Evaluation of Planetary Boundary Layer (PBL) schemes in simulating heavy rainfall events over Central Java using high resolution WRF model

2019 ◽  
Author(s):  
Danang Eko Nuryanto ◽  
Ratna Satyaningsih ◽  
Tri Astuti Nuraini ◽  
Jose Rizal ◽  
Eko Heriyanto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
High Resolution ◽  
Planetary Boundary Layer ◽  
Heavy Rainfall ◽  
Wrf Model ◽  
Rainfall Events ◽  
Central Java ◽  
Heavy Rainfall Events

scholarly journals Sensitivity of Simulations of Zambian Heavy Rainfall Events to the Atmospheric Boundary Layer Schemes

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 38
Author(s):  
Mary-Jane M. Bopape ◽  
David Waitolo ◽  
Robert S. Plant ◽  
Elelwani Phaduli ◽  
Edson Nkonde ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Heavy Rainfall ◽  
Large Scale ◽  
Weather Forecasting ◽  
Weather Prediction ◽  
Wrf Model ◽  
Extreme Rainfall ◽  
Maximum Temperature ◽  
Rainfall Events ◽  
Heavy Rainfall Events

Weather forecasting relies on the use of numerical weather prediction (NWP) models, whose resolution is informed by the available computational resources. The models resolve large scale processes, while subgrid processes are parametrized. One of the processes that is parametrized is turbulence which is represented in planetary boundary layer (PBL) schemes. In this study, we evaluate the sensitivity of heavy rainfall events over Zambia to four different PBL schemes in the Weather Research and Forecasting (WRF) model using a parent domain with a 9 km grid length and a 3 km grid spacing child domain. The four PBL schemes are the Yonsei University (YSU), nonlocal first-order medium-range forecasting (MRF), University of Washington (UW) and Mellor–Yamada–Nakanishi–Niino (MYNN) schemes. Simulations were done for three case studies of extreme rainfall on 17 December 2016, 21 January 2017 and 17 April 2019. The use of YSU produced the highest rainfall peaks across all three cases; however, it produced performance statistics similar to UW that are higher than those of the two other schemes. These statistics are not maintained when adjusted for random hits, indicating that the extra events are mainly random rather than being skillfully placed. UW simulated the lowest PBL height, while MRF produced the highest PBL height, but this was not matched by the temperature simulation. The YSU and MYNN PBL heights were intermediate at the time of the peak; however, MYNN is associated with a slower decay and higher PBL heights at night. WRF underestimated the maximum temperature during all cases and for all PBL schemes, with a larger bias in the MYNN scheme. We support further use of the YSU scheme, which is the scheme selected for the tropical suite in WRF. The different simulations were in some respects more similar to one another than to the available observations. Satellite rainfall estimates and the ERA5 reanalysis showed different rainfall distributions, which indicates a need for more ground observations to assist with studies like this one.

scholarly journals 2DVD Data Revisited: Multifractal Insights into Cuts of the Spatiotemporal Rainfall Process

2015 ◽  
Vol 16 (2) ◽  
pp. 548-562 ◽  
Author(s):  
Auguste Gires ◽  
Ioulia Tchiguirinskaia ◽  
Daniel Schertzer ◽  
Alexis Berne
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Empirical Evidence ◽  
Heavy Rainfall ◽  
Resolution Time ◽  
Time Step ◽  
Measuring Device ◽  
Rainfall Events ◽  
Heavy Rainfall Events ◽  
Very High

Abstract Data collected during four heavy rainfall events that occurred in Ardèche (France) with the help of a 2D video disdrometer (2DVD) are used to investigate the structure of the raindrop distribution in both space and time. A first type of analysis is based on the reconstruction of 36-m-height vertical rainfall columns above the measuring device. This reconstruction is obtained with the help of a ballistic hypothesis applied to 1-ms time step series. The corresponding snapshots are analyzed with the help of universal multifractals. For comparison, a similar analysis is performed on the time series with 1-ms time steps, as well as on time series of accumulation maps of N consecutive recorded drops (therefore with variable time steps). It turns out that the drop distribution exhibits a good scaling behavior in the range 0.5–36 m during the heaviest portion of the events, confirming the lack of empirical evidence of the widely used homogenous assumption for drop distribution. For smaller scales, drop positions seem to be homogeneously distributed. The notion of multifractal singularity is well illustrated by the very high-resolution time series.

scholarly journals Assessment of the Weather Research and Forecasting (WRF) model for simulation of extreme rainfall events in the upper Ganga Basin

2018 ◽  
Vol 22 (2) ◽  
pp. 1095-1117 ◽  
Author(s):  
Ila Chawla ◽  
Krishna K. Osuri ◽  
Pradeep P. Mujumdar ◽  
Dev Niyogi
Keyword(s):  
Land Surface ◽  
Heavy Rainfall ◽  
Wrf Model ◽  
Extreme Rainfall ◽  
Weather Research And Forecasting ◽  
Grid Spacing ◽  
Ganga Basin ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Heavy Rainfall Events

Abstract. Reliable estimates of extreme rainfall events are necessary for an accurate prediction of floods. Most of the global rainfall products are available at a coarse resolution, rendering them less desirable for extreme rainfall analysis. Therefore, regional mesoscale models such as the advanced research version of the Weather Research and Forecasting (WRF) model are often used to provide rainfall estimates at fine grid spacing. Modelling heavy rainfall events is an enduring challenge, as such events depend on multi-scale interactions, and the model configurations such as grid spacing, physical parameterization and initialization. With this background, the WRF model is implemented in this study to investigate the impact of different processes on extreme rainfall simulation, by considering a representative event that occurred during 15–18 June 2013 over the Ganga Basin in India, which is located at the foothills of the Himalayas. This event is simulated with ensembles involving four different microphysics (MP), two cumulus (CU) parameterizations, two planetary boundary layers (PBLs) and two land surface physics options, as well as different resolutions (grid spacing) within the WRF model. The simulated rainfall is evaluated against the observations from 18 rain gauges and the Tropical Rainfall Measuring Mission Multi-Satellite Precipitation Analysis (TMPA) 3B42RT version 7 data. From the analysis, it should be noted that the choice of MP scheme influences the spatial pattern of rainfall, while the choice of PBL and CU parameterizations influences the magnitude of rainfall in the model simulations. Further, the WRF run with Goddard MP, Mellor–Yamada–Janjic PBL and Betts–Miller–Janjic CU scheme is found to perform best in simulating this heavy rain event. The selected configuration is evaluated for several heavy to extremely heavy rainfall events that occurred across different months of the monsoon season in the region. The model performance improved through incorporation of detailed land surface processes involving prognostic soil moisture evolution in Noah scheme compared to the simple Slab model. To analyse the effect of model grid spacing, two sets of downscaling ratios – (i) 1 : 3, global to regional (G2R) scale and (ii) 1 : 9, global to convection-permitting scale (G2C) – are employed. Results indicate that a higher downscaling ratio (G2C) causes higher variability and consequently large errors in the simulations. Therefore, G2R is adopted as a suitable choice for simulating heavy rainfall event in the present case study. Further, the WRF-simulated rainfall is found to exhibit less bias when compared with the NCEP FiNaL (FNL) reanalysis data.

scholarly journals Heavy Rainfall Simulation over Sinai Peninsula Using the Weather Research and Forecasting Model

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Gamal El Afandi ◽  
Mostafa Morsy ◽  
Fathy El Hussieny
Keyword(s):  
Heavy Rainfall ◽  
Flash Flood ◽  
Wrf Model ◽  
Rain Gauge ◽  
Rainfall Simulation ◽  
Weather Research And Forecasting ◽  
Sinai Peninsula ◽  
Rainfall Events ◽  
Heavy Rainfall Events ◽  
Weather Research

Heavy rainfall is one of major severe weather over Sinai Peninsula and causes many flash floods over the region. The good forecasting of rainfall is very much necessary for providing early warning before the flash flood events to avoid or minimize disasters. In the present study using the Weather Research and Forecasting (WRF) Model, heavy rainfall events that occurred over Sinai Peninsula and caused flash flood have been investigated. The flash flood that occurred on January 18, 2010, over different parts of Sinai Peninsula has been predicted and analyzed using the Advanced Weather Research and Forecast (WRF-ARW) Model. The predicted rainfall in four dimensions (space and time) has been calibrated with the measurements recorded at rain gauge stations. The results show that the WRF model was able to capture the heavy rainfall events over different regions of Sinai. It is also observed that WRF model was able to predict rainfall in a significant consistency with real measurements. In this study, several synoptic characteristics of the depressions that developed during the course of study have been investigated. Also, several dynamic characteristics during the evolution of the depressions were studied: relative vorticity, thermal advection, and geopotential height.

scholarly journals Evaluating the extreme precipitation events using a mesoscale atmosphere model and satellite based precipitation product

2013 ◽  
Vol 1 (6) ◽  
pp. 6979-7014
Author(s):  
I. Yucel ◽  
A. Onen
Keyword(s):  
Data Assimilation ◽  
Extreme Precipitation ◽  
Heavy Rainfall ◽  
Wrf Model ◽  
Hydrologic Model ◽  
Rainfall Events ◽  
Extreme Precipitation Events ◽  
Precipitation Estimates ◽  
Heavy Rainfall Events ◽  
Precipitation Events

Abstract. Quantitative precipitation estimates are obtained with more uncertainty under the influence of changing climate variability and complex topography from numerical weather prediction (NWP) models. On the other hand, hydrologic model simulations depend heavily on the availability of reliable precipitation estimates. Difficulties in estimating precipitation impose an important limitation on the possibility and reliability of hydrologic forecasting and early warning systems. This study examines the performance of the Weather Research and Forecasting (WRF) model and the Multi Precipitation Estimates (MPE) algorithm in producing the temporal and spatial characteristics of the number of extreme precipitation events observed in the West Black Sea Region of Turkey. Precipitations derived from WRF model with and without three-dimensional variational (3-DVAR) data assimilation scheme and MPE algorithm at high spatial resolution (4 km) are compared with gauge precipitation. WRF-derived precipitation showed capabilities in capturing the timing of precipitation extremes and in some extent the spatial distribution and magnitude of the heavy rainfall events wheras MPE showed relatively weak skills in these aspects. WRF skills in estimating such precipitation characteristics are enhanced with the application of 3-DVAR scheme. Direct impact of data assimilation on WRF precipitation reached to 12% and at some points there exists quantitative match for heavy rainfall events, which are critical for hydrological forecast.

Sensitivity of high-resolution precipitation to physics parameterization options in WRF over equatorial regions

2020 ◽  
Author(s):  
Martina Messmer ◽  
Santos J. González-Rojí ◽  
Christoph C. Raible ◽  
Thomas F. Stocker
Keyword(s):  
Boundary Layer ◽  
High Resolution ◽  
Planetary Boundary Layer ◽  
Large Scale ◽  
Wrf Model ◽  
Cumulus Parameterization ◽  
Wave Radiation ◽  
Strong Increase ◽  
Simulated Precipitation ◽  
The Impact

<p>Precipitation patterns and climate variability in East Africa and Western South America present high heterogeneity and complexity. This complexity is a result of large-scale and regional controls, such as surrounding oceans, lakes and topography. The combined effect of these controls has implications on precipitation and temperature, and hence, on water availability, biodiversity and ecosystem services. This study focuses on the impact of different physics parameterization in high-resolution experiments performed over equatorial regions with the Weather Research and Forecasting (WRF) model, and how these options affect the representation of precipitation in those regions.</p><p>As expected, weather and climate in equatorial regions are driven by physical processes different to those important in the mid-latitudes. Hence, it is necessary to test the parameterizations available in the WRF model. Several sensitivity simulations are performed over Kenya and Peru nesting the WRF model inside the state-of-the-art ERA5 reanalysis. A cascade of increasing grid resolutions is used in these simulations, reaching the spatial resolutions of 3 and 1 km in the innermost domains, and thus, convection permitting scales. Parameterization options of the planetary boundary layer (PBL), lake model, radiation, cumulus and microphysics schemes are changed, and their sensitivity to precipitation is tested. The year 2008 is simulated for each of the sensitivity simulations. This year is chosen as a good representative of precipitation dynamics and temperature, as it is neither abnormally wet or hot, nor dry or cold over Kenya and Peru. The simulated precipitation driven by the ERA5 reanalysis is compared against station data obtained from the WMO, and over Kenya additionally against observations from the Centre for Training and Integrated Research in ASAL Development (CETRAD).</p><p>Precipitation is strongly underestimated when adopting a typical parameterization setup for the mid-latitudes. However, results indicate that precipitation amounts and also patterns are substantially improved when changing the cumulus and PBL parameterisations. This strong increase in the simulated precipitation is obtained when using the Grell-Freitas ensemble, RRTM and the Yonsei University schemes for cumulus, long-wave radiation and planetary boundary layer, respectively. During some summer months, the accumulated precipitation is improved by up to 100 mm (80 %) compared to mid-latitudes configuration in several regions of the domains (near the Andes in Peru and over the flatlands in Kenya). Additionally, because the 1- and 2-way nesting options show a similar performance with respect to precipitation, the 1-way nesting option is preferred, as it does not overwrite the solutions in the parent domains. Hence, discontinuous solutions related to switching off the cumulus parameterization can be avoided.</p>

scholarly journals Heavy Precipitation Systems in Calabria Region (Southern Italy): High-Resolution Observed Rainfall and Large-Scale Atmospheric Pattern Analysis

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1468 ◽  
Author(s):  
Aldo Greco ◽  
Davide Luciano De Luca ◽  
Elenio Avolio
Keyword(s):  
High Resolution ◽  
Heavy Rainfall ◽  
Large Scale ◽  
Southern Italy ◽  
Early Warning Systems ◽  
Reanalysis Dataset ◽  
Rainfall Events ◽  
Calabria Region ◽  
Depth Analysis ◽  
Heavy Rainfall Events

An in-depth analysis of historical heavy rainfall fields clearly constitutes an important aspect in many related topics: as examples, mesoscale models for early warning systems and the definition of design event scenarios can be improved, with the consequent upgrading in the prediction of induced phenomena (mainly floods and landslides) into specific areas of interest. With this goal, in this work the authors focused on Calabria region (southern Italy) and classified the main precipitation systems through the analysis of selected heavy rainfall events from high resolution rain gauge network time series. Moreover, the authors investigated the relationships among the selected events and the main synoptic atmospheric patterns derived by the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 Reanalysis dataset, in order to assess the possible large-scale scenarios which can induce heavy rainfall events in the study area. The obtained results highlighted: (i) the importance of areal reduction factors, rainfall intensities and amounts in order to discriminate the investigated precipitations systems for the study area; (ii) the crucial role played by the position of the averaged low-pressure areas over the Mediterranean for the synoptic systems, and by low-level temperature for the convective systems.

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