Properties of light stratiform rain derived from 10‐ and 94‐GHz airborne Doppler radars measurements

Tian, Lin; Heymsfield, Gerald M.; Li, Lihua; Srivastava, R. C.

doi:10.1029/2006jd008144

Cited by 28 publications

(25 citation statements)

References 35 publications

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“…In this study we have primarily used the 9.6 GHz radar to evaluate retrievals made with the 94 GHz radar; however, we can also use the dual-frequency radar measurements to exploit the different scattering behaviours and retrieve additional information about the DSD. Dual-frequency ratio (DFR) and differential Doppler velocity (DDV) techniques were applied to retrievals from ER-2 measurements during the CRYSTAL-FACE field experiment over Florida in 2002 (Liao et al, 2008), and Tian et al (2007 exploited dual-frequency Doppler radar to retrieve rain DSD and vertical air motion for light stratiform rain from the same experiment. The CAPTIVATE framework can combine information from two radars by resolving differential nonRayleigh scattering and mean Doppler velocities from multiple wavelengths.…”

Section: Light Rain (12:46-12:51 Utc)mentioning

confidence: 99%

Improved rain rate and drop size retrievals from airborne Doppler radar

2017

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Abstract. Satellite remote sensing of rain is important for quantifying the hydrological cycle, atmospheric energy budget, and cloud and precipitation processes; however, radar retrievals of rain rate are sensitive to assumptions about the raindrop size distribution. The upcoming EarthCARE satellite will feature a 94 GHz Doppler radar alongside lidar and radiometer instruments, presenting opportunities for enhanced retrievals of the raindrop size distribution.We demonstrate the capability to retrieve rain rate as a function of drop size and drop number concentration from airborne 94 GHz Doppler radar measurements using CAP-TIVATE, the variational retrieval algorithm developed for EarthCARE. For a range of rain regimes observed during the Tropical Composition, Cloud and Climate Coupling field campaign, we explore the contributions of mean Doppler velocity and path-integrated attenuation (PIA) measurements to the retrieval of rain rate, and the retrievals are evaluated against independent measurements from an independent 9.6 GHz Doppler radar. The retrieved drop number concentrations vary over 5 orders of magnitude between very light rain from melting ice and warm rain from liquid clouds. In light rain conditions mean Doppler velocity facilitates estimates of rain rate without PIA, suggesting the possibility of EarthCARE rain rate estimates over land; in moderate warm rain, drop number concentration can be retrieved without mean Doppler velocity, with possible applications to CloudSat.

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Section: Light Rain (12:46-12:51 Utc)mentioning

confidence: 99%

Improved rain rate and drop size retrievals from airborne Doppler radar

2017

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“…Use of the 22 GHz absorption line has been proposed to observe water vapor within precipitation echoes (Meneghini et al 2005). Additionally, exploiting the differences in absorption by water vapor in the continuum has been proposed to retrieve water vapor (Ellis and Vivekanandan 2010;Tian et al 2007). …”

Section: Differential Absorption Radarmentioning

confidence: 99%

Emerging Technologies and Synergies for Airborne and Space-Based Measurements of Water Vapor Profiles

Nehrir

Kiemle²,

Lebsock

et al. 2017

Surv Geophys

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A deeper understanding of how clouds will respond to a warming climate is one of the outstanding challenges in climate science. Uncertainties in the response of clouds, and particularly shallow clouds, have been identified as the dominant source of the discrepancy in model estimates of equilibrium climate sensitivity. As the community gains a deeper understanding of the many processes involved, there is a growing appreciation of the critical role played by fluctuations in water vapor and the coupling of water vapor and atmospheric circulations. Reduction of uncertainties in cloud-climate feedbacks and convection initiation as well as improved understanding of processes governing these effects will result from profiling of water vapor in the lower troposphere with improved accuracy and vertical resolution compared to existing airborne and space-based measurements. This paper highlights new technologies and improved measurement approaches for measuring lower tropospheric water vapor and their expected added value to current observations. Those include differential absorption lidar and radar, microwave occultation between lowEarth orbiters, and hyperspectral microwave remote sensing. Each methodology is briefly

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“…Taking an advantage of simultaneous measurements of the Doppler velocities at X and W bands, we can derive the un-attenuated or true W-band radar profiles in rain (Tian et al, 2007;Liao et al, 2008). The differential Doppler velocity (DDV), which is defined as the difference of the Doppler velocities between X and W bands, depends only on the particle median volume diameter (D 0 ).…”

Section: Comparisons Of Simulated Profiles To Measurementsmentioning

confidence: 99%

“…The p in the plots is the shape factor of the gamma distribution, which is zero for the Marshall-Palmer size distribution (1948). Since the DDV is independent of the radar attenuation and also unaffected by air motion, D 0 can be estimated from the measured DDV (Tian et al, 2007;Liao et al, 2008). This in turn leads to a value of DFR from the differential Doppler-estimated D0.…”

Section: Comparisons Of Simulated Profiles To Measurementsmentioning

confidence: 99%

Measurements and Simulations of Nadir-Viewing Radar Returns from the Melting Layer at X and W Bands

Liao

Meneghini

Tian

et al. 2009

Journal of Applied Meteorology and Climatology

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Simulated radar signatures within the melting layer in stratiform rain, namely the radar bright band, are checked by means of comparisons with simultaneous measurements of the bright band made by the EDOP (X-band) and CRS (W-band) airborne Doppler radars during the CRYSTAL-FACE campaign in 2002. A stratified-sphere model, allowing the fractional water content to vary along the radius of the particle, is used to compute the scattering properties of individual melting snowflakes. Using the effective dielectric constants computed by the conjugate gradient-fast Fourier transform (CGFFT) numerical method for X and W bands, and expressing the fractional water content of melting particle as an exponential function in particle radius, it is found that at X band the simulated radar bright-band profiles are in an excellent agreement with the measured profiles. It is also found that the simulated W-band profiles usually resemble the shapes of the measured bright-band profiles even though persistent offsets between them are present. These offsets, however, can be explained by the attenuation caused by cloud water and water vapor at W band. This is confirmed by the comparisons of the radar profiles made in the rain regions where the un-attenuated W-band reflectivity profiles can be estimated through the X-and Wband Doppler velocity measurements. The bright-band model described in this paper has the potential to be used effectively for both radar and radiometer algorithms relevant to the TRMM and GPM satellite missions

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Properties of light stratiform rain derived from 10‐ and 94‐GHz airborne Doppler radars measurements

Cited by 28 publications

References 35 publications

Improved rain rate and drop size retrievals from airborne Doppler radar

Improved rain rate and drop size retrievals from airborne Doppler radar

Emerging Technologies and Synergies for Airborne and Space-Based Measurements of Water Vapor Profiles

Measurements and Simulations of Nadir-Viewing Radar Returns from the Melting Layer at X and W Bands

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