Sökning: "cloud base height"

Visar resultat 1 - 5 av 9 uppsatser innehållade orden cloud base height.

  1. 1. Characterisation of Low-Level Jets and their Influence on Low-Level Clouds over the Baltic Sea; Östergarnsholm Observatory, Sweden

    Kandidat-uppsats, Lunds universitet/Fysiska institutionen; Lunds universitet/Förbränningsfysik

    Författare :Johan Lundberg; [2021]
    Nyckelord :Low-level jets; Low-level clouds; LLJs; LLCs; Boundary layer; ABL; CBH; Lidar; Ceilometer; Turbulent intensity; Physics and Astronomy;

    Sammanfattning : In this study, about two years of data from Östergarnsholm in the Baltic Sea are used to analyse offshore low-level clouds (LLCs) influenced by low-level jets (LLJs) in the marine atmospheric boundary layer. The LLJs are passages of strong horizontal winds near the surface and are measured using a Doppler LiDAR, which provides information about the wind speed and wind direction up to 300 meters. LÄS MER

  3. 2. Verification of HARMONIE-AROME, ECMWF-IFS and WRF: Visibility and Cloud Base Height

    Master-uppsats, Uppsala universitet/Luft-, vatten- och landskapslära

    Författare :Elin Kindlundh; [2020]
    Nyckelord :HARMONIE-AROME; ECMWF-IFS; WRF; verification; visibility; cloud base height; HARMONIE-AROME; ECMWF-IFS; WRF; verifikation; sikt; molnbashöjd;

    Sammanfattning : Visibility and cloud base height are two important parameters within aviation meteorology and verification of operational numerical weather prediction (NWP) models with regard to these two parameters is therefore important. Visibility is often parameterized through an extinction coefficient, which is dependent on for example liquid or ice water content, however it also depends on the humidity, precipitation intensity and particle concentration. LÄS MER

  4. 3. Improving Short-Range Cloud Forecasts in Harmonie-Arome Through Cloud Initialization Using Mesan Cloud Data

    Master-uppsats, Uppsala universitet/Luft-, vatten- och landskapslära

    Författare :Joakim Pyykkö; [2019]
    Nyckelord :cloud initialization; HARMONIE-AROME; MESAN; satellite product; synoptic weather station;

    Sammanfattning : Previous studies, such as van der Veen (2012) and White et al. (2017), have demonstrated the potential of using measurement-based cloud data to improve Numerical Weather Prediction (NWP) based cloud forecasts. This can be done through cloud initialization; a process of injecting cloud data after the regular data assimilation in an NWP model. LÄS MER

  5. 4. Deriving characteristics of thin cirrus clouds from observations with the IRF lidar

    Uppsats för yrkesexamina på avancerad nivå, Luleå tekniska universitet/Institutionen för system- och rymdteknik

    Författare :Jennifer Edman; [2019]
    Nyckelord :cirrus; lidar; polar regions; optical thickness; clouds; ice clouds; BSR; backscatter coefficient;

    Sammanfattning : Cirrus clouds play an important role in radiative transfer, and thus have impact on the energy balance of the atmosphere and the climate of the Earth. Furthermore, they occur often and cover large areas globally at any time. Nevertheless, cirrus clouds are poorly studied, especially in the polar regions. LÄS MER

  7. 5. Cloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, Sweden

    Master-uppsats, Uppsala universitet/Luft-, vatten- och landskapslära

    Författare :Aron Stenlid; [2019]
    Nyckelord :Ceilometer; Stratocumulus; cloud base height; LCL; DLS; upwelling; cloud cover;

    Sammanfattning : In this study, four and a half months of ceilometer data from Östergarnsholm are used to analyze cloud related to processes in the boundary layer. Measurements are divided into two categories, which are defined by wind direction: a continental and a marine sector. LÄS MER