Sökning: "single-column model"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden single-column model.

  1. 1. Paths to improving atmospheric models across scales : The importance of the unresolved scales

    Författare :Kerstin Hartung; Gunilla Svensson; Rodrigo Caballero; Olof Runborg; Heikki Järvinen; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; global climate models; atmospheric blocking; topographic forcing; physical parametrizations; single-column model; atmosphere-ocean single-column model; air-sea interaction; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

    Sammanfattning : Correct representation of physical processes, the parametrizations, and their interaction with the resolved circulation is crucial for the performance of numerical models. Here, focus is put on understanding model biases and developing tools to alleviate existing biases. LÄS MER

  3. 2. Processes important for forecasting of clouds over snow

    Författare :Martin Hagman; Gunilla Svensson; Victoria Sinclair; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Boundary-layer meteorology; WRF; Initialization; Stratocumulus clouds; Parameterization; Stable boundary layer; Single Column Model; meteorologi; Meteorology;

    Sammanfattning : The Swedish Armed Forces setup of the Weather Research and Forecasting Model (WRF) has problems to forecast low clouds in stably stratified conditions when the ground is covered by snow. The aim of this thesis is to understand what causes this deficit. LÄS MER

  4. 3. Improved Cloud Parameterization in Global Climate Model : Aerosol effects and secondary ice production mechanisms

    Författare :Arti Jadav; MERGE: ModElling the Regional and Global Earth system; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cloud; Coud parameterization; Primary ice mechanisms; Secondary ice production; Global climate model;

    Sammanfattning : The response of clouds to the changes in climate is uncertain, and the representation of the cloud-climate feedback is a key challenge in the global circulation models (GCM) for future climate projections. Factors contributing to this uncertainty include processes that involve particles of various sizes and phases, as well as the interactions between these particles and the surrounding atmosphere. LÄS MER

  5. 4. Modelling of stably-stratified, convective and transitional atmospheric boundary layers using the explicit algebraic Reynolds-stress model

    Författare :Velibor Zeli; Gert Brethouwer; Arne V. Johansson; Stefan Wallin; Bert Holtslag; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; atmospheric turbulence; convective atmosphere; Reynolds-stress model; stably-stratified atmosphere; transitional atmosphere; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : The atmospheric boundary layer (ABL) is in continuous turbulent motion. The heating and cooling of the Earth’s surface drives mechanic and thermodynamic processes in the ABL through enhancing and damping of atmospheric turbulence. The surface forcing has a profound effect on the diurnal cycle of temperature,wind and related variables in the ABL. LÄS MER

  7. 5. Boundary Layer Parametrization in Numerical Weather Prediction Models

    Författare :Jacob Svensson; Gunilla Svensson; Michael Tjernström; Patrick Samuelsson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Boundary-Layer Meteorology; Numerical Weather Prediction; Turbulence parametrization; COAMPS; IFS; meteorologi; Meteorology;

    Sammanfattning : Numerical weather prediction (NWP) and climate models have shown to have a challenge to correctly simulate stable boundary layers and diurnal cycles. This aim of this study is to evaluate, describe and give suggestions for improvements of the descriptions of stable boundary layers in operational NWP models. Two papers are included. LÄS MER