Abstract
Water vapour in the atmosphere is the source of a major climate feedback mechanism and potential increases in the availability of water vapour could have important consequences for mean and extreme precipitation. Future precipitation changes further depend on how the hydrological cycle responds to different drivers of climate change, such as greenhouse gases and aerosols. Currently, neither the total anthropogenic influence on the hydrological cycle nor that from individual drivers is constrained sufficiently to make solid projections. We investigate how integrated water vapour (IWV) responds to different drivers of climate change. Results from 11 global climate models have been used, based on simulations where <span classCombining double low line"inline-formula">CO2</span>, methane, solar irradiance, black carbon (BC), and sulfate have been perturbed separately. While the global-mean IWV is usually assumed to increase by <span classCombining double low line"inline-formula">ĝ1/47</span>% per kelvin of surface temperature change, we find that the feedback response of IWV differs somewhat between drivers. Fast responses, which include the initial radiative effect and rapid adjustments to an external forcing, amplify these differences. The resulting net changes in IWV range from <span classCombining double low line"inline-formula">6.4±0.9</span>%K<span classCombining double low line"inline-formula">-1</span> for sulfate to <span classCombining double low line"inline-formula">9.8±2</span>%K<span classCombining double low line"inline-formula">-1</span> for BC. We further calculate the relationship between global changes in IWV and precipitation, which can be characterized by quantifying changes in atmospheric water vapour lifetime. Global climate models simulate a substantial increase in the lifetime, from <span classCombining double low line"inline-formula">8.2±0.5</span> to <span classCombining double low line"inline-formula">9.9±0.7</span>d between 1986-2005 and 2081-2100 under a high-emission scenario, and we discuss to what extent the water vapour lifetime provides additional information compared to analysis of IWV and precipitation separately. We conclude that<span idCombining double low line"page12888"/> water vapour lifetime changes are an important indicator of changes in precipitation patterns and that BC is particularly efficient in prolonging the mean time, and therefore likely the distance, between evaporation and precipitation.
| Original language | English |
|---|---|
| Pages (from-to) | 12887-12899 |
| Number of pages | 13 |
| Journal | Atmospheric Chemistry and Physics |
| Volume | 19 |
| Issue number | 20 |
| DOIs | |
| Publication status | Published - Oct 17 2019 |
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All Science Journal Classification (ASJC) codes
- Atmospheric Science
Cite this
Water vapour adjustments and responses differ between climate drivers. / Hodnebrog, Oivind; Myhre, Gunnar; Samset, Bjorn H.; Alterskjær, Kari; Andrews, Timothy; Boucher, Olivier; Faluvegi, Gregory; Fläschner, Dagmar; M Forster, Piers; Kasoar, Matthew; Kirkeväg, Alf; Lamarque, Jean Francois; Olivié, Dirk; B Richardson, Thomas; Shawki, Dilshad; Shindell, Drew; P Shine, Keith; Stier, Philip; Takemura, Toshihiko; Voulgarakis, Apostolos; Watson-Parris, Duncan.
In: Atmospheric Chemistry and Physics, Vol. 19, No. 20, 17.10.2019, p. 12887-12899.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Water vapour adjustments and responses differ between climate drivers
AU - Hodnebrog, Oivind
AU - Myhre, Gunnar
AU - Samset, Bjorn H.
AU - Alterskjær, Kari
AU - Andrews, Timothy
AU - Boucher, Olivier
AU - Faluvegi, Gregory
AU - Fläschner, Dagmar
AU - M Forster, Piers
AU - Kasoar, Matthew
AU - Kirkeväg, Alf
AU - Lamarque, Jean Francois
AU - Olivié, Dirk
AU - B Richardson, Thomas
AU - Shawki, Dilshad
AU - Shindell, Drew
AU - P Shine, Keith
AU - Stier, Philip
AU - Takemura, Toshihiko
AU - Voulgarakis, Apostolos
AU - Watson-Parris, Duncan
PY - 2019/10/17
Y1 - 2019/10/17
N2 - Water vapour in the atmosphere is the source of a major climate feedback mechanism and potential increases in the availability of water vapour could have important consequences for mean and extreme precipitation. Future precipitation changes further depend on how the hydrological cycle responds to different drivers of climate change, such as greenhouse gases and aerosols. Currently, neither the total anthropogenic influence on the hydrological cycle nor that from individual drivers is constrained sufficiently to make solid projections. We investigate how integrated water vapour (IWV) responds to different drivers of climate change. Results from 11 global climate models have been used, based on simulations where CO2, methane, solar irradiance, black carbon (BC), and sulfate have been perturbed separately. While the global-mean IWV is usually assumed to increase by ĝ1/47% per kelvin of surface temperature change, we find that the feedback response of IWV differs somewhat between drivers. Fast responses, which include the initial radiative effect and rapid adjustments to an external forcing, amplify these differences. The resulting net changes in IWV range from 6.4±0.9%K-1 for sulfate to 9.8±2%K-1 for BC. We further calculate the relationship between global changes in IWV and precipitation, which can be characterized by quantifying changes in atmospheric water vapour lifetime. Global climate models simulate a substantial increase in the lifetime, from 8.2±0.5 to 9.9±0.7d between 1986-2005 and 2081-2100 under a high-emission scenario, and we discuss to what extent the water vapour lifetime provides additional information compared to analysis of IWV and precipitation separately. We conclude that water vapour lifetime changes are an important indicator of changes in precipitation patterns and that BC is particularly efficient in prolonging the mean time, and therefore likely the distance, between evaporation and precipitation.
AB - Water vapour in the atmosphere is the source of a major climate feedback mechanism and potential increases in the availability of water vapour could have important consequences for mean and extreme precipitation. Future precipitation changes further depend on how the hydrological cycle responds to different drivers of climate change, such as greenhouse gases and aerosols. Currently, neither the total anthropogenic influence on the hydrological cycle nor that from individual drivers is constrained sufficiently to make solid projections. We investigate how integrated water vapour (IWV) responds to different drivers of climate change. Results from 11 global climate models have been used, based on simulations where CO2, methane, solar irradiance, black carbon (BC), and sulfate have been perturbed separately. While the global-mean IWV is usually assumed to increase by ĝ1/47% per kelvin of surface temperature change, we find that the feedback response of IWV differs somewhat between drivers. Fast responses, which include the initial radiative effect and rapid adjustments to an external forcing, amplify these differences. The resulting net changes in IWV range from 6.4±0.9%K-1 for sulfate to 9.8±2%K-1 for BC. We further calculate the relationship between global changes in IWV and precipitation, which can be characterized by quantifying changes in atmospheric water vapour lifetime. Global climate models simulate a substantial increase in the lifetime, from 8.2±0.5 to 9.9±0.7d between 1986-2005 and 2081-2100 under a high-emission scenario, and we discuss to what extent the water vapour lifetime provides additional information compared to analysis of IWV and precipitation separately. We conclude that water vapour lifetime changes are an important indicator of changes in precipitation patterns and that BC is particularly efficient in prolonging the mean time, and therefore likely the distance, between evaporation and precipitation.
UR - http://www.scopus.com/inward/record.url?scp=85073709505&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85073709505&partnerID=8YFLogxK
U2 - 10.5194/acp-19-12887-2019
DO - 10.5194/acp-19-12887-2019
M3 - Article
AN - SCOPUS:85073709505
VL - 19
SP - 12887
EP - 12899
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
SN - 1680-7316
IS - 20
ER -