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Search Results: 1 - 10 of 322 matches for " WRF "
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Application of WRF Model for Vehicular Pollution Modelling Using AERMOD  [PDF]
Awkash Kumar, Anil Kumar Dikshit, Sadaf Fatima, Rashmi S. Patil
Atmospheric and Climate Sciences (ACS) , 2015, DOI: 10.4236/acs.2015.52004
Abstract: Vehicular pollution is becoming significant in urban areas because of increasing population. This is at ground level, so it gives high population exposure. In this study, Chembur, which is the most polluted area in Mumbai city due to industrial and vehicular sources, is selected for vehicular pollution modeling using AMS/EPA Regulatory Model (AERMOD). Meteorological parameters, land use surface characteristics and source emission data are collected as required by AERMOD. The results of modelling depend upon reliability of input data and meteorological data has a vital role in the performance of the model. Generally, temporally and spatially interpolated meteorological data is used in modeling. This is generally collected from nearby meteorological station but this causes inaccuracy of the results. In this paper, the Weather Research and Forecasting (WRF) model has been used to generate onsite data on nine meteorological parameters. The modeling of six roads of Chembur has been performed using above meteorological data. This approach gives good results of traffic modeling. The results of AERMOD are compared with observed air quality which has contribution from all sources in the region and relative contribution of vehicular sources identified.
Impacts on the Urban Air Quality and Health of Global Climate Scenarios Using Different Dynamical Downscaling Approaches  [PDF]
Roberto San José, Juan L. Pérez, Libia Pérez, Rosa M. González, Julia Pecci, Antonio Garzón, Marino Palacios
Journal of Geoscience and Environment Protection (GEP) , 2016, DOI: 10.4236/gep.2016.44020

The objective of this publication is to present a modeling system that allows investigating the possible climate change-driven effects of air pollutants on human health. The system connects global climate change to ambient air pollution concentrations that then are linked to epidemiological endpoints. The tool has been applied to quantify the future (2030, 2050 and 2100) impact on air pollution and health of two of the IPCC global climate scenarios over the cities: Madrid, Milan and London (zone Kensington-Chelsea) with different very high spatial resolutions (100, 200 and 10 meters) respect to the present (2011). Results indicate how ambient air pollutant concentrations respond to different climatic conditions, and how human health could be affected by changes in air pollution induced by global warning. The system includes global climate simulations, nested with regional/urban meteorological models (prognostic and diagnostic) to drive chemical transport models (offline and online modes) and a computational fluid dynamic model keeping anthropogenic emissions and the urban landscape at reference level (2011) to isolate the effects of the global climate over the city. The results of these simulations suggest that climate will have an important effect on urban air pollution and health over the next several decades, especially under the IPCC RCP 8.5 scenario.

Modeling Near-Surface Air Temperature and Precipitation Using WRF with 5-km Resolution in the Northern Patagonia Icefield: A Pilot Simulation  [PDF]
Claudia Villarroel, Jorge F. Carrasco, Gino Casassa, Mark Falvey
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.48113

The regional Weather and Research Forecast (WRF) Model was run for the 2000-2010 period over the Northern Patagonia Icefield (NPI) with an horizontal resolution of 5 km. The regional model was initialized using the NCEP/NCAR atmospheric Reanalysis database. The simulation results, centered over the NPI, were validated against the observed data from the local surface stations in order to evaluate the improvement of the model results due to its increased horizontal resolution with respect to the lower resolution from Global Climate Model simulations. Interest in the NPI is due to 1) the large body of frozen water exposed to the impact of the warming planet, 2) the scarce availability of observed meteorological and glaciological information in this large and remote icefield, and 3) the need to validate the model behavior in simulating the current climate and its variability in complex terrain. The results will shed light on the degree of confidence in simulating future climate scenarios in the region and also in similar geographical settings. Based on this study subsequent model runs will allow to model future climate changes in Patagonia, which is basic information for estimating glacier variations to be expected during this century.

Assimilation of GPS RO Refractivity Data and Its Impact on Simulations of Trade Wind Inversion and a Winter Cold Front  [PDF]
Chunhua Zhou, Yi-Leng Chen
Natural Science (NS) , 2014, DOI: 10.4236/ns.2014.68060

Assimilation of Global Positioning System (GPS) Radio Occultation (RO) refractivity based on WRF-3DVAR is applied to numerical weather predictions (NWP) in Hawaii, where limited conventional observations and poor representation of local circulations in global analysis constrain the quality of numerical weather predictions. For a summer trade wind case, with GPS RO refractivity assimilated, the trade wind inversion is better predicted. For a winter cold front case, the propagation of the cold front is also better simulated when GPS RO refractivity is assimilated. Furthermore, the moist tongue associated with the cold front is better defined and the vertical profiles of temperature and moisture are largely improved when compared to the model run without GPS RO assimilation.

The Impacts of Topography on Spatial and Temporal Rainfall Distribution over Rwanda Based on WRF Model  [PDF]
Didier Ntwali, Bob Alex Ogwang, Victor Ongoma
Atmospheric and Climate Sciences (ACS) , 2016, DOI: 10.4236/acs.2016.62013
Abstract: The impact of topography on heavy rainfall during two rain seasons was investigated in order to explain their mechanisms on rainfall distribution over Rwanda. Weather Research and Forecasting (WRF-ARW) model was used to study two historical cases of heavy rainfall which took place over Rwanda during two rain seasons, March to May (MAM) and September to December (SOND), from April 7 to 9, 2012 (for MAM) and from October 29 to 31, 2012 (during SOND). The control experiment was done with actual topography, whereas sensitivity experiment was carried out with topography reduced by half. Results show that rainfall distribution over Rwanda significantly changes when topography is reduced. The reduction in topography leads to a decrease in rainfall amounts in both MAM and SOND seasons, with varying magnitudes. This reveals the importance of orography in determining rainfall amounts and distribution over the region. The accumulated rainfall amount from WRF underestimate or overestimate rain gauge stations data by region and by season, but there is good agreement especially in altitude below 1490 m and above 1554 m during April and October respectively. The results may motivate modelling carters to further improve parameterization schemes in the mountainous regions.
Numerical Simulations of Arctic Climate with Regional Atmospheric Models Based on Two Different Versions of WRF—Results of Annual Mean

柏统贵, 刘喜迎, 张涛, 王文杰
Advances in Geosciences (AG) , 2013, DOI: 10.12677/AG.2013.31008
用基于WRF3.2.1PWRF3.3.1的两个版本区域气候模式对北极气候进行了数值模拟试验,对比分析了两个版本模式对北极气候的模拟能力。结果显示:在温度场中,基于WRF3.2.1的气候模式模拟的结果偏低;在位势高度场中,两者的模拟结果均偏低,差异性较大的区域主要在维多利亚岛附近;海平面气压场中,基于WRF3.2.1的模式模拟的低值区域较大,没有基于PWRF3.3.1的模式模拟的结果好;两个模式风场差异伸展到高层并随高度的升高而风速差值增大,到200 hPa时风速差值最大为40 m/s;两者的降水模拟结果比较相似,对流性降水模拟的结果较好,对稳定性降水模拟的位置偏北且降水量偏大,对整体降水的模拟结果不好。在数值模拟试验中,基于PWRF3.3.1的气候模式整体显示出优于基于WRF3.2.1模式的性能。
Numerical simulation test is made for Arctic climate with regional climate models based on WRF3.2.1 and PWRF3.3.1 versions, and simulation capabilities for Arctic climate of two versions are compared and analyzed. Ac- cording to results: within temperature field, simulation result of climate model based on WRF3.2.1 is relatively low; simulation result within potential height field is also relative low, and zones with larger difference are mainly around Victoria Island; within sea-level pressure field, for simulation based on WRF3.2.1 model, zone with low value is rela- tive large, and it is not as good as simulation based on PWRF3.3.1 model; Wind difference of both models exists up to high altitude, wind speed difference will increase with increasing of altitude, and max wind speed difference40m/s will be reached at 200 hPa; rainfall simulation results of both models are similar, simulation result for unsteady rainfall is relatively good, simulation result for steady rainfall shows position with northward difference and rainfall is relatively large, and rainfall simulation result in whole is not good. In numerical simulation test, performance of climate model based on PWRF3.3.1 is better than one based on WRF3.2.1 inwhole.
生态学杂志 , 2012,
Abstract: ?叶绿素a的浓度是水环境评价的重要参数。根据2005—2009年太湖全湖32个采样点的20次太湖采样数据,结合气象要素资料模拟的太湖风场,探求了风场对太湖叶绿素a空间分布的影响。结果表明:叶绿素a浓度的高值中心位于太湖西北侧、竺山湾以及梅梁湾流域,而太湖东南部的叶绿素a浓度较低;全太湖全年以东南风为主,南部风速较大,北部风速较弱;风场对叶绿素a的输移作用明显,在风场作用下,叶绿素向太湖西北部和北部输移,造成了该地区太湖流域叶绿素浓度普遍偏高。
Hydrometeorological Modeling Study of Tropical Cyclone Phet in the Arabian Sea in 2010  [PDF]
Mohammed Haggag, Hesham Badry
Atmospheric and Climate Sciences (ACS) , 2012, DOI: 10.4236/acs.2012.22018
Abstract: Tropical cyclone Phet is the second strongest tropical cyclone ever recorded in the Arabian Sea. Phet made landfall in the northeast mountainous area of Oman in early morning on 4 June in 2010, causing a breaking record rainfall in this arid region of 488 mm/48 h. The cyclone heavy rainfall triggered flash floods causing enormous losses in lives and infrastructure in northeast Oman. The state of the art Advanced Research WRF model is used to study the atmospheric circulation and to reproduce the heavy rainfall over Oman. Three one-way nested domains with 32 vertical layers with terrain following sigma coordinate are used to setup eight numerical experiments aiming to investigate the effect of initialization time, horizontal grid resolution and terrain elevations on reproducing the cyclone track, intensity and heavy rainfall. Simulation results show negligible effect of model initialization time on cyclone track, intensity and rainfall. In contrast, the orographic effect played a substantial role in rainfall simulation over northeast Oman. The heavy rainfall was a combination of the cyclone circulation effect and the orographic lifting in the mountains. The northeasterly cyclone moist-warm wind was lifted in the Omani mountains releasing its potential energy and enhancing further thermal convection. The numerical experiment with the highest terrain elevation (RUN3.3-C) resulted in overestimation of observed rainfall due to the enhanced topographic lifting of the saturated cyclone wind. Experiment with similar horizontal grid resolution but smoother terrain elevation (RUN3.3-TER) resulted in much less rainfall amount comparable to the observed values. The increased precipitation in RUN3.3-C is due to the increase in the rain- water and cloud water and graupel of the explicit moisture scheme.
A Tool for Public PM2.5-Concentration Advisory Based on Mobile Measurements  [PDF]
Huy N. Tran, Ketsiri Leelasakultum, Nicole Molders
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.312183

A tool was developed that interpolates mobile measurements of PM2.5-concentrations into unmonitored areas of the Fairbanksnonattainment area for public air-quality advisory. The tool uses simulations with theAlaskaadapted version of the Weather Research and Forecasting (WRF) and the Community Modeling and Analysis Quality (CMAQ) modeling system as a database. The tool uses the GPS-data of the vehicle’s route, and the database to determine linear regression equations for the relationships between the PM2.5-concentrations at the locations on the route and those outside the route. Once the interpolation equations are determined, the tool uses the mobile measurements as input into these equations that interpolate the measurements into the unmonitored neighborhoods. An episode of winter 2009/10 served as database for the tool’s interpolation algorithm. An independent episode of winter 2010/11 served to demonstrate and evaluate the performance of the tool. The evaluation showed that the tool well reproduced the spatial distribution of the observed as well as simulated concentrations. It is demonstrated that the tool does not require a database that contains data of the episode for which the interpolation is to be made. Potential challenges in applying this tools and its transferability are discussed critically.

Impact of Convective Parameterization Schemes on the Quality of Rainfall Forecast over Tanzania Using WRF-Model  [PDF]
Alfred L. Kondowe
Natural Science (NS) , 2014, DOI: 10.4236/ns.2014.610069
Abstract: To describe the evolution of atmospheric processes and rainfall forecast in Tanzania, the Advanced Weather Research and Forecasting (WRF-ARW) model was used. The principal objectives of this study were 1) the understanding of mesoscale WRF model and adapting the model for Tanzania; 2) to conduct numerical experiments using WRF model with different convective parameterization schemes (CP’s) and investigate the impact of each scheme on the quality of rainfall forecast; and 3) the investigation of the capability of WRF model to successfully simulate rainfall amount during strong downpour. The impact on the quality of rainfall forecast of six CP’s was investigated. Two rainy seasons, short season Vuli from October to December (OND) and long season Masika from March to May (MAM) were targeted. The results of numerical experiments showed that for rainfall prediction in Dar es Salaam and (the entire coast of the Indian Ocean), GD scheme performed better during OND and BMJ scheme during MAM. Results also showed that NC scheme should not be used, which is in agreement to the fact that in tropics rainfall is from convective activities. WRF model to some extent performs better in the cases of extreme rainfall.

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