scholarly journals Assessment of the spatio-temporal variability of the added value on precipitation of convection-permitting simulation over the Iberian Peninsula using the RegIPSL regional earth system model

2021 ◽  
Author(s):  
Namendra Kumar Shahi ◽  
Jan Polcher‬ ◽  
Sophie Bastin ◽  
Romain Pennel ◽  
Lluís Fita
Keyword(s):  
Iberian Peninsula ◽  
Regional Climate ◽  
Temporal Distribution ◽  
Heavy Precipitation ◽  
Earth System Model ◽  
Added Value ◽  
System Model ◽  
Earth System ◽  
Precipitation Frequency ◽  
Spatio Temporal

Abstract In this study, we have assessed the added value on the spatio-temporal distribution of the precipitation of convection-permitting simulation (3km) compared to the parent coarser-scale parameterized convection simulation (20km) with the high-resolution observational datasets i.e. SPREAD (5km) and IBERIA01 (10km) over the Iberian Peninsula in all four seasons during 2000-2009. Both simulations are evaluation runs based on ERA-Interim reanalysis and performed with the RegIPSL regional earth system model in the frame of the European Climate Prediction system (EUCP) H2020 project and COordinated Regional climate Downscaling Experiment (CORDEX). We have not found significant improvement in the convection-permitting simulation compared to the parent coarser-scale simulation for the seasonal mean precipitation of the Iberian Peninsula except the spatial variation over mountainous peaks. The kilometer-scale simulation significantly underestimates the observed seasonal mean precipitation over the western parts of the Iberian Peninsula compared to the coarser-scale simulation, which may be attributed to a change of local dynamics in the kilometer-scale simulation with a weakening and southward shifts of the westerly winds and also an enhancement of warm and dry southerly winds over the Iberian Peninsula. However, the added value of kilometer-scale simulation over the driving coarser-scale simulation is obtained for various indices; in the representation of the spatio-temporal distribution of the wet-day precipitation frequency and intensity, and the extreme/heavy precipitation events for each season at both resolutions i.e. downscaled and upscaled. It has also been noted that the spatio-temporal distribution of precipitation for all metrics used varies between the two observational datasets for all seasons.

scholarly journals Assessment of the spatial variability of the added value on precipitation of convection-permitting simulation over the Iberian Peninsula using the RegIPSL regional earth system model

2021 ◽  
Author(s):  
Namendra Kumar Shahi ◽  
Jan Polcher ◽  
Sophie Bastin ◽  
Romain Pennel ◽  
Lluís Fita
Keyword(s):  
Iberian Peninsula ◽  
Land Surface ◽  
Regional Climate ◽  
Temporal Distribution ◽  
Heavy Precipitation ◽  
High Impact ◽  
Added Value ◽  
Rich Diversity ◽  
Simulated Precipitation ◽  
Resolution Simulation

<p>In the frame of the European Climate Prediction system (EUCP) H2020 project and COordinated Regional climate Downscaling Experiment (CORDEX), we have performed the ERA-Interim driven regional climate simulations with the coupled atmosphere (WRF)-land surface (ORCHIDEE) RegIPSL model at 20 km (EUR20; with parameterized convection) and 3 km (SWE3; convection-permitting/resolving) horizontal grid spacing over the Iberian Peninsula (IP) for the period of 2000-2009. The Iberian Peninsula is an area with a rich diversity of climates which is affected by several high impact extreme events such as droughts and flash floods for which the coupling processes between land surface and atmosphere play a key role. The aim of this first study is to evaluate the added value of the simulated mean and extreme precipitation in the convection-permitting simulation compared to the coarser resolution simulation for the four seasons (DJF, MAM, JJA, and SON). Experiment is performed as a chain of simulations while the EUR20 simulation is forced by the 6-hourly ERA-Interim initial and lateral boundary conditions (IC-LBCs) and the SWE3 simulation is forced by the 3-hourly EUR20 simulated IC-LBCs. The SPREAD (5 km) and Iberia01 (10 km) high-resolution daily gridded mean precipitation have been used as reference datasets for the validation of the simulated precipitation.</p><p>We have not found any consistent improvement in the SWE3 simulation compared to the parent EUR20 simulation for the seasonal mean precipitation of the IP except the spatial variation over mountainous peaks. The analysis shows a lack of mean precipitation in the western and southern parts of the domain in the SWE3 which explains that on average over the whole domain, the spatial-temporal pattern of the observed mean precipitation is quantitatively better represented by the EUR20 than the SWE3 simulation. The added value of kilometer scale simulation over the driving coarser scale simulation is obtained at various indices; in the representation of the spatial-temporal distribution of the Kolmogorov-Smirnov (K-S) distance, wet-day frequency and intensity for each season at both resolutions i.e. downscaled (3km) and upscaled (20km), although the SWE3 simulation slightly underestimates the observed frequency and intensity of the wet-day precipitation. The improvement of finer scale simulation over the coarser resolution simulation has also been found in the spatial-temporal distribution of the heavy precipitation events. It has also been noted that the spatial-temporal distribution of precipitation for all metrics used varies slightly between the two observation datasets for all seasons, and it may be due to the different resolution of both datasets. The absence of sub-daily observed datasets did not allow us to further investigate the added value of the convective permitting simulation at hourly time scales, but we also noticed heavier hourly precipitation and a shift in the diurnal cycle. These results demonstrate a clear advantage of using a RegIPSL model at the kilometric scale over the IP in simulation for high impact weather events, consistently with previous studies over other areas. Further analysis will be done on the hydrological processes in response to these shifts of precipitation distribution between the two simulations.</p>

scholarly journals Effects of Horizontal Resolution on Hourly Precipitation in AGCM Simulations

2020 ◽  
Vol 21 (4) ◽  
pp. 643-670 ◽  
Author(s):  
Xianghui Kong ◽  
Aihui Wang ◽  
Xunqiang Bi ◽  
Xingyu Li ◽  
He Zhang
Keyword(s):  
High Resolution ◽  
Heavy Rainfall ◽  
Heavy Precipitation ◽  
Horizontal Resolution ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Low Resolution ◽  
Precipitation Frequency ◽  
Hourly Precipitation

AbstractTo analyze the effects of horizontal resolution on hourly precipitation, four Atmospheric Model Intercomparison Project simulations are carried out using the Chinese Academy of Sciences Earth System Model (CAS-ESM) and the Community Earth System Model (CESM) during 1998–2016. They include CAS-ESM at resolutions of 1.4° latitude × 1.4° longitude (CAS-ESM L) and 0.5° × 0.5° (CAS-ESM H), and CESM at resolutions of 1.9° latitude × 2.5° longitude (CESM L) and 0.47° × 0.63° (CESM H), respectively. We focus on the simulated hourly precipitation frequency and assess the frequency with respect to high-resolution satellite observations and reanalysis. The high-resolution experiments show some improvements of measurable precipitation (>0.02 mm h−1) frequency. Noticeable improvement of heavy rainfall (>2 mm h−1) frequency is demonstrated at the high resolutions. The zonal mean, seasonal mean, and area-weighted average frequency support the above results. The high-resolution experiments outperform the low-resolution experiments in reproducing hourly precipitation intensity and amount. The added value is apparent in heavy precipitation intensity from CAS-ESM H and CESM H. Over the monsoon regions and tropical convergence zones, the patterns of probability density functions for precipitation from high-resolution experiments are closer to the observations and reanalysis than those from the low-resolution simulations. The improvement of measurable precipitation frequency is mainly caused by the reductions of the convective rainfall occurrence at high resolutions. The increasing large-scale precipitation and reasonable integrated water vapor flux contribute to the improvements in measurable rainfall intensity and heavy precipitation characteristics. The results of this study support the concept that high-resolution global simulations could produce improved hourly precipitation capabilities, especially for heavy rainfall.

scholarly journals Regional Climate Simulations With the Community Earth System Model

2018 ◽  
Vol 10 (6) ◽  
pp. 1245-1265 ◽  
Author(s):  
A. Gettelman ◽  
P. Callaghan ◽  
V. E. Larson ◽  
C. M. Zarzycki ◽  
J. T. Bacmeister ◽  
...  
Keyword(s):  
Regional Climate ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Climate Simulations ◽  
Community Earth System Model

scholarly journals Bergen Earth system model (BCM-C): model description and regional climate-carbon cycle feedbacks assessment

2010 ◽  
Vol 3 (1) ◽  
pp. 123-141 ◽  
Author(s):  
J. F. Tjiputra ◽  
K. Assmann ◽  
M. Bentsen ◽  
I. Bethke ◽  
O. H. Otterå ◽  
...  
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Regional Climate ◽  
Earth System Model ◽  
System Model ◽  
Model Description ◽  
Earth System ◽  
Carbon Cycle Model ◽  
Enhanced Production ◽  
Positive Climate

Abstract. We developed a complex Earth system model by coupling terrestrial and oceanic carbon cycle components into the Bergen Climate Model. For this study, we have generated two model simulations (one with climate change inclusions and the other without) to study the large scale climate and carbon cycle variability as well as its feedback for the period 1850–2100. The simulations are performed based on historical and future IPCC CO2 emission scenarios. Globally, a pronounced positive climate-carbon cycle feedback is simulated by the terrestrial carbon cycle model, but smaller signals are shown by the oceanic counterpart. Over land, the regional climate-carbon cycle feedback is highlighted by increased soil respiration, which exceeds the enhanced production due to the atmospheric CO2 fertilization effect, in the equatorial and northern hemisphere mid-latitude regions. For the ocean, our analysis indicates that there are substantial temporal and spatial variations in climate impact on the air-sea CO2 fluxes. This implies feedback mechanisms act inhomogeneously in different ocean regions. In the North Atlantic subpolar gyre, the simulated future cooling of SST improves the CO2 gas solubility in seawater and, hence, reduces the strength of positive climate carbon cycle feedback in this region. In most ocean regions, the changes in the Revelle factor is dominated by changes in surface pCO2, and not by the warming of SST. Therefore, the solubility-associated positive feedback is more prominent than the buffer capacity feedback. In our climate change simulation, the retreat of Southern Ocean sea ice due to melting allows an additional ~20 Pg C uptake as compared to the simulation without climate change.

Monitoring and Modelling of Soil Moisture in Lower Franconia (Germany)

2020 ◽  
Author(s):  
Julian Krause ◽  
Christian Schäfer ◽  
Birgit Terhorst ◽  
Roland Baumhauer ◽  
Heiko Paeth
Keyword(s):  
Soil Moisture ◽  
Extreme Precipitation ◽  
Regional Climate ◽  
Earth System Model ◽  
System Model ◽  
Future Scenarios ◽  
Earth System ◽  
Extreme Precipitation Events ◽  
Lower Franconia ◽  
Precipitation Events

<p>This research is part of the integrated project “BigData@Geo - Advanced Environmental Technology Using AI In The Web” funded by the European Regional Development Fund (ERDF). The aim of this ERDF-project is to develop a high-resolution regional earth system model for the region of Lower Franconia. One sub-project is dedicated to regional soil moisture modelling created with WaSiM-ETH based on soil moisture monitoring data. The second sub-project aims to improve the resolution of the regional climate model REMO. Both models will be combined to form the earth system model.</p><p>Lower Franconia is amongst the regions in Germany, which will be strongly affected by climate change. Regional climate models show that average temperatures will rise and dry periods as well as extreme precipitation events occur more often. However, it is still not known, what effect the changing climate conditions – especially dry periods and extreme precipitation events – will have on the soils in Lower Franconia.</p><p>Yields of forestry and agriculture (including viticulture and pomiculture) depend very much on the availability of soil water. During the growing season the water retention capacity of soils is therefore highly relevant. Up to present, datasets as well as modelling results of future scenarios on soil moisture are only scarcely available on local as well as on regional scale. In order to generate future scenarios, calculation of the soil moisture regime forms the base in order to evaluate present day conditions as well as to develop prognostic studies. As we intend to obtain most realistic parameters, generation of real-time data with high temporal resolution at selected sites is crucial. They are characteristic for Lower Franconia serving as calibration regions for modelling approaches. The operating monitoring stations record soil moisture and - temperature as well as meteorological parameters.</p><p>In order to obtain data on dynamics and causes of soil moisture fluctuation as well as to understand process flows, soil geographical surveys form an essential component of our research design for selected sites related to the monitoring stations. Furthermore, relevant sedimentological and pedological parameters such as grain size distribution, permeability, and bulk density are analyzed in the laboratory. Thus, our representative test sites combine detailed ground-truth data combining soil moisture and soil quality and thus, form consecutive modules as parts of soil moisture models. These modules drive and control the modelling procedures of the sub-project and they further serve for assessment and calibration of the area-wide hydrological and climate modelling in the “BigData@Geo” ERDF-project.</p>

Comparison of the surface mass and energy balance of CESM and MAR forced by CESM over Greenland: present and future

2020 ◽  
Author(s):  
Charlotte Lang ◽  
Charles Amory ◽  
Alison Delhasse ◽  
Stefan Hofer ◽  
Christoph Kittel ◽  
...  
Keyword(s):  
Energy Balance ◽  
Climate Models ◽  
Climate Model ◽  
Ice Sheet ◽  
Earth System Model ◽  
Global Climate Models ◽  
Added Value ◽  
System Model ◽  
Earth System ◽  
Surface Mass

<p>We have compared the surface mass (SMB) and energy balance of the Earth System model (ESM) CESM (Community Earth System Model) with those of the regional climate model (RCM) MAR (Modèle Atmosphérique Régional) forced by CESM over the present era (1981 — 2010) and the future (2011 — 2100 with SSP585 scenario).</p><p>Until now, global climate models (GCM) and ESMs forcing RCMs such as MAR didn’t include a module able to simulate snow and energy balance at the surface of a snow pack like the SISVAT module of MAR and were therefore not able to simulate the SMB of an ice sheet. Evaluating the added value of an RCM compared to a GCM could only be done by comparing atmospheric outputs (temperature, wind, precipitation …) in both models. CESM is the first ESM including a land model capable of simulating the surface of an ice sheet and thus to directly compare the SMB of an RCM and an ESM the first time.</p><p>Our results show that, if the SMB and is components are very similar in CESM and MAR over the present era, they quickly start to diverge in our future projection, the SMB of MAR decreasing more than that of CESM. This difference in SMB evolution is almost exclusively explained by a much larger increase of the melter runoff in MAR compared to CESM whereas the temporal evolution of snowfall, rainfall and sublimation is comparable in both runs.</p>

scholarly journals Surface mass balance downscaling through elevation classes in an Earth system model: application to the Greenland ice sheet

2019 ◽  
Vol 13 (12) ◽  
pp. 3193-3208 ◽  
Author(s):  
Raymond Sellevold ◽  
Leonardus van Kampenhout ◽  
Jan T. M. Lenaerts ◽  
Brice Noël ◽  
William H. Lipscomb ◽  
...  
Keyword(s):  
Mass Balance ◽  
Regional Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Lapse Rate ◽  
Surface Mass Balance ◽  
Earth System ◽  
Surface Mass

Abstract. The modeling of ice sheets in Earth system models (ESMs) is an active area of research with applications to future sea level rise projections and paleoclimate studies. A major challenge for surface mass balance (SMB) modeling with ESMs arises from their coarse resolution. This paper evaluates the elevation class (EC) method as an SMB downscaling alternative to the dynamical downscaling of regional climate models. To this end, we compare EC-simulated elevation-dependent surface energy and mass balance gradients from the Community Earth System Model 1.0 (CESM1.0) with those from the regional climate model RACMO2.3. The EC implementation in CESM1.0 combines prognostic snow albedo, a multilayer snow model, and elevation corrections for two atmospheric forcing variables: temperature and humidity. Despite making no corrections for incoming radiation and precipitation, we find that the EC method in CESM1.0 yields similar SMB gradients to RACMO2.3, in part due to compensating biases in snowfall, surface melt, and refreezing gradients. We discuss the sensitivity of the results to the lapse rate used for the temperature correction. We also evaluate the impact of the EC method on the climate simulated by the ESM and find minor cooling over the Greenland ice sheet and Barents and Greenland seas, which compensates for a warm bias in the ESM due to topographic smoothing. Based on our diagnostic procedure to evaluate the EC method, we make several recommendations for future implementations.

scholarly journals Present-day and future Greenland Ice Sheet precipitation frequency from CloudSat observations and the Community Earth System Model

2020 ◽  
Vol 14 (7) ◽  
pp. 2253-2265
Author(s):  
Jan T. M. Lenaerts ◽  
M. Drew Camron ◽  
Christopher R. Wyburn-Powell ◽  
Jennifer E. Kay
Keyword(s):  
Climate Models ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Precipitation Frequency ◽  
Worst Case ◽  
Rainfall Frequency ◽  
Community Earth System Model

Abstract. The dominant mass input component of the Greenland Ice Sheet (GrIS) is precipitation, whose amounts and phase are poorly constrained by observations. Here we use spaceborne radar observations from CloudSat to map the precipitation frequency and phase on the GrIS, and we use those observations, in combination with a satellite simulator to enable direct comparison between observations and model, to evaluate present-day precipitation frequency in the Community Earth System Model (CESM). The observations show that substantial variability of snowfall frequency over the GrIS exists, that snowfall occurs throughout the year, and that snowfall frequency peaks in spring and fall. Rainfall is rare over the GrIS and only occurs in regions under 2000 m elevation and in the peak summer season. Although CESM overestimates the rainfall frequency, it reproduces the spatial and seasonal variability of precipitation frequency reasonably well. Driven by the high-emission, worst-case Representative Concentration Pathway (RCP) 8.5 scenario, CESM indicates that rainfall frequency will increase considerably across the GrIS, and will occur at higher elevations, potentially exposing a much larger GrIS area to rain and associated meltwater refreezing, firn warming, and reduced storage capacity. This technique can be applied to evaluate precipitation frequency in other climate models and can aid in planning future satellite campaigns.

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