Dust flux in the eastern equatorial Pacific
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| Format: | Dataset Open Access |
| Sprache: | en |
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PANGAEA
2007
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| _version_ | 1867167660565856256 |
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| author | McGee, David Marcantonio, Franco Lynch-Stieglitz, Jean |
| author_facet | McGee, David Marcantonio, Franco Lynch-Stieglitz, Jean |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Atmospheric dust levels may play important roles in feedbacks linking continental source areas, tropical convection, marine productivity, and global climate. These feedbacks appear to be particularly significant in the tropical Pacific, where variations in local convection and productivity have been demonstrated to have impacts on climate at higher latitudes. Modeling of past dust levels and related feedbacks has been limited, however, by a paucity of observational data. In this study we present a temporal and spatial survey of dust fluxes to the eastern equatorial Pacific over the past 30 kyr. Glacial and Holocene fluxes of 232Th, a proxy for continental material, were calculated by normalization to 230Th from a north-south transect of cores along 110°W between 3°S and 7°N (ODP sites 848-853). Fluxes were 30-100% higher during the last glacial, suggesting increased dustiness in both hemispheres during the glacial period. In both time periods, dust fluxes decrease towards the south, reflecting scavenging of Northern Hemisphere dust by precipitation at the ITCZ. The Holocene meridional dust flux gradient between 7°N and 3°S is characterized by a steep drop in dust levels at the southern edge of the modern range of the ITCZ, while the gradient is shallower and more nearly linear during the last glacial. This change may indicate that the glacial ITCZ in this region was a less effective barrier to interhemispheric dust transport, most likely due to a decrease in convective intensity and precipitation during the last glacial; alternatively, the change in gradient may be explained by increased variability in the location of the glacial ITCZ. Our data do not appear to require a mean southerly displacement of the glacial ITCZ, as suggested by the results of other studies. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_707256 |
| institution | PANGAEA |
| language | en |
| publishDate | 2007 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Dust flux in the eastern equatorial Pacific McGee, David Marcantonio, Franco Lynch-Stieglitz, Jean 138-848B; 138-849A; 138-850A; 138-851E; 138-852A; 138-853B; DRILL; Drilling/drill rig; Joides Resolution; Leg138; North Pacific Ocean; Ocean Drilling Program; ODP; South Pacific Ocean Atmospheric dust levels may play important roles in feedbacks linking continental source areas, tropical convection, marine productivity, and global climate. These feedbacks appear to be particularly significant in the tropical Pacific, where variations in local convection and productivity have been demonstrated to have impacts on climate at higher latitudes. Modeling of past dust levels and related feedbacks has been limited, however, by a paucity of observational data. In this study we present a temporal and spatial survey of dust fluxes to the eastern equatorial Pacific over the past 30 kyr. Glacial and Holocene fluxes of 232Th, a proxy for continental material, were calculated by normalization to 230Th from a north-south transect of cores along 110°W between 3°S and 7°N (ODP sites 848-853). Fluxes were 30-100% higher during the last glacial, suggesting increased dustiness in both hemispheres during the glacial period. In both time periods, dust fluxes decrease towards the south, reflecting scavenging of Northern Hemisphere dust by precipitation at the ITCZ. The Holocene meridional dust flux gradient between 7°N and 3°S is characterized by a steep drop in dust levels at the southern edge of the modern range of the ITCZ, while the gradient is shallower and more nearly linear during the last glacial. This change may indicate that the glacial ITCZ in this region was a less effective barrier to interhemispheric dust transport, most likely due to a decrease in convective intensity and precipitation during the last glacial; alternatively, the change in gradient may be explained by increased variability in the location of the glacial ITCZ. Our data do not appear to require a mean southerly displacement of the glacial ITCZ, as suggested by the results of other studies. |
| title | Dust flux in the eastern equatorial Pacific |
| topic | 138-848B; 138-849A; 138-850A; 138-851E; 138-852A; 138-853B; DRILL; Drilling/drill rig; Joides Resolution; Leg138; North Pacific Ocean; Ocean Drilling Program; ODP; South Pacific Ocean |
| url | https://doi.org/10.1594/PANGAEA.707256 |