Project Details
Projekt
Characterization of orography-influenced riming and secondary ice production and their effects on precipitation rates using radar polarimetry and Doppler spectra (CORSIPP)
Applicants
Dr. Heike Kalesse-Los; Dr. Maximilian Maahn
Subject Area
Atmospheric Science
Term
since 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 408008112
Precipitation is a major component of the hydrological cycle. A comprehensive understanding of the precipitation formation processes is required to understand how the water budget is changing in a warming climate. In mid-latitudes, most precipitation is generated through the ice phase in mixed-phase clouds, but the exact pathways through which ice, liquid water, cloud dynamics, orographic forcing, and aerosol particles are interacting during ice, snow and rain formation are not well understood. This is particularly true for riming and secondary ice production (SIP) processes that are likely related to the largest uncertainties with respect to quantitative snowfall formation. Filling the gaps in our understanding of SIP and riming is especially crucial for mountainous regions that are particularly vulnerable to changes in precipitation and the water budget such as the ratio between rain and snowfall. Here, we propose a research project dedicated to understanding riming and SIP processes in complex terrain. For this, we will operate an innovative simultaneous-transmission-simultaneous-reception (STSR) scanning W-band cloud radar together with a novel in situ snowfall camera for one entire winter season in the Colorado Rocky Mountain. The instruments will be part of the Atmospheric Radiation Measurement (ARM) Surface Atmosphere Integrated Field Laboratory (SAIL) campaign where a Ka-band and a X-band radar will be deployed. Combining spectral polarimetric and multi frequency Doppler radar observations with empirical and Bayesian machine learning retrieval techniques, we will identify riming and SIP events and quantify their impact on snowfall rates. This goal requires extending the Passive and Active Microwave radiative TRAnsfer model (PAMTRA) with additional polarimetric variables and state of the art scattering capabilities. Finally, using the extensive collocated measurements of SAIL will allow us to relate the observed process rates to environmental conditions such as temperature, humidity and liquid water path as well as cloud dynamics. In addition, we will put a special focus on the impact of vertical air motions that appear frequently in orographic conditions. Combined, the proposed project will enhance our understanding of riming and SIP processes in complex terrain.
DFG Programme
Priority Programmes
Major Instrumentation
Radar Scanning Unit
Instrumentation Group
6670 Radaranlagen (außer Distanzmesser 062 und Doppler-Radar 664 und 886)
