Spatial-temporal responses of Arctic amplification to carbon-concentration and carbon-climate feedbacks in CMIP6 simulations
(2023) In Student thesis series INES NGEM01 20231Dept of Physical Geography and Ecosystem Science
- Abstract
- The Arctic is experiencing a phenomenon called Arctic amplification (AA) which has caused a rapid warming rate two to three times greater than that of the Northern Hemisphere (NH) or global in both observed and modelled data over the past few decades. Previous studies focused mostly on temperature and sea ice albedo feedbacks; however, the impacts of biosphere feedbacks especially from carbon cycle feedbacks, are largely underexplored. In this study, different coupling experiments simulated by 11 Earth system models (ESMs) were used to assess the spatial and temporal changes of AA, as well as to identify potential causes related to carbon cycle feedbacks.
The results show that in the model experiments considering two carbon cycle... (More) - The Arctic is experiencing a phenomenon called Arctic amplification (AA) which has caused a rapid warming rate two to three times greater than that of the Northern Hemisphere (NH) or global in both observed and modelled data over the past few decades. Previous studies focused mostly on temperature and sea ice albedo feedbacks; however, the impacts of biosphere feedbacks especially from carbon cycle feedbacks, are largely underexplored. In this study, different coupling experiments simulated by 11 Earth system models (ESMs) were used to assess the spatial and temporal changes of AA, as well as to identify potential causes related to carbon cycle feedbacks.
The results show that in the model experiments considering two carbon cycle feedbacks (carbon-climate, related to the responses to the changes of temperature, and carbon-concentration, caused by the changes of atmospheric CO2 concentration) and considering only carbon-climate feedback, the speed of warming in the Arctic is ~2 times faster than the NH over the whole simulated period. AA is notable in the Arctic Ocean and maintains a consistent spatial pattern over the experiment period under aforementioned experiments. By contrast, the experiment only considering carbon-concentration feedback shows stronger but fluctuating AA index, ranging from 1 to 4 (the mean value is 2.5), and its primary manifestation was found in the Barents Sea. The interaction between the two carbon cycle feedbacks intensified the increase in temperature and sea ice melting and mitigated the reduction of evapotranspiration (ET) caused by the response of plants to CO2 forcing (CO2 physiological effect). In addition, heat from decreased ET at lower latitudes may be transported to higher latitudes, accelerating sea ice melting, and thereby exacerbating AA.
While the CMIP6 models generally agree on the long-term temperature trends as well as the changes in sea ice area and ET, they exhibit greater uncertainties at high latitudes and in the experiment that quantifies the carbon-concentration feedback. This highlights the need to constrain CO2 physiological effects in ESMs to facilitate an accurate evaluation of AA and the effects of carbon cycle feedbacks. (Less) - Popular Abstract
- The modelled and field study has proved that the Arctic region is experiencing a phenomenon known as Arctic amplification (AA), characterized by a rapid warming rate that is two to three times higher than that of the Northern Hemisphere (NH) or global. In previous studies, the AA is mostly attributed to the physical process underlying temperature changes and sea ice changes, with little attention paid to the impact of ecosystem processes especially carbon cycle. In this study, 3 experiments from 11 Earth system models (ESMs) were used to investigate their spatial temporal pattern of AA, and the potential causes. These experiments were designed for quantifying the responses of biogeochemical process to changes in temperature... (More)
- The modelled and field study has proved that the Arctic region is experiencing a phenomenon known as Arctic amplification (AA), characterized by a rapid warming rate that is two to three times higher than that of the Northern Hemisphere (NH) or global. In previous studies, the AA is mostly attributed to the physical process underlying temperature changes and sea ice changes, with little attention paid to the impact of ecosystem processes especially carbon cycle. In this study, 3 experiments from 11 Earth system models (ESMs) were used to investigate their spatial temporal pattern of AA, and the potential causes. These experiments were designed for quantifying the responses of biogeochemical process to changes in temperature (carbon-climate) and atmospheric CO2 (carbon-concentration).
The results of this study found that the speed of Arctic warming is ~2 times faster than the NH when considering the response of biogeochemical process to temperature changes and considering to both temperature and atmospheric CO2 changes. The warming is concentrated in the Arctic Ocean, with land being slightly weaker. The spatial distribution remained unchanged throughout the entire period of experiment. By contrast, in the experiment only considering the response of biogeochemical process to changes in atmospheric CO2, the range of warming rate is larger but fluctuating (1~4, the mean value is 2.5), and the warming is mainly focused on the Barents Sea. The study also found that the interaction between these two responses increased temperature and melting of sea ice. However, the reduction in evapotranspiration was lessoned. The excessive heat resulting from reduced evapotranspiration can be transported to higher latitudes, leading to further melting of sea ice and enhancing the effects of AA.
The study showed that while the CMIP6 models agree on temperature trends and changes in sea ice and evapotranspiration, they have more uncertainties at high latitudes and in measuring the response to atmospheric CO2 changes. This indicates that there is a need to improve models by accurately evaluating the effects of CO2 and biogeochemical response in order to better understand Arctic warming. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9128023
- author
- Xie, Zhicong LU
- supervisor
-
- Wenxin Zhang LU
- Hans Chen LU
- organization
- course
- NGEM01 20231
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Geography, Physical Geography, Ecosystem Analysis, Arctic amplification, Carbon cycle feedbacks, CO2 physiological effect, CMIP6
- publication/series
- Student thesis series INES
- report number
- 609
- language
- English
- id
- 9128023
- date added to LUP
- 2023-06-21 09:33:26
- date last changed
- 2023-11-24 15:47:59
@misc{9128023,
abstract = {{The Arctic is experiencing a phenomenon called Arctic amplification (AA) which has caused a rapid warming rate two to three times greater than that of the Northern Hemisphere (NH) or global in both observed and modelled data over the past few decades. Previous studies focused mostly on temperature and sea ice albedo feedbacks; however, the impacts of biosphere feedbacks especially from carbon cycle feedbacks, are largely underexplored. In this study, different coupling experiments simulated by 11 Earth system models (ESMs) were used to assess the spatial and temporal changes of AA, as well as to identify potential causes related to carbon cycle feedbacks.
The results show that in the model experiments considering two carbon cycle feedbacks (carbon-climate, related to the responses to the changes of temperature, and carbon-concentration, caused by the changes of atmospheric CO2 concentration) and considering only carbon-climate feedback, the speed of warming in the Arctic is ~2 times faster than the NH over the whole simulated period. AA is notable in the Arctic Ocean and maintains a consistent spatial pattern over the experiment period under aforementioned experiments. By contrast, the experiment only considering carbon-concentration feedback shows stronger but fluctuating AA index, ranging from 1 to 4 (the mean value is 2.5), and its primary manifestation was found in the Barents Sea. The interaction between the two carbon cycle feedbacks intensified the increase in temperature and sea ice melting and mitigated the reduction of evapotranspiration (ET) caused by the response of plants to CO2 forcing (CO2 physiological effect). In addition, heat from decreased ET at lower latitudes may be transported to higher latitudes, accelerating sea ice melting, and thereby exacerbating AA.
While the CMIP6 models generally agree on the long-term temperature trends as well as the changes in sea ice area and ET, they exhibit greater uncertainties at high latitudes and in the experiment that quantifies the carbon-concentration feedback. This highlights the need to constrain CO2 physiological effects in ESMs to facilitate an accurate evaluation of AA and the effects of carbon cycle feedbacks.}},
author = {{Xie, Zhicong}},
language = {{eng}},
note = {{Student Paper}},
series = {{Student thesis series INES}},
title = {{Spatial-temporal responses of Arctic amplification to carbon-concentration and carbon-climate feedbacks in CMIP6 simulations}},
year = {{2023}},
}