scholarly journals Implementation and evaluation of online gas-phase chemistry within a regional climate model (RegCM-CHEM4)

2012 ◽  
Vol 5 (3) ◽  
pp. 741-760 ◽  
Author(s):  
A. Shalaby ◽  
A. S. Zakey ◽  
A. B. Tawfik ◽  
F. Solmon ◽  
F. Giorgi ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Gas Phase ◽  
Heat Wave ◽  
Climate Model ◽  
Regional Climate ◽  
Theoretical Physics ◽  
Analysis Model ◽  
Gas Phase Chemistry ◽  
Ozone Concentrations ◽  
Phase Chemistry

Abstract. The RegCM-CHEM4 is a new online climate-chemistry model based on the International Centre for Theoretical Physics (ICTP) regional climate model (RegCM4). Tropospheric gas-phase chemistry is integrated into the climate model using the condensed version of the Carbon Bond Mechanism (CBM-Z; Zaveri and Peters, 1999) with a fast solver based on radical balances. We evaluate the model over continental Europe for two different time scales: (1) an event-based analysis of the ozone episode associated with the heat wave of August 2003 and (2) a climatological analysis of a six-year simulation (2000–2005). For the episode analysis, model simulations show good agreement with European Monitoring and Evaluation Programme (EMEP) observations of hourly ozone over different regions in Europe and capture ozone concentrations during and after the summer 2003 heat wave event. For long-term climate simulations, the model captures the seasonal cycle of ozone concentrations with some over prediction of ozone concentrations in non-heat wave summers. Overall, the ozone and ozone precursor evaluation shows the feasibility of using RegCM-CHEM4 for decadal-length simulations of chemistry-climate interactions.

scholarly journals Implementation and evaluation of online gas-phase chemistry within a regional climate model (RegCM-CHEM4)

2012 ◽  
Vol 5 (1) ◽  
pp. 149-188 ◽  
Author(s):  
A. K. Shalaby ◽  
A. S. Zakey ◽  
A. B. Tawfik ◽  
F. Solmon ◽  
F. Giorgi ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Gas Phase ◽  
Heat Wave ◽  
Climate Model ◽  
Regional Climate ◽  
Theoretical Physics ◽  
Analysis Model ◽  
Gas Phase Chemistry ◽  
Ozone Concentrations ◽  
Phase Chemistry

Abstract. The RegCM-CHEM4 is a new online climate-chemistry model based on the International Centre for Theoretical Physics (ICTP) regional climate model (RegCM4). Tropospheric gas-phase chemistry is integrated into the climate model using the condensed version of the Carbon Bond Mechanism (CBM-Z; Zaveri and Peters, 1999) with a fast solver based on radical balances. We evaluate the model over Continental Europe for two different time scales: (1) an event-based analysis of the ozone episode associated with the heat wave of August 2003 and (2) a climatological analysis of a six-year simulation (2000–2005). For the episode analysis, model simulations show good agreement with European Monitoring and Evaluation Program (EMEP) observations of hourly ozone over different regions in Europe and capture ozone concentrations during and after the August 2003 heat wave event. For long-term climate simulations, the model captures the seasonal cycle of ozone concentrations with some over prediction of ozone concentrations in non-heat wave summers. Overall, the ozone and ozone precursor evaluation shows the feasibility of using RegCM-CHEM4 for decadal-length simulations of chemistry-climate interactions.

A Regional Climate Model Laboratory for Understanding Coastal Climate

2021 ◽  
Author(s):  
Travis O'Brien ◽  
Thomas Burkle ◽  
Michael Krauter ◽  
Thomas Trapp
Keyword(s):  
Steady State ◽  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Cloud Fraction ◽  
Theoretical Physics ◽  
Coastal Regions ◽  
Local Climate ◽  
Coastal Climate ◽  
Mean Climate

<p>Midlatitude western coastal regions are recognized as being important for the global energy cycle, marine and terrestrial biodiversity, and regional economies.  These coastal regions exhibit a rich range of weather and climate phenomena, including persistent stratocumulus clouds, sea-breeze circulations, coastally-trapped Kelvin waves, and wind-driven upwelling. During the summer season, when impacts from transient synoptic systems are relatively reduced, the local climate is governed by a complex set of interactions among the atmosphere, land, and ocean.  This complexity has so far inhibited basic understanding of the drivers of western coastal climate, climate variability, and climate change.</p><p>As a way of simplifying the system, we have developed a hierarchical regional climate model experimental framework focused on the western United States. We modify the International Centre for Theoretical Physics RegCM4 to use steady-state initial, lateral, and top-of-model boundary conditions: average July insolation (no diurnal cycle) and average meteorological state (winds, temperature, humidity, surface pressure).  This July <em>Base State</em> simulation rapidly reaches a steady state solution that closely resembles the observed mean climate and the mean climate achieved using RegCM4 in a standard reanalysis-driven configuration.  It is particularly notable that the near-coastal stratocumulus field is spatially similar to the satellite-observed stratocumulus field during arbitrary July days: including gaps in stratocumulus coverage downwind of capes. We run similar <em>Base State</em> simulations for the other calendar months and find that these simulations mimic the annual cycle.  This suggests that the summer coastal stratocumulus field results from the steady-state response of the marine boundary layer to summertime climatological forcing; if true for the real world, this would imply that stratocumulus cloud fraction, within a given month, is temporally modulated by deviations from the summer base state (e.g., transient synoptic disturbances that interrupt the cloud field).  We describe modifications to this simplified experimental framework aimed at understanding the factors that govern stratocumulus cloud fraction and its variability.</p>

scholarly journals Simulation of Rainfall over Bangladesh Using Regional Climate Model (RegCM4.7)

Jalawaayu ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 1-19
Author(s):  
Muhammad Tanjilur Rahman ◽  
Md. Nazmul Ahasan ◽  
Md. Abdul Mannan ◽  
Madan Sigdel ◽  
Dibas Shrestha ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Bias Correction ◽  
Climate Model ◽  
Regional Climate ◽  
Rainfall Simulation ◽  
Theoretical Physics ◽  
Convective Precipitation ◽  
Annual Rainfall ◽  
Linear Scaling ◽  
Simulated Rainfall

Regional climate model is a scientific tool to monitor present climate change and to provide reliable estimation of future climate projection. In this study, the Regional Climate Model version 4.7 (RegCM4.7) developed by International Centre for Theoretical Physics (ICTP) has been adopted to simulate rainfall scenario of Bangladesh. The study examines model performance of rainfall simulation through the period of 1991-2018 with ERA-Interim75 data of 75 km horizontal resolution as lateral boundaries, downscaled at 25km resolution using the mixed convective precipitation scheme; MIT-Emanuel scheme over land and Grell scheme with Fritsch-Chappell closure over ocean. The simulated rainfall has been compared both at spatial and temporal scales (monthly, seasonal and annual) with observed data collected from Bangladesh Meteorological Department (BMD) and Climate Research Unit (CRU). Simulated annual rainfall showed that the model overestimated in most of the years. Overestimation has been observed in the monsoon and underestimation in pre-monsoon and post-monsoon seasons. Spatial distribution of simulated rainfall depicts overestimation in the southeast coastal region and underestimation in the northwest and northeast border regions of Bangladesh. Better estimation of rainfall has been found in the central and eastern parts of the country. The simulated annual rainfall has been validated through the Linear Scaling bias correction method for the years of 2016, 2017, and 2018 considering the rainfall of 1991-2015 as reference. The bias correction with linear scaling method gives fairly satisfactory results and it can be considered in the future projection of rainfall over Bangladesh.

scholarly journals Validation of gas phase chemistry in the WRF-Chem model over Europe

2017 ◽  
Vol 14 ◽  
pp. 181-186 ◽  
Author(s):  
Jan Karlický ◽  
Peter Huszár ◽  
Tomáš Halenka
Keyword(s):  
Gas Phase ◽  
Wet Deposition ◽  
Meteorological Conditions ◽  
Negative Bias ◽  
Daily Cycle ◽  
Gas Phase Chemistry ◽  
Ozone Concentrations ◽  
Station Data ◽  
European Station ◽  
Phase Chemistry

Abstract. This work presents the evaluation of the WRF-Chem model applied for a European domain over the year 2008 and employing two different chemical modules. Airbase European station data and E-OBS database are used for validation of the simulated meteorological conditions as well as concentrations of NO2, SO2 and ozone. In both experiments, underestimation of the amplitude of temperature daily cycle (by about 1 °C) and precipitation overestimation (by about 25 %) were found, with possible impact on chemistry processes due to increased removal via wet deposition. The modelled ozone concentrations match the observations quite well, while the simulated concentrations of other gases show highly negative bias.

scholarly journals Regional Climate Model Projections and Uncertainties of U.S. Summer Heat Waves

2010 ◽  
Vol 23 (16) ◽  
pp. 4447-4458 ◽  
Author(s):  
Kenneth E. Kunkel ◽  
Xin-Zhong Liang ◽  
Jinhong Zhu
Keyword(s):  
United States ◽  
Regional Climate Model ◽  
Heat Wave ◽  
General Circulation ◽  
Climate Model ◽  
Heat Waves ◽  
Regional Climate ◽  
General Circulation Models ◽  
Threshold Temperature ◽  
Wave Characteristics

Abstract Regional climate model (RCM) simulations, driven by low and high climate-sensitivity coupled general circulation models (CGCMs) under various future emissions scenarios, were compared to projected changes in heat wave characteristics. The RCM downscaling reduces the CGCM biases in heat wave threshold temperature by a factor of 2, suggesting a higher credibility in the future projections. All of the RCM simulations suggest that there is a high probability of heat waves of unprecedented severity by the end of the twenty-first century if a high emissions path is followed. In particular, the annual 3-day heat wave temperature increases generally by 3°–8°C; the number of heat wave days increases by 30–60 day yr−1 over much of the western and southern United States with slightly smaller increases elsewhere; the variance spectra for intermediate, 3–7 days (prolonged, 7–14 days), temperature extremes increase (decrease) in the central (western) United States. If a lower emissions path is followed, then the outcomes range from quite small changes to substantial increases. In all cases, the mean temperature climatological shift is the dominant change in heat wave characteristics, suggesting that adaptation and acclimatization could reduce effects.

scholarly journals Analysis of projected changes in the occurrence of heat waves in Hungary

2013 ◽  
Vol 35 ◽  
pp. 115-122 ◽  
Author(s):  
R. Pongrácz ◽  
J. Bartholy ◽  
E. B. Bartha
Keyword(s):  
Regional Climate Model ◽  
Heat Wave ◽  
Climate Model ◽  
Heat Waves ◽  
Meteorological Data ◽  
Regional Climate ◽  
Warning System ◽  
Emissions Scenarios ◽  
Projected Changes ◽  
Regional Climates

Abstract. Heat wave events are important temperature-related hazards due to their impacts on human health. In 2004, a Heat Health Warning System including three levels of heat wave warning was developed on the basis of a retrospective analysis of mortality and meteorological data in Hungary to anticipate heat waves that may result in a large excess of mortality. Projected changes in the frequency of different heat wave warning levels are analysed for the 21st century. For this purpose, outputs of regional climate model PRECIS (Providing REgional Climates for Impacts Studies) are used taking into account three different global emissions scenarios (A2, A1B, B2). The results clearly show an increase in occurrence and length of heat waves with respect to the underlying emissions scenarios and regional climate model used. Moreover, the potential season of heat wave occurrences is projected to be lengthened by two months in 2071–2100 compared to 1961–1990.

scholarly journals Regional Climate Modeling for the Developing World: The ICTP RegCM3 and RegCNET

2007 ◽  
Vol 88 (9) ◽  
pp. 1395-1410 ◽  
Author(s):  
Jeremy S. Pal ◽  
Filippo Giorgi ◽  
Xunqiang Bi ◽  
Nellie Elguindi ◽  
Fabien Solmon ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Climate Models ◽  
Climate Model ◽  
Climate Modeling ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Regional Climate Modeling ◽  
Theoretical Physics ◽  
Research Network ◽  
Diverse Range

Regional climate models are important research tools available to scientists around the world, including in economically developing nations (EDNs). The Earth Systems Physics (ESP) group of the Abdus Salam International Centre for Theoretical Physics (ICTP) maintains and distributes a state-of-the-science regional climate model called the ICTP Regional Climate Model version 3 (RegCM3), which is currently being used by a large research community for a diverse range of climate-related studies. The RegCM3 is the central, but not only, tool of the ICTP-maintained Regional Climate Research Network (RegCNET) aimed at creating south–south and north–south scientific interactions on the topic of climate and associated impacts research and modeling. In this paper, RegCNET, RegCM3, and illustrative results from RegCM3 benchmark simulations applied over south Asia, Africa, and South America are presented. It is shown that RegCM3 performs reasonably well over these regions and is therefore useful for climate studies in EDNs.

scholarly journals The effect of topography on east African rainfall based on regional climate model

MAUSAM ◽  
2021 ◽  
Vol 67 (2) ◽  
pp. 431-440
Author(s):  
BOB ALEX OGWANG ◽  
HAISHAN CHEN ◽  
L. I. XING
Keyword(s):  
Regional Climate Model ◽  
East Africa ◽  
Climate Model ◽  
Regional Climate ◽  
Research Unit ◽  
Theoretical Physics ◽  
East African ◽  
Maximum Rainfall ◽  
Low Level ◽  
The Mean

The effect of topography on June to August (JJA) rainfall over east Africa is investigated using the International Centre for Theoretical Physics (ICTP) Regional Climate Model (RegCM4.0). Grell convection scheme with Fritsch-Chappell closure assumption is used. The control simulation is done with actual topography and sensitivity experiments are carried out with topography reduced to 75%, 25% and to zero. The model output was evaluated against Climate Research Unit (CRU) dataset, gridded at 0.5 degree resolution and ERA-interim datasets, gridded at 0.75 degree resolution. Results show that the mean JJA rainfall significantly reduces over the region when topography elevation is reduced. Based on the model, when the topography over the selected region (KTU) is reduced to 25%, the mean JJA rainfall over east Africa is reduced by roughly half. The maximum rainfall reduction is however observed around the region over which topography is reduced. The reduction in topography resulted into an anomalous moisture divergence over the region at low level (850 hPa). Divergence at low level results in vertical shrinking which suppresses convection due to subsidence. The strength of moisture transport and the zonal wind speed at 850hpa increased with decrease in topography, which may be responsible for the observed shift in moisture convergence zone from western Kenya to northern Uganda. The findings from this study would provide insight into the effect of topography on the east African climate and call for more detailed investigative research, particularly in the region. The results may motivate researchers and modeling centers to further improve on the performance of the model over the region.

scholarly journals Improvement of surface albedo parameterization within a regional climate model (RegCM3)

2009 ◽  
Vol 6 (2) ◽  
pp. 1651-1676 ◽  
Author(s):  
Y. Bao ◽  
S. Lü
Keyword(s):  
East Asia ◽  
Regional Climate Model ◽  
Surface Albedo ◽  
Climate Model ◽  
Vegetation Type ◽  
Regional Climate ◽  
Northwest China ◽  
Heat Fluxes ◽  
Theoretical Physics ◽  
Cold Bias

Abstract. A parameterization for calculating surface albedo of Solar Zenith Angel (SZA) dependence with coefficient for each vegetation type determined on the Moderate Resolution Imaging Spectro-radiometer (MODIS) reformed by the Bidirectional Reflectance Distribution Function (BRDF) is incorporated within the latest Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model (RegCM3), and evaluated with a high resolution one-way nesting simulation in China using the Climate Research Unit (CRU) data and the observations from the Field Experiment on Interaction between Land and Atmosphere in Arid Region of Northwest China (NWC-ALIEX). The performance of the SZA method modeling surface characteristic is investigated.Results indicate, RegCM with SZA method (RCM_SZA) considerably improve the cold bias of original RegCM (RCM_ORI) in air surface temperature in East Asia with 1.2 degree increased in summer due to the lower albedo produced by SZA method which makes more solar radiation absorbed by the surface and used for heating the atmosphere near to the surface. The simulated diurnal cycle of ground temperature conforms fairly well to the observation in the nesting simulation in Northwest China, especially during the noon time when the SZA has the lowest value. However, the modification can not obviously affect the East Asia summer monsoon precipitation simulation although RCM_SZA produce more evapo-transpiration in surface with more than 2 Wm−2 increases in simulated latent heat fluxes both in East Asia and in Northwest China compared to RCM_ORI.

scholarly journals Interactions among ENSO, the Monsoon, and Diurnal Cycle in Rainfall Variability over Java, Indonesia

2010 ◽  
Vol 67 (11) ◽  
pp. 3509-3524 ◽  
Author(s):  
Jian-Hua Qian ◽  
Andrew W. Robertson ◽  
Vincent Moron
Keyword(s):  
Regional Climate Model ◽  
Diurnal Cycle ◽  
El Niño ◽  
Climate Model ◽  
El Nino ◽  
Rainfall Variability ◽  
Regional Climate ◽  
Theoretical Physics ◽  
Northern Coast ◽  
Wet Season

Abstract Using a high-resolution regional climate model—the Abdus Salam International Centre for Theoretical Physics Regional Climate Model version 3 (RegCM3)—and station and satellite observations, the authors have studied the spatial heterogeneity of climate variability over Java Island, Indonesia. Besides the well-known anomalous dry conditions that characterize the dry and transition seasons during an El Niño year, analysis of regional model output reveals a wet mountainous south versus dry northern plains in precipitation anomalies associated with El Niño over Java during the peak rainy season. Modeling experiments indicate that this mountains/plains contrast is caused by the interaction of the El Niño–induced monsoonal wind anomalies and the island/mountain-induced local diurnal cycle of winds and precipitation. During the wet season of El Niño years, anomalous southeasterly winds over the Indonesian region oppose the climatological northwesterly monsoon, thus reducing the strength of the monsoon winds over Java. This weakening is found to amplify the local diurnal cycle of land–sea breezes and mountain–valley winds, producing more rainfall over the mountains, which are located closer to the southern coast than to the northern coast. Therefore, the variability of the diurnal cycle associated with this local spatial asymmetry of topography is the underlying cause for the heterogeneous pattern of wet south/dry north rainfall anomalies during El Niño years. It is further shown that the mean southeasterly wind anomalies during December–February of El Niño years result from more frequent occurrence of a quiescent monsoon weather type, during which the strengthened sea-breeze and valley-breeze convergence leads to above normal rainfall over the mountains.

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