scholarly journals Arabian Sea upwelling over the last millennium and in the 21st century as simulated by Earth System Models

2016 ◽  
Author(s):  
Xing Yi ◽  
Eduardo Zorita
Keyword(s):  
21St Century ◽  
Arabian Sea ◽  
Greenhouse Gas Emission ◽  
Positive Trend ◽  
Last Millennium ◽  
Earth System ◽  
System Models ◽  
Sediment Records ◽  
Arabian Sea Upwelling ◽  
Earth System Models

Abstract. Arabian Sea upwelling in the past has been generally studied based on the sediment records. We apply two earth system models and analyse the simulated water vertical velocity to investigate the variations of the coastal upwelling in the western Arabian Sea over the last millennium. In addition, the same models, with slightly different configurations, are also employed to study the changes in upwelling in the 21st century under the strongest and the weakest greenhouse gas emission scenarios. With a negative long-term trend caused by the orbital forcing of the models, the upwelling over the last millennium is found to be closely correlated with the sea surface temperature, the Indian summer Monsoon and sediment records. The future upwelling under the Representative Concentration Pathway (RCP) 8.5 scenario reveals a negative trend, in contrast with the positive trend displayed by the upwelling favourable along-shore winds. Therefore, it is likely that other factors, like water stratification in the upper ocean layers caused by the stronger surface warming overrides the effect from the upwelling favourable wind. No significant trend is found for the upwelling under the RCP2.6 scenario, which is likely due to a compensation between the opposing effects of the increase in upwelling favourable winds and the stratification of the water column.

scholarly journals Evolution of the Arabian Sea Upwelling from the Last Millennium to the Future as Simulated by Earth System Models

Climate ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 72
Author(s):  
Xing Yi ◽  
Birgit Hünicke ◽  
Eduardo Zorita
Keyword(s):  
Arabian Sea ◽  
Positive Trend ◽  
Last Millennium ◽  
Earth System ◽  
System Models ◽  
Sediment Records ◽  
The Future ◽  
Water Stratification ◽  
Arabian Sea Upwelling ◽  
Earth System Models

Arabian Sea upwelling in the past has been generally studied based on the sediment records. We apply two earth system models and analyze the simulated water vertical velocity to investigate coastal upwelling in the western Arabian Sea over the last millennium. In addition, two models with slightly different configurations are also employed to study the upwelling in the 21st century under the strongest and the weakest greenhouse gas emission scenarios. With a negative long-term trend caused by the orbital forcing of the models, the upwelling over the last millennium is found to be closely correlated with the sea surface temperature, the Indian summer Monsoon and the sediment records. The future upwelling under the Representative Concentration Pathway (RCP) 8.5 scenario reveals a negative trend, in contrast with the positive trend displayed by the upwelling favorable along-shore winds. Therefore, it is likely that other factors, like water stratification in the upper ocean layers caused by the stronger surface warming, overrides the effect from the upwelling favorable wind. No significant trend is found for the upwelling under the RCP2.6 scenario, which is likely due to a compensation between the opposing effects of the increase in upwelling favorable winds and the water stratification.

scholarly journals Evolution of the Arabian Sea upwelling in the past centuries and in the future as simulated by Earth System Models

2018 ◽  
Author(s):  
Xing Yi ◽  
Birgit Hünicke ◽  
Eduardo Zorita
Keyword(s):  
Arabian Sea ◽  
Positive Trend ◽  
Last Millennium ◽  
Earth System ◽  
System Models ◽  
The Past ◽  
Sediment Records ◽  
The Future ◽  
Arabian Sea Upwelling ◽  
Earth System Models

Abstract. Arabian Sea upwelling in the past has been generally studied based on the sediment records. We apply two earth system models and analyse the simulated water vertical velocity to investigate the variations of the coastal upwelling in the western Arabian Sea over the last millennium. In addition, two models with slightly different configurations are also employed to study the changes in upwelling in the 21st century under the strongest and the weakest greenhouse gas emission scenarios. With a negative long-term trend caused by the orbital forcing of the models, the upwelling over the last millennium is found to be closely correlated with the sea surface temperature, the Indian summer Monsoon and sediment records. The future upwelling under the Representative Concentration Pathway (RCP) 8.5 scenario reveals a negative trend, in contrast with the positive trend displayed by the upwelling favourable along-shore winds. Therefore, it is likely that other factors, like water stratification in the upper ocean layers caused by the stronger surface warming overrides the effect from the upwelling favourable wind. No significant trend is found for the upwelling under the RCP2.6 scenario, which is likely due to a compensation between the opposing effects of the increase in upwelling favourable winds and the stratification of the water column.

scholarly journals Changes in interannual climate sensitivities of terrestrial carbon fluxes during the 21st century predicted by CMIP5 Earth System Models

2016 ◽  
Vol 121 (3) ◽  
pp. 903-918 ◽  
Author(s):  
Yongwen Liu ◽  
Tao Wang ◽  
Mengtian Huang ◽  
Yitong Yao ◽  
Philippe Ciais ◽  
...  
Keyword(s):  
21St Century ◽  
Carbon Fluxes ◽  
Earth System ◽  
Terrestrial Carbon ◽  
System Models ◽  
Earth System Models

scholarly journals Changes in soil organic carbon storage predicted by Earth system models during the 21st century

2013 ◽  
Vol 10 (12) ◽  
pp. 18969-19004 ◽  
Author(s):  
K. E. O. Todd-Brown ◽  
J. T. Randerson ◽  
F. Hopkins ◽  
V. Arora ◽  
T. Hajima ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
21St Century ◽  
Decomposition Rate ◽  
Radiative Forcing ◽  
Atmospheric Carbon Dioxide ◽  
Earth System ◽  
System Models ◽  
Organic Carbon Storage ◽  
Earth System Models

Abstract. Soil is currently thought to be a sink for carbon; however, the response of this sink to increasing levels of atmospheric carbon dioxide and climate change is uncertain. In this study, we analyzed soil organic carbon (SOC) changes from 11 Earth system models (ESMs) under the historical and high radiative forcing (RCP 8.5) scenarios between 1850 and 2100. We used a reduced complexity model based on temperature and moisture sensitivities to analyze the drivers of SOC losses. ESM estimates of SOC change over the 21st century (2090–2099 minus 1997–2006) ranged from a loss of 72 Pg C to a gain 253 Pg C with a multi-model mean gain of 63 Pg C. All ESMs showed cumulative increases in both NPP (15% to 59%) and decreases in SOC turnover times (15% to 28%) over the 21st century. Most of the model-to-model variation in SOC change was explained by initial SOC stocks combined with the relative changes in soil inputs and decomposition rates (R2 = 0.88, p<0.01). Between models, increases in decomposition rate were well explained by a combination of initial decomposition rate, ESM-specific Q10-factors, and changes in soil temperature (R2 = 0.80, p<0.01). All SOC changes depended on sustained increases in NPP with global change (primarily driven by increasing CO2) and conversion of additional plant inputs into SOC. Most ESMs omit potential constraints on SOC storage, such as priming effects, nutrient availability, mineral surface stabilization and aggregate formation. Future models that represent these constraints are likely to estimate smaller increases in SOC storage during the 21st century.

Causes of uncertainty in China's net primary production over the 21st century projected by the CMIP5 Earth system models

2015 ◽  
Vol 36 (5) ◽  
pp. 2323-2334 ◽  
Author(s):  
Tao Wang ◽  
Xin Lin ◽  
Yongwen Liu ◽  
Sarah Dantec-Nédélec ◽  
Catherine Ottlé
Keyword(s):  
Primary Production ◽  
21St Century ◽  
Net Primary Production ◽  
Earth System ◽  
System Models ◽  
Earth System Models

scholarly journals Spatially resolved evaluation of Earth system models with satellite column-averaged CO2

2021 ◽  
Author(s):  
Bettina K. Gier ◽  
Michael Buchwitz ◽  
Maximilian Reuter ◽  
Peter M. Cox ◽  
Pierre Friedlingstein ◽  
...  
Keyword(s):  
Satellite Data ◽  
Near Infrared ◽  
Early Period ◽  
Coupled Model ◽  
Negative Trend ◽  
Positive Trend ◽  
Earth System ◽  
Evaluation Tool ◽  
System Models ◽  
Earth System Models

&lt;p&gt;Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) showed large uncertainties in simulating atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentrations. We utilize the Earth System Model Evaluation Tool (ESMValTool) to evaluate emission-driven CMIP5 and CMIP6 simulations with satellite data of column-average CO&lt;sub&gt;2&lt;/sub&gt; mole fractions (XCO&lt;sub&gt;2&lt;/sub&gt;). XCO&lt;sub&gt;2&lt;/sub&gt; time series show a large spread among the model ensembles both in CMIP5 and CMIP6. Using the satellite observations as reference, the CMIP6 models have a &lt;span&gt;l&lt;/span&gt;ower bias in the the multi-model mean than CMIP5, but the spread remains large. The satellite data are a combined data product covering the period 2003&amp;#8211;2014 based on the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY)/Envisat (2003&amp;#8211;2012) and Thermal And Near infrared Sensor for carbon Observation Fourier transform spectrometer/Greenhouse Gases Observing Satellite (TANSO-FTS/GOSAT) (2009&amp;#8211;2014) instruments. While the combined satellite product shows a strong negative trend of decreasing &lt;span&gt;seasonal cycle amplitude (SCA)&lt;/span&gt; with increasing XCO&lt;sub&gt;2&lt;/sub&gt; in the northern midlatitudes, both CMIP ensembles instead show a non-significant positive trend in the multi-model mean. The negative trend is reproduced by the models when sampling them as the observations, attributing it to sampling characteristics. Applying a mask of the mean data coverage of each satellite to the models, the SCA is higher for the SCIAMACHY/Envisat mask than when using the TANSO-FTS/GOSAT mask. This induces an artificial negative trend when using observational sampling over the full period, as SCIAMACHY/Envisat covers the early period until 2012, with TANSO-FTS/GOSAT measurements starting in 2009. Overall, the CMIP6 ensemble shows better agreement with the satellite data than the CMIP5 ensemble in all considered quantities (mean XCO&lt;sub&gt;2&lt;/sub&gt;, growth rate, SCA and trend in SCA). This study shows that the availability of column-integral CO&lt;sub&gt;2&lt;/sub&gt; from satellite provides a promising new way to evaluate the performance of Earth system models on a global scale, complementing existing studies that are based on in situ measurements from single ground-based stations.&lt;/p&gt;

scholarly journals Spatially resolved evaluation of Earth system models with satellite column-averaged CO<sub>2</sub>

2020 ◽  
Vol 17 (23) ◽  
pp. 6115-6144
Author(s):  
Bettina K. Gier ◽  
Michael Buchwitz ◽  
Maximilian Reuter ◽  
Peter M. Cox ◽  
Pierre Friedlingstein ◽  
...  
Keyword(s):  
Satellite Data ◽  
Missing Values ◽  
Near Infrared ◽  
Early Period ◽  
Negative Trend ◽  
Positive Trend ◽  
Earth System ◽  
Evaluation Tool ◽  
System Models ◽  
Earth System Models

Abstract. Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) showed large uncertainties in simulating atmospheric CO2 concentrations. We utilize the Earth System Model Evaluation Tool (ESMValTool) to evaluate emission-driven CMIP5 and CMIP6 simulations with satellite data of column-average CO2 mole fractions (XCO2). XCO2 time series show a large spread among the model ensembles both in CMIP5 and CMIP6. Compared to the satellite observations, the models have a bias of +25 to −20 ppmv in CMIP5 and +20 to −15 ppmv in CMIP6, with the multi-model mean biases at +10 and +2 ppmv, respectively. The derived mean atmospheric XCO2 growth rate (GR) of 2.0 ppmv yr−1 is overestimated by 0.4 ppmv yr−1 in CMIP5 and 0.3 ppmv yr−1 in CMIP6 for the multi-model mean, with a good reproduction of the interannual variability. All models capture the expected increase of the seasonal cycle amplitude (SCA) with increasing latitude, but most models underestimate the SCA. Any SCA derived from data with missing values can only be considered an “effective” SCA, as the missing values could occur at the peaks or troughs. The satellite data are a combined data product covering the period 2003–2014 based on the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY)/Envisat (2003–2012) and Thermal And Near infrared Sensor for carbon Observation Fourier transform spectrometer/Greenhouse Gases Observing Satellite (TANSO-FTS/GOSAT) (2009–2014) instruments. While the combined satellite product shows a strong negative trend of decreasing effective SCA with increasing XCO2 in the northern midlatitudes, both CMIP ensembles instead show a non-significant positive trend in the multi-model mean. The negative trend is reproduced by the models when sampling them as the observations, attributing it to sampling characteristics. Applying a mask of the mean data coverage of each satellite to the models, the effective SCA is higher for the SCIAMACHY/Envisat mask than when using the TANSO-FTS/GOSAT mask. This induces an artificial negative trend when using observational sampling over the full period, as SCIAMACHY/Envisat covers the early period until 2012, with TANSO-FTS/GOSAT measurements starting in 2009. Overall, the CMIP6 ensemble shows better agreement with the satellite data than the CMIP5 ensemble in all considered quantities (XCO2, GR, SCA and trend in SCA). This study shows that the availability of column-integral CO2 from satellite provides a promising new way to evaluate the performance of Earth system models on a global scale, complementing existing studies that are based on in situ measurements from single ground-based stations.

scholarly journals Projected Shifts in 21st Century Sardine Distribution and Catch in the California Current

2021 ◽  
Vol 8 ◽  
Author(s):  
Jerome Fiechter ◽  
Mercedes Pozo Buil ◽  
Michael G. Jacox ◽  
Michael A. Alexander ◽  
Kenneth A. Rose
Keyword(s):  
High Resolution ◽  
21St Century ◽  
Global Climate ◽  
California Current ◽  
Climate Forcing ◽  
Earth System ◽  
System Models ◽  
Sardine Population ◽  
End To End ◽  
Earth System Models

Predicting changes in the abundance and distribution of small pelagic fish species in response to anthropogenic climate forcing is of paramount importance due to the ecological and socioeconomic importance of these species, especially in eastern boundary current upwelling regions. Coastal upwelling systems are notorious for the wide range of spatial (from local to basin) and temporal (from days to decades) scales influencing their physical and biogeochemical environments and, thus, forage fish habitat. Bridging those scales can be achieved by using high-resolution regional models that integrate global climate forcing downscaled from coarser resolution earth system models. Here, “end-to-end” projections for 21st century sardine population dynamics and catch in the California Current system (CCS) are generated by coupling three dynamically downscaled earth system model solutions to an individual-based fish model and an agent-based fishing fleet model. Simulated sardine population biomass during 2000–2100 exhibits primarily low-frequency (decadal) variability, and a progressive poleward shift driven by thermal habitat preference. The magnitude of poleward displacement varies noticeably under lower and higher warming conditions (500 and 800 km, respectively). Following the redistribution of the sardine population, catch is projected to increase by 50–70% in the northern CCS and decrease by 30–70% in the southern and central CCS. However, the late-century increase in sardine abundance (and hence, catch) in the northern CCS exhibits a large ensemble spread and is not statistically identical across the three downscaled projections. Overall, the results illustrate the benefit of using dynamical downscaling from multiple earth system models as input to high-resolution regional end-to-end (“physics to fish”) models for projecting population responses of higher trophic organisms to global climate change.

scholarly journals Continued increase in atmospheric CO<sub>2</sub> seasonal amplitude in the 21st century projected by the CMIP5 Earth system models

2014 ◽  
Vol 5 (2) ◽  
pp. 423-439 ◽  
Author(s):  
F. Zhao ◽  
N. Zeng
Keyword(s):  
Northern Hemisphere ◽  
21St Century ◽  
Seasonal Cycle ◽  
Co2 Concentration ◽  
Growing Season ◽  
Carbon Uptake ◽  
Earth System ◽  
System Models ◽  
Amplitude Increase ◽  
Earth System Models

Abstract. In the Northern Hemisphere, atmospheric CO2 concentration declines in spring and summer, and rises in fall and winter. Ground-based and aircraft-based observation records indicate that the amplitude of this seasonal cycle has increased in the past. Will this trend continue in the future? In this paper, we analyzed simulations for historical (1850–2005) and future (RCP8.5, 2006–2100) periods produced by 10 Earth system models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Our results present a model consensus that the increase of CO2 seasonal amplitude continues throughout the 21st century. Multi-model ensemble relative amplitude of detrended global mean CO2 seasonal cycle increases by 62 ± 19% in 2081–2090, compared to 1961–1970. This amplitude increase corresponds to a 68 ± 25% increase in net biosphere production (NBP). The results show that the increase of NBP amplitude mainly comes from enhanced ecosystem uptake during Northern Hemisphere growing season under future CO2 and temperature conditions. Separate analyses on net primary production (NPP) and respiration reveal that enhanced ecosystem carbon uptake contributes about 75% of the amplitude increase. Stimulated by higher CO2 concentration and high-latitude warming, enhanced NPP likely outcompetes increased respiration at higher temperature, resulting in a higher net uptake during the northern growing season. The zonal distribution and spatial pattern of NBP change suggest that regions north of 45° N dominate the amplitude increase. Models that simulate a stronger carbon uptake also tend to show a larger increase of NBP seasonal amplitude, and the cross-model correlation is significant (R=0.73, p< 0.05).

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