East Asian summer monsoon intensity inferred from iron oxide mineralogy in the Xiashu Loess in southern China

AbstractThis study revisits the long-term variabilities of East Asian summer monsoon (EASM) in 1958-2017 through examining diurnal cycles. We group monsoon days into four dynamic quadrants, with emphasis on the strong daily southerlies coupled with a large (Q1) or small (Q4) diurnal amplitude over Southeast China. The occurrence day of Q1 increases in June-July with the seasonal progress of EASM. It is most pronounced in 1960s-1970s and declines to the lowest in 1980s-1990s, while the Q4 occurrence increases notably from 1970s to 1990s; both groups return to normal in recent years. The interdecadal decrease (increase) of Q1 (Q4) occurrence corresponds well to the known weakening of EASM in the 20th century, and it also coincides with the rainfall anomalies over China shifting from “North flooding and South drought” to “North drought and South flooding” modes. The rainfall under Q1 (Q4) can account for ∼60% of the interannual variance of summer rainfall in northern (southern) China. The contrasting effects of Q1 and Q4 on rainfall are due to their remarkably different regulation on water vapor transports and convergence. The interannual/interdecadal variations of Q1 (Q4) occurrence determine the anomalous water vapor transports to northern (southern) China, in association with the various expansion of the western Pacific subtropical high. In particular, Q1 condition can greatly intensify nighttime moisture convergence, which is responsible for the long-term variations of rainfall in northern China. The results highlight that the diurnal cycles in monsoon flow act as a key regional process working with large-scale circulations to regulate the spatial distributions and long-term variabilities of EASM rainfall.

Download Full-text

A stalagmite δ18O record from Jinfo Cave, southern China reveals early-mid holocene variations in the East Asian Summer Monsoon

Quaternary International ◽

10.1016/j.quaint.2020.01.002 ◽

2020 ◽

Vol 537 ◽

pp. 61-68 ◽

Cited By ~ 2

Author(s):

Xunlin Yang ◽

Ruikai Liu ◽

Rui Zhang ◽

Baoyan Wang ◽

Riping Zhang ◽

...

Keyword(s):

Summer Monsoon ◽

East Asian Summer Monsoon ◽

Southern China ◽

Asian Summer Monsoon ◽

East Asian ◽

Asian Summer

Download Full-text

Evidence for wetter climate recorded in the Jingxian red clay section since approximately 840 ka ago and its relationship with the East Asian summer monsoon intensity

Quaternary International ◽

10.1016/j.quaint.2019.09.031 ◽

2019 ◽

Vol 532 ◽

pp. 57-65

Author(s):

Chunsheng Hu ◽

Wenhui Li ◽

Le Cao ◽

Guanglai Xu ◽

Yingqiu Zhou

Keyword(s):

Summer Monsoon ◽

East Asian Summer Monsoon ◽

Asian Summer Monsoon ◽

East Asian ◽

Red Clay ◽

Monsoon Intensity ◽

Asian Summer

Download Full-text

Modeling a strong East Asian summer monsoon in a globally cool Earth, the MIS-13 case

Climate of the Past Discussions ◽

10.5194/cpd-3-1261-2007 ◽

2007 ◽

Vol 3 (6) ◽

pp. 1261-1282 ◽

Cited By ~ 1

Author(s):

Q. Z. Yin ◽

A. Berger ◽

E. Driesschaert ◽

H. Goosse ◽

M. F. Loutre ◽

...

Keyword(s):

Tibetan Plateau ◽

Summer Monsoon ◽

East Asian Summer Monsoon ◽

Southern China ◽

Asian Summer Monsoon ◽

East Asian ◽

Ice Sheet ◽

The Tibetan Plateau ◽

Three Dimension ◽

Asian Summer

Abstract. Deep-sea and ice-core records show a significant reduced amplitude of the ice volume, temperature and greenhouse gases variations before Marine Isotope Stage (MIS) 11, about 400 000 years ago, with less warm (more glaciated) interglacials and less cold glacials. At the same time, the loess in northern China, the sedimentary core in the eastern Tibetan Plateau and the palaeosols in southern China all record an unusually warm and wet climate during MIS-13 (about 500 000 years ago), indicating an extremely strong East Asian summer monsoon. To understand this seeming paradox of a strong East Asian summer monsoon occurring during the cool MIS-13, a three-dimension Earth system Model of Intermediate complexity is used. Modeling results show that this very strong MIS-13 East Asian summer monsoon, identified from the precipitation, horizontal and vertical (omega) wind, and pressure (geopotential) fields, results from the astronomical and ice sheet forcings. North Hemisphere summer at perihelion both at 529 and 506 ka BP leads to an East Asian summer monsoon stronger than during the Pre-Industrial time. In addition, the ice sheets reinforce the East Asian summer monsoon through the propagation of a perturbation wave which is induced mainly by the Eurasian ice sheet and is influenced by the Tibetan Plateau.

Download Full-text