rightcol-21[ <a href="https://www.theguardian.com/world/2022/jun/17/italy-drought-po-river-climate-crisis"><img alt="Screenshot of guardian article on 2022 Italian snow drought" src="fig/guardian2.png"></a> ] .footnote[Source: https://www.theguardian.com/world/2022/jun/17/italy-drought-po-river-climate-crisis] --- class: center, middle, inverse # How is snow measured? ### (focus here: macroscopic snow variables) --- # In-situ: manual snow depth .center[<img height="500" alt="Manual snow depth measurements with rods and rulers" src="fig/snow-measurement1.png">] .footnote[Source: [European Snow Booklet](https://doi.org/10.16904/envidat.59)] --- # In-situ: automatic snow depth .center[<img height="500" alt="Sonic sensors for snow depth measurement" src="fig/snow-measurement2.png">] .footnote[Source: [European Snow Booklet](https://doi.org/10.16904/envidat.59)] --- # In-situ: manual snow water equivalent (SWE) .center[<img height="500" alt="measuring snow water equivalent with snow cylinders" src="fig/snow-measurement3.png">] .footnote[Source: [European Snow Booklet](https://doi.org/10.16904/envidat.59)] --- # In-situ: automatic snow water equivalent (SWE) .center[<img height="500" alt="measuring snow water equivalent with snow pillows" src="fig/snow-measurement4.png">] .footnote[Source: [European Snow Booklet](https://doi.org/10.16904/envidat.59)] --- # Remote .center[<img height="500" alt="measuring snow water equivalent with snow pillows" src="fig/hu-2017-fig5.png">] .footnote[Source: [Hu et al., 2017](https://doi.org/10.3390/rs9101067)] --- class: center, middle, inverse # Snow climatology in the European Alps --- # In-situ snow depth observations: Time period <img alt="Matiu et al. 2021, Fig 2a" src="fig/matiu-2021-fig2a.png"> .footnote[Source: [Matiu et al., 2021](https://doi.org/10.5194/tc-15-1343-2021)] --- # In-situ snow depth observations: Spatial coverage .pull-left[ <img alt="Matiu et al. 2021, Fig 1b" src="fig/matiu-2021-fig1b.png"> ] .pull-right[ <img alt="Matiu et al. 2021, Fig 2c" src="fig/matiu-2021-fig2c.png"> ] .footnote[Source: [Matiu et al., 2021](https://doi.org/10.5194/tc-15-1343-2021)] --- # Average snow depth 1981-2010 .center[<img height="500" alt="Matiu et al. 2021, Fig 6a, modified" src="fig/matiu-2021-hs-clim-noregion.png">] .footnote[Source: [Matiu et al., 2021](https://doi.org/10.5194/tc-15-1343-2021)] --- # Common variability in daily snow depth (1981-2010) .center[<img height="500" alt="Matiu et al. 2021, Fig 3" src="fig/matiu-2021-pca-sub4.jpg">] .footnote[Source: [Matiu et al., 2021](https://doi.org/10.5194/tc-15-1343-2021)] --- class: center, middle ### Interactive: https://clirsnow.netlify.app/dash-results/dash-climatology.html#explore-climatic-boundaries --- class: center, middle, inverse # Past and future trends of snow cover --- # Past trends 1971-2019 .center[<img height="500" alt="Matiu et al. 2021, Fig. C1 modified" src="fig/matiu-2021-hs-seasonal-trends-noregion.png">] .footnote[Source: [Matiu et al., 2021](https://doi.org/10.5194/tc-15-1343-2021)] --- # Past trends 1971-2019: Summary table .center[<img height="500" alt="Matiu et al. 2021, Table 3" src="fig/matiu-2021-table3.png">] .footnote[Source: [Matiu et al., 2021](https://doi.org/10.5194/tc-15-1343-2021)] --- background-image: url("fig/info-future_EN.png") background-size: contain --- class: center, middle, inverse # Conclusions --- # Conclusions - The Alps has one of the densest in-situ observation networks of snow cover in the world and a long history of observations. But not all elevations are well monitored: + Good below 2000m, sparse between 2000 and 3000m, and almost none above 3000m. - Satellite remote sensing offers long-term and full spatial coverage, but currently only offers snow cover area and not snow mass or proxies thereof. -- - The orography of the Alps is the main impact on snow climatology. + The location of a station with respect to climate forcing zone impacts variability at the daily scale and also trend magnitude and trend sign. + `-> ` Generalizing from one region to the other should be done carefully, if at all. -- - Past trends show widespread decreases of snow cover in the Alps for the last 50 years, which will continue in the future. + Stronger relative decreases found at lower elevations and in spring. + The magnitude of future changes depends on greenhouse gas concentrations and are 2-3x larger for a 4-5°C warmer world as compared to 1.5-2°C. --- class: center, middle, inverse # ? -> ! -> ??? <br><br><br><br> Contact: [michael.matiu@unitn.it](michael.matiu@unitn.it) Homepage: [mitmat.eu](https://mitmat.eu) Slides available at: [github.com/mitmat/slides](https://github.com/mitmat/slides) Work performed during project: [clirsnow.netlify.app](https://clirsnow.netlify.app)