Search results for "Tropical Atlantic"
showing 8 items of 18 documents
Last interglacial temperature seasonality reconstructed from tropical Atlantic corals
2016
Abstract Reconstructions of last interglacial (LIG, MIS 5e, ∼127–117 ka) climate offer insights into the natural response and variability of the climate system during a period partially analogous to future climate change scenarios. We present well preserved fossil corals (Diploria strigosa) recovered from the southern Caribbean island of Bonaire (Caribbean Netherlands). These have been precisely dated by the 230Th/U-method to between 130 and 120 ka ago. Annual banding of the coral skeleton enabled construction of time windows of monthly resolved strontium/calcium (Sr/Ca) temperature proxy records. In conjunction with a previously published 118 ka coral record, our eight records of up to 37 …
Linear relationship between effective radius and precipitation water content near the top of convective clouds: measurement results from ACRIDICON–CH…
2021
Quantifying the precipitation within clouds is a crucial challenge to improve our current understanding of the Earth's hydrological cycle. We have investigated the relationship between the effective radius of droplets and ice particles (re) and precipitation water content (PWC) measured by cloud probes near the top of growing convective cumuli. The data for this study were collected during the ACRIDICON–CHUVA campaign on the HALO research aircraft in clean and polluted conditions over the Amazon Basin and over the western tropical Atlantic in September 2014. Our results indicate a threshold of re∼13 µm for warm rain initiation in convective clouds, which is in agreement with previous studie…
Last Interglacial Hydroclimate Seasonality Reconstructed From Tropical Atlantic Corals
2018
The seasonality of hydroclimate during past periods of warmer than modern global temperatures is a critical component for understanding future climate change scenarios. Although only partially analogous to these scenarios, the last interglacial (LIG, Marine Isotope Stage 5e, ~127–117 ka) is a popular test bed. We present coral δ18O monthly resolved records from multiple Bonaire (southern Caribbean) fossil corals (Diploria strigosa) that date to between 130 and 118 ka. These records represent up to 37 years and cover a total of 105 years, offering insights into the seasonality and characteristics of LIG tropical Atlantic hydroclimate. Our coral δ18O records and available coral Sr/Ca-sea surf…
The Stationarity of Lead-Lag Teleconnections with East Africa Rainfall and its Incidence on Seasonal Predictability
2001
East Africa experiences large interannual rainfall variations, which can lead to severe droughts, as in 1984 in Ethiopia, or extensive flooding, as in 1997 in Somalia and Kenya. In the last 15 years, significant advances have been made in relating these variations to large-scale ocean-atmosphere anomalies, of which those associated to ENSO (El Nino Southern Oscillation) come first. The additional importance of sea-surface variations in the Tropical Atlantic and Indian Oceans is becoming established. Although 20th century East African precipitation series did not experience decadal-scale trends as significant as those found in the sahelian belt, the correlation with ENSO, the Indian monsoon …
Droughts Over Amazonia in 2005, 2010, and 2015: A Cloud Cover Perspective
2018
Amazon forests experienced recent severe droughts in an anomalous short period induced by different mechanisms and had different length periods and spatial patterns. Droughts of 2005 and 2010 were attributed to anomalous Sea Surface Temperature (SST) over the Tropical North Atlantic (TNA) during the dry season, but the 2010 drought was more severe and remained for a longer period because it was also induced in late 2009 by a moderate to strong El Niño (EN). Drought in 2015 led to unprecedented warming and extreme soil moisture deficits over some regions, and it was attributed to a very strong EN. Several studies analyzed these drought events regarding different climatic factors such as anom…
Variations in intensity of the westerly monsoon-like flow from the tropical Atlantic and summer rainfall over equatorial and tropical southern Africa
2009
International audience; An empirical orthogonal function (EOF) of the onshore flow of moisture along the west coast of southern Africa using NCEP-DOE AMIP-2 re-analyses suggests two dominant modes of variability that are linked to: (a) variations within the circulation linked to the mid-latitude westerlies and the South Atlantic anticyclone, (b) the intensity of the westerly flow from the tropical Atlantic. The second mode, referred to as the Equatorial Westerly mode, contributes the most to moisture input from the Atlantic onto the subconti-nent at tropical latitudes. This mode appears to be associated with large-scale rainfall anomalies over the upper lands surrounding the Congo basin in …
Tropical Atlantic temperature seasonality at the end of the last interglacial
2015
The end of the last interglacial period, ~118 kyr ago, was characterized by substantial ocean circulation and climate perturbations resulting from instabilities of polar ice sheets. These perturbations are crucial for a better understanding of future climate change. The seasonal temperature changes of the tropical ocean, however, which play an important role in seasonal climate extremes such as hurricanes, floods and droughts at the present day, are not well known for this period that led into the last glacial. Here we present a monthly resolved snapshot of reconstructed sea surface temperature in the tropical North Atlantic Ocean for 117.7±0.8 kyr ago, using coral Sr/Ca and δ18O records. W…
Control of Seasonality and Interannual to Centennial Climate Variability in the Caribbean During the Holocene—Combining Coral Records, Stalagmite Rec…
2014
This study aimed at quantifying the amplitudes of seasonality and interannual to centennial climate variability in the Caribbean region throughout the Holocene, by using marine (shallow-water corals) and terrestrial (speleothems) climate archives, and climate model simulations (COSMOS). Sea-surface temperature (SST) variability on interdecadal to multidecadal timescales was more pronounced during the mid-Holocene compared to the late Holocene. The amplitude of the SST annual cycle was within the present-day range throughout most of the last 6,000 years. Exceptions include slightly increased SST seasonality at 6,200 years ago, which can be attributed mainly to insolation forcing on orbital t…