What model resolution is required in climatological downscaling over complex terrain?

El-Samra, R.; Bou‐Zeid, Elie; El‐Fadel, Mutasem

doi:10.1016/j.atmosres.2017.11.030

Cited by 22 publications

(16 citation statements)

References 53 publications

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“…To address this huge developing challenge in the Middle East, there is a specific need to depict a complete and more accurate picture of future water scarcity and drought under climate change conditions to ensure water security and diminish the negative effects and the costs to the society. The projections of global climate models (GCMs) point to an overall drying signal for the Middle East (Dai 2013, IPCC 2013; however, the precipitation simulations by GCMs with a coarse spatial resolution of 1°-3°may be biased for the region with a complex terrain (Black et al 2010) and variable land surfaces (e.g., mountains, deserts, coastlines, inland water bodies) (Maraun et al 2017, El-Samra et al 2018. A more trustworthy representation of the land surface features along with a better simulation of meso-spatial scale processes and the atmospheric circulation and gradients are provided at finer spatial resolutions of regional climate models (RCMs) (Torma et al 2015, Mohan and Sati 2016, Lucas-Picher et al 2017, Ahmadalipour and Moradkhani 2018, Minder et al 2018.…”

Section: Introductionmentioning

confidence: 99%

More prolonged droughts by the end of the century in the Middle East

Tabari

Willems

2018

Environ. Res. Lett.

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Climate change can put an intense pressure on already scarce water resources in the Middle East, potentially catalyzing the risk of serious water conflicts. Albeit most efforts to quantify the potential impact of climate change in the Middle East use global climate model outputs, here we employ two regional climate model outputs which are expected to provide more trustworthy projections for the region with a complex terrain and variable land surfaces. We find that not ubiquitous does future climate change lead to a decline in annual precipitation total in the region; nevertheless, the projected decline stems from an increase in number of dry days (NDD) rather than a decrease in precipitation intensity on rainy days. The increase in annual precipitation total in the southern part is driven by changes in both NDD and precipitation intensity. The drought periods will be longer (up to 90%) in about 80% of the Middle East area. The prolonged droughts in the future will increase the already high level of water stress in the region and force people to migrate or live in dreadful conditions of water poverty.

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Section: Introductionmentioning

confidence: 99%

More prolonged droughts by the end of the century in the Middle East

Tabari

Willems

2018

Environ. Res. Lett.

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“…For this reason, we opted not to adopt a convective parameterization for the largest domain (9 km) based on that body of literature and our own previous studies in Talbot et al () and Li et al (). The same WRF configuration used here also performed well in historic simulations over the study area forced by the National Centers for Environment Prediction Final Analysis (FNL) data (1° resolution; El‐Samra et al, , ). We changed the atmospheric equivalent CO 2 concentration in each simulated year of WRF to match the respective scenarios RCP4.5 and RCP8.5 and to be consistent with HIRAM.…”

Section: Methodsmentioning

confidence: 69%

“…The inner nested domain (d02; 462 km × 579 km) has a spatial resolution of 3 km and is focused on the study area (Figures b and c). The highest resolution of 3 km was shown to be sufficient in previous tests comparing historic WRF simulations over the study area to a wide array of ground observations; no significant improvement was noted when the resolution was further increased to 1 km (El‐Samra et al, ). Moderate Resolution Imaging Spectroradiometer (MODIS; Friedl et al, ) land use data were adopted with 21 land categories and Lambert Conformal projection (most suitable for midlatitude locations since it results in nearly uniform grid spacing).…”

Section: Methodsmentioning

confidence: 85%

“…The time step used was 30 s for the largest domain, and all domains had 28 vertical levels (with a vertically stretched grid) set according to terrain‐following hydrostatic pressure coordinates. The number of vertical levels is also based on the tests for historic periods conducted in El‐Samra et al ().…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, prior to the use of a downscaling model for climate‐change studies, it is essential to evaluate the ability of that model to capture regional climate characteristics in order to analyze whether the downscaling model provides an improvement over the driving data (Chotamonsak et al, ; García‐Valdecasas Ojeda et al, ; Oh et al, ). In this context, El‐Samra et al (, ) demonstrated the ability of the Weather Research and Forecasting (WRF) model (Skamarock et al, ), used as the NWP model for downscaling in this study to capture the frequency and the main spatial patterns of temperature and rainfall in the study area (which are the most important variable related to heat waves and drought events), as well as to improve on the projections from coarser climate models.…”

Section: Introductionmentioning

confidence: 95%

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Seasonal and Regional Patterns of Future Temperature Extremes: High‐Resolution Dynamic Downscaling Over a Complex Terrain

et al. 2018

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The combined impacts of projected/simulated climate change and variability on temperature extremes over a complex topographical terrain along the eastern Mediterranean are assessed in this study. High-resolution dynamical temperature downscaling is conducted for the past (2008) and the near future (until 2050) during eight extreme hot and dry years under two Representative Concentration Pathways (RCP 4.5 and RCP 8.5). The Weather Research and Forecasting (WRF) model is used for the downscaling process with two nested resolutions of 9 and 3 km, forced by the global High-Resolution Atmospheric Model (HiRAM) at a resolution of 25 km. Climate indices resultant from daily simulated temperature illustrate considerable changes in daily maximum summer and minimum winter temperature extremes during the future simulated years in comparison with the historic 2008 selected as reference and control period. While average yearly temperatures increase in both scenarios and most regions as expected, the seasonal variability is forecasted to intensify even more significantly resulting in colder winter and warmer summer conditions. Moreover, the interseasonal variability was most pronounced in the years with the highest averaged temperatures. A notable increase in the annual incidence of hot nights and heat wave events relative to 2008 conditions is also expected. The orographic complexity resulted in significant regional differences, with the most affected regions experiencing more than a doubling of extreme indices during the hottest and driest years of near-future decades. This strong spatial variability highlights the need for high-resolution downscaling.Intergovernmental Panel on Climate Change (IPCC) (2013) defines an extreme climatic event as one that is rare (i.e., falling on the extremes of a probability density function) at a particular place and time of year. In Key Points:• A downscaled GCM predicts exacerbated seasonal swings in Lebanon, including decreasing winter and spring temperatures and increasing temperature in summer and fall • Projections of increases in maximum summer temperatures and extreme heat indices are severe over the study area • Regional differences in impact over the focus area's complex terrain are very significant, require high-resolution downscaling El-Fadel, M. (2018). Seasonal and regional patterns of future temperature extremes: High-resolution dynamic downscaling over a complex terrain.

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Performance of the Weather Research and Forecasting model in simulating climate over northern Asia

Bai

Sun

et al. 2022

Intl Journal of Climatology

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High-resolution simulation is important for understanding climate change and its impact over regions with complex terrain. Northern Asia (NA) is such a region and sensitive to global warming. However, the performance of the regional model over NA is still unclear. In this study, we conducted a twodecade-long high-resolution (25 km) simulation over NA using the Weather Research and Forecasting (WRF) model forced by the ERA-Interim reanalysis and then evaluated the performance of WRF against the observations. The results show that the WRF simulation, set up with selections of the physical schemes, can reasonably reproduce the spatial and temporal features of surface air temperature and precipitation over NA. In addition, the WRF simulation can add more regional details on the climate features than the ERA-Interim data, especially over the NA regions with complex terrain. The spatial-pattern correlation coefficient of summer precipitation over NA between the WRF simulation and observations is higher than that of the ERA-Interim data. WRF can reasonably reproduce the annual cycles of precipitation. Moreover, the observed year-to-year variations in summer surface air temperature and precipitation over most NA subregions could be generally captured by the WRF. In conclusion, although systemic model bias still exists, the evaluations in this study indicate that WRF shows reasonable performance in a high-resolution simulation of climate over NA, consequently providing a scientific basis for future simulation studies over the region.

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What model resolution is required in climatological downscaling over complex terrain?

Cited by 22 publications

References 53 publications

More prolonged droughts by the end of the century in the Middle East

More prolonged droughts by the end of the century in the Middle East

Seasonal and Regional Patterns of Future Temperature Extremes: High‐Resolution Dynamic Downscaling Over a Complex Terrain

Performance of the Weather Research and Forecasting model in simulating climate over northern Asia

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