Classification of Precipitating Clouds in the Tropics Using 915-MHz Wind Profilers

Williams, C. R.; Ecklund, W. L.; Gage, K. S.

doi:10.1175/1520-0426(1995)012<0996:copcit>2.0.co;2

Cited by 186 publications

(142 citation statements)

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“…Over a 2-minute window, the radar dynamic range changes to observe heavy precipitation (30-sec), moderate precipitation (30-sec), and then anvil clouds (60-sec). The S-PROF radars are used primarily for real-time HMT applications by analyzing the vertical gradient in Doppler velocity to identify the height where frozen particles are melting into raindrops [Williams et al, 1995;White et al, 2002]. The S-PROF radar observations are not routinely calibrated to produce reflectivity estimates.…”

Section: Event Description and Observationsmentioning

confidence: 99%

Evaluation of cloud microphysics schemes in simulations of a winter storm using radar and radiometer measurements

et al. 2013

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[1] Using observations from a space-borne radiometer and a ground-based precipitation profiling radar, the impact of cloud microphysics schemes in the WRF model on the simulation of microwave brightness temperature (T b ), radar reflectivity, and Doppler velocity (V dop ) is studied for a winter storm in California. The unique assumptions of particles size distributions, number concentrations, shapes, and fall speeds in different microphysics schemes are implemented into a satellite simulator and customized calculations for the radar are performed to ensure consistent representation of precipitation properties between the microphysics schemes and the radiative transfer models. [2] Simulations with four different schemes in the WRF model, including the Goddard scheme (GSFC), the WRF single-moment 6-class scheme (WSM6), the Thompson scheme (THOM), and the Morrison double-moment scheme (MORR), are compared directly with measurements from the sensors. Results show large variations in the simulated radiative properties. General biases of~20 K or larger are found in (polarization-corrected) T b , which is linked to an overestimate of the precipitating ice aloft. The simulated reflectivity with THOM appears to agree well with the observations, while high biases of~5À10 dBZ are found in GSFC, WSM6 and MORR. Peak reflectivity in MORR exceeds other schemes. These biases are attributable to the snow intercept parameters or the snow number concentrations. Simulated V dop values based on GSFC agree with the observations well, while other schemes appear to have a~1 m s -1 high bias in the ice layer. In the rain layer, the model representations of Doppler velocity vary at different sites.Citation: Han, M., S. A. Braun, T. Matsui, and C. R. Williams (2013), Evaluation of cloud microphysics schemes in simulations of a winter storm using radar and radiometer measurements,

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Section: Event Description and Observationsmentioning

confidence: 99%

Evaluation of cloud microphysics schemes in simulations of a winter storm using radar and radiometer measurements

et al. 2013

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“…The vertical structure of tropical mesoscale convective systems (MCSs) has been studied using various instruments during many international campaigns, including GATE (GARP Atlantic Tropical Experiment) in the eastern Atlantic ocean (Williams et al, 1995;Leary and Houze, 1979), EMEX (Equatorial Mesoscale Experiment), winter MONEX in South China Sea, DUNDEE (Down Under Doppler and Electricity Experiment) (Cifelli and Rutledge, 1994), and TOGA-COARE (Tropical Ocean Global Atmosphere, Coupled Ocean-Atmosphere Response Experiment) (Williams and Hacker, 1997;Johnson and Lin, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…Temporal variations of precipitating clouds in equatorial Indonesia have been studied based on observations with 1357.5 MHz boundary layer radars at Serpong (6.4 • S, 106.7 • E) near Jakarta and Bukittinggi (0.2 • S, 100.3 • E) in West Sumatera. We have classified precipitating clouds into four types: stratiform, mixed stratiform-convective, deep convective, and shallow convective clouds, using the Williams et al (1995) method. Diurnal variations of the occurrence of precipitating clouds at Serpong and Bukittinggi have showed the same characteristics, namely, that the precipitating clouds primarily occur in the afternoon and the peak of the stratiform cloud comes after the peak of the deep convective cloud.…”

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Precipitating clouds observed by 1.3-GHz boundary layer radars in equatorial Indonesia

Renggono¹,

Hashiguchi

Fukao

et al. 2001

Ann. Geophys.

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Abstract. Temporal variations of precipitating clouds in equatorial Indonesia have been studied based on observations with 1357.5 MHz boundary layer radars at Serpong (6.4 • S, 106.7 • E) near Jakarta and Bukittinggi (0.2 • S, 100.3 • E) in West Sumatera. We have classified precipitating clouds into four types: stratiform, mixed stratiform-convective, deep convective, and shallow convective clouds, using the Williams et al. (1995) method. Diurnal variations of the occurrence of precipitating clouds at Serpong and Bukittinggi have showed the same characteristics, namely, that the precipitating clouds primarily occur in the afternoon and the peak of the stratiform cloud comes after the peak of the deep convective cloud. The time delay between the peaks of stratiform and deep convective clouds corresponds to the life cycle of the mesoscale convective system. The precipitating clouds which occur in the early morning at Serpong are dominated by stratiform cloud. Concerning seasonal variations of the precipitating clouds, we have found that the occurrence of the stratiform cloud is most frequent in the rainy season, while the occurrence of the deep convective cloud is predominant in the dry season.

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“…To determine the precipitating cloud type from wind profiler data, the 30-min averaged reflectivity, and Doppler Velocity derived from the vertical-pointing beam are calculated. For the present study, we adopted modified algorithm based on Williams et al (1995) the vertical structure of the precipitating cloud systems as deep/shallow convective [without existence of bright band (hereafter, BB)], mixed clouds (transition of convective and stratiform clouds developed due to expansion of convection cloud into a broad hinged/banded cloud system with BB existence @4.5 km altitude), and stratiform (BB presence without convective clouds). This algorithm is based on the judgment of presence of a melting layer and the presence of hydrometeors above the melting layer.…”

Section: Topography and Experimental Set-upmentioning

confidence: 99%

“…Another advantage of the wind profiler is to measure directly the vertical profiles of reflectivity and Doppler velocity within a convective environment (Gage et al 1994). Several researchers (Gage et al 1994;Hashiguchi et al 1995;Williams et al 1995;Reddy et al 2002;Atlas and Williams 2003;Pan et al 2010) have used wind profiler to reveal details about the vertical structure of mesoscale precipitating cloud systems. Since the vertical distribution of diabatic heating depends on the vertical structure of the convective system (Simpson et al 1988), it is important to study the vertical structure of the precipitating clouds occurring during Mei-yu period.…”

Section: Introductionmentioning

confidence: 99%

Wind Profiler Observation on Vertical Structure of a Mei-yu Front Cloud Bands

Lai

2011

Journal of the Meteorological Society of Japan

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An L-band wind profiler deployed at an industrial park (120.38 E, 22.6 N) close to Kao-Hsiung city in southern Taiwan is utilized to diagnose the vertical structure of Mei-yu frontal precipitating cloud systems observed during 9-11 June 2006. Observational results show several mesoscale convection systems associated with the Mei-yu frontal cloud produced heavy rainfall over Taiwan island. Mei-yu precipitating clouds are classified into three types: convective, mixed convective-stratiform and stratiform based on vertical profile of Signal-to-noise ratio (SNR)/Reflectivity and Doppler velocity during approaching, passing, and leaving stages of the cloud systems. In approaching and pre-passing stages of Mei-yu frontal clouds, a pre-dominant convective precipitation without a significant bright band is observed. In contrast, a pronounced bright band around 4 km was observed during post-passing and leaving stages of the frontal clouds with stratiform precipitation. Doppler velocity profiles show hydrometeors (ice/snow) at 5 km and rain below 4 km for stratiform precipitation. For Mei-yu frontal stratiform precipitation the melting particles accelerations of 3.3 ms À1 km À1 are observed for the bright band region.

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Classification of Precipitating Clouds in the Tropics Using 915-MHz Wind Profilers

Cited by 186 publications

References 0 publications

Evaluation of cloud microphysics schemes in simulations of a winter storm using radar and radiometer measurements

Evaluation of cloud microphysics schemes in simulations of a winter storm using radar and radiometer measurements

Precipitating clouds observed by 1.3-GHz boundary layer radars in equatorial Indonesia

Wind Profiler Observation on Vertical Structure of a Mei-yu Front Cloud Bands

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