A persistent northern boundary of Indian Summer Monsoon precipitation over Central Asia during the Holocene

Abstract It has been suggested that summer rainfall over Central Asia (CA) is significantly correlated with the summer thermal distribution of the Tibetan Plateau (TP) and the Indian summer monsoon (ISM). However, relatively few studies have investigated their synergistic effects of different distribution. This study documents the significant correlations between precipitation in CA and the diabatic heating of TP and the ISM based on the results of statistical analysis and numerical simulation. Precipitation in CA is is dominated by two water vapor transport branches from the south which are related to the two primary modes of anomalous diabatic heating distribution related to the TP and ISM precipitation, that is, the “+-” dipole mode in the southeastern TP and the Indian subcontinent (IS), and the “+-+” tripole mode in the southeastern TP, the IS, and southern India. Both modes exhibit obvious mid-latitude Silk Road pattern (SRP) wave trains with cyclone anomalies over CA, but with different transient and stationary eddies over south Asia. The different locations of anomalous anticyclones over India govern two water vapor transport branches to CA, which are from the Arabian Sea and the Bay of Bengal. The water vapor flux climbs while being transported northward and can be transported to CA with the cooperation of cyclonic circulation. The convergent water vapor and ascending motion caused by cyclonic anomalies favor the precipitation in CA. Further analysis corroborates the negative South Indian Ocean Dipole (NSIOD) in February could affect the tripole mode distribution of TP heating and ISM via the atmospheric circulation, water vapor transport and an anomalous Hadley cell circulation. The results indicate a reliable prediction reference for precipitation in CA.

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Intraseasonal Teleconnection between the Summer Eurasian Wave Train and the Indian Monsoon*

Journal of Climate ◽

10.1175/jcli4221.1 ◽

2007 ◽

Vol 20 (15) ◽

pp. 3751-3767 ◽

Cited By ~ 164

Author(s):

Qinghua Ding ◽

Bin Wang

Keyword(s):

High Pressure ◽

Central Asia ◽

Summer Monsoon ◽

Indian Summer Monsoon ◽

Wave Train ◽

Intraseasonal Variability ◽

The Other ◽

Vertical Shear ◽

Central Asian ◽

Northeastern Atlantic

Abstract This study investigated the most recurrent coupled pattern of intraseasonal variability between midlatitude circulation and the Indian summer monsoon (ISM). The leading singular vector decomposition (SVD) pattern reveals a significant, coupled intraseasonal variation between a Rossby wave train across the Eurasian continent and the summer monsoon convection in northwestern India and Pakistan (hereafter referred to as NISM). The wave train associated with an active phase of NISM rainfall displays two high pressure anomalies, one located over central Asia and the other over northeastern Asia. They are accompanied by increased rainfall over the western Siberia plain and northern China and decreased rainfall over the eastern Mediterranean Sea and southern Japan. The circulation of the wave train shows a barotropic structure everywhere except the anomalous central Asian high, located to the northwest of India, where a heat-induced baroclinic circulation structure dominates. The time-lagged SVD analysis shows that the midlatitude wave train originates from the northeastern Atlantic and traverses Europe to central Asia. The wave train enhances the upper-level high pressure and reinforces the convection over the NISM region; meanwhile, it propagates farther toward East Asia along the waveguide provided by the westerly jet. After an outbreak of NISM convection, the anomalous central Asian high retreats westward. Composite analysis suggests a coupling between the central Asian high and the convective fluctuation in the NISM. The significance of the midlatitude–ISM interaction is also revealed by the close resemblance between the individual empirical orthogonal functions and the coupled (SVD) modes of the midlatitude circulation and the ISM. It is hypothesized that the eastward and southward propagation of the wave train originating from the northeastern Atlantic contributes to the intraseasonal variability in the NISM by changing the intensity of the monsoonal easterly vertical shear and its associated moist dynamic instability. On the other hand, the rainfall variations over the NISM reinforce the variations of the central Asian high through the “monsoon–desert” mechanism, thus reenergizing the downstream propagation of the wave train. The coupling between the Eurasian wave train and NISM may be instrumental for understanding their interaction and can provide a way to predict the intraseasonal variations of the Indian summer monsoon and East Asian summer monsoon.

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Holocene climate variability and Indian Summer Monsoon: An overview

The Holocene ◽

10.1177/0959683619895577 ◽

2020 ◽

Vol 30 (5) ◽

pp. 744-773 ◽

Cited By ~ 3

Author(s):

Upasana S Banerji ◽

P Arulbalaji ◽

D Padmalal

Keyword(s):

Indian Ocean ◽

Summer Monsoon ◽

Indian Summer Monsoon ◽

Indian Subcontinent ◽

Ice Age ◽

Interglacial Period ◽

Northern Indian Ocean ◽

The Holocene ◽

Indian Landmass ◽

Holocene Period

The response of the Indian Summer Monsoon (ISM) to forcing factors and climate variables has not yet fully explored, even though the ISM plays a pivotal role in the socio-economics of the Indian subcontinent and nearby areas. The ISM progression over Indian landmass is a manifestation of the Intertropical Convergence Zone (ITCZ) migration over the northern Indian Ocean and the Indian subcontinent. The recent anomalous behaviour of ISM raises the need for a better understanding of its spatio-temporal changes during the ongoing interglacial period termed as the Holocene period. The Holocene period has been classified further based on the globally observed abrupt climatic events at 8.2 and 4.2 ka. The 8.2 ka global cooling events have been recorded from northern Indian Ocean marine archives but limited records from the continental archives of the Indian landmass has demonstrated the 8.2 ka event. At the same time, the 4.2 ka dry climate has been endorsed by both marine as well as continental records and agrees with the global studies. During the ‘Little Ice Age’ (LIA), in the India subcontinent, wet conditions prevailed in the northern, central and western regions while a dry climate existed over the greater part of peninsular India. The present review offers an account of ISM signatures and possible mechanisms associated with the monsoon variability in the Indian subcontinent and the northern Indian Ocean during the Holocene period.

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Strengthened Indian Summer Monsoon Precipitation Susceptibility Linked to Dust‐Induced Ice Cloud Modification

Geophysical Research Letters ◽

10.1029/2018gl081634 ◽

2019 ◽

Vol 46 (14) ◽

pp. 8431-8441 ◽

Cited By ~ 2

Author(s):

Piyushkumar N. Patel ◽

Ritesh Gautam ◽

Takuro Michibata ◽

Harish Gadhavi

Keyword(s):

Summer Monsoon ◽

Indian Summer Monsoon ◽

Monsoon Precipitation ◽

Ice Cloud

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Tree-ring-inferred glacier mass balance variation in southeastern Tibetan Plateau and its linkage with climate variability

Climate of the Past ◽

10.5194/cp-9-2451-2013 ◽

2013 ◽

Vol 9 (6) ◽

pp. 2451-2458 ◽

Cited By ~ 6

Author(s):

J. Duan ◽

L. Wang ◽

L. Li ◽

Y. Sun

Keyword(s):

Tibetan Plateau ◽

Climate Variability ◽

Mass Balance ◽

Tree Ring ◽

Summer Monsoon ◽

Indian Summer Monsoon ◽

Dominant Factor ◽

Glacier Mass Balance ◽

Monsoon Precipitation

Abstract. A large number of glaciers in the Tibetan Plateau (TP) have experienced wastage in recent decades. And the wastage is different from region to region, even from glacier to glacier. A better understanding of long-term glacier variations and their linkage with climate variability requires extending the presently observed records. Here we present the first tree-ring-based glacier mass balance (MB) reconstruction in the TP, performed at the Hailuogou Glacier in southeastern TP during 1868–2007. The reconstructed MB is characterized mainly by ablation over the past 140 yr, and typical melting periods occurred in 1910s–1920s, 1930s–1960s, 1970s–1980s, and the last 20 yr. After the 1900s, only a few short periods (i.e., 1920s–1930s, the 1960s and the late 1980s) were characterized by accumulation. These variations can be validated by the terminus retreat velocity of Hailuogou Glacier and the ice-core accumulation rate in Guliya and respond well to regional and Northern Hemisphere temperature anomaly. In addition, the reconstructed MB is significantly and negatively correlated with August–September all-India monsoon rainfall (AIR) (r1871-2008 = −0.342, p < 0.0001). These results suggest that temperature variability is the dominant factor for the long-term MB variation at the Hailuogou Glacier. Indian summer monsoon precipitation does not affect the MB variation, yet the significant negative correlation between the MB and the AIR implies the positive effect of summer heating of the TP on Indian summer monsoon precipitation.

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