Microphysics and dynamics of snowfall associated to a warm conveyor belt over Korea

Gehring, Josué; Oertel, Annika; Vignon, Étienne; Jullien, Nicolas; Bešič, Nikola; Berne, Alexis

doi:10.5194/acp-2019-1173

Cited by 3 publications

(13 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…U is obtained by calculating the mean wind velocity from radiosoundings between 500 m (EV1) or 2000 m (EV2) and D z a.g.l. during the events (see Vignon et al, 2019a, b;Gehring et al, 2020b for details on radiosonde data acquisition and processing).W is measured from vertical Doppler velocity measurements. We use MXPol data for EV1 while we prefer using WProf measurements for EV2 given its higher temporal frequency.…”

Section: Applicability Of the Methods And Implementationmentioning

confidence: 99%

“…It was an intense precipitation event (55 mm of equivalent liquid precipitation) associated with a warm conveyor belt (WCB, i.e. a warm and moist airstream ascending along the cold front of an extratropical cyclone, see Green et al (1966), Harrold (1973), Browning et al (1973) Two main sites at different altitudes and locations were instrumented (see Fig.1 in Gehring et al, 2020b…”

Section: Ice-pop Campaign In South Korea (Ev2)mentioning

confidence: 99%

“…The added value of radar polarimetry (e.g., Kumjian, 2012;Tiira and Moisseev, 2020) is of particular relevance for characterizing salient features in radar profiles like the melting layer (Griffin et al, 2020) but also for deciphering the microphysical structure of snowfall. Bader et al (1987), Andrić et al (2013), Schneebeli et al (2013), Moisseev et al (2015), Grazioli et al (2015), Besic et al (2018), Gehring et al (2020b) among others show the potential of dual-polarization variables to study some characteristics of snowflakes (e.g., type, shape, orientation, size, phase) as well as the underlying microphysical processes that drive their evolution.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, the onset of aggregation was identified by Moisseev et al (2015) as bands of high values of specific differential phase K dp . Kennedy and Rutledge (2011); Gehring et al (2020b) identified a region dominated by aggregation with a decrease in differential reflectivity (Z DR ) collocated with an increase of reflectivity (Z H ) while Schrom and Kumjian (2016) identified aggregation as a maximum in the downward relative gradient of reflectivity ∂ z Z H below the −15 • C isotherm and a positive downward gradient of absolute Doppler velocity ∂ z |V r | > 0.…”

Section: Introductionmentioning

confidence: 99%

“…The authors emphasize that the noise and standard deviation of the signal are strongly reduced owing to the azimuthal averaging. Range Height Indicator (RHI) scans can also be used to extract vertical profiles at a given azimuth (e.g., Andrić et al, 2013;Moisseev et al, 2015;Gehring et al, 2020b). The analysis of vertical profiles of dual-polarization variables from RHI scans has been further developed by Tiira and Moisseev (2020) with a multivariate unsupervised classification of vertical profiles of Z H , Z DR and K dp .…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Identification of snowfall microphysical processes from vertical gradients of polarimetric radar variables

Planat¹,

Gehring²,

Vignon³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Polarimetric radar systems are commonly used to study the microphysics of precipitation. While they offer continuous measurements with a large spatial coverage, retrieving information about the microphysical processes that govern the evolution of snowfall from the polarimetric signal is challenging. The present study develops a new method, called Process Identification based on Vertical gradient Signs (PIVS), to spatially identify the occurrence of the main microphysical processes (aggregation and riming, crystal growth by vapor deposition, and sublimation) in snowfall from dual-polarization Doppler radar scans. We first derive an analytical framework to assess in which meteorological conditions the local vertical gradients of radar variables reliably inform about microphysical processes. In such conditions, we then identify regions dominated by (i) vapor deposition, (ii) aggregation and riming and (iii) snowflake sublimation and possibly snowflake breakup based on the sign of the local vertical gradients of the reflectivity ZH and the differential reflectivity ZDR. The method is then applied to data from two frontal snowfall events: one in coastal Adélie Land, Antarctica and one in the Taebaeck mountains in South Korea. The validity of the method is assessed by comparing its outcome with snowflake observations using a Multi-Angle Snowflake Camera and with the output of a hydrometeor classification based on polarimetric radar signal. The application of the method further makes it possible to better characterize and understand how snowfall forms, grows and decays in two different geographical and meteorological contexts. For the Antarctic case study, we show that crystal growth by vapor deposition dominates above 2500 m a.g.l., aggregation and riming prevail between 1500 and 2500 m a.g.l. and snowflake sublimation by low-level katabatic winds occurs below 1500 m a.g.l.. For the event in South Korea, aggregation and riming dominate between 4000 and 4800 m a.g.l., with local sublimation below and vapor deposition above. We infer some microphysical characteristics in terms of radar variables from statistical analysis of the method output (e.g. ZH and ZDR distribution for each process). We finally highlight the potential for extensive application to cold precipitation events in different meteorological contexts.

show abstract

Section: Applicability Of the Methods And Implementationmentioning

confidence: 99%

Section: Ice-pop Campaign In South Korea (Ev2)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Identification of snowfall microphysical processes from vertical gradients of polarimetric radar variables

Planat¹,

Gehring²,

Vignon³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

Measured ice nucleating particle concentrations improve the simulation of mid-level mixed-phase clouds over the high-latitude Southern Ocean

Berne¹,

Vignon

Alexander

et al. 2020

Preprint

View full text Add to dashboard Cite

WRF simulations of mixed-phase clouds over the high-latitude Southern Ocean are evaluated with remotely-sensed data from the MARCUS ;• Accounting for the low concentration of ice nucleating particles is critical to simulate thin supercooled liquid water layer at cloud top;• Further parameterization developments targeting the convection at cloud top are needed to reproduce the turbulence-microphysics interplay.

show abstract

Challenging and Improving the Simulation of Mid‐Level Mixed‐Phase Clouds Over the High‐Latitude Southern Ocean

et al. 2021

Self Cite

View full text Add to dashboard Cite

Climate models exhibit major radiative biases over the Southern Ocean owing to a poor representation of mixed‐phase clouds. This study uses the remote‐sensing dataset from the Measurements of Aerosols, Radiation and Clouds over the Southern Ocean (MARCUS) campaign to assess the ability of the Weather Research and Forecasting (WRF) model to reproduce frontal clouds off Antarctica. It focuses on the modeling of thin mid‐level supercooled liquid water layers which precipitate ice. The standard version of WRF produces almost fully glaciated clouds and cannot reproduce cloud top turbulence. Our work demonstrates the importance of adapting the ice nucleation parameterization to the pristine austral atmosphere to reproduce the supercooled liquid layers. Once simulated, droplets significantly impact the cloud radiative effect by increasing downwelling longwave fluxes and decreasing downwelling shortwave fluxes at the surface. The net radiative effect is a warming of snow and ice covered surfaces and a cooling of the ocean. Despite improvements in our simulations, the local turbulent circulation related to cloud‐top radiative cooling is not properly reproduced, advocating for the need to develop a parameterization for top‐down convection to capture the turbulence‐microphysics interplay at cloud top.

show abstract

Microphysics and dynamics of snowfall associated to a warm conveyor belt over Korea

Cited by 3 publications

References 33 publications

Identification of snowfall microphysical processes from vertical gradients of polarimetric radar variables

Identification of snowfall microphysical processes from vertical gradients of polarimetric radar variables

Measured ice nucleating particle concentrations improve the simulation of mid-level mixed-phase clouds over the high-latitude Southern Ocean

Challenging and Improving the Simulation of Mid‐Level Mixed‐Phase Clouds Over the High‐Latitude Southern Ocean

Contact Info

Product

Resources

About