Indian Monsoon Rainfall Variability and associated Climatic forcings in the last two millennia inferred by a Stalagmite from the peninsular India

2020 ◽  
Author(s):  
Naveen Gandhi ◽  
Phannindra Reddy A. ◽  
Raghavan Krishnan ◽  
Madhusudan G. Yadava
Keyword(s):  
Little Ice Age ◽  
Monsoon Rainfall ◽  
Southern Oscillation ◽  
Indian Subcontinent ◽  
Rainfall Variability ◽  
Warm Period ◽  
Ice Age ◽  
Peninsular India ◽  
Rainfall Variations ◽  
The Last Two Millennia

<p>We present high temporal (near-annually) resolved δ<sup>18</sup>O values from absolutely dated stalagmite record that represents the Indian Summer Monsoon (ISM) rainfall variations for the Indian subcontinent spanning from 207 AD to 2014 AD. This rainfall reconstruction shows ISM varaitions for four major global climatic periods viz., Roman Warm Period (RWP), Dark Ages Cold Period (DACP), Medieval Warm Period (MWP) and Little Ice Age (LIA). Cave records from different patrs of the sub-continent synchronously show enhanced precipitation during DACP. This wet period was forced by Solar-induced El-NiNo Southern Oscillation (ENSO) and Tibetan Plateau Temperature. Cliamtic conditions were wetter during LIA than that during MWP, as the former witnessed more number of wet monsoon years. However, MWP witnessed the strongest and the weakest monsoon years in the last two millennia. The direct influence of Soalr activity on the position of Inter Tropical Convergance zone (ITCZ) might have caused the observed ISM variability of MWP. Altough ISM shows largest variability during MWP, the overall monsoon state was moving towards wetter conditions, forced by ENSO. Solar induced forcings on ENSO influenced ISM during LIA. Our results suggest of non-stationary dynamical forcings over ISM during different periods in the last two millennia.</p>

scholarly journals Rainfall variability in southeast and west-central Africa during the Little Ice Age: do documentary and proxy records agree?

2021 ◽  
Vol 168 (1-2) ◽  
Author(s):  
Matthew J. Hannaford ◽  
Kristen K. Beck
Keyword(s):  
Southern Africa ◽  
Little Ice Age ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
Central Africa ◽  
Ice Age ◽  
West Central ◽  
Early Colonial ◽  
Instrumental Records

AbstractUnderstanding of long-term climatic change prior to instrumental records necessitates reconstructions from documentary and palaeoclimate archives. In southern Africa, documentary-derived chronologies of nineteenth century rainfall variability and palaeoclimate records have permitted new insights into rainfall variability over past centuries. Rarely considered, however, is the climatic information within early colonial documentary records that emerge from the late fifteenth century onwards. This paper examines evidence for (multi-)seasonal dry and wet events within these earlier written records (c. 1550–1830 CE) from southeast Africa (Mozambique) and west-central Africa (Angola) in conjunction with palaeoclimate records from multiple proxies. Specifically, it aims to understand whether these sources agree in their signals of rainfall variability over a 280-year period covering the ‘main phase’ Little Ice Age (LIA) in southern Africa. The two source types generally, but do not always, show agreement within the two regions. This appears to reflect both the nature of rainfall variability and the context behind documentary recording. Both source types indicate that southeast and west-central Africa were distinct regions of rainfall variability over seasonal and longer timescales during the LIA, with southeast Africa being generally drier and west-central Africa generally wetter. However, the documentary records reveal considerable variability within these mean state climatic conditions, with multi-year droughts a recurrent feature in both regions. An analysis of long-term rainfall links with the El Niño–Southern Oscillation (ENSO) in southeast Africa suggests a complex and possibly non-stationary relationship. Overall, early colonial records provide valuable information for constraining hydroclimate variability where palaeoclimate records remain sparse.

scholarly journals Climate Variability in Central Europe during the Last 2500 Years Reconstructed from Four High-Resolution Multi-Proxy Speleothem Records

Geosciences ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 166
Author(s):  
Sarah Waltgenbach ◽  
Dana F. C. Riechelmann ◽  
Christoph Spötl ◽  
Klaus P. Jochum ◽  
Jens Fohlmeister ◽  
...  
Keyword(s):  
Trace Elements ◽  
High Resolution ◽  
Climate Variability ◽  
Little Ice Age ◽  
Medieval Warm Period ◽  
Warm Period ◽  
Ice Age ◽  
Cold Period ◽  
Cave System ◽  
Dark Ages

The Late Holocene was characterized by several centennial-scale climate oscillations including the Roman Warm Period, the Dark Ages Cold Period, the Medieval Warm Period and the Little Ice Age. The detection and investigation of such climate anomalies requires paleoclimate archives with an accurate chronology as well as a high temporal resolution. Here, we present 230Th/U-dated high-resolution multi-proxy records (δ13C, δ18O and trace elements) for the last 2500 years of four speleothems from Bunker Cave and the Herbstlabyrinth cave system in Germany. The multi-proxy data of all four speleothems show evidence of two warm and two cold phases during the last 2500 years, which coincide with the Roman Warm Period and the Medieval Warm Period, as well as the Dark Ages Cold Period and the Little Ice Age, respectively. During these four cold and warm periods, the δ18O and δ13C records of all four speleothems and the Mg concentration of the speleothems Bu4 (Bunker Cave) and TV1 (Herbstlabyrinth cave system) show common features and are thus interpreted to be related to past climate variability. Comparison with other paleoclimate records suggests a strong influence of the North Atlantic Oscillation at the two caves sites, which is reflected by warm and humid conditions during the Roman Warm Period and the Medieval Warm Period, and cold and dry climate during the Dark Ages Cold period and the Little Ice Age. The Mg records of speleothems Bu1 (Bunker Cave) and NG01 (Herbstlabyrinth) as well as the inconsistent patterns of Sr, Ba and P suggests that the processes controlling the abundance of these trace elements are dominated by site-specific effects rather than being related to supra-regional climate variability.

scholarly journals Late Holocene environmental reconstructions and their implications on flood events, typhoon, and agricultural activities in NE Taiwan

2014 ◽  
Vol 10 (5) ◽  
pp. 1857-1869 ◽  
Author(s):  
L.-C. Wang ◽  
H. Behling ◽  
T.-Q. Lee ◽  
H.-C. Li ◽  
C.-A. Huh ◽  
...  
Keyword(s):  
Little Ice Age ◽  
Southern Oscillation ◽  
Phase 1 ◽  
Warm Pool ◽  
Ice Age ◽  
Agricultural Activities ◽  
Flood Events ◽  
Climate Conditions ◽  
Hydrological Conditions ◽  
Enso Events

Abstract. We reconstructed paleoenvironmental changes from a sediment archive of a lake in the floodplain of the Ilan Plain of NE Taiwan on multi-decadal resolution for the last ca. 1900 years. On the basis of pollen and diatom records, we evaluated past floods, typhoons, and agricultural activities in this area which are sensitive to the hydrological conditions in the western Pacific. Considering the high sedimentation rates with low microfossil preservations in our sedimentary record, multiple flood events were. identified during the period AD 100–1400. During the Little Ice Age phase 1 (LIA 1 – AD 1400–1620), the abundant occurrences of wetland plant (Cyperaceae) and diatom frustules imply less flood events under stable climate conditions in this period. Between AD 500 and 700 and the Little Ice Age phase 2 (LIA 2 – AD 1630–1850), the frequent typhoons were inferred by coarse sediments and planktonic diatoms, which represented more dynamical climate conditions than in the LIA 1. By comparing our results with the reconstructed changes in tropical hydrological conditions, we suggested that the local hydrology in NE Taiwan is strongly influenced by typhoon-triggered heavy rainfalls, which could be influenced by the variation of global temperature, the expansion of the Pacific warm pool, and the intensification of El Niño–Southern Oscillation (ENSO) events.

Sedimentary Dynamics Within the Sedimentary Filling of Sebkha Sidi El Hani, Eastern Tunisia

2022 ◽  
pp. 235-259
Author(s):  
Elhoucine Essefi ◽  
Soumaya Hajji ◽  
Mohamed Ali Tagorti
Keyword(s):  
Little Ice Age ◽  
Climatic Variability ◽  
Ice Age ◽  
Genetic Approach ◽  
Grey Scale ◽  
Stable Conditions ◽  
Salt Crust ◽  
Sedimentary Dynamics ◽  
Core Description ◽  
The Last Two Millennia

The Sidi El Hani Wetland is located in Eastern Tunisia. It represents the natural outlet of an endorheic system, Mechertate-Chrita-Sidi El Hani, and it collects all the eroded sediment from this watershed. In this chapter, the visual core description focused on three reference sandy bands and on the concept of grey scale variability in order to infer the clay pan response to the climatic variability and erosion during the last two millennia. First, in the uppermost part, the stage Warming Present (WP) stretches from (1954-80= 1874) to 1993, i.e. ≈120yrs; the establishment of modern conditions is characterized by stable conditions with high grey scale. Added to a small salt crust, this period is dominated by a clayey sedimentation. Second, the stage C4 is called the Late Little Ice Age (Late LIA); it stretches between the 80yrBP and 400yrBP, i.e., 320yrs. It is characterized by intermediate GS values; the clayey sedimentation makes up the twofold and threefold laminates. Based on laser granulometer, the genetic approach shows the interplay of eolian and hydraulic erosion.

scholarly journals The Response Time of Glaciers in Iceland to Changes in climate

1986 ◽  
Vol 8 ◽  
pp. 100-101 ◽  
Author(s):  
Tómas Jóhannesson
Keyword(s):  
Response Time ◽  
Time Variation ◽  
Little Ice Age ◽  
Wave Theory ◽  
Warm Period ◽  
Ice Age ◽  
Kinematic Wave

Records of the time variation of the terminus position of Icelandic glaciers since 1700 show clear responses to the little ice age and to the warm period from 1930 to 1960. These data are used to deduce limits for the response time of the glaciers. The response time turns out to be of the order of one or two hundred years. This is much shorter than the “long response time” of Nye’s kinematic wave theory.

scholarly journals Rainfall variations in central Indo-Pacific over the past 2,700 y

2019 ◽  
Vol 116 (35) ◽  
pp. 17201-17206 ◽  
Author(s):  
Liangcheng Tan ◽  
Chuan-Chou Shen ◽  
Ludvig Löwemark ◽  
Sakonvan Chawchai ◽  
R. Lawrence Edwards ◽  
...  
Keyword(s):  
Rainfall Variability ◽  
Walker Circulation ◽  
Warm Period ◽  
Tropical Rainfall ◽  
The Past ◽  
Decadal Scale ◽  
Continuous Record ◽  
Southern Central ◽  
Drying Trend ◽  
Rainfall Variations

Tropical rainfall variability is closely linked to meridional shifts of the Intertropical Convergence Zone (ITCZ) and zonal movements of the Walker circulation. The characteristics and mechanisms of tropical rainfall variations on centennial to decadal scales are, however, still unclear. Here, we reconstruct a replicated stalagmite-based 2,700-y-long, continuous record of rainfall for the deeply convective northern central Indo-Pacific (NCIP) region. Our record reveals decreasing rainfall in the NCIP over the past 2,700 y, similar to other records from the northern tropics. Notable centennial- to decadal-scale dry climate episodes occurred in both the NCIP and the southern central Indo-Pacific (SCIP) during the 20th century [Current Warm Period (CWP)] and the Medieval Warm Period (MWP), resembling enhanced El Niño-like conditions. Further, we developed a 2,000-y-long ITCZ shift index record that supports an overall southward ITCZ shift in the central Indo-Pacific and indicates southward mean ITCZ positions during the early MWP and the CWP. As a result, the drying trend since the 20th century in the northern tropics is similar to that observed during the past warm period, suggesting that a possible anthropogenic forcing of rainfall remains indistinguishable from natural variability.

Past monsoon rainfall variations in peninsular India recorded in a 331-year-old speleothem

The Holocene ◽  
2004 ◽  
Vol 14 (4) ◽  
pp. 517-524 ◽  
Author(s):  
M. G. Yadava ◽  
R. Ramesh ◽  
G. B. Pant
Keyword(s):  
Monsoon Rainfall ◽  
Peninsular India ◽  
Rainfall Variations

scholarly journals Record of the Climatic Variability and the Sedimentary Dynamics during the Last Two Millennia at Sebkha Dkhila, Eastern Tunisia

ISRN Geology ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Elhoucine Essefi ◽  
Jamel Touir ◽  
Mohamed Ali Tagorti ◽  
Chokri Yaich
Keyword(s):  
Little Ice Age ◽  
Climatic Variability ◽  
Low Frequency ◽  
Climatic Conditions ◽  
Ice Age ◽  
Global Changes ◽  
Medieval Climatic Anomaly ◽  
Grey Scale ◽  
Sedimentary Dynamics ◽  
The Last Two Millennia

This paper aimed to study the record of the climatic variability during the last two millennia within the sebkha of Dkhila. Six climatic stages were recognized along the 104 cm core: the Warming Present (WP), the Late Little Ice Age (Late LIA), the Early Little Ice Age (ELIA), the Medieval Climatic Anomaly (MCA), the Dark Age (DA), and the Roman Warm Period (RWP). The WP stretches along the uppermost 1 cm with a high grey scale as sign of a dry climate. The Late LIA is located between 1 cm and 6 cm. The ELIA is located between 6 cm and 40 cm. The MCA spanning from 40 cm to 72 cm is marked by a sharp increase of the GS revealing a wet period. The DA appears along the part between 72 cm and 84 cm; a shift from light to dark sediments is recorded. The RWP appears between 84 cm and 104 cm. Based on the grain size distribution, two low frequency cycles were identified indicating radical global changes of climatic conditions, the differential tectonics, and the groundwater fluctuations. On the other hand, high frequency cycles indicate local modifications of the climatic conditions.

scholarly journals The Response Time of Glaciers in Iceland to Changes in climate

1986 ◽  
Vol 8 ◽  
pp. 100-101 ◽  
Author(s):  
Tómas Jóhannesson
Keyword(s):  
Response Time ◽  
Time Variation ◽  
Little Ice Age ◽  
Wave Theory ◽  
Warm Period ◽  
Ice Age ◽  
Kinematic Wave

Records of the time variation of the terminus position of Icelandic glaciers since 1700 show clear responses to the little ice age and to the warm period from 1930 to 1960. These data are used to deduce limits for the response time of the glaciers. The response time turns out to be of the order of one or two hundred years. This is much shorter than the “long response time” of Nye’s kinematic wave theory.

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