Development of a Single-Moment Cloud Microphysics Scheme with Prognostic Hail for the Weather Research and Forecasting (WRF) Model

Bae, Sung‐Heui; Hong, Song‐You; Tao, Wei‐Kuo

doi:10.1007/s13143-018-0066-3

Cited by 46 publications

(34 citation statements)

References 24 publications

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“…reflectivity (,35 dBZ). The area of stratiform precipitation is significantly narrower than those obtained by Morrison et al (2009) and Bae et al (2019), while the associated radar reflectivities are smaller by about 10 dBZ. A comparison of simulations using the Morrison scheme (Morrison et al 2009) and Milbrandt-Yau two-moment scheme (MY05a,b) are presented in the appendix.…”

Section: B Control Run Cloud Structures 1) Precipitation Evolutioncontrasting

confidence: 60%

“…Figure 4 shows the Hovmöller diagram of surface precipitation and column-maximum radar reflectivity. One can see a narrow band of convective core (.25 mm h 21 and .45 dBZ), which remained stationary for the first 2 h, then traveled 100 km eastward for the next 4 h. This result is quite similar to that of Bae et al (2019) but different from that of Morrison et al (2009), who showed an eastward movement of the convective core less than an hour after the start of the simulation. To the west of the convective core is the trailing stratiform zone with much weaker precipitation intensity (,10 mm h 21 ) and radar FIG.…”

Section: B Control Run Cloud Structures 1) Precipitation Evolutioncontrasting

confidence: 52%

“…Fig. 4) is weaker and more narrowly distributed than that simulated by Morrison et al (2009) and Bae et al (2019). The shape and moment treatments discussed above could contribute to such differences.…”

Section: Sensitivity Simulations a Shape And Moment Effectsmentioning

confidence: 59%

“…The National Taiwan University (NTU) multimoment bulk microphysical scheme has been implemented into the WRF Model (Skamarock et al 2008), version 3.8.1, and tested with a standard two-dimensional idealized squall-line case, which has been frequently used to examine the performance of microphysics schemes (e.g., Morrison et al 2009;Van Weverberg et al 2012;Morrison and Milbrandt 2015;Song et al 2017;Bae et al 2019).…”

Section: Idealized Squall-line Simulationsmentioning

confidence: 99%

See 3 more Smart Citations

Multimoment Ice Bulk Microphysics Scheme with Consideration for Particle Shape and Apparent Density. Part I: Methodology and Idealized Simulation

Tsai

Chen

2020

Journal of the Atmospheric Sciences

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To improve the parameterization of ice-phase microphysics in regional meteorological models, this study developed a triple-moment bulk scheme, which also tracks the variations in the shape and density of several hydrometeors. Solid-phase hydrometeors are classified into pristine ice, snow aggregates, rimed ice, and hailstones based on their physical mechanisms. The new scheme has been incorporated into the Weather Research and Forecasting Model and tested with an idealized two-dimensional simulation of a squall-line system. The simulation successfully revealed the smooth transition from the convective core to the stratiform anvil as well as the alternating pattern in the hydrometeor vertical distributions, as was similarly demonstrated in other similar studies. A few sensitivity tests were performed to reveal the importance of including shape and density variations, which strongly affect the mean particle size by up to 50% and fall speed by as much as 100% for individual hydrometeor categories. Furthermore, the inclusion of a third moment could enhance the diffusional growth rate of small crystals and reduce the ventilation effect of large particles compared with the conventional double-moment approach. These factors have a significant influence on cloud structure and precipitation amounts.

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Section: B Control Run Cloud Structures 1) Precipitation Evolutioncontrasting

confidence: 60%

Section: B Control Run Cloud Structures 1) Precipitation Evolutioncontrasting

confidence: 52%

Section: Sensitivity Simulations a Shape And Moment Effectsmentioning

confidence: 59%

Section: Idealized Squall-line Simulationsmentioning

confidence: 99%

See 2 more Smart Citations

Multimoment Ice Bulk Microphysics Scheme with Consideration for Particle Shape and Apparent Density. Part I: Methodology and Idealized Simulation

Tsai

Chen

2020

Journal of the Atmospheric Sciences

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“…This problem has been approached within the framework of microphysical parameterizations, as it is not computationally feasible to explicitly resolve the complex microphysical processes that occur among hydrometeors in the atmosphere at sub-meter scales, such as collision and coalescence. Much work has been dedicated to improving microphysical parameterizations, from the inclusion of more hydrometeor species (e.g., the work by the authors of [1]), to the development of double moment schemes (e.g., the works by the authors of [2][3][4]).…”

Section: Introductionmentioning

confidence: 99%

The Potential for Discriminating Microphysical Processes in Numerical Weather Forecasts Using Airborne Polarimetric Radio Occultations

et al. 2019

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Accurate representation of cloud microphysical processes in numerical weather and climate models has proven challenging, in part because of the highly specialized instrumentation required for diagnosing errors in simulated distributions of hydrometeors. Global Navigation Satellite System (GNSS) polarimetric radio occultation (PRO) is a promising new technique that is sensitive to hydrometeors and has the potential to help address these challenges by providing microphysical observations that are relevant to larger spatial scales, especially if this type of observing system can be implemented on aircraft that can target heavy precipitation events. Two numerical experiments were run using a mesoscale model configured with two different microphysical parameterization schemes for a very intense atmospheric river (AR) event that was sampled by aircraft deploying dropsondes just before it made landfall in California, during the CalWater 2015 field campaign. The numerical experiments were used to simulate profiles of airborne polarimetric differential phase delay observations. The differential phase delay due to liquid water hydrometeors below the freezing level differed significantly in the two experiments, as well as the height of the maximum differential phase delay due to all hydrometeors combined. These results suggest that PRO observations from aircraft have the potential to contribute to validating and improving the representation of microphysical processes in numerical weather forecasts once these observations become available.

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How does the air-sea coupling frequency affect convection during the MJO passage?

Zhao

Nasuno²

2020

Preprint

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The importance of air-sea coupling in the simulation and prediction of the Madden-Julian Oscillation (MJO) has been well established. However, it remains unclear how air-sea coupling modulates the convection and related oceanic features on the subdaily scale. Based on a regional cloud-permitting coupled model, we evaluated the impact of the air-sea coupling on the convection during the convectively active phase of the MJO by varying the coupling frequency. The model successfully reproduced the atmospheric and oceanic variations observed by satellite and in situ measurements but with some quantitative biases. According to the sensitivity experiments, we found that stronger convection was mainly caused by the higher sea surface temperatures (SSTs) generated in high-frequency coupled experiments, especially when the coupling frequency was 1 hr or shorter. A lower coupling frequency would generate the phase lags in the diurnal cycle of SST and related turbulent heat fluxes. Our analyses further demonstrated that the phase-lagged diurnal cycle of SST suppressed deep convection through a decrease in daytime moistening in the lower troposphere. Meanwhile, in the upper ocean, the high-frequency air-sea coupling helped maintain the shallower mixed and isothermal layers by diurnal heating and cooling at the sea surface, which led to a higher mean SST. In contrast, the low-frequency coupled experiments underestimated the SST and therefore convective activities. Overall, our results demonstrated that high-frequency air-sea coupling (1 hr or shorter) could improve the reproducibility of the intensity and temporal variation in both diurnal convection and upper ocean processes. Plain Language SummaryThe Madden-Julian Oscillation (MJO) is one of the most important sources of atmospheric variability in tropical regions; however, even the modern numerical models could not well reproduce the MJO. We believe that the underestimation of air-sea coupling may cause some parts of such biases in simulating/predicting the MJO. Therefore, our study is aimed to uncover the impact of the air-sea coupling on convection and the related oceanic feature during the MJO. By varying the air-sea coupling frequency, our results showed that the 1-hr or higher-frequency coupled experiments had better performance due to the well-reproduced sea surface temperature, while suppressed convection was found in low-frequency coupled experiments. In general, our study suggested that the high-frequency air-sea coupling could improve the reproducibility of both convection and upper ocean features during the MJO.

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Development of a Single-Moment Cloud Microphysics Scheme with Prognostic Hail for the Weather Research and Forecasting (WRF) Model

Cited by 46 publications

References 24 publications

Multimoment Ice Bulk Microphysics Scheme with Consideration for Particle Shape and Apparent Density. Part I: Methodology and Idealized Simulation

Multimoment Ice Bulk Microphysics Scheme with Consideration for Particle Shape and Apparent Density. Part I: Methodology and Idealized Simulation

The Potential for Discriminating Microphysical Processes in Numerical Weather Forecasts Using Airborne Polarimetric Radio Occultations

How does the air-sea coupling frequency affect convection during the MJO passage?

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