Day 4

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Paper title Towards the investigation of radiative effects in long-range-transported Saharan dust layers with EarthCARE
Authors
  1. Manuel Gutleben Ludwig-Maximilians-Universität München Speaker
  2. Silke Groß German Aerospace Center (DLR)
  3. Martin Wirth DLR - Institute of Atmospheric Physics
Form of presentation Poster
Topics
  • A1. Atmosphere
    • A1.09 EarthCARE: Preparing for the Scientific Mission Exploitation to Quantify the Impact of Clouds and Aerosols on Radiation
Abstract text The Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) mission will carry a depolarization-sensitive high-spectral-resolution lidar as well as a Doppler radar for global measurements of aerosol and cloud properties. These observations will be used in radiative transfer simulations to pursue the main objective of the mission: the radiative closure of the Earth’s radiation budget at top-of-the-atmosphere (TOA) using complementary on-board passive remote sensing observations for comparison. To achieve best possible agreements between the derived radiative fluxes from active remote sensing and passive measurements, the distributions of radiatively active constituents of the atmosphere have to be known. Especially the vertical distribution of water vapor should be precisely characterized, as it is spatially and temporally extremely variable. However, with water vapor profiles not being directly measured by EarthCARE, radiative transfer models have to rely on modeled vertical atmospheric water vapor distributions and standard atmospheric profiles.
During two airborne research campaigns over the western Atlantic Ocean, we conducted lidar measurements aboard the German HALO (High Altitude and Long Range) research aircraft above transported Saharan dust layers. All measurements indicated enhanced concentrations of water vapor inside the dust layers compared to the surrounding free atmosphere. We found that the embedded water vapor in the dust layers has a great effect on the vertical heating rate profiles as well as on TOA radiation. Hence, with the main goal of EarthCARE being the closure of the Earth’s radiation budget at TOA, particular attention has to be payed to a correct parametrization of the vertical water vapor profile and its possible radiative effects.
In our presentation, we will present the derived radiative effects of long-range-transported Saharan dust layers from EarthCARE-like remote-sensing with HALO during both boreal winter and summer. We will highlight the contribution of enhanced concentrations of water vapor in the dust layers to calculated TOA radiative effects as well as heating rates. Additionally, we compare our results to radiative transfer calculations where standard distributions of water vapor are used.