Planetary Boundary Layer Schemes Research Articles

A Preliminary Examination of WRF Ensemble Prediction of Convective Mode Evolution

Abstract Accurately simulating convective mode evolution can assist forecasters in the severe weather warning process. A few prior studies have examined the skill of simulating convective modes using single, deterministic forecasts. The present study extends the earlier evaluations to a small, four-member ensemble, with each member incorporating varying initial and lateral boundary conditions, microphysics schemes, and planetary boundary layer schemes. Simulated convective modes from thirty-two 12-h simulations were categorized into nine classifications using a classification scheme developed from previous studies. Multiple methods were used to derive forecasts of these convective classifications, creating an hourly deterministic ensemble mode forecast and probabilistic forecasts for 1-, 6-, and 12-h periods. Forecasts were compared with observed radar reflectivity for verification. In general, hourly deterministic ensemble mode forecasts showed improvement over individual member forecasts. The small ensemble produced more skillful individual cellular convective mode forecasts than individual linear mode forecasts, with the least skill present for bow echoes and squall lines with trailing stratiform precipitation. In contrast, the ensemble was more skillful at forecasting the broader linear convective group than the broader cellular convective group. For a limited number of these cases, a test was performed using a larger 10-member ensemble run by the National Center for Atmospheric Research (NCAR) to examine what impacts the small ensemble size might have. The results did not differ substantially, suggesting the findings from the small ensemble can be generalized. Probabilistic forecasts for longer time periods were more skillful than shorter-term probabilistic forecasts.

Dispersion simulations using HYSPLIT for the Sagebrush Tracer Experiment

The Sagebrush experiment, led by NOAA's Field Research Division of the Air Resources Laboratory, consisted of five releases (intensive observation periods, or IOPs) of a chemically inert trace gas on five days in October 2013. All releases occurred in the afternoon under either near neutral stability conditions with high wind speeds or unstable conditions with low wind speeds. The sampling network for the tracer concentrations covered distances 200 m–3200 m from the release location and samples were obtained in 10-min averages. HYSPLIT, NOAA's transport and dispersion model, was used to simulate the spatial and temporal distribution of the tracer. The dispersion simulations were driven by WRF meteorological data with 27-km to 333-m grid spacing and using the inline and offline approaches as well as different planetary boundary layer schemes and a large-eddy simulation parameterization. Comparisons with measured wind speeds showed that none of the WRF PBL schemes or the large-eddy simulation parameterization was able to reproduce the rapid increase in high wind speeds observed during IOP3. The dispersion results were compared with the tracer measurements obtained during the experiment. The HYSPLIT dispersion simulations for IOP3, driven by the WRF data generated with various PBL schemes, showed greater concentration variability than the simulations performed for IOP5. The comparison between the inline and offline HYSPLIT simulations showed that the inline approach statistically outperformed the offline approach in three out of four IOPs because the tight coupling between the advection and dispersion processes implemented in the inline approach produced higher simulated concentrations close to the release location.

Sensitivity of PBL parameterizations on PM10 and ozone simulation using chemical transport model WRF-Chem over a sub-tropical urban airshed in India

Meteorology plays vital role in predicting air quality parameters in regional chemical transport models. WRF-Chem is one such chemical transport model that includes various physics and chemistry options for simulating ozone and PM10 concentrations. In this study, WRF-Chem model was used to compare the performance of different Planetary Boundary Layer (PBL) parameterization namely, the Yonsei University (YSU) and Asymmetric Convective Model v2 (ACM2) PBL schemes, over the Delhi megacity urban airshed. Surface observations were used for comparisons and evaluating model performance for both meteorological and air quality variables. The ACM2 PBL scheme resulted in better model performance for simulating ozone and PM10 concentrations along with an improvement in temperature and wind speeds due to incorporation of both local and non-local characteristics. The dependency of ozone and PM10 concentrations on meteorological parameters temperature and wind speed were studied. The influence of PBL height and ventilation coefficient on model performance was analysed as dispersion of pollutants strongly depend on these factors. The PBL height was highly over estimated during evening hours which was also reflected in the corresponding ventilation coefficient values. Even though ACM2 PBL scheme was concluded as the best PBL scheme for the study region, it still requires significant improvement for simulating air quality parameters. Further, ozone and PM10 concentrations were scrutinized for varying ranges of temperature and wind speed. Model performance for ozone and PM10 concentrations was good for temperature values below 40 °C and wind speed ≤8 m/s. A poor model performance was observed for regions with high wind speed values. Even though certain limitations were observed in the model evaluation of PBL height and high wind speed values, WRF-Chem model can be effectively employed for simulating ozone and PM10 concentrations giving due considerations to limitations on high temperature and high wind speed regime.

A new gust parameterization for weather prediction models

We analyze Uruguyan measurements, focusing on gusts at turbine hub height. Large gusts, exceeding 15 m/s, are observed to occur when the surface layer (as assessed by the bulk Richardson number Ri) is neutral, and are uncommon when the layer is stable or even unstable. Gust factors (the ratio of the gusts to the mean winds) are inversely related to the mean winds but increase as the atmosphere becomes more unstable. Numerical simulations using different planetary boundary layer (PBL) schemes and mesoscale grid resolutions are employed in the development of a gust parameterization (GP) utilizing forecasts of surface layer Ri and winds above hub height. The GP, which provides gust factors to be applied to predicted turbine-level winds, provides higher skill at relatively coarser resolution than a simpler algorithm based solely on surface layer information, although its success is strongly dependent on the PBL and surface layer schemes selected.

A Grid-Refinement-Based Approach for Modeling the Convective Boundary Layer in the Gray Zone: Algorithm Implementation and Testing

Abstract A grid-refinement-based method is implemented in a community atmospheric model to improve the representation of convective boundary layer (CBL) turbulence on gray-zone [i.e., ~O(1) km] grids. At this resolution, CBL convection is partially resolved and partially subgrid scale (SGS), such that neither traditional mesoscale planetary boundary layer (PBL) schemes nor SGS closures for large-eddy simulations (LESs) are appropriate. The proposed method utilizes two-way interactive nesting to refine the horizontal resolution of the unstable surface layer of the daytime CBL. SGS turbulent mixing in the fine nest and coarse parent grids are parameterized by an LES turbulence closure and a PBL scheme, respectively. The method does not rely on predetermined empirical functions to introduce grid (scale) dependency and in theory works with any PBL scheme. Compared to the stand-alone gray-zone simulation, the proposed approach shows improvements in terms of higher-order statistics, the timing of the onset of resolved convection, and the convective structures. A deficiency of the method exists when the nest domain is limited to the surface layer; the convective structures become gradually contaminated by spurious convection on the parent gray-zone grid. A deeper nest domain alleviates the issue at increased computational costs.

Assessment of Planetary-Boundary-Layer Schemes in the Weather Research and Forecasting Model Within and Above an Urban Canopy Layer

We tested several planetary-boundary-layer (PBL) schemes available in the Weather Research and Forecasting (WRF) model against measured wind speed and direction, temperature and turbulent kinetic energy (TKE) at three levels (5, 9, 25 m). The Urban Turbulence Project dataset, gathered from the outskirts of Turin, Italy and used for the comparison, provides measurements made by sonic anemometers for more than 1 year. In contrast to other similar studies, which have mainly focused on short-time periods, we considered 2 months of measurements (January and July) representing both the seasonal and the daily variabilities. To understand how the WRF-model PBL schemes perform in an urban environment, often characterized by low wind-speed conditions, we first compared six PBL schemes against observations taken by the highest anemometer located in the inertial sub-layer. The availability of the TKE measurements allows us to directly evaluate the performances of the model; results of the model evaluation are presented in terms of quantile versus quantile plots and statistical indices. Secondly, we considered WRF-model PBL schemes that can be coupled to the urban-surface exchange parametrizations and compared the simulation results with measurements from the two lower anemometers located inside the canopy layer. We find that the PBL schemes accounting for TKE are more accurate and the model representation of the roughness sub-layer improves when the urban model is coupled to each PBL scheme.

WRF simulations for a heavy rainfall event in southern Italy: Verification and sensitivity tests

In this paper we study the sensitivity of the quantitative precipitation forecast (QPF) to different physical parameterization schemes and configuration settings of WRF (Weather Research and Forecasting) model for a catastrophic event occurred in Calabria, Southern Italy.The event lasted four days, from 30 October 2015 to 2 November 2015, and affected mostly the eastern side of the peninsula. Several raingauges measured >500 mm for the whole event, with the maximum recorded in Chiaravalle (739 mm for the whole event, which is about half of the yearly rainfall). Damages to railway, roads and properties were extensive.To show the sensitivity of the QPF to the model settings and physical parameterization schemes, twelve configurations of WRF are considered, in addition to the control run (CC), which is the configuration used for the operational forecast at ISAC-CNR in Lamezia Terme. In particular, we tested the sensitivity of the QPF to four different microphysical schemes, three Planetary Boundary Layer (PBL) schemes (non-local and local), two cumulus parameterization schemes, two different horizontal resolutions (1 km vs 3 km), and different initial and boundary conditions. The QPF is verified both by quantitative measures and qualitative scores, using the observations of 156 raingauges quite uniformly distributed over Calabria. The analysis refers to 12 h and 24 h rainfall, but some details are given also for shorter time scales.Results show that most of the WRF configurations are able to predict most of the features of the precipitation field. However, there are differences at the local scale (few tens of kilometers) that are important for several purposes, including civil protection. In particular, using a non-local PBL closure scheme was fundamental to correctly simulate the heavy precipitation close to the sea for this case, while other configurations predicted the rainfall more anchored to mountain peaks. The good performance of non-local PBL scheme confirms the findings of a previous study over Calabria.The results of this paper show the sensitivity of the QPF at the local scale for different WRF configurations and an ensemble approach is envisaged to improve the prediction of such catastrophic events.

Evaluating Mesoscale Simulations of the Coastal Flow Using Lidar Measurements

AbstractThe atmospheric flow in the coastal zone is investigated using lidar and mast measurements and model simulations. Novel dual‐Doppler scanning lidars were used to investigate the flow over a 7 km transect across the coast, and vertically profiling lidars were used to study the vertical wind profile at offshore and onshore positions. The Weather, Research and Forecasting model is set up in 12 different configurations using 2 planetary boundary layer schemes, 3 horizontal grid spacings and varied sources of land use, and initial and lower boundary conditions. All model simulations describe the observed mean wind profile well at different onshore and offshore locations from the surface up to 500 m. The simulated mean horizontal wind speed gradient across the shoreline is close to that observed, although all simulations show wind speeds that are slightly higher than those observed. Inland at the lowest observed height, the model has the largest deviations compared to the observations. Taylor diagrams show that using ERA‐Interim data as boundary conditions improves the model skill scores. Simulations with 0.5 and 1 km horizontal grid spacing show poorer model performance compared to those with a 2 km spacing, partially because smaller resolved wave lengths degrade standard error metrics. Modeled and observed velocity spectra were compared and showed that simulations with the finest horizontal grid spacing resolved more high‐frequency atmospheric motion.

Coupled WRF-OpenFOAM study of wind flow over complex terrain

This study addresses turbulence modelling issues related to the simulation of flow over complex terrain using a coupling between NWP (numerical weather prediction) code and a classical CFD (computational fluid dynamics) code. A new planetary boundary layer (PBL) parameterization scheme, which is specifically formulated for coupling purposes, is presented. The capability of the developed closure models to be applied to the whole atmospheric boundary layer, not only to the surface layer is assessed by performing idealized simulations and comparing the results with the Leipzig dataset. CFD simulations sustained with inflow conditions acquired from mesoscale simulations are performed with different turbulence closures for the Askervein Hill case and their performances are evaluated in comparison with wind speed and turbulence kinetic energy measurements. Finally, the proposed turbulence modelling methodology is applied to the Ria de Ferrol Case. The new PBL scheme is implemented and tested with the open source mesoscale code, Weather Research and Forecasting (WRF) model. Microscale simulations and the turbulence model implementation are performed with the open source computational fluid dynamics (CFD) toolbox, OpenFOAM v. 2.3.1.

Comparison of WRF local and nonlocal boundary layer Physics in Greater Kuala Lumpur, Malaysia

The urban boundary layer (UBL) is the internal advection layer of atmosphere above urban region which determines the exchanges of momentum, water and other atmospheric constituents between the urban land surface and the free troposphere. This paper tested the performance of three planetary boundary layer (PBL) physics schemes of Weather Research and Forecast (WRF) software to ensure the appropriate representation of vertical structure of UBL in Greater Kuala Lumpur (GKL). Comparison was conducted on the performance of respective PBL schemes to generate vertical and near-surface weather profile and rainfall. Mellor-Yamada- Janjíc (MYJ) local PBL scheme coupled with Eta MM5 surface layer scheme was found to predict the near-surface temperature and wind profile and mixing height better than the nonlocal schemes during the intermonsoonal period with least influences of the synoptic background weather.

Performance of the WRF Model for Surface Wind Prediction around Qatar

AbstractThe performance of the Weather Research and Forecasting (WRF) Model is examined for the region around Qatar in the context of surface winds. The wind fields around this peninsula can be complicated owing to its small size, to a complex pattern of land and sea breezes influenced by the prevailing shamal winds, and to its dry and arid nature. Modeled winds are verified with data from 19 land stations and two offshore buoys. A comparison with these data shows that nonlocal planetary boundary layer (PBL) schemes generally perform better than local schemes over land stations during the daytime, when convective conditions prevail; at nighttime, over land and over water, both schemes yield similar results. Among other parameters, modifications to standard USGS land-use descriptors were necessary to reduce model errors. The RMSE values are comparable to those reported elsewhere. Simulated winds, when used with a wave model, result in wave heights comparable to buoy measurements. Furthermore, WRF results, confirmed by data, show that at times sea breezes develop from both coasts, leading to convergence in the middle of the country; at other times, the large-scale wind impedes the formation of sea breezes on one or both coasts. Simulations also indicate greater land/sea-breeze activity in the summer than in the winter. Differences in the diurnal evolution of surface winds over land and water are found to be related to differences in the boundary layer stability. Overall, the results indicate that the WRF Model as configured here yields reliable simulations and can be used for various practical applications.

Modeling the Evolution and Life Cycle of Radiative Cold Pools and Fog

Abstract Despite an increased understanding of the physical processes involved, forecasting radiative cold pools and their associated meteorological phenomena (e.g., fog and freezing rain) remains a challenging problem in mesoscale models. The present study is focused on California’s tule fog where the Weather Research and Forecasting (WRF) Model’s frequent inability to forecast these events is addressed and substantially improved. Specifically, this was accomplished with four major changes from a commonly employed, default configuration. First, horizontal model diffusion and numerical filtering along terrain slopes was deactivated (or mitigated) since it is unphysical and can completely prevent the development of fog. However, this often resulted in unrealistically persistent foggy boundary layers that failed to lift. Next, changes specific to the Yonsei University (YSU) planetary boundary layer (PBL) scheme were adopted that include using the ice–liquid-water potential temperature to determine vertical stability, a reversed eddy mixing K profile to represent the consequences of negatively buoyant thermals originating near the fog (PBL) top, and an additional entrainment term to account for the turbulence generated by cloud-top (radiative and evaporative) cooling. While other changes will be discussed, it is these modifications that create, to a sizable degree, marked improvements in modeling the evolution and life cycle of fog, low stratus clouds, and adiabatic cold pools.

Simulation of Monsoon Low Pressure System and its Associated Rainfall Over Bangladesh Using WRF Model

In this paper an effort has been made to simulate the monsoon Low Pressure System (LPS) and its associated rainfall event of 16-20 August, 2013 using Weather Research and Forecasting (WRF) model. The model was run for 24-h, 48-h and 72-h in a single domain of 10 km horizontal resolution using The National Centre for Environmental Prediction (NCEP) high-resolution Global Final (FNL) Analysis 6-hourly data using initial and lateral boundary conditions. WRF double-moment 5 class micro physics scheme, Kain–Fritsch (new Eta) cumulus physics scheme,Yonsei University planetary boundary layer scheme, Revised MM5 surface layer physics scheme, Unified Noah LSM as land surface model, Rapid Radiative Transfer Model (RRTM) for long-wave and Dudhia scheme for short-wave scheme are used for the simulation. The performance of the model is evaluated analyzing Mean Sea Level Pressure (MSLP), Wind Pattern, Vorticity, Vertical Wind Shear and Rainfall Distribution. The model successfully captured the low pressure system, initial condition, propagation, landfall time and location reasonably well. The model simulated rainfall amount and associated areas sensibly well compared with the observed data by BMD and Tropical Rainfall Measuring Mission (TRMM).
 Dhaka Univ. J. Sci. 66(1): 29-35, 2018 (January)

A Case Study of Low‐Level Jets in Yerevan Simulated by the WRF Model

AbstractCapabilities of high‐resolution (3 km) Weather Research and Forecasting (WRF) simulations to reproduce topographically induced mountain‐valley winds and low‐level jets (LLJs) in Yerevan have been evaluated using high‐frequency observational and modeled data. High sensitivities of simulations of near‐surface winds and LLJ characteristics observed on 4 July 2015 to both boundary layer and initial and lateral boundary conditions setup have been demonstrated. Among the nine tested planetary boundary layer (PBL) parameterization schemes the MYJ, QNSE, and TEMF PBL schemes showed greater skill in simulation of near‐surface valley winds over Yerevan, while the other PBL schemes tend to significantly underestimate the strength of valley winds, with the BouLac PBL scheme being the worst performer. Most of PBL schemes simulate well‐defined LLJs in Yerevan associated with evening valley winds. The simulated jet cores are mostly located between 150 and 250 m above ground with magnitudes varying from 12 to 21 m s−1. However, the intensity of the observed nocturnal LLJ in Yerevan (located at 110 m above ground) is strongly underestimated by most of the WRF runs while the Shin and Hong and YSU PBL schemes simulate nocturnal LLJs higher than the observed LLJ. The WRF runs initiated with newly released European Centre for Medium‐Range Weather Forecasts ERA‐5 data set showed improved simulation of near‐surface winds and nighttime potential temperatures in Yerevan relative to those forced by the Global Forecast System fields.

The Performance of a Scale-Aware Nonlocal PBL Scheme for the Subkilometer Simulation of a Deep CBL over the Taklimakan Desert

Although realistic representation of the convective boundary layer (CBL) in the desert region in Northwest China is important for weather forecasts and climate simulations, evaluations of the performance of various planetary boundary layer (PBL) schemes in simulating the CBL in the region are rare. In this study, the performance of a scale-aware PBL scheme newly implemented into the Weather Research and Forecasting (WRF) model in simulating the CBL in the Taklimakan desert is evaluated based on a comparison with both the WRF-LES simulations and observations, with the focus on scale dependencies of the simulations compared to the conventional PBL scheme. A series of simulations are performed with a scale-aware PBL scheme (Shin-Hong) and the conventional PBL scheme (YSU) for a deep CBL observed at Tazhong station in the central Taklimakan on 1 July 2016. The CBL was over 5000 m deep with wider and deeper rolls than in a shallow boundary layer. The results showed that the vertical structure simulated with the Shin-Hong scheme was closer to that in both the WRF-LES (large-eddy-simulation) and observations than that simulated with the YSU. The simulation with the scale-aware scheme reproduced cellular rolls similar to those in the WRF-LES, while the conventional PBL scheme struggled to trigger intense convective cells rather than cellular rolls. The results strongly suggest that the scale-aware nonlocal PBL scheme can be used to adequately reproduce the scale and evolution of the observed rolls in the deep CBL in Taklimakan desert at subkilometer resolutions.

Evaluation of the WRF-UCM mesoscale model and ECMWF global operational forecasts over the Paris region in the prospect of tracer atmospheric transport modeling

The quantification of CO2 emissions from cities using atmospheric measurements requires accurate knowledge of the atmospheric transport. Complex urban terrains significantly modify surface roughness, augment surface energy budgets, and create heat islands, all of which lead to lower horizontal winds and enhanced convection over urban areas. The question remains whether these processes should be included in atmospheric transport models that are used for city scale CO2 inversion, and whether they need to be tailored on a city basis. In this study, we use the WRF model over Paris to address the following research question: does WRF runs at a 3 km resolution, including urban effects and the assimilation of local weather data, perform better than ECMWF forecasts that give fields at 16 km resolution? The analysis of model performances focuses on three variables: air temperature, wind and the planetary boundary layer (PBL) height. The results show that the use of objective analysis and nudging tools are required to obtain good agreements between WRF simulated fields with observations. Surface temperature is well reproduced by both WRF and ECMWF forecasts, with correlation coefficients with hourly observations larger than 0.92 and MBEs within 1°C over one month. Wind speed correlations with hourly observations are similar for WRF (range 0.76~0.85 across stations) and ECMWF (0.79~0.84), but the associated RMSEs and MBEs are better for ECMWF. Conversely, WRF outperforms ECMWF forecasts for its description of wind direction, horizontal and vertical gradients. Sensitivity tests with different WRF physics schemes show that the wind speed and the PBL height are strongly influenced by PBL schemes. The marginal advantage of WRF over ECMWF for the desired application is sufficient to motive additional testing with prescribed CO2 flux maps for comparing modeled CO2 concentrations with available observations in an urban environment.

Vertical Ozone Concentration Profiles in the Arabian Gulf Region during Summer and Winter: Sensitivity of WRF-Chem to Planetary Boundary Layer Schemes

Air quality in the Middle East is changing due to extensive land conversion, intense industrialization and rapid urbanization. In this study, we analyze data from an ozonesonde station operated in Doha, Qatar, by the Qatar Environment and Energy Research Institute (QEERI). Ozonesondes were launched weekly at 13:00 LT (10:00 UTC) during a summer month (August 2015) representative of extremely hot and humid atmospheric conditions and during a winter period (January–February 2016) representative of cool conditions in the area. Unlike similar studies in the region, this work focuses on the lower troposphere and combines high frequency vertical measurement data with the use of the Weather Research Forecasting model coupled with Chemistry (WRF-Chem). A sensitivity study was conducted to identify the most representative planetary boundary layer (PBL) parameterization. Although all three parameterizations that were examined produced similar results, the Yonsei University (YSU) PBL scheme was found to be statistically superior. Comparisons of model predictions against observations show high correlation coefficients and encouragingly low biases in all meteorological variables. During wintertime, ozone is well predicted overall (fractional bias = –0.1). Results from the summertime comparison are more challenging and point towards possible biases in the anthropogenic emission inventory of the Middle East, especially for rapidly-changing urban environments.

Turbulence Dissipation Rate in the Atmospheric Boundary Layer: Observations and WRF Mesoscale Modeling during the XPIA Field Campaign

Abstract A better understanding and prediction of turbulence dissipation rate ε in the atmospheric boundary layer (ABL) is important for many applications. Herein, sonic anemometer data from the Experimental Planetary boundary layer Instrumentation Assessment (XPIA) field campaign (March–May 2015) are used to derive energy dissipation rate (EDR; =) within the first 300 m above the ground employing second-order structure functions. Turbulence dissipation rate is found to be strongly driven by the diurnal evolution of the ABL, presenting a distinct statistical behavior between daytime and nighttime conditions that follows log–Weibull and lognormal distributions, respectively. In addition, the vertical structure of EDR is characterized by a decrease with height above the surface, with the largest gradients occurring within the surface layer (z < 50 m). Convection-permitting mesoscale simulations were carried out with all of the 1.5-order turbulent kinetic energy (TKE) closure planetary boundary layer (PBL) schemes available in the Weather Research and Forecasting (WRF) Model. Overall, the three PBL schemes capture the observed diurnal evolution of EDR as well as the statistical behavior and vertical structure. However, the Mellor–Yamada-type schemes underestimate the large EDR levels during the bulk of daytime conditions, with the quasi-normal scale elimination (QNSE) scheme providing the best agreement with observations. During stably stratified nighttime conditions, Mellor–Yamada–Janjić (MYJ) and QNSE tend to exhibit an artificial “clipping” to their background TKE levels. A reduction in the model constant in the dissipation term for the Mellor–Yamada–Nakanishi–Niino (MYNN) scheme did not have a noticeable impact on EDR estimates. In contrast, application of a postprocessing statistical remapping technique reduced the systematic negative bias in the MYNN results by 75%.

Application of the Pola r WRF model for Svalbard - sensitivity to planetary boundary layer, radiation and microphysics schemes

Application of the Pola r WRF model for Svalbard - sensitivity to planetary boundary layer, radiation and microphysics schemes

Characterization and Modeling of Fog in the Mexico Basin

The character of fog in a region centered at Mexico City International Airport was investigated using 10 years of historical data. Hourly surface observations, synoptic charts, satellite images and twice-a-day radiosondes were used to identify fog events under the influence of various synoptic and mesoscale features. A quantitative assessment on the likelihood of which mechanisms lead to fog formation was obtained. Also, three fog events (radiation, advection and frontal) were simulated with the Weather Research and Forecasting (WRF) model, and the results were compared to observations. The study included a comparison of the skills of different planetary boundary layer (PBL) and microphysical schemes. A sort of generalization cannot easily be applied, but allows one to determine which parameterizations performed better for each case in a high, tropical region. In general, from the model results for liquid water content, the cloud microphysics WSM3 and PBL Yonsei University schemes reproduced advection and frontal fog events quite well, whereas CAM 5.1 and Quasi-Normal Scale Elimination schemes worked better for radiation fog episodes.