Hearings

am Campus der Universität Wien

(LMD Paris)

"A Synergistic Description of Upper Tropospheric Cloud Systems and Diabatic Heating: Towards Enhanced Process Understanding"

Upper tropospheric clouds are most abundant in the tropics and often form as cirrus anvils from convective outflow, building mesoscale systems (MCS). While latent heating is released into the atmosphere by the precipitating parts of these MCSs, the long-lasting anvils play a crucial role in modulating the Earth’s energy budget and heat transport. Convective organization may change the relationship between latent and radiative heating within and around the MCSs.

A coherent long-term dataset is presented which describes tropical UT cloud systems for process and climate studies. In order to investigate also the cirrus surrounding these anvils, we used CIRS (Clouds from IR Sounders) data, retrieved from AIRS (Atmospheric InfraRed Sounder) and IASI (Infrared Atmospheric Sounding Inferometer) measurements, together with atmospheric and surface properties from the meteorological ERA reanalyses as input to artificial neural network (ANN) models to simulate the cloud vertical structure and radiative heating rates derived from CloudSat radar – CALIPSO lidar measurements, available only along narrow nadir tracks. In this way, we could expand this sparse sampling in space and in time. Furthermore, a rain rate classification, with an accuracy of about 70%, allows to build objects of strong precipitation to identify convective organization. This dataset is now available at gewex-utcc-proes.aeris-data.fr/data/.

In combination with a cloud system analysis we found that deeper convection leads to larger heavy rain areas, with a slightly smaller thick anvil emissivity. Convective organization enhances the mean atmospheric cloud radiative effect (ACRE) of the MCSs by about 10 Wm-2.

Über Leben in autoritären Zeiten

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