High-resolution isotopic simulations from ECHAM6-wiso nudged with ERA5 reanalyses: new products for isotopic model-data comparisons

Global Network ◽

Climate Data ◽

Isotopic Data ◽

Surrounding Water ◽

Weather Forecasts ◽

The Impact ◽

Water Isotope

For several decades, the comparison of climate data with results from water isotope-enabled Atmosphere General Circulation Models (AGCMs) significantly helped to a better understanding of the processes ruling the water cycle, which is one of the main drivers of the climate variability. For the modern period, the use of AGCMs nudged with weather forecasts reanalyses is a powerful way to obtain model outputs under the same weather conditions than at the sampling time of the observations.Here we present new isotopic simulations results from ECHAM6-wiso [1] nudged with the last reanalyses dataset from the European Centre for Medium-Range Weather Forecasts (ECMWF), ERA5 [2], at different spatial resolutions over the period 1979-2018. Model results are evaluated against isotopic data compilations, including GNIP (Global Network of Isotopes in Precipitation [3]), speleothems [4], ice cores datasets and water vapor measurements. To quantify the impact of these reanalyses on our simulations, we also performed nudged simulations with the previous model version ECHAM5-wiso [5] by using ERA5 data and its predecessor ERA-Interim [6].These new simulation products could be a useful contribution to the isotopic data community for the interpretation of their water isotope records and for the exploration of the mechanisms controlling the variability of the surrounding water isotopic composition.&#160;[1] Cauquoin et al., Clim. Past, 15, 1913&#8211;1937, https://doi.org/10.5194/cp-15-1913-2019, 2019.[2] Copernicus Climate Change Service (C3S), 2017.[3] IAEA, the GNIP Database, available at: https://nucleus.iaea.org/wiser.[4] Comas-Bru et al., Clim. Past, 15, 1557&#8211;1579, https://doi.org/10.5194/cp-15-1557-2019, 2019.[5] Werner et al., Geosci. Model Dev., 9, 647&#8211;670, https://doi.org/10.5194/gmd-9-647-2016, 2016.[6] Dee et al., Q. J. R. Meteorol. Soc., 137, 553&#8211;597, https://doi.org/10.1002/qj.828, 2011.

Impact of precipitation intermittency on NAO-temperature signals in proxy records

Climate of the Past ◽

10.5194/cp-9-871-2013 ◽

2013 ◽

Vol 9 (2) ◽

pp. 871-886 ◽

Cited By ~ 23

Author(s):

M. Casado ◽

P. Ortega ◽

V. Masson-Delmotte ◽

C. Risi ◽

D. Swingedouw ◽

...

Keyword(s):

General Circulation ◽

Ice Core ◽

Circulation Model ◽

Ice Cores ◽

Stable Isotope Ratio ◽

Global Network ◽

Temporal Correlations ◽

The North ◽

The North Atlantic Oscillation ◽

Abstract. In mid and high latitudes, the stable isotope ratio in precipitation is driven by changes in temperature, which control atmospheric distillation. This relationship forms the basis for many continental paleoclimatic reconstructions using direct (e.g. ice cores) or indirect (e.g. tree ring cellulose, speleothem calcite) archives of past precipitation. However, the archiving process is inherently biased by intermittency of precipitation. Here, we use two sets of atmospheric reanalyses (NCEP (National Centers for Environmental Prediction) and ERA-interim) to quantify this precipitation intermittency bias, by comparing seasonal (winter and summer) temperatures estimated with and without precipitation weighting. We show that this bias reaches up to 10 °C and has large interannual variability. We then assess the impact of precipitation intermittency on the strength and stability of temporal correlations between seasonal temperatures and the North Atlantic Oscillation (NAO). Precipitation weighting reduces the correlation between winter NAO and temperature in some areas (e.g. Québec, South-East USA, East Greenland, East Siberia, Mediterranean sector) but does not alter the main patterns of correlation. The correlations between NAO, δ18O in precipitation, temperature and precipitation weighted temperature are investigated using outputs of an atmospheric general circulation model enabled with stable isotopes and nudged using reanalyses (LMDZiso (Laboratoire de Météorologie Dynamique Zoom)). In winter, LMDZiso shows similar correlation values between the NAO and both the precipitation weighted temperature and δ18O in precipitation, thus suggesting limited impacts of moisture origin. Correlations of comparable magnitude are obtained for the available observational evidence (GNIP (Global Network of Isotopes in Precipitation) and Greenland ice core data). Our findings support the use of archives of past δ18O for NAO reconstructions.

Sensitivity of simulated oxygen isotopes in ice cores and speleothems to Last Glacial Maximum surface conditions

10.5194/egusphere-egu21-2305 ◽

2021 ◽

Author(s):

André Paul ◽

Alexandre Cauquoin ◽

Stefan Mulitza ◽

Thejna Tharammal ◽

Martin Werner

Keyword(s):

Last Glacial Maximum ◽

General Circulation ◽

Ice Cores ◽

Glacial Maximum ◽

Sea Surface ◽

Surface Conditions ◽

Last Glacial ◽

The Impact ◽

Mean Square Errors

In simulations of the climate during the Last Glacial Maximum (LGM), we employ two different isotope-enabled atmospheric general circulation models (NCAR iCAM3 and MPI ECHAM6-wiso) and use simulated (by coupled climate models) as well as reconstructed (from a new global climatology of the ocean surface duing the LGM, GLOMAP) surface conditions.The resulting atmospheric fields reflect the more pronounced structure and gradients in the reconstructions, for example, the precipitation is more depleted in oxygen-18 in the high latitudes and more enriched in low latitudes, especially in the tropical convective regions over the maritime continent in the equatorial Pacific and Indian Oceans and over the equatorial Atlantic Ocean. Furthermore, at the sites of ice cores and speleothems, the model-data fit improves in terms of the coefficients of determination and root-mean square errors.In additional sensitivity experiments, we also use the climatologies by Annan and Hargreaves (2013) and Tierney et al. (2020) and consider the impact of changes in reconstructed sea-ice extent and the global-mean sea-surface temperature.Our findings imply that the correct simulation or reconstruction of patterns and gradients in sea-surface conditions are crucial for a successful comparison to oxygen-isotope data from ice cores and speleothems.

Intra-annual variability of Antarctic precipitation from weather forecasts and high-resolution climate models

Annals of Glaciology ◽

10.3189/1998aog27-1-488-494 ◽

1998 ◽

Vol 27 ◽

pp. 488-494 ◽

Cited By ~ 11

Author(s):

Christophe Genthon ◽

Gerhard Krinner ◽

Michel Déqué

Keyword(s):

General Circulation ◽

Atmospheric Dynamics ◽

Small Scale ◽

Weather Forecasts ◽

Annual Variability ◽

Climate Simulations ◽

Antarctic Precipitation ◽

The Antarctic ◽

The intra-annual variability of Antarctic precipitation from the European Centre for Medium-range Weather Forecasts short-term meteorological forecasts and from climate simulations by the ARPÈGE and LMD-Zoom general circulation models is presented and discussed. The spatial resolution of forecasts and simulations is high over the Antarctic region, about 100 km, so that the impact of topography and small-scale atmospheric dynamics are better resolved than with more conventional model grids (about 300 km). All the models and forecasts show that the seasonality of precipitation is spatially very variable. Meridional coast-to-interior contrasts are marked, but equally strong variations are unexpectedly found where more homogeneity might be expected because of the homogeneity of the environment, e.g. on the high Antarctic plateau. Neither the forecasts nor the simulations confirm that precipitation is mostly maximum in winter over much of East Antarctica as suggested by scarce and potentially unreliable observations (Bromwich, 1988). Spring and fall maxima are quite frequent too, though summer maxima are rare. Daily precipitation statistics show more spatial pattern, with increasingly infrequent precipitation as distance from the coast toward the interior of the ice sheet increases Several aspects of the intra-annual variability of precipitation can be interpreted in terms of atmospheric dynamics, but at both daily and seasonal time-scales the different forecasts and climate simulations often locally and regionally disagree with each other. Discrimination between models and their ability to reproduce the dynamics of Antarctic hydrology, and progress on simulating such aspects of the Antarctic climate, is limited by the lack of reliable observation of precipitation variability.

Simulated impact of climate change on hydrology of multiple watersheds using traditional and recommended snowmelt runoff model methodology

Journal of Water and Climate Change ◽

10.2166/wcc.2016.097 ◽

2016 ◽

Vol 7 (4) ◽

pp. 665-682 ◽

Cited By ~ 1

Author(s):

Emile Elias ◽

Albert Rango ◽

Caitriana M. Steele ◽

John F. Mejia ◽

Ruben Baca ◽

...

Keyword(s):

Climate Change ◽

General Circulation ◽

Future Application ◽

Climate Data ◽

Snowmelt Runoff ◽

Change Analysis ◽

The Impact ◽

Runoff Model ◽

Impacts Of Climate Change

For more than two decades researchers have utilized the snowmelt runoff model (SRM) to test the impacts of climate change on streamflow of snow-fed systems. SRM developers recommend a parameter shift during simulations of future climate, but this is often omitted. Here we show the impact of this omission on model results. In this study, the hydrological effects of climate change are modeled over three sequential years with typical and recommended SRM methodology. We predict the impacts of climate change on water resources of five subbasins of an arid region. Climate data are downscaled to weather stations. Period change analysis gives temperature and precipitation changes for 55 general circulation models which are then subsampled to produce four future states per basin. Results indicate an increase in temperature between 3.0 and 6.2 °C and an 18% decrease to 26% increase in precipitation. Without modifications to the snow runoff coefficient (cS), mean results across all basins range from a reduction in total volume of 21% to an increase of 4%. Modifications to cS resulted in a 0–10% difference in simulated annual volume. Future application of SRM should include a parameter shift representing the changed climate.

Investigation of the response of water isotope records to the changes in orbital forcing with the isotope-enabled AGCM MIROC5-iso

10.5194/egusphere-egu2020-12420 ◽

2020 ◽

Author(s):

Kanon Kino ◽

Atsushi Okazaki ◽

Alexandre Cauquoin ◽

Kei Yosnimura

Keyword(s):

General Circulation ◽

Ice Cores ◽

Orbital Forcing ◽

Stable Water Isotopes ◽

Orbital Parameters ◽

Ice Coverage ◽

Milankovitch Theory ◽

Simulation Results ◽

Water Isotope

It has been well demonstrated that the variations of orbital parameters, known as Milankovitch theory, are one of the most important drivers of the Earth&#8217;s climate system. However, the way how the changes in orbital forcing imprint the glacial-interglacial cycles recorded in paleo-proxies, such as stable water isotopes in ice cores and speleothems, is still unclear. One way to progress in this question is to make direct comparisons of isotopic data with simulation results from isotope-enabled General Circulation Models (GCMs). We use here such a model, the Japanese atmospheric GCM MIROC5-iso[1], to perform simulations under different idealized paleoclimate conditions. For that, corresponding orbital parameters and greenhouse gases concentrations are set. Prescribed sea surface temperature and sea ice coverage boundary conditions from the fully coupled atmosphere-ocean GCM MIROC (MIROC-AOGCM) experiments are used, after an adaptation to the MIROC5-iso grid. Because earlier version of MIROC-AOGCM has been widely used for paleoclimate modeling purposes, the climatological mean states of MIROC5-iso under preindustrial conditions are evaluated against simulation results from different versions of MIROC-AOGCM (MIROC4m, which is a slightly updated version of MIROC3.2(med), and MIROC5 [2]). In addition, several interglacial periods and idealized paleoclimate experiments will be investigated and implications for the interpretation of water isotope response to the changes in orbital forcing will be discussed.[1] Okazaki and Yoshimura, J. Geophys. Res. Atmos, 124, 8972&#8211;8993, 2019.[2] Watanabe et al., J. Climate, 23, 6312&#8211;6335, 2010.

The impact of the climate change on discharge of Suir River Catchment (Ireland) under different climate scenarios

Natural Hazards and Earth System Science ◽

10.5194/nhess-6-387-2006 ◽

2006 ◽

Vol 6 (3) ◽

pp. 387-395 ◽

Cited By ~ 22

Author(s):

S. Wang ◽

R. McGrath ◽

T. Semmler ◽

C. Sweeney ◽

P. Nolan

Keyword(s):

Climate Change ◽

General Circulation ◽

Hydrological Model ◽

Climate Model ◽

Global Climate ◽

Regional Climate ◽

Climate Data ◽

River Catchment ◽

Abstract. The impact of climate change on local discharge variability is investigated in the Suir River Catchment which is located in the south-east of Ireland. In this paper, the Rossby Centre Regional Atmospheric Model (RCA) is driven by different global climate data sets. For the past climate (1961–2000), the model is driven by ECMWF reanalysis (ERA-40) data as well as by the output of the general circulation models (GCM's) ECHAM4 and ECHAM5. For the future simulation (2021–2060), the model is driven by two GCM scenarios: ECHAM4_B2 and ECHAM5_A2. To investigate the influence of changed future climate on local discharge, the precipitation of the model output is used as input for the HBV hydrological model. The calibration and validation results of our ERA-40 driven present day simulation shows that the HBV model can reproduce the discharge fairly well, except the extreme discharge is systematically underestimated by about 15–20%. Altogether the application of a high resolution regional climate model in connection with a conceptual hydrological model is capable of capturing the local variability of river discharge for present-day climate using boundary values assimilated with observations such as ERA-40 data. However, using GCM data to drive RCA and HBV suggests, that there is still large uncertainty connected with the GCM formulation: For present day climate the validation of the ECHAM4 and ECHAM5 driven simulations indicates stronger discharge compared to the observations due to overprediction of precipitation, especially for the ECHAM5 driven simulation in the summer season. Whereas according to the ECHAM4_B2 scenario the discharge generally increases – most pronounced in the wet winter time, there are only slight increases in winter and considerable decreases in summer according to the ECHAM5_A2 scenario. This also leads to a different behaviour in the evolution of return levels of extreme discharge events: Strong increases according to the ECHAM4_B2 scenario and slight decreases according to the ECHAM5_A2 scenario.

Effect of Climate Change on the Rainfall Trends: A case study of Pune, India

10.21203/rs.3.rs-1035885/v1 ◽

2021 ◽

Author(s):

Shalaka Shah ◽

Shreenivas Londhe

Keyword(s):

Climate Change ◽

General Circulation ◽

Climate Data ◽

Maximum Rainfall ◽

Accurate Model ◽

Impact Of Climate Change ◽

The Future ◽

Grid Points ◽

Abstract It is the need of the hour to predict the impact of climate change, especially rainfall on the future environmental conditions on local as well as global scales. The present work aims at studying the impact of climate change on the rainfall occurring over Pune, the eighth largest city in India. The General Circulation Models (GCMs) are predominantly used to obtain the climate data all over the globe, at various grid points, for past and future years. Rainfall values obtained from these grid points need to be downscaled to make them location specific. This study proposes a soft computing tool, Artificial Neural Network (ANN) for the purpose of downscaling. The rainfall data at 4 grid points surrounding Pune, was extracted from 5 different GCMs and given as input to ANN with observed rainfall as output, thus forming 5 models. For comparison, a pre-existing downscaling technique, Distribution based scaling (DBS) was used. The coefficient of correlation (r) showed that ANN was working better than DBS. The value of r for ANN was 0.73 for its least accurate model whereas DBS managed to reach 0.73 for its most accurate model. The future rainfall estimated with the help of the trained ANN models show an increase in mean rainfall over the Pune region by ∼2 – 15% and decrease in maximum rainfall by ∼40 – 65%. Peak prediction of rainfall simulated by ANN was not very accurate and hence there is still an opportunity for improvement which is the future scope of this study.

PLASIM-ENTSem: a spatio-temporal emulator of future climate change for impacts assessment

Geoscientific Model Development Discussions ◽

10.5194/gmdd-6-3349-2013 ◽

2013 ◽

Vol 6 (2) ◽

pp. 3349-3380 ◽

Cited By ~ 5

Author(s):

P. B. Holden ◽

N. R. Edwards ◽

P. H. Garthwaite ◽

K. Fraedrich ◽

F. Lunkeit ◽

...

Keyword(s):

Radiative Forcing ◽

General Circulation ◽

Coupled Model ◽

Co2 Concentration ◽

Climate Impacts ◽

Future Climate ◽

Future Climate Change ◽

Climate Data ◽

Spatio Temporal

Abstract. Many applications in the evaluation of climate impacts and environmental policy require detailed spatio-temporal projections of future climate. To capture feedbacks from impacted natural or socio-economic systems requires interactive two-way coupling but this is generally computationally infeasible with even moderately complex general circulation models (GCMs). Dimension reduction using emulation is one solution to this problem, demonstrated here with the GCM PLASIM-ENTS. Our approach generates temporally evolving spatial patterns of climate variables, considering multiple modes of variability in order to capture non-linear feedbacks. The emulator provides a 188-member ensemble of decadally and spatially resolved (~ 5° resolution) seasonal climate data in response to an arbitrary future CO2 concentration and radiative forcing scenario. We present the PLASIM-ENTS coupled model, the construction of its emulator from an ensemble of transient future simulations, an application of the emulator methodology to produce heating and cooling degree-day projections, and the validation of the results against empirical data and higher-complexity models. We also demonstrate the application to estimates of sea-level rise and associated uncertainty.

A Simplistic Approach for Assessing Hydroclimatic Vulnerability of Lakes and Reservoirs with Regulated Superficial Outflow

Hydrology ◽

10.3390/hydrology6030061 ◽

2019 ◽

Vol 6 (3) ◽

pp. 61 ◽

Cited By ~ 1

Author(s):

Kleoniki Demertzi ◽

Dimitris Papadimos ◽

Vassilis Aschonitis ◽

Dimitris Papamichail

Keyword(s):

Climate Change ◽

General Circulation ◽

Drainage Basin ◽

Management Strategies ◽

Climatic Conditions ◽

Modified Model ◽

Natural Lakes ◽

The Future ◽

This study proposes a simplistic model for assessing the hydroclimatic vulnerability of lakes/reservoirs (LRs) that preserve their steady-state conditions based on regulated superficial discharge (Qd) out of the LR drainage basin. The model is a modification of the Bracht-Flyr et al. method that was initially proposed for natural lakes in closed basins with no superficial discharge outside the basin (Qd = 0) and under water-limited environmental conditions {mean annual ratio of potential/reference evapotranspiration (ETo) versus rainfall (P) greater than 1}. In the proposed modified approach, an additional Qd function is included. The modified model is applied using as a case study the Oreastiada Lake, which is located inside the Kastoria basin in Greece. Six years of observed data of P, ETo, Qd, and lake topography were used to calibrate the modified model based on the current conditions. The calibrated model was also used to assess the future lake conditions based on the future climatic projections (mean conditions of 2061-2080) derived by 19 general circulation models (GCMs) for three cases of climate change (three cases of Representative Concentration Pathways: RCP2.6, RCP4.5 and RCP8.5). The modified method can be used as a diagnostic tool in water-limited environments for analyzing the superficial discharge changes of LRs under different climatic conditions and to support the design of new management strategies for mitigating the impact of climate change on (a) flooding conditions, (b) hydroelectric production, (c) irrigation/industrial/domestic use and (d) minimum ecological flows to downstream rivers.