scholarly journals Inclusion of ash and SO<sub>2</sub> emissions from volcanic eruptions in WRF-Chem: development and some applications

2013 ◽  
Vol 6 (2) ◽  
pp. 457-468 ◽  
Author(s):  
M. Stuefer ◽  
S. R. Freitas ◽  
G. Grell ◽  
P. Webley ◽  
S. Peckham ◽  
...  
Keyword(s):  
Transport Model ◽  
Three Dimensional ◽  
Wrf Model ◽  
Volcanic Eruptions ◽  
Weather Research And Forecasting ◽  
Tephra Fall ◽  
Additional Information ◽  
Volcanic Emission ◽  
Good Coincidence ◽  
Fall Deposits

Abstract. We describe a new functionality within the Weather Research and Forecasting (WRF) model with coupled Chemistry (WRF-Chem) that allows simulating emission, transport, dispersion, transformation and sedimentation of pollutants released during volcanic activities. Emissions from both an explosive eruption case and a relatively calm degassing situation are considered using the most recent volcanic emission databases. A preprocessor tool provides emission fields and additional information needed to establish the initial three-dimensional cloud umbrella/vertical distribution within the transport model grid, as well as the timing and duration of an eruption. From this source condition, the transport, dispersion and sedimentation of the ash cloud can be realistically simulated by WRF-Chem using its own dynamics and physical parameterization as well as data assimilation. Examples of model applications include a comparison of tephra fall deposits from the 1989 eruption of Mount Redoubt (Alaska) and the dispersion of ash from the 2010 Eyjafjallajökull eruption in Iceland. Both model applications show good coincidence between WRF-Chem and observations.

scholarly journals Inclusion of Ash and SO<sub>2</sub> emissions from volcanic eruptions in WRF-CHEM: development and some applications

2012 ◽  
Vol 5 (3) ◽  
pp. 2571-2597 ◽  
Author(s):  
M. Stuefer ◽  
S. R. Freitas ◽  
G. Grell ◽  
P. Webley ◽  
S. Peckham ◽  
...  
Keyword(s):  
Explosive Eruption ◽  
Transport Model ◽  
Three Dimensional ◽  
Volcanic Eruptions ◽  
Weather Research And Forecasting ◽  
Tephra Fall ◽  
Additional Information ◽  
Volcanic Emission ◽  
Good Coincidence ◽  
Fall Deposits

Abstract. We describe a new functionality within the Weather Research and Forecasting model with coupled Chemistry (WRF-Chem) that allows simulating emission, transport, dispersion, transformation and sedimentation of pollutants released during volcanic activities. Emissions from both an explosive eruption case and relatively calm degassing situation are considered using the most recent volcanic emission databases. A preprocessor tool provides emission fields and additional information needed to establish the initial three-dimensional cloud umbrella/vertical distribution within the transport model grid, as well as the timing and duration of an eruption. From this source condition, the transport, dispersion and sedimentation of the ash-cloud can be realistically simulated by WRF-Chem using its own dynamics, physical parameterization as well as data assimilation. Examples of model validation include a comparison of tephra fall deposits from the 1989 eruption of Mount Redoubt (Alaska), and the dispersion of ash from the 2010 Eyjafjallajökull eruption in Iceland. Both model applications show good coincidence between WRF-Chem and observations.

Comparison of Two-Moment Bulk Microphysics Schemes in Idealized Supercell Thunderstorm Simulations

2011 ◽  
Vol 139 (4) ◽  
pp. 1103-1130 ◽  
Author(s):  
Hugh Morrison ◽  
Jason Milbrandt
Keyword(s):  
Three Dimensional ◽  
Wrf Model ◽  
Weather Research And Forecasting ◽  
Cold Pool ◽  
Fall Velocity ◽  
Surface Precipitation ◽  
Single Category ◽  
Supercell Thunderstorm ◽  
Drop Size Distributions ◽  
Reduced Surface

Idealized three-dimensional supercell simulations were performed using the two-moment bulk microphysics schemes of Morrison and Milbrandt–Yau in the Weather Research and Forecasting (WRF) model. Despite general similarities in these schemes, the simulations were found to produce distinct differences in storm structure, precipitation, and cold pool strength. In particular, the Morrison scheme produced much higher surface precipitation rates and a stronger cold pool, especially in the early stages of storm development. A series of sensitivity experiments was conducted to identify the primary differences between the two schemes that resulted in the large discrepancies in the simulations. Different approaches in treating graupel and hail were found to be responsible for many of the key differences between the baseline simulations. The inclusion of hail in the baseline simulation using the Milbrant–Yau scheme with two rimed-ice categories (graupel and hail) had little impact, and therefore resulted in a much different storm than the baseline run with the single-category (hail) Morrison scheme. With graupel as the choice of the single rimed-ice category, the simulated storms had considerably more frozen condensate in the anvil region, a weaker cold pool, and reduced surface precipitation compared to the runs with only hail, whose higher terminal fall velocity inhibited lofting. The cold pool strength was also found to be sensitive to the parameterization of raindrop breakup, particularly for the Morrison scheme, because of the effects on the drop size distributions and the corresponding evaporative cooling rates. The use of a more aggressive implicit treatment of drop breakup in the baseline Morrison scheme, by limiting the mean–mass raindrop diameter to a maximum of 0.9 mm, opposed the tendency of this scheme to otherwise produce large mean drop sizes and a weaker cold pool compared to the hail-only run using the Milbrandt–Yau scheme.

scholarly journals Extension of the WRF-Chem volcanic emission preprocessor to integrate complex source terms and evaluation for different emission scenarios of the Grimsvötn 2011 eruption

2020 ◽  
Vol 20 (11) ◽  
pp. 3099-3115
Author(s):  
Marcus Hirtl ◽  
Barbara Scherllin-Pirscher ◽  
Martin Stuefer ◽  
Delia Arnold ◽  
Rocio Baro ◽  
...  
Keyword(s):  
Transport Model ◽  
Vertical Wind Shear ◽  
Volcanic Eruptions ◽  
Complex Method ◽  
Emission Scenarios ◽  
Source Terms ◽  
Chemical Transport Model ◽  
Complex Source ◽  
Emission Fluxes ◽  
Volcanic Emission

Abstract. Volcanic eruptions may generate volcanic ash and sulfur dioxide (SO2) plumes with strong temporal and vertical variations. When simulating these changing volcanic plumes and the afar dispersion of emissions, it is important to provide the best available information on the temporal and vertical emission distribution during the eruption. The volcanic emission preprocessor of the chemical transport model WRF-Chem has been extended to allow the integration of detailed temporally and vertically resolved input data from volcanic eruptions. The new emission preprocessor is tested and evaluated for the eruption of the Grimsvötn volcano in Iceland 2011. The initial ash plumes of the Grimsvötn eruption differed significantly from the SO2 plumes, posing challenges to simulate plume dynamics within existing modelling environments: observations of the Grimsvötn plumes revealed strong vertical wind shear that led to different transport directions of the respective ash and SO2 clouds. Three source terms, each of them based on different assumptions and observational data, are applied in the model simulations. The emission scenarios range from (i) a simple approach, which assumes constant emission fluxes and a predefined vertical emission profile, to (ii) a more complex approach, which integrates temporarily varying observed plume-top heights and estimated emissions based on them, to (iii) the most complex method that calculates temporal and vertical variability of the emission fluxes based on satellite observations and inversion techniques. Comparisons between model results and independent observations from satellites, lidar, and surface air quality measurements reveal the best performance of the most complex source term.

scholarly journals Evaluation of the Simulation of Typhoon Lekima (2019) Based on Different Physical Parameterization Schemes and FY-3D Satellite’s MWHS-2 Data Assimilation

2021 ◽  
Vol 13 (22) ◽  
pp. 4556
Author(s):  
Dongmei Xu ◽  
Xuewei Zhang ◽  
Hong Li ◽  
Haiying Wu ◽  
Feifei Shen ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Three Dimensional ◽  
Wrf Model ◽  
Background Field ◽  
Weather Research And Forecasting ◽  
Initial Field ◽  
Parameterization Schemes ◽  
Microwave Humidity Sounder ◽  
Radiance Data ◽  
Physical Parameterization

In this study, the case of super typhoon Lekima, which landed in Jiangsu and Zhejiang Province on 4 August 2019, is numerically simulated. Based on the Weather Research and Forecasting (WRF) model, the sensitivity experiments are carried out with different combinations of physical parameterization schemes. The results show that microphysical schemes have obvious impacts on the simulation of the typhoon’s track, while the intensity of the simulated typhoon is more sensitive to surface physical schemes. Based on the results of the typhoon’s track and intensity simulation, one parameterization scheme was further selected to provide the background field for the following data assimilation experiments. Using the three-dimensional variational (3DVar) data assimilation method, the Microwave Humidity Sounder-2 (MWHS-2) radiance data onboard the Fengyun-3D satellite (FY-3D) were assimilated for this case. It was found that the assimilation of the FY-3D MWHS-2 radiance data was able to optimize the initial field of the numerical model in terms of the model variables, especially for the humidity. Finally, by the inspection of the typhoon’s track and intensity forecast, it was found that the assimilation of FY-3D MWHS-2 radiance data improved the skill of the prediction for both the typhoon’s track and intensity.

Distribution and mass of tephra-fall deposits from volcanic eruptions of Sakurajima Volcano based on posteruption surveys

2018 ◽  
Vol 80 (4) ◽  
Author(s):  
Masayuki Oishi ◽  
Kuniaki Nishiki ◽  
Nobuo Geshi ◽  
Ryuta Furukawa ◽  
Yoshihiro Ishizuka ◽  
...  
Keyword(s):  
Volcanic Eruptions ◽  
Tephra Fall ◽  
Sakurajima Volcano ◽  
Fall Deposits

scholarly journals The Impact of Assimilating Atmospheric Infrared Sounder Observation on the Forecast of Typhoon Tracks

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Chien-Ben Chou ◽  
Huei-Ping Huang
Keyword(s):  
Data Assimilation ◽  
Three Dimensional ◽  
Wrf Model ◽  
Weather Research And Forecasting ◽  
Atmospheric Infrared Sounder ◽  
Background Error ◽  
Forecasting System ◽  
Typhoon Tracks ◽  
The Impact ◽  
Decorrelation Scale

This work assesses the effects of assimilating atmospheric infrared sounder (AIRS) observations on typhoon prediction using the three-dimensional variational data assimilation (3DVAR) and forecasting system of the weather research and forecasting (WRF) model. Two major parameters in the data assimilation scheme, the spatial decorrelation scale and the magnitude of the covariance matrix of the background error, are varied in forecast experiments for the track of typhoon Sinlaku over the Western Pacific. The results show that within a wide parameter range, the inclusion of the AIRS observation improves the prediction. Outside this range, notably when the decorrelation scale of the background error is set to a large value, forcing the assimilation of AIRS data leads to degradation of the forecast. This illustrates how the impact of satellite data on the forecast depends on the adjustable parameters for data assimilation. The parameter-sweeping framework is potentially useful for improving operational typhoon prediction.

scholarly journals Extension of the WRF-Chem volcanic emission pre-processor to integrate complex source terms and evaluation for different emission scenarios of the Grimsvötn 2011 eruption

2020 ◽  
Author(s):  
Marcus Hirtl ◽  
Barbara Scherllin-Pirscher ◽  
Martin Stuefer ◽  
Delia Arnold ◽  
Rocio Baro ◽  
...  
Keyword(s):  
Transport Model ◽  
Vertical Wind Shear ◽  
Volcanic Eruptions ◽  
Complex Method ◽  
Emission Scenarios ◽  
Source Terms ◽  
Chemical Transport Model ◽  
Complex Source ◽  
Emission Fluxes ◽  
Volcanic Emission

Abstract. Volcanic eruptions may generate volcanic ash and sulfur dioxide (SO2) plumes with strong temporal and vertical variations. When simulating these changing volcanic plumes and the afar dispersion of emissions, it is important to provide the best available information on the temporal and vertical emission distribution during the eruption. The volcanic emission module of the chemical transport model WRF-Chem has been extended to allow integrating detailed temporally and vertically resolved input data from volcanic eruptions. The new emission pre-processor is tested and evaluated for the eruption of the Grimsvötn volcano in Iceland 2011. The initial ash plumes of the Grimsvötn eruption differed significantly from the SO2 plumes posing challenges to simulate plume dynamics within existing modelling environments: observations of the Grimsvötn plumes revealed strong vertical wind shear that led to different transport directions of the respective ash and SO2 clouds. Three source terms, each of them based on different assumptions and observational data are applied in the model simulations. The emission scenarios range from (i) a simple approach, which assumes constant emission fluxes and a pre-defined vertical emission profile, to (ii) a more complex approach, which integrates temporarily varying observed plume top heights and estimated emissions based on them, to (iii) the most complex method that calculates temporal and vertical variability of the emission fluxes based on satellite observations and inversion techniques. Comparisons between model results and independent observations from satellites, lidar and surface air quality measurements reveal best performance of the most complex source term.

scholarly journals An Experiment for Assimilating Different Type of Data Observations in Forecasting Heavy Rainfall over Central Highlands Region Due to the Impact of Hurricane Damrey

2019 ◽  
Vol 35 (4) ◽  
Author(s):  
Le Lan Phuong ◽  
Pham Quang Nam ◽  
Tran Quang Duc ◽  
Phan Van Tan
Keyword(s):  
Lead Time ◽  
Heavy Rainfall ◽  
Three Dimensional ◽  
Wrf Model ◽  
Weather Research And Forecasting ◽  
Data Types ◽  
Warm Start ◽  
Central Highlands ◽  
Atmospheric Motion Vectors ◽  
The Impact

This study investigates and assesses the impact of assimilating data types (observed data surface, sounding, and satellite-derived atmospheric motion vectors – AMVs) for the Weather Research and Forecasting (WRF) in forecasting heavy rainfall over Central Highlands region, due to the impact of hurricane Damrey. The WRF model combined with the Gridpoint Statistical Interpolation (GSI) system, was started running at 12Z 03/11/2017, and 84h forecasts in advance, with two kinds for running assimilation "cold start" and "warm start", and with the three-dimensional variational data assimilation (3D-Var) method. The results showed that assimilated cases have improved forecasting about spatial distribution and amount of rainfall at a 24-hour lead time, in which, the "warm start" for better forecasting. Notably, the assimilation of AMVs data with the "warm start" run has improved forecasting quality of heavy rainfall, the POD, FAR, and CSI indicators are the best at the 24-hour lead time, for rainfall thresholds greater than 80mm.    

scholarly journals Investigasi Pengaruh Skenario Modifikasi Urbanisasi pada Perubahan Hujan di Kota Makassar

2020 ◽  
Vol 5 ◽  
Author(s):  
Fitria Puspita Sari ◽  
Satriawan Nadhrotal Atsidiqi
Keyword(s):  
Urban Areas ◽  
Three Dimensional ◽  
Wrf Model ◽  
Heavy Rain ◽  
Urban Heat Islands ◽  
Weather Research And Forecasting ◽  
Rain Event ◽  
Monsoon Period ◽  
Urban Heat ◽  
Weather Research

<p class="AbstractEnglish"><strong>Abstract:</strong> Urbanization affects the atmosphere through the urban heat island (UHI) process, resulting in the change of rain patterns over urban areas. Makassar as the one of big cities in Indonesia is assumed to be suffering from this effect, thus an investigation related to the issue needs to be done.  This study contains a simulation of urbanization scenarios using a three-dimensional non-hydrostatic Weather Research and Forecasting (WRF) Model during the transition monsoon period: September-October-November (SON) 2014-2018. The study covers 5 selected heavy-rain-event during the SON period: 24 September 2016, 9 October 2016, 24 October 2016, 22 November 2016, and 23 September 2017. Result shows that the model is able to simulate some weather parameters with relatively small root-mean-square-error (RMSE) and high correlation on three rain event cases. Afterwards, scenarios of 25% and 50% increasing urban area towards Makassar coastal line (as reclamation plan) and existing urban areas have been done.  The results show that urbanization increases daily average temperature over urban areas, so does UHI maximum reach number of 1.5°C for both scenarios on 24 September 2016 rain event. Also, it increases rain accumulation up to 50% over reclamation areas and relativeky decreases rainfall over existing urban areas. </p><p class="AbstrakIndonesia"><strong>Abstrak:</strong> Peningkatan jumlah penduduk dan kegiatan urbanisasi dapat mengubah interaksi atmosfer melalui penambahan pelepasan panas yang menyebabkan terjadinya efek <em>urban heat islands </em>(UHI) serta perubahan hujan di wilayah perkotaan. Sebagai salah satu kota metropolitan di Indonesia, Makassar dimungkinkan terdampak oleh efek UHI tersebut. Sehingga penelitian ini dilakukan untuk mengetahui dampak urbanisasi terhadap perubahan akumulasi dan/atau pola hujan di wilayah Makassar sesuai skenario jumlah penduduk tahun 2045. Investigasi dilakukan dengan memanfaatkan model non-hidrostatik tiga dimensi <em>Weather Research and Forecasting (</em>WRF) pada musim transisi September-Oktober-November (SON) 2014-2018. Kejadian hujan lebat terpilih sebanyak 5 hari yakni tanggal 24 September 2016, 9 Oktober 2016, 24 Oktober 2016, 22 November 2016, dan 23 September 2017. Verifikasi model dilakukan dengan menggunakan metode statistik. Hasilnya, model mampu digunakan untuk mensimulasikan tiga dari lima kejadian hujan lebat dengan nilai RMSE relatif rendah dan korelasi tinggi. Selanjutnya, skenario modifikasi dilakukan dengan menambahkan wilayah urban sebesar 25% dan 50% untuk masing-masing area di bagian pantai (sesuai rencana reklamasi) dan taman kota. Dari hasil simulasi hujan lebat tanggal 24 September 2016 diketahui bahwa urbanisasi meningkatkan rataan suhu harian wilayah perkotaan yang menyebabakan UHI maksimum meningkat antara 0.1° hingga 1.5°C pada dua skenario modifikasi. Selain itu skenario modifikasi urbanisasi menyebabkan peningkatan hujan sebesar 50% di area reklamasi dan cenderung normal bahkan mengalami penurunan di wilayah taman kota sekitar Universitas Hasanuddin.</p>

scholarly journals Lagrangian Coherent Structures near a Subtropical Jet Stream

2010 ◽  
Vol 67 (7) ◽  
pp. 2307-2319 ◽  
Author(s):  
Wenbo Tang ◽  
Manikandan Mathur ◽  
George Haller ◽  
Douglas C. Hahn ◽  
Frank H. Ruggiero
Keyword(s):  
Coherent Structures ◽  
Three Dimensional ◽  
Wrf Model ◽  
Lagrangian Coherent Structures ◽  
Weather Research And Forecasting ◽  
Jet Stream ◽  
Forecast System ◽  
Subtropical Jet Stream ◽  
Subtropical Jet ◽  
Stability Results

Abstract Direct Lyapunov exponents and stability results are used to extract and distinguish Lagrangian coherent structures (LCS) from a three-dimensional atmospheric dataset generated from the Weather Research and Forecasting (WRF) model. The numerical model is centered at 19.78°N, 155.55°W, initialized from the Global Forecast System for the case of a subtropical jet stream near Hawaii on 12 December 2002. The LCS are identified that appear to create optical and mechanical turbulence, as evidenced by balloon data collected during a measurement campaign near Hawaii.

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