Intertropical convergence zone variability in the Neotropics during the Common Era

Asmerom, Yemane; Baldini, James U.L.; Prufer, Keith M.; Polyak, Victor J.; Ridley, Harriet E.; Aquino, Valorie V.; Baldini, Lisa M.; Breitenbach, Sebastian F. M.; Macpherson, Colin G.; Kennett, Douglas J.

doi:10.1126/sciadv.aax3644

Cited by 49 publications

(56 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Modern tropical Atlantic precipitation variability occurs on a range of time scales, including the interannual to multidecadal periods, where the latter have been associated with the Atlantic Multidecadal Oscillation (AMO) (Bhattacharya et al, 2017;Knight et al, 2006;Moreno-Chamarro et al, 2019). Speleothem stable isotope records have strongly contributed to the understanding of multidecadal to millennial precipitation dynamics in the western tropical Atlantic during the Holocene (e.g., Asmerom et al, 2020;Fensterer et al, 2012Fensterer et al, , 2013Medina-Elizalde et al, 2010). For the Last Glacial, however, the number of studies, whose temporal resolution allows for the investigation of sub-centennial variability, is very limited and provides an inconsistent picture.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the details of the spatio‐temporal structure and evolution of the Atlantic ITCZ are still not well understood (Warken et al, 2019). Mounting evidence from both modeling studies and proxy records suggests that the simple explanation of a north‐south shifting of the ITCZ is not adequate to explain the observed rainfall patterns, especially because the most northern shifts of the Atlantic ITCZ are linked to a complex set of forcings and feedbacks on different timescales (Asmerom et al, 2020; Lachniet et al, 2009; Oster et al, 2019; Roberts & Hopcroft, 2020; Singarayer et al, 2017). For instance, the magnitude and extent of the ITCZ's latitudinal movements, and the role of external forcing, such as insolation, in modulating this variability especially during pronounced and/or abrupt climate change events during glacial periods, such as Heinrich and D/O events, remain unclear.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Persistent Link Between Caribbean Precipitation and Atlantic Ocean Circulation During the Last Glacial Revealed by a Speleothem Record From Puerto Rico

Warken

Vieten

Winter

et al. 2020

Paleoceanog and Paleoclimatol

View full text Add to dashboard Cite

The sensitivity of tropical Atlantic precipitation patterns to the mean position of the Intertropical Convergence Zone (ITCZ) at different time scales is well-known. However, recent research suggests a more complex behavior of the northern hemispheric tropical rain belt related to the ITCZ in the western tropical Atlantic. Here we present a precisely dated speleothem multi-proxy record from a well-monitored cave in Puerto Rico, covering the period between 46.2 and 15.3 ka. The stable isotope and trace element records document a pronounced response of regional rainfall to abrupt climatic excursions in the North Atlantic across the Last Glacial such as Heinrich stadials and Dansgaard/Oeschger events. The annual to multidecadal resolution of the proxy time series allows substructural investigations of the recorded events. Spectral analysis suggests that multidecadal to centennial variability persisted in the regional hydroclimate mainly during interstadial conditions but also during the Last Glacial Maximum. In particular, we observe a strong agreement between the speleothem proxy data and the strength of the Atlantic meridional overturning circulation, supporting a persistent link of oceanic forcing to regional precipitation. Comparison to other paleo-precipitation records enables the reconstruction of past changes in position, strength, and extent of the ITCZ in the western tropical Atlantic in response to millennial-and orbital-scale global climate change. Plain Language Summary It is important to understand the climatic circumstances of how rainfall in the western tropical Atlantic varies under a changing climate to better manage the water supply for millions of people. However, it is not well understood how rainfall varied in the past, especially during the Last Glacial period, a time of strong climate variability and abrupt climate changes. Here, we use a stalagmite from Puerto Rico to create a new record of past changes in rainfall in this region. For this purpose, we analyzed proxy data that reveal a series of wet and dry periods during the Last Glacial corresponding to rapid global climate shifts. Our rainfall-sensitive stalagmite record captured changes of the tropical rain belt on various timescales and shows that this variability in rainfall is closely connected to changes in the strength of the ocean circulation. This suggests that the link between the ocean and the atmosphere is more robust than previously assumed. The comparison of our record with other rainfall-sensitive records from Central America and the northern Caribbean allows for a detailed reconstruction of the spatial and temporal changes of the western tropical Atlantic rain belt.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Persistent Link Between Caribbean Precipitation and Atlantic Ocean Circulation During the Last Glacial Revealed by a Speleothem Record From Puerto Rico

Warken

Vieten

Winter

et al. 2020

Paleoceanog and Paleoclimatol

View full text Add to dashboard Cite

show abstract

“…In January, the ITCZ is located near Ecuador, reaching its southernmost position during the boreal winter. The ITCZ represents a convergence zone, resulting from the coincidence of trade winds from the North and South Hadley cells [33]. This convergence promotes convective movements of the atmosphere and, consequently, produces rainfall [30,31].…”

Section: Discussionmentioning

confidence: 99%

Isomass and Probability Maps of Ash Fallout Due to Vulcanian Eruptions at Tungurahua Volcano (Ecuador) Deduced from Historical Forecasting

et al. 2020

View full text Add to dashboard Cite

Since April of 2015, the ash dispersion and ash fallout due to Vulcanian eruptions at Tungurahua, one of the most active volcanoes in Ecuador, have been forecasted daily. For this purpose, our forecasting system uses the meteorological Weather Research and Forecasting (WRF) and the FALL3D models. Previously, and based on field data, laboratory, and numerical studies, corresponding eruption source parameters (ESP) have been defined. We analyzed the historically forecasted results of the ash fallout quantities over four years (April 2015 to March 2019), in order to obtain the average isomass and probability maps for three-month periods: February–March–April (FMA), May–June–July (MJJ), August–September–October (ASO), and November–December–January (NDJ). Our results indicate similar ash fallout shapes during MJJ and ASO, with a clear and defined tendency toward the west of the volcano; this tendency is less defined during NDJ and FMA. The proximal region west of the volcano (about 100 km to the west) has the highest probability (>70%) of being affected by ash fallout. The distant region to the west (more than 100 km west) presented low to medium probabilities (10%–70%) of ash fallout. The cities of Guaranda (W, 60% to 90%), Riobamba (SW, 70%), and Ambato (NW, 50% to 60%) have the highest probabilities of being affected by ash fallout. Among the large Ecuadorian cities, Guayaquil (SW, 10% to 30%) has low probability, and Quito (N, ≤5%) and Cuenca (SSE, <5%) have very low probabilities of being affected by ash fallout. High ash clouds can move in different directions, compared to wind transport near the surface. Therefore, it is possible to detect ash clouds by remote sensing which, in Ecuador, is limited to the layers over the meteorological clouds, which move in a different direction than low wind; the latter produces ash fallout over regions in different directions compared to the detected ash clouds. In addition to the isomass/probability maps and detected ash clouds, forecasting is permanently required in Ecuador.

show abstract

“…Compared with the δ 18 O records of stalagmites, the δ 13 C records are more sensitive to the changes in the ecological environment outside the cave (Zhang et al, 2015;Liu et al, 2016;Asmerom et al, 2020). The δ 13 C of speleothems is affected by atmospheric CO2, soil, vegetation, epikarst zone, and cave conditions (temperature, humidity, ventilation) .…”

Section: Interpretation Of Proxiesmentioning

confidence: 99%

The 4.2 ka event in East Asian monsoon region, precisely reconstructed by multi-proxies of stalagmite

Chen

Yuan

et al. 2021

Preprint

View full text Add to dashboard Cite

Abstract. The 4.2 ka event is one of the most salient features of global climate change in the mid-late Holocene and influenced on the evolution of ancient civilizations. Although a lot of paleoclimate reconstructions have focused on it, the detailed structure and driving mechanism of the 4.2 ka event is still unclear. In this study, the variation of Asian summer monsoon (ASM) during 5000–3000 yr BP was reconstructed by using high-precision U-Th dating (average resolution of 7 yr) and multi-proxies (δ13C, δ18O, Ba / Ca, Sr / Ca, Mg / Ca) of stalagmite YK1306 from Yangkou Cave in southwestern China. The results showed that that the ASM weakened and precipitation decreased during 4600–4330 yr BP and 4070–3700 yr BP. During 4330–4070 yr BP, the ASM became strong, and precipitation increased. The multi-proxies variation of YK1306 showed a weak-strong-weak structure of the ASM during the 4.2 ka event, which reappeared in different geologic records. However, westerlies and Australian-Indian summer monsoon (AISM) both showed the opposite change pattern (strong-weak-strong) with the ASM. This was resulted by the different phases of North Atlantic Oscillation (NAO) on a centennial scale, which regulated by the Atlantic Meridional Overturning Circulation (AMOC). In positive NAO-like, the strength of Azores high and westerly wind restrained the intensity of ASM. Thus, the ASM and the Middle East regions experienced bimodal drought and increased dust flux from the north in both regions during the 4.2 ka event. The strengthened meridional winds in the westerlies-dominated climatic regime (WDCR) lead more water vapor from the Indian Ocean and Arabian Sea transporting to in the WDCR, and subsequently increases precipitation in the WDCR. Meanwhile, the weakening of the AMOC results in the southward migration of the Intertropical Convergence Zone (ITCZ) and strengthens the AISM in the southern Hemisphere, finally results in the opposite change of the AISM contrast to the ASM. In addition, the strong ASM in the era of the Chinese Xia Dynasty maybe produce frequent ancient floods, which led to the decline of Longshan and Liangzhu cultures. The weakening of the ASM after 4070 yr BP contributed to the successful regulation of the ancient floodwaters by Dayu in Chinese history. Therefore, it is maybe credible that the official age for the establishment of the Xia Dynasty in 4070 yr BP. Benefit from the comprehensive comparison and analysis based on the unprecedented high-precise chronology, high-resolution and multi-proxy's stalagmite records, this study not only detailed described the evolution of the ASM during the 4.2 ka event, but also is conducive to verify the age of the first dynasty of China (the Xia Dynasty), and the legend of Dayu.

show abstract

Intertropical convergence zone variability in the Neotropics during the Common Era

Cited by 49 publications

References 43 publications

Persistent Link Between Caribbean Precipitation and Atlantic Ocean Circulation During the Last Glacial Revealed by a Speleothem Record From Puerto Rico

Persistent Link Between Caribbean Precipitation and Atlantic Ocean Circulation During the Last Glacial Revealed by a Speleothem Record From Puerto Rico

Isomass and Probability Maps of Ash Fallout Due to Vulcanian Eruptions at Tungurahua Volcano (Ecuador) Deduced from Historical Forecasting

The 4.2 ka event in East Asian monsoon region, precisely reconstructed by multi-proxies of stalagmite

Contact Info

Product

Resources

About