Author
Qi Tang
Bio: Qi Tang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Precipitation & Storm. The author has an hindex of 4, co-authored 4 publications receiving 91 citations.
Papers
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TL;DR: In this paper, the characteristics of raindrop size distributions and polarimetric radar parameters retrieved by T-matrix for stratiform and convective precipitation in Beijing and Zhangbei (northern China), and Yangjiang (southern China) are studied and compared based on RSD data observed with PARSIVEL disdrometers in these three different climatic regions.
77 citations
TL;DR: In this paper, the authors investigated the role of upper and lower-level weather systems in heavy rain in Beijing and its surrounding areas from 21 to 22 July 2012, and showed that the precipitation in Beijing can be divided into two phases: a warm-sector precipitation phase, ahead of the cold front, and a cold front precipitation phase.
23 citations
TL;DR: In this article, a high-resolution slide self-consistency correction (SSCC) method was proposed to improve the performance of X-band dual-polarization radars.
Abstract: In order to improve the performance of X-band dual-polarization radars, it is necessary to conduct attenuation correction before using the X-band radar data. This study analyzes a variety of attenuation correction methods for the X-band radar reflectivity, and proposes a high-resolution slide self-consistency correction (SSCC) method, which is an improvement of Kim et al.’s method based on Bringi et al.’s original method. The new method is comprehensively evaluated with the observational data of convective cloud, stratiform cloud, and the stratiform cloud with embedded convection. Comparing with the intrinsic reflectivity at X-band calculated from the reflectivity at S-band, it is found that the new method can effectively reduce the correction errors when calculating differential propagation shift increments using the conventional self-consistency attenuation correction method. This method can efficiently correct the X-band dual-polarization radar reflectivity, in particular, for the echoes with reflectivity greater than 35 dBZ.
13 citations
TL;DR: Wang et al. as discussed by the authors investigated the effect of cloud condensation nuclei (CCN) concentrations on microphysical processes and precipitation characteristics of hailstorms in a semi-arid region of northern China.
Abstract: Numerical simulations are carried out to investigate the effect of cloud condensation nuclei (CCN) concentrations on microphysical processes and precipitation characteristics of hailstorms. Two hailstorm cases are simulated, a spring case and a summer case, in a semiarid region of northern China, with the Regional Atmospheric Modeling System. The results are used to investigate the differences and similarities of the CCN effects between spring and summer hailstorms. The similarities are: (1) The total hydrometeor mixing ratio decreases, while the total ice-phase mixing ratio enhances, with increasing CCN concentration; (2) Enhancement of the CCN concentration results in the production of a greater amount of small-sized hydrometeor particles, but a lessening of large-sized hydrometeor particles; (3) As the CCN concentration increases, the supercooled cloud water and rainwater make a lesser contribution to hail, while the ice-phase hydrometeors take on active roles in the growth of hail; (4) When the CCN concentration increases, the amount of total precipitation lessens, while the role played by liquid-phase rainfall in the amount of total precipitation reduces, relatively, compared to that of ice-phase precipitation. The differences between the two storms include: (1) An increase in the CCN concentration tends to reduce pristine ice mixing ratios in the spring case but enhance them in the summer case; (2) Ice-phase hydrometeor particles contribute more to hail growth in the spring case, while liquid water contributes more in the summer case; (3) An increase in the CCN concentration has different effects on surface hail precipitation in different seasons.
9 citations
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01 Dec 2006
TL;DR: In this article, the authors studied the characteristics of raindrop size distribution in seven tropical cyclones through impact-type disdrometer measurements at three different sites during the 2004-06 Atlantic hurricane seasons.
Abstract: Characteristics of the raindrop size distribution in seven tropical cyclones have been studied through impact-type disdrometer measurements at three different sites during the 2004–06 Atlantic hurricane seasons. One of the cyclones has been observed at two different sites. High concentrations of small and/or midsize drops were observed in the presence or absence of large drops. Even in the presence of large drops, the maximum drop diameter rarely exceeded 4 mm. These characteristics of raindrop size distribution were observed in all stages of tropical cyclones, unless the storm was in the extratropical stage where the tropical cyclone and a midlatitude frontal system had merged. The presence of relatively high concentrations of large drops in extratropical cyclones resembled the size distribution in continental thunderstorms. The integral rain parameters of drop concentration, liquid water content, and rain rate at fixed reflectivity were therefore lower in extratropical cyclones than in tropical cyclones. In tropical cyclones, at a disdrometercalculated reflectivity of 40 dBZ, the number concentration was 700 100 drops m 3 , while the liquid water content and rain rate were 0.90 0.05 g m 3 and 18.5 0.5 mm h 1 , respectively. The mean mass diameter, on the other hand, was 1.67 0.3 mm. The comparison of raindrop size distributions between Atlantic tropical cyclones and storms that occurred in the central tropical Pacific island of Roi-Namur revealed that the number density is slightly shifted toward smaller drops, resulting in higher-integral rain parameters and lower mean mass and maximum drop diameters at the latter site. Considering parameterization of the raindrop size distribution in tropical cyclones, characteristics of the normalized gamma distribution parameters were examined with respect to reflectivity. The mean mass diameter increased rapidly with reflectivity, while the normalized intercept parameter had an increasing trend with reflectivity. The shape parameter, on the other hand, decreased in a reflectivity range from 10 to 20 dBZ and remained steady at higher reflectivities. Considering the repeatability of the characteristics of the raindrop size distribution, a second impact disdrometer that was located 5.3 km away from the primary site in Wallops Island, Virginia, had similar size spectra in selected tropical cyclones.
122 citations
TL;DR: In this paper, the characteristics of raindrop size distributions and vertical structures of rainfall during the Asian summer monsoon season in East China were studied using measurements from a ground-based two-dimensional video disdrometer (2DVD) and a vertically pointing Micro Rain Radar (MRR).
Abstract: The characteristics of raindrop size distributions (DSDs) and vertical structures of rainfall during the Asian summer monsoon season in East China are studied using measurements from a ground-based two-dimensional video disdrometer (2DVD) and a vertically pointing Micro Rain Radar (MRR). Based on rainfall intensity and vertical structure of radar reflectivity, the observed rainfall is classified into convective, stratiform, and shallow precipitation types. Among them, shallow precipitation has previously been ignored or treated as outliers due to limitations in traditional surface measurements. Using advanced instruments of 2DVD and MRR, the characteristics of shallow precipitation are quantified. Furthermore, summer rainfall in the study region is found to consist mainly of stratiform rain in terms of frequency of occurrence but is dominated by convective rain in terms of accumulated rainfall amount. Further separation of the summer season into time periods before, during, and after the Meiyu season reveals that intrasummer variation of DSDs is mainly due to changes in percentage occurrence of the three precipitation types, while the characteristics of each type remain largely unchanged throughout the summer. Overall, higher raindrop concentrations and smaller diameters are found compared to monsoon precipitation at other locations in Asia. Higher local aerosol concentration is speculated to be the cause. Finally, rainfall estimation relationships using polarimetric radar measurements are derived and discussed. These new relationships agree well with rain gauge measurements and are more accurate than traditional relations, especially at high and low rain rates.
116 citations
08 Oct 2009
TL;DR: In this article, the authors proposed a method to estimate the three-dimensional distribution of hydrometeors using X-band radar data, which is necessary to correct for attenuation before applying commonly used hydrometeor classification algorithms.
Abstract: Abstract X-band and shorter radar wavelengths are preferable for mobile radar systems because a narrow beam can be realized with a moderately sized antenna. However, attenuation by precipitation becomes progressively more severe with decreasing radar wavelength. As a result, X band has become a popular choice for meteorological radar systems that balances these two considerations. Dual-polarization provides several methods by which this attenuation (and differential attenuation) can be detected and corrected, mitigating one of the primary disadvantages of X-band radars. The dynamics of severe convective storms depend, to some extent, on the distribution and type of hydrometeors within the storm. To estimate the three-dimensional distribution of hydrometeors using X-band radar data, it is necessary to correct for attenuation before applying commonly used hydrometeor classification algorithms. Since 2002, a mobile dual-polarized Doppler weather radar designed at the University of Massachusetts, Amherst has ...
110 citations
TL;DR: In this paper, the characteristics of raindrop size distributions and polarimetric radar parameters retrieved by T-matrix for stratiform and convective precipitation in Beijing and Zhangbei (northern China), and Yangjiang (southern China) are studied and compared based on RSD data observed with PARSIVEL disdrometers in these three different climatic regions.
77 citations
TL;DR: Seela et al. as discussed by the authors studied the distribution of raindrop size distribution characteristics of summer and winter season rainfall over north Taiwan, and found that raindrop sizes varied with the season.
Abstract: 1 Seela, B. K., Janapati, J., Lin, P.-L.,Wang, P. K., & Lee, M.-T. (2018). Raindrop size distribution characteristics of summer and winter season rainfall over north Taiwan. Journal of Geophysical Research: Atmospheres, 123. https://doi.org/10.1029/2018JD028307. Balaji Kumar Seela Taiwan International Graduate Program (TIGP) Earth System Science (ESS) Program Research Center for Environmental Changes (RCEC), Academia Sinica, Taiwan Institute of Atmospheric Science, National Central University, Jhongli City, Taiwan
76 citations