A Comparison of the Polarimetric Radar Characteristics of Heavy Rainfall From Hurricanes Harvey (2017) and Florence (2018)

DeHart, Jennifer C.; Bell, Michael M.

doi:10.1029/2019jd032212

Cited by 19 publications

(13 citation statements)

References 51 publications

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“…Wen et al (2018) found that 99% the rainfall in seven landfalling typhoons consisted of raindrops less than 4 mm in diameter. In contrast, the rainbands in Hurricane Harvey (2017) sometimes exhibited large concentrations of medium‐ to large‐sized raindrops (Brauer et al, 2020; DeHart & Bell, 2020; Wolff et al, 2019). Embedded convective cells within TC rainbands can generate locally enhanced concentrations of ice crystals, snow, and some graupel (Kalina et al, 2017; Wang et al, 2018), which can produce larger raindrops in the outer rainbands (Wu et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Hydrometeor Size Sorting in the Asymmetric Eyewall of Hurricane Matthew (2016)

et al. 2020

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Polarimetric radar observations of Hurricane Matthew's asymmetric eyewall were captured by WSR‐88D radars from 1500 UTC on 7 October 2016 to 0000 UTC on 8 October 2016. Raindrop size sorting was observed within the eyewall, marked by a differential reflectivity (ZDR) enhancement region situated upwind of a specific differential phase (KDP) enhancement region, both overlapping the maximum reflectivity. This signature indicated that the largest raindrops fell out of the eyewall updrafts faster than the smaller, abundant drops that were advected further downstream by the primary circulation. Airborne Doppler radar observations revealed an updraft structure in an azimuthal location consistent with the size‐sorting signature and previous observational studies of eyewall kinematic asymmetries. Given that a tropical cyclone's environment or internal dynamics can modulate the eyewall's kinematic and microphysical structure, we used a simple size‐sorting model that only includes sedimentation and advection of raindrops by the axisymmetric tangential wind to examine how an eyewall size‐sorting signature responds to artificial changes in the tangential wind speed and initial raindrop size distributions (DSDs). The axisymmetric tangential wind was retrieved from WSR‐88D radar observations using the Ground‐Based Velocity Track Display technique. The simple model was capable of producing an eyewall size‐sorting signature with an azimuthal separation between the simulated ZDR and KDP enhancements in general agreement with the observed separation (~20°) at low levels. Sensitivity tests showed that the azimuthal separation between the ZDR and KDP enhancements responded to changes in the tangential wind speed, but not to changes in the initial DSDs aloft.

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Section: Introductionmentioning

confidence: 99%

Hydrometeor Size Sorting in the Asymmetric Eyewall of Hurricane Matthew (2016)

et al. 2020

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“…Hurricane Laura provided a unique opportunity and novel data set to quantify drop size distribution characteristics in different portions of a landfalling TC using ground radar observations, space‐borne radar retrievals, and disdrometer measurements. Prior research has examined the microphysical signatures in different regions of landfalling TCs using ground and space‐borne radar observations (e.g., Brauer et al., 2021; DeHart & Bell, 2020; Didlake & Kumjian, 2017; Feng & Bell, 2019; Homeyer et al., 2021), however the use of disdrometer observations were not incorporated in order to verify PSD quantities and provide a direct comparison to estimations from remote sensing platforms as these retrievals were unavailable.…”

Section: Discussionmentioning

confidence: 99%

“…This process occurs as smaller drops have a lower terminal velocity and are therefore advected further downwind, whereas larger hydrometeors fall out of the cloud at a faster rate (Kumjian & Ryzhkov, 2012). DeHart and Bell (2020) found that polarimetric radar observations in Hurricane Harvey (2017) and Hurricane Florence (2018) exhibited signatures associated with large concentrations of small and medium drops, with Harvey having the greatest particle size distribution (PSD) variability over time. These are similar to the results from Zheng et al (2021), who also concluded that collision-coalescence and accretion are the dominant processes in mature inner rainbands.…”

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confidence: 99%

Hurricane Laura (2020): A Comparison of Drop Size Distribution Moments Using Ground and Radar Remote Sensing Retrieval Methods

et al. 2022

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Landfalling tropical cyclones (TCs) are known to produce catastrophic damage from wind, heavy rainfall, and storm surge (e.g., Rappaport, 2000Rappaport, , 2014. While wind damage is typically the main focus of TCs, Rappaport (2014) found that water-related deaths accounted for 90% of landfalling Atlantic TC fatalities. Therefore, it is important to understand and quantify processes associated with excessive precipitation in TCs.Microphysics in TCs are uncertain and observations often disagree with numerical simulations, which poses a challenge toward understanding TC structure, evolution, and intensity (e.g., Chen & Gopalakrishnan, 2014;Hristova-Veleva et al., 2021). Prior observational studies have shown that collision-coalescence and drop breakup are the dominant precipitation processes in warm rain events such as TCs (e.g., Atlas & Ulbrich, 2000; List

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“…The eye was located about 240 km SSW of the Wallops (PRF) at this time and tracking NNE between 6 and 10 m/s. A brief analysis of the hurricane azimuthal asymmetry suggested that the shear vector was directed to the NE and the outer rain bands were located in the down shear left (DL) quadrant [46]. Several studies of hurricanes have shown that stratiform rain occurs in the DL quadrant [5,6] and typically these outer rain bands are sufficiently steady that a 1D model would be sufficient to simulate the microphysical profiles.…”

Section: Overview Of Rain Bands From Radar Observations and 1d Mcsnow Modelmentioning

confidence: 99%

Hurricane Dorian Outer Rain Band Observations and 1D Particle Model Simulations: A Case Study

Bringi

Seifert

et al. 2020

Atmosphere

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The availability of high quality surface observations of precipitation and volume observations by polarimetric operational radars make it possible to constrain, evaluate, and validate numerical models with a wide variety of microphysical schemes. In this article, a novel particle-based Monte-Carlo microphysical model (called McSnow) is used to simulate the outer rain bands of Hurricane Dorian which traversed the densely instrumented precipitation research facility operated by NASA at Wallops Island, Virginia. The rain bands showed steady stratiform vertical profiles with radar signature of dendritic growth layers near −15 °C and peak reflectivity in the bright band of 55 dBZ along with polarimetric signatures of wet snow with sizes inferred to exceed 15 mm. A 2D-video disdrometer measured frequent occurrences of large drops >5 mm and combined with an optical array probe the drop size distribution was well-documented in spite of uncertainty for drops <0.5 mm due to high wind gusts and turbulence. The 1D McSnow control run and four numerical experiments were conducted and compared with observations. One of the main findings is that even at the moderate rain rate of 10 mm/h collisional breakup is essential for the shape of the drop size distribution.

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A Comparison of the Polarimetric Radar Characteristics of Heavy Rainfall From Hurricanes Harvey (2017) and Florence (2018)

Cited by 19 publications

References 51 publications

Hydrometeor Size Sorting in the Asymmetric Eyewall of Hurricane Matthew (2016)

Hydrometeor Size Sorting in the Asymmetric Eyewall of Hurricane Matthew (2016)

Hurricane Laura (2020): A Comparison of Drop Size Distribution Moments Using Ground and Radar Remote Sensing Retrieval Methods

Hurricane Dorian Outer Rain Band Observations and 1D Particle Model Simulations: A Case Study

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