From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates
The current-climate Indian monsoon is known to boost biological productivity in the Arabian Sea. This paradigm has been extensively used to reconstruct past monsoon variability from palaeo-proxies indicative of changes in surface productivity. Here, we test this paradigm by simulating changes in...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-07-01
|
| Series: | Climate of the Past |
| Online Access: | https://www.clim-past.net/13/759/2017/cp-13-759-2017.pdf |
| _version_ | 1818862970028949504 |
|---|---|
| author | P. Le Mézo L. Beaufort L. Bopp P. Braconnot M. Kageyama |
| author_facet | P. Le Mézo L. Beaufort L. Bopp P. Braconnot M. Kageyama |
| author_sort | P. Le Mézo |
| collection | DOAJ |
| description | The current-climate Indian monsoon is known to boost biological
productivity in the Arabian Sea. This paradigm has been extensively used to
reconstruct past monsoon variability from palaeo-proxies indicative of
changes in surface productivity. Here, we test this paradigm by simulating
changes in marine primary productivity for eight contrasted climates from the
last glacial–interglacial cycle. We show that there is no straightforward
correlation between boreal summer productivity of the Arabian Sea and summer
monsoon strength across the different simulated climates. Locally,
productivity is fuelled by nutrient supply driven by Ekman dynamics. Upward
transport of nutrients is modulated by a combination of alongshore wind
stress intensity, which drives coastal upwelling, and by a positive wind
stress curl to the west of the jet axis resulting in upward Ekman pumping. To
the east of the jet axis there is however a strong downward Ekman pumping due
to a negative wind stress curl. Consequently, changes in coastal alongshore
stress and/or curl depend on both the jet intensity and position. The jet
position is constrained by the Indian summer monsoon pattern, which in turn
is influenced by the astronomical parameters and the ice sheet cover. The
astronomical parameters are indeed shown to impact wind stress intensity in
the Arabian Sea through large-scale changes in the meridional gradient of
upper-tropospheric temperature. However, both the astronomical parameters and
the ice sheets affect the pattern of wind stress curl through the position of
the sea level depression barycentre over the monsoon region
(20–150° W, 30° S–60° N). The combined changes
in monsoon intensity and pattern lead to some higher glacial productivity
during the summer season, in agreement with some palaeo-productivity
reconstructions. |
| first_indexed | 2024-12-19T10:08:19Z |
| format | Article |
| id | doaj.art-568f4cddedcc480bba81d08d24d69ddb |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-12-19T10:08:19Z |
| publishDate | 2017-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-568f4cddedcc480bba81d08d24d69ddb2022-12-21T20:26:27ZengCopernicus PublicationsClimate of the Past1814-93241814-93322017-07-011375977810.5194/cp-13-759-2017From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climatesP. Le Mézo0L. Beaufort1L. Bopp2P. Braconnot3M. Kageyama4LSCE/IPSL, UMR 8112, CEA/CNRS/UVSQ, Centre CEA-Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, FranceCEREGE, UMR 7330, CNRS-IRD-Aix Marseille Université, Av. Louis Philibert, BP80, 13545 Aix-en-Provence, FranceLSCE/IPSL, UMR 8112, CEA/CNRS/UVSQ, Centre CEA-Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, FranceLSCE/IPSL, UMR 8112, CEA/CNRS/UVSQ, Centre CEA-Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, FranceLSCE/IPSL, UMR 8112, CEA/CNRS/UVSQ, Centre CEA-Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, FranceThe current-climate Indian monsoon is known to boost biological productivity in the Arabian Sea. This paradigm has been extensively used to reconstruct past monsoon variability from palaeo-proxies indicative of changes in surface productivity. Here, we test this paradigm by simulating changes in marine primary productivity for eight contrasted climates from the last glacial–interglacial cycle. We show that there is no straightforward correlation between boreal summer productivity of the Arabian Sea and summer monsoon strength across the different simulated climates. Locally, productivity is fuelled by nutrient supply driven by Ekman dynamics. Upward transport of nutrients is modulated by a combination of alongshore wind stress intensity, which drives coastal upwelling, and by a positive wind stress curl to the west of the jet axis resulting in upward Ekman pumping. To the east of the jet axis there is however a strong downward Ekman pumping due to a negative wind stress curl. Consequently, changes in coastal alongshore stress and/or curl depend on both the jet intensity and position. The jet position is constrained by the Indian summer monsoon pattern, which in turn is influenced by the astronomical parameters and the ice sheet cover. The astronomical parameters are indeed shown to impact wind stress intensity in the Arabian Sea through large-scale changes in the meridional gradient of upper-tropospheric temperature. However, both the astronomical parameters and the ice sheets affect the pattern of wind stress curl through the position of the sea level depression barycentre over the monsoon region (20–150° W, 30° S–60° N). The combined changes in monsoon intensity and pattern lead to some higher glacial productivity during the summer season, in agreement with some palaeo-productivity reconstructions.https://www.clim-past.net/13/759/2017/cp-13-759-2017.pdf |
| spellingShingle | P. Le Mézo L. Beaufort L. Bopp P. Braconnot M. Kageyama From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates Climate of the Past |
| title | From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates |
| title_full | From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates |
| title_fullStr | From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates |
| title_full_unstemmed | From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates |
| title_short | From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates |
| title_sort | from monsoon to marine productivity in the arabian sea insights from glacial and interglacial climates |
| url | https://www.clim-past.net/13/759/2017/cp-13-759-2017.pdf |
| work_keys_str_mv | AT plemezo frommonsoontomarineproductivityinthearabianseainsightsfromglacialandinterglacialclimates AT lbeaufort frommonsoontomarineproductivityinthearabianseainsightsfromglacialandinterglacialclimates AT lbopp frommonsoontomarineproductivityinthearabianseainsightsfromglacialandinterglacialclimates AT pbraconnot frommonsoontomarineproductivityinthearabianseainsightsfromglacialandinterglacialclimates AT mkageyama frommonsoontomarineproductivityinthearabianseainsightsfromglacialandinterglacialclimates |