scholarly journals Sensitivity to Convective Schemes on Precipitation Simulated by the Regional Climate Model MAR over Belgium (1987–2017)

Atmosphere ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 34 ◽  
Author(s):  
Sébastien Doutreloup ◽  
Coraline Wyard ◽  
Charles Amory ◽  
Christoph Kittel ◽  
Michel Erpicum ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Precipitation Amount ◽  
Regional Model ◽  
Convective Precipitation ◽  
Mean Annual Precipitation ◽  
The North ◽  
Simulated Precipitation ◽  
The North Sea

The aim of this study is to assess the sensitivity of convective precipitation modelled by the regional climate model MAR (Modèle Atmosphérique Régional) over 1987–2017 to four newly implemented convective schemes: the Bechtold scheme coming from the MESO-NH regional model and the Betts-Miller-Janjić, Kain-Fritsch and modified Tiedtke schemes coming from the WRF regional model. MAR version 3.9 is used here at a resolution of 10 km over a domain covering Belgium using the ERA-Interim reanalysis as forcing. The simulated precipitation is compared against SYNOP and E-OBS gridded precipitation data. Trends in total and convective precipitation over 1987–2017 are discussed. None of the MAR experiments compares better with observations than the others and they all show the same trends in (extreme) precipitation. Over the period 1987–2017, MAR suggests a significant increase in the mean annual precipitation amount over the North Sea but a significant decrease over High Belgium.

Northeast Atlantic and North Sea Storminess as Simulated by a Regional Climate Model during 1958–2001 and Comparison with Observations

2005 ◽  
Vol 18 (3) ◽  
pp. 465-479 ◽  
Author(s):  
Ralf Weisse ◽  
Hans von Storch ◽  
Frauke Feser
Keyword(s):  
Regional Climate Model ◽  
North Sea ◽  
North Atlantic ◽  
Climate Model ◽  
Regional Climate ◽  
Near Surface ◽  
Severe Storms ◽  
Northeast Atlantic ◽  
The North ◽  
The North Sea

Abstract An analysis of the storm climate of the northeast Atlantic and the North Sea as simulated by a regional climate model for the past 44 yr is presented. The model simulates the period 1958–2001 driven by the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis. Comparison with observations shows that the model is capable of reproducing impact-related storm indices such as the number of severe and moderate storms per year or the total number of storms and upper intra-annual percentiles of near-surface wind speed. The indices describe both the year-to-year variability of the frequency, as well as changes in the average intensity of storm events. Analysis of these indices reveals that the average number of storms per year has increased near the exit of the North Atlantic storm track and over the southern North Sea since the beginning of the simulation period (1958), but the increase has attenuated later over the North Sea and the average number of storms per year has been decreasing over the northeast Atlantic since about 1990–95. The frequency of the most severe storms follows a similar pattern over the northeast North Atlantic while too few severe storms occurred in other areas of the model domain, preventing a statistical analysis for these areas.

scholarly journals Regional climate model experiments to investigate the Asian monsoon in the Late Miocene

2011 ◽  
Vol 7 (3) ◽  
pp. 847-868 ◽  
Author(s):  
H. Tang ◽  
A. Micheels ◽  
J. Eronen ◽  
M. Fortelius
Keyword(s):  
Tibetan Plateau ◽  
Regional Climate Model ◽  
Late Miocene ◽  
Asian Monsoon ◽  
Climate Model ◽  
Regional Climate ◽  
Northern China ◽  
Regional Model ◽  
Monsoon Climate ◽  
Northern Tibetan Plateau

Abstract. The Late Miocene (11.6–5.3 Ma) is a crucial period in the history of the Asian monsoon. Significant changes in the Asian climate regime have been documented for this period, which saw the formation of the modern Asian monsoon system. However, the spatiotemporal structure of these changes is still ambiguous, and the associated mechanisms are debated. Here, we present a simulation of the average state of the Asian monsoon climate for the Tortonian (11–7 Ma) using the regional climate model CCLM3.2. We employ relatively high spatial resolution (1° × 1°) and adapt the physical boundary conditions such as topography, land-sea distribution and vegetation in the regional model to represent the Late Miocene. As climatological forcing, the output of a Tortonian run with a fully-coupled atmosphere-ocean general circulation model is used. Our regional Tortonian run shows a stronger-than-present East Asian winter monsoon wind as a result of the enhanced mid-latitude westerly wind of our global forcing and the lowered present-day northern Tibetan Plateau in the regional model. The summer monsoon circulation is generally weakened in our regional Tortonian run compared to today. However, the changes of summer monsoon precipitation exhibit major regional differences. Precipitation decreases in northern China and northern India, but increases in southern China, the western coast and the southern tip of India. This can be attributed to the changes in both the regional topography (e.g. the lower northern Tibetan Plateau) and the global climate conditions (e.g. the higher sea surface temperature). The spread of dry summer conditions over northern China and northern Pakistan in our Tortonian run further implies that the monsoonal climate may not have been fully established in these regions in the Tortonian. Compared with the global model, the high resolution regional model highlights the spatial differences of the Asian monsoon climate in the Tortonian, and better characterizes the convective activity and its response to regional topographical changes. It therefore provides a useful and compared to global models, a complementary tool to improve our understanding of the Asian monsoon evolution in the Late Miocene.

Impact of climate change on runoff timing over the Hindukush Karakorum Himalaya (HKH) region using CORDEX-CORE scenario simulations

2021 ◽  
Author(s):  
Wajeeha Shafeeq ◽  
Erika Coppola ◽  
Fabio Di Sante
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Regional Climate ◽  
Indus Basin ◽  
Convective Precipitation ◽  
The South ◽  
Unique Region ◽  
Vast Number ◽  
The North ◽  
Mitigation And Adaptation

<p>Hindukush Karakorum and Himalayan (HKH) is a unique region with a vast number of glaciers and lies in the north of the South Asia landmass, which serves as the main reservoir for the South Asian freshwater resources. By using CORDEX-CORE downscaled simulations with ICTP Regional Climate Model (RegCM4.7) the climate change impact on the water resources of the HKH region is analysed. HKH contains Indus, Ganges and Brahmaputra water basins, which are feed from both snow as well as precipitation. Due to the temperature increase over this region, the snowmelt timing will be affected, and therefore the snowmelt driven runoff (SDR) in the whole HKH basin. This effect will be combined with the projected increase of precipitation and in particular convective precipitation mostly due to extreme precipitation increase. As a result for the whole HKH basin, the water year will be longer with a shift (negative) toward the earlier months of the year of the time when the 25th (~2-3 months), 50th( ~1month), and 75th (~1 month) percentile of the total runoff is observed in a certain point, in the upper part of the basin and a positive shift (~10 days) in the lower part of the basin for the 50th and 75th percentile. The results show that the Indus basin is the one most affected by the snow melt time change followed by the Brahmaputra and Ganges as the last one. This study indicates that changing climate may result in a shift in the discharge timing over the HKH region and this information may be crucial for planning the mitigation and adaptation actions like for example building dams, changing dam regulation options, and changing agriculture strategies.</p>

scholarly journals Melting over the northeast Antarctic Peninsula (1999–2009): evaluation of a high-resolution regional climate model

2018 ◽  
Vol 12 (9) ◽  
pp. 2901-2922 ◽  
Author(s):  
Rajashree Tri Datta ◽  
Marco Tedesco ◽  
Cecile Agosta ◽  
Xavier Fettweis ◽  
Peter Kuipers Munneke ◽  
...  
Keyword(s):  
High Resolution ◽  
Regional Climate Model ◽  
Antarctic Peninsula ◽  
Climate Model ◽  
Regional Climate ◽  
Ocean Energy ◽  
Ice Shelf ◽  
The North ◽  
Mass Balance Models ◽  
Westerly Winds

Abstract. Surface melting over the Antarctic Peninsula (AP) may impact the stability of ice shelves and thus the rate at which grounded ice is discharged into the ocean. Energy and mass balance models are needed to understand how climatic change and atmospheric circulation variability drive current and future melting. In this study, we evaluate the regional climate model MAR over the AP at a 10 km spatial resolution between 1999 and 2009, a period when active microwave data from the QuikSCAT mission is available. This model has been validated extensively over Greenland, has is applied here to the AP at a high resolution and for a relatively long time period (full outputs are available to 2014). We find that melting in the northeastern AP, the focus area of this study, can be initiated both by sporadic westerly föhn flow over the AP mountains and by northerly winds advecting warm air from lower latitudes. A comparison of MAR with satellite and automatic weather station (AWS) data reveals that satellite estimates show greater melt frequency, a larger melt extent, and a quicker expansion to peak melt extent than MAR in the centre and east of the Larsen C ice shelf. These differences are reduced in the north and west of the ice shelf, where the comparison with satellite data suggests that MAR is accurately capturing melt produced by warm westerly winds. MAR shows an overall warm bias and a cool bias at temperatures above 0 ∘C as well as fewer warm, strong westerly winds than reported by AWS stations located on the eastern edge of the Larsen C ice shelf, suggesting that the underestimation of melt in this region may be the product of limited eastward flow. At higher resolutions (5 km), MAR shows a further increase in wind biases and a decrease in meltwater production. We conclude that non-hydrostatic models at spatial resolutions better than 5 km are needed to better-resolve the effects of föhn winds on the eastern edges of the Larsen C ice shelf.

scholarly journals Long-Term Changes in the Climatology of Transient Inverted Troughs over the North American Monsoon Region and Their Effects on Precipitation

2016 ◽  
Vol 29 (17) ◽  
pp. 6037-6064 ◽  
Author(s):  
Timothy M. Lahmers ◽  
Christopher L. Castro ◽  
David K. Adams ◽  
Yolande L. Serra ◽  
John J. Brost ◽  
...  
Keyword(s):  
North American ◽  
Climate Model ◽  
Regional Climate ◽  
Track Density ◽  
North American Monsoon ◽  
Northwest Mexico ◽  
The North ◽  
Simulated Precipitation ◽  
Precipitation Estimates ◽  
Resolution Model

Abstract Transient inverted troughs (IVs) are a trigger for severe weather during the North American monsoon (NAM) in the southwest contiguous United States (CONUS) and northwest Mexico. These upper-tropospheric disturbances enhance the synoptic-scale and mesoscale environment for organized convection, increasing the chances for microbursts, straight-line winds, blowing dust, and flash flooding. This work considers changes in the track density climatology of IVs between 1951 and 2010. IVs are tracked as potential vorticity (PV) anomalies on the 250-hPa surface from a regional climate model that dynamically downscales the NCEP–NCAR Reanalysis 1. Late in the NAM season, a significant increase in IV track density over the 60-yr period is observed over Southern California and western Arizona, coupled with a slight decrease over northwest Mexico. Changes in precipitation are evaluated on days when an IV is observed and days without an IV, using high-resolution model-simulated precipitation estimates and CPC gridded precipitation observations. Because of changes in the spatial distribution of IVs during the 1951–2010 analysis period, which are associated with a strengthening of the monsoon ridge, it is suggested that IVs have played a lesser role in the initiation and organization of monsoon convection in the southwest CONUS during recent warm seasons.

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 Impacts of using spectral nudging on regional climate model RCA4 simulations of the Arctic

2013 ◽  
Vol 6 (3) ◽  
pp. 849-859 ◽  
Author(s):  
P. Berg ◽  
R. Döscher ◽  
T. Koenigk
Keyword(s):  
Sea Ice ◽  
Regional Climate Model ◽  
Large Scale ◽  
Climate Model ◽  
Regional Climate ◽  
Coupled System ◽  
The Arctic ◽  
Spectral Nudging ◽  
The North ◽  
Temperature And Precipitation

Abstract. The performance of the Rossby Centre regional climate model RCA4 is investigated for the Arctic CORDEX (COordinated Regional climate Downscaling EXperiment) region, with an emphasis on its suitability to be coupled to a regional ocean and sea ice model. Large biases in mean sea level pressure (MSLP) are identified, with pronounced too-high pressure centred over the North Pole in summer of over 5 hPa, and too-low pressure in winter of a similar magnitude. These lead to biases in the surface winds, which will potentially lead to strong sea ice biases in a future coupled system. The large-scale circulation is believed to be the major reason for the biases, and an implementation of spectral nudging is applied to remedy the problems by constraining the large-scale components of the driving fields within the interior domain. It is found that the spectral nudging generally corrects for the MSLP and wind biases, while not significantly affecting other variables, such as surface radiative components, two-metre temperature and precipitation.

scholarly journals Future projections of the climate and surface mass balance of Svalbard with the regional climate model MAR

2015 ◽  
Vol 9 (1) ◽  
pp. 115-140 ◽  
Author(s):  
C. Lang ◽  
X. Fettweis ◽  
M. Erpicum
Keyword(s):  
Regional Climate Model ◽  
Mass Balance ◽  
Climate Model ◽  
Regional Climate ◽  
Surface Mass Balance ◽  
Near Surface ◽  
Future Projections ◽  
Surface Mass ◽  
Ice Caps ◽  
The North

Abstract. We have performed future projections of the climate and surface mass balance (SMB) of Svalbard with the MAR regional climate model forced by the MIROC5 global model, following the RCP8.5 scenario at a spatial resolution of 10 km. MAR predicts a similar evolution of increasing surface melt everywhere in Svalbard followed by a sudden acceleration of the melt around 2050, with a larger melt increase in the south compared to the north of the archipelago and the ice caps. This melt acceleration around 2050 is mainly driven by the albedo-melt feedback associated with the expansion of the ablation/bare ice zone. This effect is dampened in part as the solar radiation itself is projected to decrease due to cloudiness increase. The near-surface temperature is projected to increase more in winter than in summer as the temperature is already close to 0 °C in summer. The model also projects a strong winter west-to-east temperature gradient, related to the large decrease of sea ice cover around Svalbard. At the end of the century (2070–2099 mean), SMB is projected to be negative over the entire Svalbard and, by 2085, all glaciated regions of Svalbard are predicted to undergo net ablation, meaning that, under the RCP8.5 scenario, all the glaciers and ice caps are predicted to start their irreversible retreat before the end of the 21st century.

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