Battaglia_et_al-2016-Journal_of_Geophysical_Research-_Atmospheres.pdf (5.34 MB)
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Using a multiwavelength suite of microwave instruments to investigate the microphysical structure of deep convective cores.

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journal contribution
posted on 15.11.2016, 16:10 by A. Battaglia, K. Mroz, T. Lang, F. Tridon, S. Tanelli, L. Tian, G. M. Heymsfield
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).

Funding

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.

History

Citation

Journal of Geophysical Research: Atmospheres, 2016, 121 (16), pp. 9356-9381

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Journal of Geophysical Research: Atmospheres

Publisher

American Geophysical Union (AGU), Wiley

issn

2169-897X;2169-8996

Acceptance date

31/07/2016

Copyright date

2016

Available date

15/11/2016

Publisher version

http://onlinelibrary.wiley.com/doi/10.1002/2016JD025269/abstract

Notes

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.

Language

en

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