A193-07
Contribution of different ice formation processes to the precipitation budget over ocean measured from ground and space

Tuesday, 15 December 2020: 07:21
Virtual
Johannes Buehl1, Patric Seifert2, Martin Radenz1, Rodanthi-Elisavet Mamouri3, Diofantos Hadjimitsis3, Albert Ansmann1, Heike Konow4 and Stefan Kinne5, (1)Leibniz Institute for Tropospheric Research, Leipzig, Germany, (2)Leibniz Institute for Tropospheric Research - TROPOS, Leipzig, Germany, (3)ERATOSTHENES Center of Excellence, Limassol, Cyprus, (4)University of Hamburg, Hamburg, Germany, (5)Max Planck Institute for Meteorology, Atmosphere, Hamburg, Germany
Recorded Presentation
Abstract:
Aerosols have a decisive impact on precipitation formation because they act as ice nucleating particles for heterogeneous ice formation in clouds. In this work, the impact of different precipitation forming regimes (homogeneous freezing, heterogeneous freezing and warm rain) on the global precipitation budget is analyzed by connecting rain events at ground with their initiation level and initiation temperature at cloud top. We present histograms of precipitation amount initiated in a certain temperature interval measured with CloudSat and Cloudnet scaled with global statistics of annual rainfall from GPM (Global Precipitation Mission) satellite.

The precipitation product PRECIP-2C of CloudSat features an estimate of precipitation rate (RR) over the ocean surface and an estimate of the lowest cloud top height (CTH) which is found to be vertically connected to the precipitation events. Global numerical weather model reanalysis datasets allow subsequent estimation of corresponding cloud top temperature (CTT). The impact of CTT on global precipitation amount is analyzed by summing the retrieved RR over each interval of CTT. The resulting distribution yields the relative contribution of precipitation amount of each interval. The total precipitation amount contained in the histograms is scaled using the annual mean precipitation from the GPM-IMERG dataset for the given locations. For comparison and validation, the same methodology is applied to several Cloudnet datasets which are located close to the sea (Deebles-Point, Barbados; Limassol, Cyprus; Punta Arenas, Chile).

The study identifies locations with possibly high influence of aerosol particles on precipitation formation. Special emphasis is laid on the eastern Mediterranean region where complex mixtures of aerosols are found aloft. A strong relative contribution of the heterogeneous ice formation regime in this region is indicative for a possible change of precipitation formation under changing aerosol conditions.

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