Impacts of Mass-dimension and Area-dimension relationships on retrieval ice particle effective radius from radar and lidar measurements
Abstract
In the retrieval of ice clouds from Radar and Lidar Measurements, mass-Dimension (m-D) and Area-Dimension (A-D) relationships are often used to describe nonspherical ice particle shapes. This study analytically investigates how the assumption of m-D and A-D relationships affects retrieval of ice effective radius. We use gamma and lognormal particle distributions and integrate optical parameters over the size distribution. The effective radius is expressed as a function of radar reflectivity factor, visible extinction coefficient, and parameters describing m-D and A-D relationships. The analytic expressions are used for converting effective radius retrieved from one set of m-D and A-D relationships into that with another set of m-D and A-D, including plates, solid columns, bullets, and mixture of different habits. The conversion method can be used for consistent radiative transfer simulation with cloud retrieval algorithms. In addition, when we want to merge cloud effective radii retrieved from different m-D and A-D, the conversion method can be efficiently used to remove undesired biases caused by m-D and A-D assumptions. Furthermore, the sensitivity of the effective radius to m-D and A-D relationships can be quantified by taking the first derivative of the effective radius with respect to parameters expressing the m-D and A-D relationships.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.A33F0310H
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0319 Cloud optics;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0321 Cloud/radiation interaction;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0360 Radiation: transmission and scattering;
- ATMOSPHERIC COMPOSITION AND STRUCTURE