Northwestward shift of the northern boundary of the East Asian summer monsoon during the mid-Holocene caused by orbital forcing and vegetation feedbacks
(2021) In Quaternary Science Reviews 268.- Abstract
The East Asian summer monsoon (EASM) northern boundary is a critical indicator of EASM variations. Movement of the boundary is modulated by both the EASM and the mid-latitude westerlies. Here, we use the Earth system model EC-Earth to quantify the contribution of orbital forcing and vegetation feedbacks in modulating the movement of EASM northern boundary. The results show that the simulated EASM northern boundary during the mid-Holocene shifts by a maximum of ∼213 km northwestward due to orbital forcing. When the model was coupled with a dynamic vegetation module LPJ-GUESS, the northern boundary shifts further northwestward by a maximum of ∼90 km, indicating the importance of vegetation feedbacks. During the mid-Holocene, temperature... (More)
The East Asian summer monsoon (EASM) northern boundary is a critical indicator of EASM variations. Movement of the boundary is modulated by both the EASM and the mid-latitude westerlies. Here, we use the Earth system model EC-Earth to quantify the contribution of orbital forcing and vegetation feedbacks in modulating the movement of EASM northern boundary. The results show that the simulated EASM northern boundary during the mid-Holocene shifts by a maximum of ∼213 km northwestward due to orbital forcing. When the model was coupled with a dynamic vegetation module LPJ-GUESS, the northern boundary shifts further northwestward by a maximum of ∼90 km, indicating the importance of vegetation feedbacks. During the mid-Holocene, temperature increased in the mid-latitude during the boreal summer due to insolation, leading to increased meridional air temperature differences (MTDs) over the region north of 45°N and to decreased MTDs to the south. The changes in the temperature gradient weakened the East Asian Westly Jet (EAWJ) and displaced it northward, resulting in an earlier transition of the Meiyu stage and a more prolonged Midsummer stage. The northward movement of EAWJ, combined with the enhanced southerly moisture flow from South China, caused more precipitation in North China and eventually to a northwestward shift of the northern boundary of the EASM. The coupled dynamic vegetation module LPJ-GUESS simulated more grassland and less forest over Northeast Asia during the mid-Holocene. The increased surface albedo tended to lower the temperature in the region, and further enhanced the MTDs in mid-latitude East Asia, leading to the further northward movement of the EAWJ and a northwestward shift of the EASM northern boundary. Although the simulated vegetation distribution in several regions may be not accurate, it reflects the substantial contribution of climate-vegetation interaction on modulating the EASM.
(Less)
- author
- Chen, Jie ; Zhang, Qiong ; Huang, Wei ; Lu, Zhengyao LU ; Zhang, Zhiping and Chen, Fahu
- organization
- publishing date
- 2021-09-15
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- East Asian summer monsoon northern boundary, East Asian westerly jet, Mid-Holocene, Orbital forcing, Vegetation feedbacks
- in
- Quaternary Science Reviews
- volume
- 268
- article number
- 107136
- publisher
- Elsevier
- external identifiers
-
- scopus:85112752748
- ISSN
- 0277-3791
- DOI
- 10.1016/j.quascirev.2021.107136
- language
- English
- LU publication?
- yes
- id
- 7bea9e9a-ae28-46eb-8647-8571ebf795e3
- date added to LUP
- 2021-09-08 13:42:49
- date last changed
- 2022-04-27 03:47:50
@article{7bea9e9a-ae28-46eb-8647-8571ebf795e3,
abstract = {{<p>The East Asian summer monsoon (EASM) northern boundary is a critical indicator of EASM variations. Movement of the boundary is modulated by both the EASM and the mid-latitude westerlies. Here, we use the Earth system model EC-Earth to quantify the contribution of orbital forcing and vegetation feedbacks in modulating the movement of EASM northern boundary. The results show that the simulated EASM northern boundary during the mid-Holocene shifts by a maximum of ∼213 km northwestward due to orbital forcing. When the model was coupled with a dynamic vegetation module LPJ-GUESS, the northern boundary shifts further northwestward by a maximum of ∼90 km, indicating the importance of vegetation feedbacks. During the mid-Holocene, temperature increased in the mid-latitude during the boreal summer due to insolation, leading to increased meridional air temperature differences (MTDs) over the region north of 45°N and to decreased MTDs to the south. The changes in the temperature gradient weakened the East Asian Westly Jet (EAWJ) and displaced it northward, resulting in an earlier transition of the Meiyu stage and a more prolonged Midsummer stage. The northward movement of EAWJ, combined with the enhanced southerly moisture flow from South China, caused more precipitation in North China and eventually to a northwestward shift of the northern boundary of the EASM. The coupled dynamic vegetation module LPJ-GUESS simulated more grassland and less forest over Northeast Asia during the mid-Holocene. The increased surface albedo tended to lower the temperature in the region, and further enhanced the MTDs in mid-latitude East Asia, leading to the further northward movement of the EAWJ and a northwestward shift of the EASM northern boundary. Although the simulated vegetation distribution in several regions may be not accurate, it reflects the substantial contribution of climate-vegetation interaction on modulating the EASM.</p>}},
author = {{Chen, Jie and Zhang, Qiong and Huang, Wei and Lu, Zhengyao and Zhang, Zhiping and Chen, Fahu}},
issn = {{0277-3791}},
keywords = {{East Asian summer monsoon northern boundary; East Asian westerly jet; Mid-Holocene; Orbital forcing; Vegetation feedbacks}},
language = {{eng}},
month = {{09}},
publisher = {{Elsevier}},
series = {{Quaternary Science Reviews}},
title = {{Northwestward shift of the northern boundary of the East Asian summer monsoon during the mid-Holocene caused by orbital forcing and vegetation feedbacks}},
url = {{http://dx.doi.org/10.1016/j.quascirev.2021.107136}},
doi = {{10.1016/j.quascirev.2021.107136}},
volume = {{268}},
year = {{2021}},
}