Disdrometer

About: Disdrometer is a research topic. Over the lifetime, 930 publications have been published within this topic receiving 23092 citations.

Precipitation measurement with a C‐band weather radar in southern Ontario

Abstract: Three years of seasonal radar and raindrop disdrometer data have been correlated to determine a relationship between radar reflectivity factor and rainfall rate (Z∼R) for Southern Ontario storms during rain periods. It was found that instantaneous rainfall rates for small areas can be estimated from equivalent radar reflectivity factor measurements using a best‐fit relation Ze = 295 R1.43 with a standard error of 0.288 in the logarithm of R. The accuracy in estimating storm rainfalls from a modest number of observations is of significance for hydrometeorological applications. The analyses revealed a correctable systematic bias in the measurements not associated with the instrument systems but accountable to atmospheric effects inherent in the standard measurement technique. Only insignificant improvements were found in the relationship by stratifying the data by synoptic or storm type. Correlation of Z and R from the drop size distributions alone shows the characteristic power law relationship co...

Vertically resolved precipitation intensity retrieved through a synergy between the ground-based NASA MPLNET lidar network measurements, surface disdrometer datasets and an analytical model solution

Abstract: In this paper, we illustrate a new, simple and complementary ground-based methodology to retrieve the vertically resolved atmospheric precipitation intensity through a synergy between measurements from the National Aeronautics and Space Administration (NASA) Micropulse Lidar network (MPLNET), an analytical model solution and ground-based disdrometer measurements. The presented results are obtained at two mid-latitude MPLNET permanent observational sites, located respectively at NASA Goddard Space Flight Center, USA, and at the Universitat Politecnica de Catalunya, Barcelona, Spain. The methodology is suitable to be applied to existing and/or future lidar/ceilometer networks with the main objective of either providing near real-time (3 h latency) rainfall intensity measurements and/or to validate satellite missions, especially for critical light precipitation (<3 mm h−1).

Characteristics of the raindrop size distribution for freezing precipitation observed in southern China

Abstract: [1] Freezing precipitation (i.e., freezing rain or freezing drizzle) is an extremely hazardous weather that can cause severe socioeconomic loss and compromise human safety. To better document and understand the microphysics of this type of precipitation, drop size spectra were collected with an optical disdrometer during a freezing precipitation event on 27 January 2008 in southern China. The drop size distribution (DSD) characteristics, the correlations between the shape (μ), slope (Λ), and intercept (N0) of the gamma distribution, and the relations between the reflectivity (Z) and rainfall rate (R) have been investigated. It was found that the DSDs of freezing precipitation were characterized by weak stratiform rain with a small mass-weighted diameter (Dm, 0.63 mm) and a large normalized intercept (Nw, 4.25 log10 mm−1 m−3). This indicated that freezing precipitation was not formed by the melting of larger, dry snowflakes but by the melting of smaller, rimed ice particles. Furthermore, the derived μ-Λ, N0-μ, and Z-R relations are distinctly different from the convective rains or tropical stratiform rains reported in the literature.

Further evidence for superterminal raindrops

Abstract: A network of optical disdrometers (including laser precipitation monitors and a two-dimensional video disdrometer) was utilized to determine whether the recent reports of “superterminal” raindrops were spurious results of drop breakup occurring on instrumentation. Results unequivocally show that superterminal raindrops at small (less than 1 mm) sizes are ubiquitous, are measurable over an extended area, and appear in every rain event investigated. No evidence was found to suggest that superterminal drops are the result of drop breakup due to impact with the measurement instrument; thus, if the superterminal drops are the result of drop fragmentation, this fragmentation happens in the ambient atmosphere during all rain events measured in this study. The ubiquity of superterminal drops at small drop sizes raises natural questions regarding rain accumulation estimations, estimates of drop size distributions, and erosion characterization.

Impact of rain attenuation on 5G millimeter wave communication systems in equatorial Malaysia investigated through disdrometer data

Abstract: Next-generation 5G cellular networks are expected to operate on the millimeter wavelength frequencies (e.g., 28 GHz and 38 GHz) to offer broader bandwidths and higher data rates. In this frequency band, rain is a major impairment to received signal power. This work aims to improve predictions of rain attenuation for 5G wireless networks operating at 28 GHz and 38 GHz in heavy rain regions, by exploiting three years of raindrop size distribution (DSD) data collected at Kuala Lumpur (Malaysia). The specific attenuation is calculated by means of point matching technique and each minute of DSD data. The empirical power law relationship between specific attenuation and rainfall intensity are subsequently derived and compared with those for Rec. ITU-R P.838-3 and Singapore results. The results indicate substantial local deviations from the ITU-R model, especially at 38 GHz. Next, gamma and normalized gamma models are employed to compute the specific attenuation values. The performances of these models are assessed in terms by cumulative distribution function. These results offer important information for predicting rain attenuation of 5G wireless communication systems in heavy rain regions.