The characteristics and structure of extra-tropical cyclones in a warmer climate

Peer reviewe

Pan-Eurasian Experiment (PEEX) Program : An Overview of the First 5 Years in Operation and Future Prospects

The Pan-Eurasian Experiment (PEEX) program was initiated as a bottom-up approach by the researchers coming from Finland and Russia in October 2012. The PEEX China kick off meeting was held in November 2013. During its five years in operation, the program has established a governance structure and delivered a science plan for the Northern Eurasian region. PEEX has also introduced a concept design for a modelling platform and ground-based in situ observation systems for detecting land-atmosphere and ocean-atmosphere interactions. Today, PEEX has an extensive researcher’s network representing research communities coming from the Nordic countries, Russia and China. PEEX is currently carrying out its research activities on a project basis, but is looking for more coordinated funding bases, especially in Russia and in China. The near-future challenge in implementing the PEEX research agenda is to achieve a successful integration and identification of the methodological approaches of the socio-economic research to environmental sciences. Here we give insight into these issues and provide an overview on the main tasks for the upcoming years.The Pan-Eurasian Experiment (PEEX) program was initiated as a bottom-up approach by the researchers coming from Finland and Russia in October 2012. The PEEX China kick off meeting was held in November 2013. During its five years in operation, the program has established a governance structure and delivered a science plan for the Northern Eurasian region. PEEX has also introduced a concept design for a modelling platform and ground-based in situ observation systems for detecting land-atmosphere and ocean-atmosphere interactions. Today, PEEX has an extensive researcher’s network representing research communities coming from the Nordic countries, Russia and China. PEEX is currently carrying out its research activities on a project basis, but is looking for more coordinated funding bases, especially in Russia and in China. The near-future challenge in implementing the PEEX research agenda is to achieve a successful integration and identification of the methodological approaches of the socio-economic research to environmental sciences. Here we give insight into these issues and provide an overview on the main tasks for the upcoming years.The Pan-Eurasian Experiment (PEEX) program was initiated as a bottom-up approach by the researchers coming from Finland and Russia in October 2012. The PEEX China kick off meeting was held in November 2013. During its five years in operation, the program has established a governance structure and delivered a science plan for the Northern Eurasian region. PEEX has also introduced a concept design for a modelling platform and ground-based in situ observation systems for detecting land-atmosphere and ocean-atmosphere interactions. Today, PEEX has an extensive researcher’s network representing research communities coming from the Nordic countries, Russia and China. PEEX is currently carrying out its research activities on a project basis, but is looking for more coordinated funding bases, especially in Russia and in China. The near-future challenge in implementing the PEEX research agenda is to achieve a successful integration and identification of the methodological approaches of the socio-economic research to environmental sciences. Here we give insight into these issues and provide an overview on the main tasks for the upcoming years.Peer reviewe

Ilmakehän jään ja pölyn auringonsäteilyvaikutukset

Both atmospheric ice and mineral dust are considered to play important roles in our climate system through their impacts on the radiative energy budget. These impacts depend on the size, shape, composition and concentration of the ice and dust particles. However, the non-spherical shape of these particles yields uncertainties in our understanding how they interact with radiation. One of the main aims of this work is to better understand the impacts of particle size-shape distributions on radiative effects of ice and dust. For dust particles, the overall goal is to improve the treatment of optical properties of dust in global aerosol-climate models. In this thesis, the solar radiative effects of variously sized and shaped ice and dust particles are simulated using radiative transfer models. In addition, a global aerosol–climate model is used to investigate the impact of dust particle nonsphericity. Different radiative transfer models, atmospheric and surface properties etc. are used, based on the requirements of each study. Size-shape distributions of ice clouds are based on in-situ measurements, whereas for dust, carefully validated shape models of spheroids are used. This thesis offers a broad outlook on the effects of ice clouds on solar irradiances and on the angular dependence of the circumsolar radiance. In addition, it offers interesting new insight into the connections between particle morphology, cloud microphysics and cloud radiative effects. It is found that solar radiation is sensitive to the concentration of small ice crystals. In addition, comparison of simulated and measured radiation in the presence of ice clouds suggests that most natural ice crystals are not pristine, but can either have some surface roughness or other non-idealities in their shape. The results reveal that the use of spheroidal shape distributions has only small or moderate impacts on regional and global-scale direct radiative effects of dust. Consistent with this, experiments with a global aerosol–climate model indicate that the assumption of spherical shape for dust particles is not a considerable error source in climate simulations. Most probably, however, this conclusion cannot be extended to remote sensing applications. Keywords: ice crystal, mineral dust, single-scattering properties, solar radiation, circumsolar radiation, radiative transfer modelling, spheroidsIlmakehässä olevat jääkiteet ja mineraalipölyhiukkaset vaikuttavat maapallon säteilytaseeseen ja ilmastoon. Jään ja pölyn suorat vaikutukset auringonsäteilyn kulkuun ilmakehässä ovat merkittäviä, mutta niiden tarkka määritteleminen on hankalaa ja epävarmaa. Suorat säteilyvaikutukset riippuvat muunmuassa näiden partikkeleiden määrästä ilmakehässä sekä niiden koosta, muodosta ja koostumuksesta. Yksi tämän väitöskirjatutkimuksen päätavoitteista on lisätä ymmärrystä siitä, miten jään ja pölyn vaikutus auringonsäteilyyn riippuu partikkeleiden muodosta ja kokojakaumasta. Lisäksi tavoitteena on kehittää mineraalipölyn optisten ominaisuuksien käsittelyä aerosoli-ilmastomalleissa. Tässä tutkimuksessa on mallinnettu säteilynkulkumalleilla ilmakehässä olevien monenkokoisten ja -muotoisten jääkiteiden ja mineraalipölyhiukkasten suoria vaikutuksia auringonsäteilyyn. Säteilynkulkumallit samoin kuin tutkitun ilmakehän (mukaan lukien jääkiteet ja/tai pöly) ja maanpinnan ominaisuudet on valittu huomioiden kunkin tutkimuskohteen vaatimukset. Jääkiteiden muotokokojakaumat pohjautuvat lentokonemittauksiin, kun taas mineraalipölyn muotojakauma tarkasti validoituun sferoidimuotojakaumaan. Jääpilvien tapauksessa mallinnettuja säteilysuureita verrataan maanpinnalta tehtyihin vastaaviin säteilymittauksiin. Pölyn osalta on säteilynkulkumallien tulosten analysoinnin lisäksi tutkittu aerosoli-ilmastomallin tulosten herkkyyttä mineraalipölyhiukkasten muodolle. Tämä väitöskirja lisää tietoamme jääpilvien vaikutuksista auringonsäteilyn vuohon ja auringon suunnasta tulevan säteilyn kulmariippuvuuteen. Lisäksi se tarjoaa uusia näkökulmia pilven mikrofysiikan ja säteilyvaikutuksien yhteyksien ymmärtämiseen. Tulokset osoittavat auringonsäteilyn olevan herkkä pienten jääkiteiden määrälle. Lisäksi tuloksista voidaan päätellä, että jääkiteissä on pinnan karheutta tai muita epäsäännöllisyyksiä muodossa. Yksi päätuloksista on, että mineraalipölyn optisten ominaisuuksien kuvaaminen sferoidimuotojakaumilla pallojen sijaan muuttaa vain vähän pölyn suoraa vaikutusta auringonsäteilyyn, ja ettei pallomaisten mallihiukkasten käyttö pölylle ole merkittävä virhelähde ilmastomalleissa. Hyvin todennäköisesti tämä ei kuitenkaan päde pölyn kaukokartoitussovelluksille. Avainsanat: jääkide, mineraalipöly,yksittäissirontaominaisuudet, auringonsäteily, sirkumsolaarinen säteily, säteilynkulkumallitus,sferoid