Volcanic-induced global monsoon drying modulated by diverse El Niño responses

<p>This study identifies a crucial cause of the large uncertainty in global precipitation response after volcanic eruptions. We find an important contribution of diverse El Ni&#241;o responses to the inter-simulation spread in the global monsoon drying responses to tropical eruptions. Most Coupled Model Intercomparison Project Phase 5 (CMIP5) models simulate El Ni&#241;o&#8211;like equatorial eastern Pacific warming at the year after eruptions but with different amplitudes, which drive a large spread of summer monsoon weakening and corresponding precipitation reduction. Two factors are further identified for the diverse El Ni&#241;o responses among CMIP5 model simulations. First, difference in imposed volcanic forcings induces systematic differences in the Maritime Continent precipitation drying and subsequent westerly winds over equatorial western Pacific, accounting for a large portion (29%) of inter-simulation spread in El Ni&#241;o intensities following eruptions. In addition, the internally generated warm water volume over the equatorial western Pacific in the pre-eruption month also contributes to the diverse El Ni&#241;o development, explaining about 14% of the total inter-simulation variance through the recharge oscillator mechanism. Our findings based on CMIP5 multi-model simulations confirm that reliable estimates of the volcanic forcing magnitude as well as the pre-eruption oceanic condition are required to obtain more reliable simulations or predictions of the hydrological responses to tropical eruptions.</p>

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Volcanic-induced global monsoon drying modulated by diverse El Niño responses

Science Advances ◽

10.1126/sciadv.aba1212 ◽

2020 ◽

Vol 6 (21) ◽

pp. eaba1212 ◽

Cited By ~ 1

Author(s):

Seungmok Paik ◽

Seung-Ki Min ◽

Carley E. Iles ◽

Erich M. Fischer ◽

Andrew P. Schurer

Keyword(s):

El Niño ◽

Climate Models ◽

El Nino ◽

Volcanic Eruptions ◽

Western Pacific ◽

Water Volume ◽

Global Monsoon ◽

Two Factors ◽

Solar Geoengineering ◽

Hydrologic Responses

There remains large intersimulation spread in the hydrologic responses to tropical volcanic eruptions, and identifying the sources of diverse responses has important implications for assessing the side effects of solar geoengineering and improving decadal predictions. Here, we show that the intersimulation spread in the global monsoon drying response strongly relates to diverse El Niño responses to tropical eruptions. Most of the coupled climate models simulate El Niño–like equatorial eastern Pacific warming after volcanic eruptions but with different amplitudes, which drive a large spread of summer monsoon weakening and corresponding precipitation reduction. Two factors are further identified for the diverse El Niño responses. Different volcanic forcings induce systematic differences in the Maritime Continent drying and subsequent westerly winds over equatorial western Pacific, varying El Niño intensity. The internally generated warm water volume over the equatorial western Pacific in the pre-eruption month also contributes to the diverse El Niño development.

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Intercomparison of temperature trends in IPCC CMIP5 simulations with observations, reanalyses and CMIP3 models

Geoscientific Model Development ◽

10.5194/gmd-6-1705-2013 ◽

2013 ◽

Vol 6 (5) ◽

pp. 1705-1714 ◽

Cited By ~ 11

Author(s):

J. Xu ◽

L. Zhao ◽

Keyword(s):

Coupled Model ◽

Temperature Trend ◽

The Arctic ◽

Cmip5 Models ◽

Model Intercomparison ◽

Model Simulations ◽

Temperature Trends ◽

Intercomparison Project ◽

Stratospheric Cooling ◽

The Tropics

Abstract. On the basis of the fifth Coupled Model Intercomparison Project (CMIP5) and the climate model simulations covering 1979 through 2005, the temperature trends and their uncertainties have been examined to note the similarities or differences compared to the radiosonde observations, reanalyses and the third Coupled Model Intercomparison Project (CMIP3) simulations. The results show noticeable discrepancies for the estimated temperature trends in the four data groups (radiosonde, reanalysis, CMIP3 and CMIP5), although similarities can be observed. Compared to the CMIP3 model simulations, the simulations in some of the CMIP5 models were improved. The CMIP5 models displayed a negative temperature trend in the stratosphere closer to the strong negative trend seen in the observations. However, the positive tropospheric trend in the tropics is overestimated by the CMIP5 models relative to CMIP3 models. While some of the models produce temperature trend patterns more highly correlated with the observed patterns in CMIP5, the other models (such as CCSM4 and IPSL_CM5A-LR) exhibit the reverse tendency. The CMIP5 temperature trend uncertainty was significantly reduced in most areas, especially in the Arctic and Antarctic stratosphere, compared to the CMIP3 simulations. Similar to the CMIP3, the CMIP5 simulations overestimated the tropospheric warming in the tropics and Southern Hemisphere and underestimated the stratospheric cooling. The crossover point where tropospheric warming changes into stratospheric cooling occurred near 100 hPa in the tropics, which is higher than in the radiosonde and reanalysis data. The result is likely related to the overestimation of convective activity over the tropical areas in both the CMIP3 and CMIP5 models. Generally, for the temperature trend estimates associated with the numerical models including the reanalyses and global climate models, the uncertainty in the stratosphere is much larger than that in the troposphere, and the uncertainty in the Antarctic is the largest. In addition, note that the reanalyses show the largest uncertainty in the lower tropical stratosphere, and the CMIP3 simulations show the largest uncertainty in both the south and north polar regions.

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Reconciling Theories for Human and Natural Attribution of Recent East Africa Drying

Journal of Climate ◽

10.1175/jcli-d-16-0558.1 ◽

2017 ◽

Vol 30 (6) ◽

pp. 1939-1957 ◽

Cited By ~ 15

Author(s):

Andrew Hoell ◽

Martin Hoerling ◽

Jon Eischeid ◽

Xiao-Wei Quan ◽

Brant Liebmann

Keyword(s):

Global Warming ◽

East Africa ◽

Decadal Variability ◽

Coupled Model ◽

Western Pacific ◽

East African ◽

Coupled Models ◽

Central Pacific ◽

Model Simulations ◽

African Rainfall

Abstract Two theories for observed East Africa drying trends during March–May 1979–2013 are reconciled. Both hypothesize that variations in tropical sea surface temperatures (SSTs) caused East Africa drying. The first invokes a mainly human cause resulting from sensitivity to secular warming of Indo–western Pacific SSTs. The second invokes a mainly natural cause resulting from sensitivity to a strong articulation of ENSO-like Pacific decadal variability involving warming of the western Pacific and cooling of the central Pacific. Historical atmospheric model simulations indicate that observed SST variations contributed significantly to the East Africa drying trend during March–May 1979–2013. By contrast, historical coupled model simulations suggest that external radiative forcing alone, including the ocean’s response to that forcing, did not contribute significantly to East Africa drying. Recognizing that the observed SST variations involved a commingling of natural and anthropogenic effects, this study diagnosed how East African rainfall sensitivity was conditionally dependent on the interplay of those factors. East African rainfall trends in historical coupled models were intercompared between two composites of ENSO-like decadal variability, one operating in the early twentieth century before appreciable global warming and the other in the early twenty-first century of strong global warming. The authors find the coaction of global warming with ENSO-like decadal variability can significantly enhance 35-yr East Africa drying trends relative to when the natural mode of ocean variability acts alone. A human-induced change via its interplay with an extreme articulation of natural variability may thus have been key to Africa drying; however, these results are speculative owing to differences among two independent suites of coupled model ensembles.

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Diverse Influences of ENSO on the East Asian–Western Pacific Winter Climate Tied to Different ENSO Properties in CMIP5 Models

Journal of Climate ◽

10.1175/jcli-d-14-00405.1 ◽

2015 ◽

Vol 28 (6) ◽

pp. 2187-2202 ◽

Cited By ~ 33

Author(s):

Hainan Gong ◽

Lin Wang ◽

Wen Chen ◽

Debashis Nath ◽

Gang Huang ◽

...

Keyword(s):

Rossby Wave ◽

Southern Oscillation ◽

East Asian ◽

Coupled Model ◽

Western Pacific ◽

Cmip5 Models ◽

Boreal Winter ◽

Winter Climate ◽

Climatic Responses ◽

Longitudinal Extension

Abstract The influence of El Niño–Southern Oscillation (ENSO) on the East Asian–western Pacific (EAWP) climate in boreal winter is investigated in the phase 5 of the Coupled Model Intercomparison Project (CMIP5) model results and then compared to that in the phase 3 (CMIP3) results. In particular, the role played by the differences among models in ENSO properties, including the amplitude and longitudinal extension of ENSO’s sea surface temperature (SST) pattern, is analyzed. Results show that an eastward shrinking of ENSO’s SST pattern leads to quite weak circulation and climatic responses over the EAWP regions in the models. On the contrary, a westward expansion of the SST pattern shifts the anomalous Walker circulation too far west. The resultant precipitation anomalies and lower-tropospheric atmospheric Rossby wave responses both extend unrealistically into the Indian Ocean, and the hemispheric asymmetry of the Rossby wave response is missing. All these features lead to unrealistic climatic impacts of ENSO over the EAWP regions. In contrast to the above two cases, a reasonable longitudinal extension of ENSO’s SST pattern corresponds to better ENSO teleconnections over the EAWP regions. Nevertheless, the atmospheric responses over the western Pacific are still located farther west than observed, implying a common bias of CMIP5 models. In this case, a larger amplitude of ENSO variability to some extent helps to reduce model biases and facilitate better climatic responses to ENSO in the EAWP regions. Compared with CMIP3 models, CMIP5 models perform better in representing ENSO’s impacts on the East Asian winter climate.

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Intercomparison of temperature trends in IPCC CMIP5 simulations with observations, reanalyses and CMIP3 models

Geoscientific Model Development Discussions ◽

10.5194/gmdd-5-3621-2012 ◽

2012 ◽

Vol 5 (4) ◽

pp. 3621-3645 ◽

Cited By ~ 1

Author(s):

J. Xu ◽

A. M. Powell

Keyword(s):

Coupled Model ◽

Temperature Trend ◽

The Arctic ◽

Cmip5 Models ◽

Model Intercomparison ◽

Model Simulations ◽

Temperature Trends ◽

Intercomparison Project ◽

Stratospheric Cooling ◽

The Tropics

Abstract. On the basis of the fifth Coupled Model Intercomparison Project (CMIP5) and the climate model simulations covering 1979 through 2005, the temperature trends and their uncertainties have been examined to note the similarities or differences compared to the radiosonde observations, reanalyses and the third Coupled Model Intercomparison Project (CMIP3) simulations. The results show noticeable discrepancies for the estimated temperature trends in the four data groups (Radiosonde, Reanalysis, CMIP3 and CMIP5) although similarities can be observed. Compared to the CMIP3 model simulations, the simulation in some of CMIP5 models were improved. The CMIP5 models displayed a negative temperature trend in the stratosphere closer to the strong negative trend seen in the observations. However, the positive tropospheric trend in the tropics is overestimated by the CMIP5 models relative to CMIP3 models. While some of the models produce temperature trend patterns more highly correlated with the observed patterns in CMIP5, the other models (such as CCSM4 and IPSL_CM5A-LR) exhibit the reverse tendency. The CMIP5 temperature trend uncertainty was significantly reduced in most areas, especially in the Arctic and Antarctic stratosphere, compared to the CMIP3 simulations. Similar to the CMIP3, the CMIP5 simulations overestimated the tropospheric warming in the tropics and Southern Hemisphere and underestimated the stratospheric cooling. The crossover point where tropospheric warming changes into stratospheric cooling occurred near 100 hPa in the tropics, which is higher than in the radiosonde and reanalysis data. The result is likely related to the overestimation of convective activity over the tropical areas in both the CMIP3 and CMIP5 models. Generally, for the temperature trend estimates associated with the numerical models including the reanalyses and global climate models, the uncertainty in the stratosphere is much larger than that in the troposphere, and the uncertainty in the Antarctic is the largest. In addition, note that the reanalyses show the largest uncertainty in the lower tropical stratosphere, and the CMIP3 simulations show the largest uncertainty in both the south and north polar regions.

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Biases in the albedo sensitivity to deforestation in CMIP5 models and their impacts on the associated historical Radiative Forcing

10.5194/esd-2019-94 ◽

2020 ◽

Cited By ~ 2

Author(s):

Quentin Lejeune ◽

Edouard L. Davin ◽

Grégory Duveiller ◽

Bas Crezee ◽

Ronny Meier ◽

...

Keyword(s):

Land Cover ◽

Radiative Forcing ◽

Climate Model ◽

Coupled Model ◽

Climate Impact ◽

Cmip5 Models ◽

Land Cover Changes ◽

Model Simulations ◽

Land Cover Types ◽

Conversion Rates

Abstract. Climate model biases in the representation of albedo variations between land cover types contribute to uncertainties on the climate impact of land cover changes since pre-industrial times, and especially on the associated Radiative Forcing. The recent publications of new observation-based datasets offer opportunities to investigate these biases and their impact on historical albedo changes in simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Conducting such an assessment is however complicated by the non-availability of albedo values for specific land cover types, as well as the limited number of simulations isolating the land use forcing in CMIP. In this study, we demonstrate the suitability of a new methodology to extract the albedo of trees and crops/grasses in standard climate model simulations. We then apply it to historical runs from 13 CMIP5 models and compare the obtained results to satellite-derived reference data. This allows us to identify substantial biases in the representation of the albedo of trees, crops/grasses, and the albedo change due to the transition between these two land cover types in the analysed models. Additionally, we reconstruct the local albedo changes induced by historical conversions between trees and crops/grasses for 15 CMIP5 models. This allows us to derive estimates of the Radiative Forcing from land cover changes since pre-industrial times ranging between 0 and −0.22 W/m2, with a mean value of −0.07 W/m2. Constraining the albedo response to transitions between trees and crops/grasses from the models with satellite-derived data leads to an increase in this range, however after excluding two models with unrealistic conversion rates from trees to crops/grasses we obtain a revised model mean estimate of −0.11 W/m2 (with individual model results between −0.04 and −0.16 W/m2). These numbers are at the lower end of the range provided by the IPCC AR5 (−0.15 ± 0.10 W/m2). The approach described in this study can be applied on other model simulations, such as those from CMIP6, especially as a diagnostic enabling the reproduction of the model evaluation part has been included in the ESMValTool v2.0.

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The global precipitation response to volcanic eruptions in the CMIP5 models

Environmental Research Letters ◽

10.1088/1748-9326/9/10/104012 ◽

2014 ◽

Vol 9 (10) ◽

pp. 104012 ◽

Cited By ~ 54

Author(s):

Carley E Iles ◽

Gabriele C Hegerl

Keyword(s):

Volcanic Eruptions ◽

Cmip5 Models ◽

Precipitation Response ◽

Global Precipitation

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Biases in the albedo sensitivity to deforestation in CMIP5 models and their impacts on the associated historical radiative forcing

Earth System Dynamics ◽

10.5194/esd-11-1209-2020 ◽

2020 ◽

Vol 11 (4) ◽

pp. 1209-1232

Author(s):

Quentin Lejeune ◽

Edouard L. Davin ◽

Grégory Duveiller ◽

Bas Crezee ◽

Ronny Meier ◽

...

Keyword(s):

Land Cover ◽

Radiative Forcing ◽

Surface Albedo ◽

Climate Model ◽

Coupled Model ◽

Climate Impact ◽

Cmip5 Models ◽

Land Cover Changes ◽

Model Simulations ◽

Conversion Rates

Abstract. Climate model biases in the representation of albedo variations between land cover classes contribute to uncertainties on the climate impact of land cover changes since pre-industrial times, especially on the associated radiative forcing. Recent publications of new observation-based datasets offer opportunities to investigate these biases and their impact on historical surface albedo changes in simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Conducting such an assessment is, however, complicated by the non-availability of albedo values for specific land cover classes in CMIP and the limited number of simulations isolating the land use forcing. In this study, we demonstrate the suitability of a new methodology to extract the albedo of trees and crops–grasses in standard climate model simulations. We then apply it to historical runs from 17 CMIP5 models and compare the obtained results to satellite-derived reference data. This allows us to identify substantial biases in the representation of the albedo of trees and crops–grasses as well as the surface albedo change due to the transition between these two land cover classes in the analysed models. Additionally, we reconstruct the local surface albedo changes induced by historical conversions between trees and crops–grasses for 15 CMIP5 models. This allows us to derive estimates of the albedo-induced radiative forcing from land cover changes since pre-industrial times. We find a multi-model range from 0 to −0.17 W m−2, with a mean value of −0.07 W m−2. Constraining the surface albedo response to transitions between trees and crops–grasses from the models with satellite-derived data leads to a revised multi-model mean estimate of −0.09 W m−2 but an increase in the multi-model range. However, after excluding one model with unrealistic conversion rates from trees to crops–grasses the remaining individual model results vary between −0.03 and −0.11 W m−2. These numbers are at the lower end of the range provided by the IPCC AR5 (-0.15±0.10 W m−2). The approach described in this study can be applied to other model simulations, such as those from CMIP6, especially as the evaluation diagnostic described here has been included in the ESMValTool v2.0.

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Uncertainty and detectability of climate surface response to large volcanic eruptions

10.5194/acp-2016-173 ◽

2016 ◽

Author(s):

Fabian Wunderlich ◽

Daniel M. Mitchell

Keyword(s):

El Niño ◽

El Nino ◽

Temperature Response ◽

Coupled Model ◽

Volcanic Eruptions ◽

Shortwave Radiation ◽

Cmip5 Models ◽

Surface Cooling ◽

Positive Tendency ◽

Large Volcanic Eruptions

Abstract. In light of the range in presently available observational, reanalysis and model data, we revisit the surface climate response to large tropical volcanic eruptions from the end of the 19th century until present. We focus on the dynamical driven response of the North Atlantic Oscillation (NAO) and the radiative driven tropical temperature response. Using ten different reanalysis products and the Hadley Centre Sea Level Pressure observational dataset (HadSLP2) we confirm a positive tendency in the phase of the NAO during boreal winters following large volcanic eruptions, although conclude that it is not as clear cut as the current literature suggests. Especially during poorly observed periods where higher uncertainties produce a less robust signal. The phase of the NAO leads to a dynamically driven warm anomaly over Northern Europe. At the same time, there is a general cooling of the tropical surface temperatures due to the reduced incoming shortwave radiation. The magnitude of this cooling is uncertain and is hard to isolate using observational data alone (mainly due to the presence of El Niño). Therefore we use regression-based detection and attribution techniques to investigate the volcanic temperature signal with eight Coupled Model Inter-comparison Project phase 5 (CMIP5) models. In all models the volcanic signal can be detected but a general overestimation of the surface cooling is found. The enhanced surface cooling in models is likely driven, in part, by an over absorption of SW radiation in the lower stratosphere, but aliasing with El Niño events is also an issue and further process based studies are necessary to confirm these.

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