scholarly journals Indian summer monsoon variability and vegetation changes in the core monsoon zone, India, during the Holocene: A multiproxy study

The Holocene ◽  
2018 ◽  
Vol 29 (1) ◽  
pp. 110-119 ◽  
Author(s):  
Kamlesh Kumar ◽  
Shailesh Agrawal ◽  
Anupam Sharma ◽  
Shilpa Pandey
Keyword(s):  
Magnetic Susceptibility ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Central India ◽  
Vegetation Changes ◽  
Sudden Increase ◽  
The Holocene ◽  
The Core ◽  
Monsoon Variability ◽  
Three Stages

We present the results of sediment texture, δ13C values, TOC, TN, TOC/TN, and magnetic susceptibility (χlf) of a 1.54-m deep sediment trench recovered from the core monsoon zone (CMZ) of central India, to understand the paleovegetational history and Indian summer monsoon (ISM) variability during the Holocene. The lower δ13C values, TOC/TN ratio, and magnetic susceptibility (χlf) from ~11.4 to 9.5 ka BP suggest enhanced ISM intensity, which is well correlated with other available ISM records from both terrestrial as well as marine archives. A gradual stepwise expansion of C4 plants during ~8.1 and 6.3 ka BP, ~6.3 to 4.7 ka BP, and ~3.0 to 2.0 ka BP suggests a gradual weakening of ISM. The highest δ13C values (–18.7‰) recorded at ~2.0 ka BP indicate the dominance of C4 plants suggesting the weakest phase of ISM in the study area. The expansion of C3 plants from ~2.0 to 1.6 ka BP indicates a sudden increase in ISM intensity. Subsequently, three stages of enhanced ISM have been recorded between ~1.6 and 0.93 ka BP, ~0.76 and 0.42 ka BP, and ~0.28 ka BP to present.

Holocene Indian Summer Monsoon variability from the core monsoon zone of India, a pollen-based review

Grana ◽  
2019 ◽  
Vol 58 (5) ◽  
pp. 311-327
Author(s):  
Sheikh Nawaz Ali ◽  
Jyotsna Dubey ◽  
Mayank Shekhar ◽  
P. Morthekai
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
The Core ◽  
Monsoon Variability

Holocene climate variability and Indian Summer Monsoon: An overview

The Holocene ◽  
2020 ◽  
Vol 30 (5) ◽  
pp. 744-773 ◽  
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.

scholarly journals On the Detection of Onset and Activity of the Indian Summer Monsoon Using GPS RO Refractivity Profiles

2013 ◽  
Vol 141 (6) ◽  
pp. 2096-2106 ◽  
Author(s):  
V. V. M. Jagannadha Rao ◽  
M. Venkat Ratnam ◽  
Y. Durga Santhi ◽  
M. Roja Raman ◽  
M. Rajeevan ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Arabian Sea ◽  
Active Phase ◽  
Monsoon Onset ◽  
Tropospheric Temperature ◽  
Sudden Increase ◽  
Atmospheric Conditions ◽  
Good Relation ◽  
Onset Phase

Abstract Global positioning system (GPS) radio occultation (RO) data available during 2001–10 have been used to examine the variations in the refractivity during the onset of Indian summer monsoon (ISM) over the east Arabian Sea (5°–15°N, 65°–75°E). An enhancement of 5–10 N-units in the refractivity is observed around 4.8 km (~600 hPa) a few days (9.23 ± 3.6 days) before onset of the monsoon over Kerala, India. This is attributed to moisture buildup over the Arabian Sea during the monsoon onset phase. A sudden increase (1.5–2 K) in mean upper-tropospheric temperature at the time of onset and during the active phase of the monsoon is attributed to convective activity and the release of latent heat. On the day of monsoon onset over Kerala, an appreciable dip in the refractivity is observed that persisted for 1–3 days followed by an enhancement in refractivity with the active phase of the monsoon. An arbitrary value of 128 N-units difference between 4.8 km (~600 hPa) and 16 km (~100 hPa) coupled with a dip in refractivity on the day of monsoon arrival might give an indication of clear transition of atmospheric conditions and the detection of monsoon onset. Further, a good relation is also found between the activity of monsoon and variability in the refractivity.

Sign in / Sign up

Export Citation Format

Share Document