G band atmospheric radars: new frontiers in cloud physics

Abstract

Abstract. Clouds and associated precipitation are the largest source of uncertainty in current weather and future climate simulations. Observations of the microphysical, dynamical and radiative processes that act at cloud scales are needed to improve our understanding of clouds. The rapid expansion of ground-based super-sites and the availability of continuous profiling and scanning multi-frequency radar observations at 35 and 94 GHz have significantly improved our ability to probe the internal structure of clouds in high temporal-spatial resolution, and to retrieve quantitative cloud and precipitation properties. However, there are still gaps in our ability to probe clouds due to large uncertainties in the retrievals.The present work discusses the potential of G band (frequency between 110 and 300 GHz) Doppler radars in combination with lower frequencies to further improve the retrievals of microphysical properties. Our results show that, thanks to a larger dynamic range in dual-wavelength reflectivity, dual-wavelength attenuation and dual-wavelength Doppler velocity (with respect to a Rayleigh reference), the inclusion of frequencies in the G band can significantly improve current profiling capabilities in three key areas: boundary layer clouds, cirrus and mid-level ice clouds, and precipitating snow.

Rain retrieval from dual‐frequency radar Doppler spectra: validation and potential for a midlatitude precipitating case‐study

“…For reference, the component due to gas is only about 1.4 dB at 3 km. Liquid clouds can also produce significant one‐way attenuation of 5 dB km −1 (g m −3 ) −1 (Battaglia et al , ). A collocated ceilometer detects the presence of some intermittent clouds at varying heights (black dots).…”

Evaporation in action sensed by multiwavelength Doppler radars

“…Therefore, though the retrieval of RH from DSD profiles as described in this paper cannot be widely applied, this work paves the way toward the exploitation of multisensor active remote sensing observations for disentangling rain microphysical processes. In this regard, future studies should explore the potential of radars in the G band, including the 183 GHz water vapor absorption line [ Battaglia et al , ; Lebsock et al , ], in retrieving simultaneously liquid precipitation microphysics and water vapor profiles.…”

A polarimetric scattering database for non-spherical ice particles at microwave wavelengths

“…As studies on these topics have advanced, so has awareness of the importance of developing models of ice particles with realistic shapes (e.g., Westbrook et al, 2004;Maruyama and Fujiyoshi 2005) and radiative scattering properties (e.g., Kim, 2006;Liu, 2008;Petty and Huang, 2010;Kulie et al, 2010;Johnson et al, 2012). As ice-particle research has gained momentum, so has the importance of ice-particle identification via remote sensing, leading to many studies on the value of multiple frequencies (e.g., Matrosov, 1998;Kneifel et al, 2011Kneifel et al, , 2015Leinonen et al, 2012Battaglia et al, 2014;Kulie et al, 2014;Stein et al, 2015;Leinonen and Moisseev, 2015), polarization (e.g., Straka et al, 2000;Aydin and Singh, 2004;Chandrasekar et al, 2013;Kumjian, 2013), and the two combined (e.g., Tyynelä and Chandrasekhar, 2014) in their identification. Polarimetric, multi-frequency measurements also provide one path forward for quantitative estimation of ice water content (IWC).…”