scholarly journals Assessing the Effects of Microphysical Scheme on Convective and Stratiform Characteristics in a Mei-Yu Rainfall Combining WRF Simulation and Field Campaign Observations

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Lin Liu ◽  
Chunze Lin ◽  
Yongqing Bai ◽  
Dengxin He
Keyword(s):  
Wrf Model ◽  
Cloud Microphysics ◽  
Middle Level ◽  
Weather Research And Forecasting ◽  
Field Campaign ◽  
Microphysical Properties ◽  
Double Moment ◽  
Storm Dynamics ◽  
Precipitation Structure ◽  
Upper Level

Microphysics parameterization becomes increasingly important as the model grid spacing increases toward convection-resolving scales. Using observations from a field campaign for Mei-Yu rainfall in China, four bulk cloud microphysics schemes in the Weather Research and Forecasting (WRF) model were evaluated with respect to their ability to simulate precipitation, structure, and cloud microphysical properties over convective and stratiform regimes. These are the Thompson (THOM), Morrison graupel/hail (MOR_G/H), Stony Brook University (SBU_YLIN), and WRF double-moment six-class microphysics graupel/hail (WDM6_G/H). All schemes were able to predict the rain band but underestimated the total precipitation by 23%–35%. This is mainly attributed to the underestimation of stratiform precipitation and overestimation of convective rain. For the vertical distribution of radar reflectivity, many problems remain, such as lower reflectivity values aloft in both convective and stratiform regions and higher reflectivity values at middle level. Each bulk scheme has its advantages and shortcomings for different cloud regimes. Overall, the discrepancies between model output and observations mostly exist in the midlevel to upper level, which results from the inability of the model to accurately represent the particle size distribution, ice processes, and storm dynamics. Further observations from major field campaigns and more detailed evaluation are still necessary.

Pathways to the Production of Precipitating Hydrometeors and Tropical Cyclone Development

2016 ◽  
Vol 144 (6) ◽  
pp. 2395-2420 ◽  
Author(s):  
J.-W. Bao ◽  
S. A. Michelson ◽  
E. D. Grell
Keyword(s):  
Tropical Cyclone ◽  
Wrf Model ◽  
Cloud Microphysics ◽  
Weather Research And Forecasting ◽  
Rapid Intensification ◽  
Latent Heating ◽  
Vertical Distributions ◽  
Double Moment ◽  
Microphysical Processes ◽  
Definition Of

Abstract Pathways to the production of precipitation in two cloud microphysics schemes available in the Weather Research and Forecasting (WRF) Model are investigated in a scenario of tropical cyclone intensification. Comparisons of the results from the WRF Model simulations indicate that the variation in the simulated initial rapid intensification of an idealized tropical cyclone is due to the differences between the two cloud microphysics schemes in their representations of pathways to the formation and growth of precipitating hydrometeors. Diagnoses of the source and sink terms of the hydrometeor budget equations indicate that the major differences in the production of hydrometeors between the schemes are in the spectral definition of individual hydrometeor categories and spectrum-dependent microphysical processes, such as accretion growth and sedimentation. These differences lead to different horizontally averaged vertical profiles of net latent heating rate associated with significantly different horizontally averaged vertical distributions and production rates of hydrometeors in the simulated clouds. Results from this study also highlight the possibility that the advantage of double-moment formulations can be overshadowed by the uncertainties in the spectral definition of individual hydrometeor categories and spectrum-dependent microphysical processes.

scholarly journals Sensitivity of WRF Cloud Microphysics to Simulations of a Convective Storm Over the Nepal Himalayas

2017 ◽  
Vol 11 (1) ◽  
pp. 29-43 ◽  
Author(s):  
Rudra K. Shrestha ◽  
Paul J. Connolly ◽  
Martin W. Gallagher
Keyword(s):  
Monsoon Season ◽  
Wrf Model ◽  
Tropical Rainfall Measuring Mission ◽  
Cloud Microphysics ◽  
Convective Storm ◽  
Forming Process ◽  
Double Moment ◽  
Upper Level ◽  
Set Up ◽  
Storm Characteristics

Background:This paper investigates sensitivity of bulk microphysical parameterization (BMP) schemes within the Weather Research and Forecasting (WRF) model to simulate a convective storm that generally evolves during pre-monsoon season (March – May) across the foothills of the Himalayas.Method:Four mixed-phase BMP schemes (Morrison, Lin, WDM6, and WSM6), which are parameterized with an increasing complexity from single to double moments of particle distribution to represent cloud processes, are used with an explicit convection permitting grid resolution (3 km x 3 km). Experiments are set up to simulate a convective storm that occurred in the late afternoon of 18thMay 2011 and compared with i) Satellite-based tropical rainfall measuring mission (TRMM) 3B42 v7 data, and ii) Ground-based observations at Nagarkot (27.7°N, 85.5°E), Nepal.Result:Our results show that the simulated storm characteristics are not overly sensitive to the chosen BMP schemes. In general, all the BMP schemes produce similar rainfall characteristics and compares reasonably well with the observations across Siwalik Hills and Middle Mountains, which act as a topographic barrier to low level circulations and receive more rain. The schemes, however, show negative bias across central Nepal including the Kathmandu Valley, albeit the magnitude and spatial distribution of bias are different between the schemes. In contrast, upper level total water condensate and cloud fraction show a strong sensitivity to the BMP schemes.Conclusion:Overall, the Morrison scheme, in addition to warm clouds which also predict double moment distribution of all hydrometeors in the cold-cloud processes, a dominant cloud forming process in the Himalayas, accurately represents the mechanism and outperforms the simplified schemes based on root mean square error (RMSE) analysis.

scholarly journals Polar Winds: Airborne Doppler Wind Lidar Missions in the Arctic for Atmospheric Observations and Numerical Model Comparisons

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1141
Author(s):  
Steven Greco ◽  
George D. Emmitt ◽  
Alice DuVivier ◽  
Keith Hines ◽  
Michael Kavaya
Keyword(s):  
Wrf Model ◽  
The Arctic ◽  
Weather Research And Forecasting ◽  
Dynamic Features ◽  
Wind Retrieval ◽  
Atmospheric Observations ◽  
Wind Lidar ◽  
Upper Level ◽  
Upper Level Jet ◽  
Doppler Wind Lidar

During October–November 2014 and May 2015, NASA sponsored and conducted a pair of airborne campaigns called Polar Winds to investigate atmospheric circulations, particularly in the boundary layer, over the Arctic using NASA’s Doppler Aerosol WiNd (DAWN) lidar. A description of the campaigns, the DAWN instrument, wind retrieval methods and data processing is provided. During the campaigns, the DAWN instrument faced backscatter sensitivity issues in the low aerosol conditions that were fairly frequent in the 2–6 km altitude range. However, when DAWN was able to make measurements, comparisons with dropsondes show good agreement and very low bias and supports the use of an airborne Doppler wind lidar such as DAWN that can provide profiles with high velocity precision, ~65 m vertical resolution and horizontal spacing as fine as 3–7 km. Case study analyses of a Greenland tip jet, barrier winds and an upper level jet are presented and show how, despite sensitivity issues, DAWN data can be confidently used in diagnostic studies of dynamic features in the Arctic. Comparisons with both an operational and research Weather Research and Forecasting (WRF) model for these events also show the potential for utilization in model validation. The sensitivity issues of the DAWN laser have since been corrected.

Comparison of WRF Model-Simulated and MODIS-Derived Cloud Data

2008 ◽  
Vol 136 (6) ◽  
pp. 1957-1970 ◽  
Author(s):  
Jason A. Otkin ◽  
Thomas J. Greenwald
Keyword(s):  
Wrf Model ◽  
Detailed Comparison ◽  
Cloud Microphysics ◽  
Cloud Data ◽  
Parameterization Schemes ◽  
Cloud Properties ◽  
Pbl Scheme ◽  
Resolution Model ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Upper Level

Abstract In this study, the ability of different combinations of bulk cloud microphysics and planetary boundary layer (PBL) parameterization schemes implemented in the Weather Research and Forecasting Model to realistically simulate the wide variety of cloud types associated with an extratropical cyclone is examined. An ensemble of high-resolution model simulations was constructed for this case using four microphysics and two PBL schemes characterized by different levels of complexity. Simulated cloud properties, including cloud optical thickness, cloud water path, cloud-top pressure, and radiative cloud phase, were subsequently compared to cloud data from three Moderate Resolution Imaging Spectroradiometer (MODIS) overpasses across different portions of the domain. A detailed comparison of the simulated datasets revealed that the PBL and cloud microphysics schemes both exerted a strong influence on the spatial distribution and physical properties of the simulated cloud fields. In particular, the low-level cloud properties were found to be very sensitive to the PBL scheme while the upper-level clouds were sensitive to both the microphysics and PBL schemes. Overall, the simulated cloud properties were broadly similar to the MODIS observations, with the most realistic cloud fields produced by the more sophisticated parameterization schemes.

Impacts of A Priori Databases Using Six WRF Microphysics Schemes on Passive Microwave Rainfall Retrievals

2013 ◽  
Vol 30 (10) ◽  
pp. 2367-2381 ◽  
Author(s):  
Ju-Hye Kim ◽  
Dong-Bin Shin ◽  
Christian Kummerow
Keyword(s):  
A Priori ◽  
Wrf Model ◽  
Tropical Rainfall Measuring Mission ◽  
Cloud Microphysics ◽  
Passive Microwave ◽  
A Priori Information ◽  
Physically Based ◽  
Double Moment ◽  
Priori Information ◽  
The Individual

Abstract Physically based rainfall retrievals from passive microwave sensors often make use of cloud-resolving models (CRMs) to build a priori databases of potential rain structures. Each CRM, however, has its own cloud microphysics assumptions. Hence, approximated microphysics may cause uncertainties in the a priori information resulting in inaccurate rainfall estimates. This study first builds a priori databases by combining the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) observations and simulations from the Weather Research and Forecasting (WRF) model with six different cloud microphysics schemes. The microphysics schemes include the Purdue–Lin (LIN), WRF Single-Moment 6 (WSM6), Goddard Cumulus Ensemble (GCE), Thompson (THOM), WRF Double-Moment 6 (WDM6), and Morrison (MORR) schemes. As expected, the characteristics of the a priori databases are inherited from the individual cloud microphysics schemes. There are several distinct differences in the databases. Particularly, excessive graupel and snow exist with the LIN and THOM schemes, while more rainwater is incorporated into the a priori information with WDM6 than with any of the other schemes. Major results show that convective rainfall regions are not well captured by the LIN and THOM schemes-based retrievals. Rainfall distributions and their quantities retrieved from the WSM6 and WDM6 schemes-based estimations, however, show relatively better agreement with the PR observations. Based on the comparisons of the various microphysics schemes in the retrievals, it appears that differences in the a priori databases considerably affect the properties of rainfall estimations.

scholarly journals A Comparative Study of Bin and Bulk Cloud Microphysics Schemes in Simulating a Heavy Precipitation Case

Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 475 ◽  
Author(s):  
Hyunho Lee ◽  
Jong-Jin Baik
Keyword(s):  
Heat Release ◽  
Latent Heat ◽  
Wrf Model ◽  
Heavy Precipitation ◽  
Cloud Microphysics ◽  
Latent Heat Release ◽  
Microphysics Scheme ◽  
Surface Precipitation ◽  
Double Moment ◽  
Bin Microphysics

Comparisons between bin and bulk cloud microphysics schemes are conducted by simulating a heavy precipitation case using a bin microphysics scheme and four double-moment bulk microphysics schemes in the Weather Research and Forecasting (WRF) model. For this, we implemented an updated bin microphysics scheme in the WRF model. All of the microphysics schemes underestimate observed strong precipitation, but the bin microphysics scheme yields the result that is closest to observations. The differences among the schemes are more pronounced in terms of hydrometeor number concentration than in terms of hydrometeor mixing ratio. In this case, the bin scheme exhibits remarkably more latent heat release by deposition and riming than the bulk schemes. This causes stronger updrafts and more upward transport of water vapor, which leads to more deposition, and again, increases the latent heat release. An additional simulation using the bin scheme but excluding the riming of cloud droplets on ice crystals, which is not or poorly treated in the examined bulk schemes, shows that surface precipitation is slightly weakened and moved farther downwind compared to that of the control simulation. This implies that the more appropriate representation of microphysical processes in the bin microphysics scheme contributes to the more accurate prediction of precipitation in this case.

Airborne Atmospheric Measurements with the Max Planck CloudKites

2021 ◽  
Author(s):  
Marcel Schröder ◽  
Freja Nordsiek ◽  
Oliver Schlenczek ◽  
Antonio Ibañez Landeta ◽  
Johannes Güttler ◽  
...  
Keyword(s):  
Particle Image Velocimetry Data ◽  
Cloud Microphysics ◽  
Max Planck ◽  
Atmospheric Measurements ◽  
Field Campaign ◽  
Flight Data ◽  
Microphysical Properties ◽  
Image Velocimetry ◽  
The Caribbean

<p>To investigate cloud microphysics and turbulence in clouds and in the atmospheric boundary layer, we specially developed airborne platforms, one Max-Planck-CloudKite + (MPCK+) and two mini-Max-Planck-CloudKites (mini-MPCK). They are deployed aboard balloon-kite hybrids conducting <em>in situ</em> measurements of meteorological and cloud microphysical properties with high spatial and temporal resolution. During the EUREC4A-ATOMIC field campaign in the Caribbean January-February 2020, the MPCK+ and one mini-MPCK sampled clouds aboard a 250 m<sup>3</sup> aerostat launched from the R.V. Maria S. Merian where both instruments were operated between MSL and 1500m MSL. In addition, one mini-MPCK profiled the atmosphere between MSL and 1000 m MSL aboard a 74 m<sup>3</sup> aerostat launched from the R.V. Meteor. In total, we acquired 145 h of flight-data on RV Maria S. Merian and 52 h of flight-data on RV Meteor. For the MPCK+, this included 5 hr of Particle Image Velocimetry data and 3 hr of inline holography data inside clouds and near the cloud edges. We present <em>in situ</em> data measured by the MPCKs during the EUREC4A-ATOMIC field campaign and report on preliminary assessment of turbulence features.</p>

scholarly journals Satellite-Based Assessment of Various Cloud Microphysics Schemes in Simulating Typhoon Hydrometeors

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Ying Zhang ◽  
Yu Wang ◽  
Guosheng Liu ◽  
Jianping Guo ◽  
Yuanjian Yang ◽  
...  
Keyword(s):  
Microwave Radiometer ◽  
Wrf Model ◽  
Cloud Microphysics ◽  
Horizontal Distribution ◽  
Microwave Brightness Temperature ◽  
Joint Histogram ◽  
Double Moment ◽  
Significant Intensity ◽  
Scattering Index ◽  
Ice Water

The accurate simulation of typhoon hydrometeors remains a challenge. This study attempts to evaluate the performances of five microphysics schemes (MPSs) in the Weather Research and Forecasting (WRF) model in simulating the supertyphoon Neoguri in July 2014. The observed microwave brightness temperature, as well as retrieved data from the microwave radiometer imager (MWRI) onboard Chinese FY-3B satellite, are used to test hydrometeor simulations. In particular, two MWRI radiance indices, including the emission index (EI) and scattering index (SI), are used to assess the performance of five MPSs in simulating liquid and frozen hydrometeors, respectively. Overall, the WRF model can well reproduce the overall pattern of typhoon-produced precipitation, albeit with slightly overestimated precipitation in the inner rainband and underestimated precipitation in the stratiform rainband. Moreover, ice water paths (IWPs) from all five MPS simulations are higher than those estimated from MWRI retrieval in most areas, and the spatial pattern and values of IWP for the National Severe Storms Laboratory double-moment MPS (NSSL) are much closer to those for MWRI. The NSSL scheme reproduces a more realistic joint histogram distribution of SI and EI than other MPSs do, relative to the observation. Besides, the nonlinear Lucas–Kanade optical flow approach has been used to reflect the horizontal distribution of hydrometeors in the typhoon. The results show that the simulated EI and SI from the five MPSs show a systematic southwest bias of approximately about 10∼20 km and significant intensity bias in the convection area. Further model sensitivity tests confirm that the NSSL scheme generates more realistic graupel and supercooled water close to the observations among all MPSs. The findings suggest that satellite measurements would be helpful to assess MPSs in numeric weather models, especially for hydrometeor distributions in the whole typhoon system.

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