Using a multiwavelength suite of microwave instruments to investigate the microphysical structure of deep convective cores.

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Battaglia, A., Mroz, K., Lang, T., Tridon, F., Tanelli, S., Tian, L., Heymsfield, G. M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union (AGU), Wiley 2016
• Subjects: convection; microphysics; radar; retrieval; Leicester; North Atlantic
• Online Access: http://onlinelibrary.wiley.com/doi/10.1002/2016JD025269/abstract; http://hdl.handle.net/2381/38572; https://doi.org/10.1002/2016JD025269

NEXRAD processing code is available from https://github.com/ARM-DOE/pyart, https://github.com/CSU-Radarmet/CSU_RadarTools, and https://github.com/nasa/DualPol. AMPR processing code is available from https://github.com/nasa/PyAMPR. Due to the large natural variability of its microphysical properties, the characterization of solid precipitation is a longstanding problem. Since in situ observations are unavailable in severe convective systems, innovative remote sensing retrievals are needed to extend our understanding of such systems. This study presents a novel technique able to retrieve the density, mass, and effective diameter of graupel and hail in severe convection through the combination of airborne microwave remote sensing instruments. The retrieval is applied to measure solid precipitation properties within two convective cells observed on 23-24 May 2014 over North Carolina during the IPHEx campaign by the NASA ER-2 instrument suite. Between 30 and 40 degrees of freedom of signal are associated with the measurements, which is insufficient to provide full microphysics profiling. The measurements have the largest impact on the retrieval of ice particle sizes, followed by ice water contents. Ice densities are mainly driven by a priori assumptions, though low relative errors in ice densities suggest that in extensive regions of the convective system, only particles with densities larger than 0.4 g/cm(3) are compatible with the observations. This is in agreement with reports of large hail on the ground and with hydrometeor classification derived from ground-based polarimetric radars observations. This work confirms that multiple scattering generated by large ice hydrometeors in deep convection is relevant for airborne radar systems already at Ku band. A fortiori, multiple scattering will play a pivotal role in such conditions also for Ku band spaceborne radars (e.g., the GPM Dual Precipitation Radar). The work done by A. Battaglia and F. Tridon was funded by the project “Calibration and validation studies over the North Atlantic and UK for the Global Precipitation Mission” funded by the UK NERC (NE/L007169/1). The forward radar model code was courteously provided by R. Hogan (http://www.met.rdg.ac.uk/clouds/multiscatter/). This research used the ALICE High Performance Computing Facility at the University of Leicester. CRS was supported by the NASA ACE Mission formulation. HIWRAP was supported by GPM Ground Validation. EXRAD was supported by the NASA Airborne Instrument Technology Transition (AITT). ER-2 flights were jointly sponsored by GPM ground validation and the ACE Decadal Mission study. AMPRs participation was supported by GPM GV. Timothy Lang was supported by GPM GV. The work performed by Simone Tanelli was carried out at the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA in support to the preformulation phase studies for the ACE mission concept and to the GPM Science Team. NEXRAD data were obtained from NOAA via the online data set hosted by Amazon Web Services. Peer-reviewed Publisher Version