The Experts below are selected from a list of 191964 Experts worldwide ranked by ideXlab platform

Akira Misawa - One of the best experts on this subject based on the ideXlab platform.

Kyota Hattori - One of the best experts on this subject based on the ideXlab platform.

Manfred Wendisch - One of the best experts on this subject based on the ideXlab platform.

  • Spectral Optical Layer properties of cirrus from collocated airborne measurements and simulations
    Atmospheric Chemistry and Physics, 2016
    Co-Authors: Fanny Finger, Frank Werner, Marcus Klingebiel, André Ehrlich, Evelyn Jäkel, Matthias Voigt, Stephan Borrmann, Peter Spichtinger, Manfred Wendisch
    Abstract:

    Abstract. Spectral upward and downward solar irradiances from vertically collocated measurements above and below a cirrus Layer are used to derive cirrus Optical Layer properties such as spectral transmissivity, absorptivity, reflectivity, and cloud top albedo. The radiation measurements are complemented by in situ cirrus crystal size distribution measurements and radiative transfer simulations based on the microphysical data. The close collocation of the radiative and microphysical measurements, above, beneath, and inside the cirrus, is accomplished by using a research aircraft (Learjet 35A) in tandem with the towed sensor platform AIRTOSS (AIRcraft TOwed Sensor Shuttle). AIRTOSS can be released from and retracted back to the research aircraft by means of a cable up to a distance of 4 km. Data were collected from two field campaigns over the North Sea and the Baltic Sea in spring and late summer 2013. One measurement flight over the North Sea proved to be exemplary, and as such the results are used to illustrate the benefits of collocated sampling. The radiative transfer simulations were applied to quantify the impact of cloud particle properties such as crystal shape, effective radius reff, and Optical thickness τ on cirrus spectral Optical Layer properties. Furthermore, the radiative effects of low-level, liquid water (warm) clouds as frequently observed beneath the cirrus are evaluated. They may cause changes in the radiative forcing of the cirrus by a factor of 2. When low-level clouds below the cirrus are not taken into account, the radiative cooling effect (caused by reflection of solar radiation) due to the cirrus in the solar (shortwave) spectral range is significantly overestimated.

  • Spectral Optical Layer properties of cirrus from collocated airborne measurements – a feasibility study
    2015
    Co-Authors: Fanny Finger, Frank Werner, Marcus Klingebiel, André Ehrlich, Evelyn Jäkel, Matthias Voigt, Stephan Borrmann, Peter Spichtinger, Manfred Wendisch
    Abstract:

    Abstract. Spectral Optical Layer properties of cirrus are derived from simultaneous and vertically collocated measurements of spectral upward and downward solar irradiance above and below the cloud Layer and concurrent in situ microphysical sampling. From the irradiance data spectral transmissivity, absorptivity, reflectivity, and cloud top albedo of the observed cirrus Layer are obtained. At the same time microphysical properties of the cirrus were sampled. The close collocation of the radiative and microphysical measurements, above, beneath and inside the cirrus, is obtained by using a research aircraft (Learjet 35A) in tandem with a towed platform called AIRTOSS (AIRcraft TOwed Sensor Shuttle). AIRTOSS can be released from and retracted back to the research aircraft by means of a cable up to a distance of 4 km. Data were collected in two field campaigns above the North and Baltic Sea in spring and late summer 2013. Exemplary results from one measuring flight are discussed also to illustrate the benefits of collocated sampling. Based on the measured cirrus microphysical properties, radiative transfer simulations were applied to quantify the impact of cloud particle properties such as crystal shape, effective radius reff, and Optical thickness τ on cirrus Optical Layer properties. The effects of clouds beneath the cirrus are evaluated in addition. They cause differences in the Layer properties of the cirrus by a factor of 2 to 3, and for cirrus radiative forcing by up to a factor of 4. If low-level clouds below cirrus are not considered the solar cooling due to the cirrus is significantly overestimated.

Masahiro Nakagawa - One of the best experts on this subject based on the ideXlab platform.

Masaru Katayama - One of the best experts on this subject based on the ideXlab platform.