Impact of river runoff into the ocean on climate in a coupled model
In order to study the impact of global runoff, sensitivity experiment (NoRiv) was carried out by shutting down the entire runoff into the ocean for a period of 200 years. The changes in NoRiv, compared to the reference simulation (CR), shows the impact of global runoff (NoRiv minus CR). The evolutio...
Main Author: | |
---|---|
Other Authors: | , |
Format: | Thesis |
Language: | English |
Published: |
2019
|
Subjects: | |
Online Access: | https://etd.iisc.ac.in/handle/2005/4378 |
id |
ftiiscdiss:oai:etd.iisc.ac.in:2005/4378 |
---|---|
record_format |
openpolar |
spelling |
ftiiscdiss:oai:etd.iisc.ac.in:2005/4378 2024-06-09T07:44:32+00:00 Impact of river runoff into the ocean on climate in a coupled model Sharif, Jahfer Vinayachandran, P N Nanjundiah, Ravi S 2019 application/pdf https://etd.iisc.ac.in/handle/2005/4378 en_US eng https://etd.iisc.ac.in/handle/2005/4378 I grant Indian Institute of Science the right to archive and to make available my thesis or dissertation in whole or in part in all forms of media, now hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation Global runoff NoRiv AMOC Atlantic meridional overturning circulation Research Subject Categories::NATURAL SCIENCES::Earth sciences::Atmosphere and hydrosphere sciences::Oceanography Thesis 2019 ftiiscdiss 2024-05-15T03:03:44Z In order to study the impact of global runoff, sensitivity experiment (NoRiv) was carried out by shutting down the entire runoff into the ocean for a period of 200 years. The changes in NoRiv, compared to the reference simulation (CR), shows the impact of global runoff (NoRiv minus CR). The evolution of mean ocean SSS in the major ocean basins show that the upper– ocean reached a quasi-stabilized stage in the first 100 years in the NoRiv. Globally, when there is no runoff, the surface ocean turns saltier with the largest increase occurring off the mouths of major river systems. High salinity patches of more than 2 psu are found near the mouths of Amazon, Congo, Ganga–Brahmaputra, Yangtze, etc. The upper–ocean currents distribute the positive salinity anomalies generated near the river mouth of NoRiv to far away regions and open ocean. In accordance with our results using CCSM3.0 model, CESM1.0 also shows that the impact of runoff into the ocean on SSS is significantly higher in the extratropical ocean than in the tropics, though the tropical runoff is considerably higher (Vinayachandran, Jahfer, and Nanjundiah, 2015). Arctic Ocean recorded the highest rise in salinity as the ratio of runoff to the surface area of the basin is highest. The open ocean regions of Pacific exhibited the least change in salinity due to the vastness of the basin. We further analyzed the significance of this rise in SSS on the upper–ocean temperature, air–sea interaction, and rainfall. A saltier ocean in the NoRiv deepens the mixed layer of the upper–ocean owing to the increase in surface density. Though the mean MLD in the NoRiv is found to be deeper than the CR, the SST response to this change in ML is complex. In the simulation without runoff, the northern hemisphere oceans recorded a comparatively higher rise in surface temperature, mostly in the Atlantic Ocean. The change in SST in the NoRiv is primarily due to the weakening of upper–ocean stratification or due to changes in air–sea interaction in the coupled system. The equatorial ... Thesis Arctic Arctic Ocean Indian Instiute of Science, Bangalore: etd@IIsc (Electronic Theses and Disserations) Arctic Arctic Ocean Pacific |
institution |
Open Polar |
collection |
Indian Instiute of Science, Bangalore: etd@IIsc (Electronic Theses and Disserations) |
op_collection_id |
ftiiscdiss |
language |
English |
topic |
Global runoff NoRiv AMOC Atlantic meridional overturning circulation Research Subject Categories::NATURAL SCIENCES::Earth sciences::Atmosphere and hydrosphere sciences::Oceanography |
spellingShingle |
Global runoff NoRiv AMOC Atlantic meridional overturning circulation Research Subject Categories::NATURAL SCIENCES::Earth sciences::Atmosphere and hydrosphere sciences::Oceanography Sharif, Jahfer Impact of river runoff into the ocean on climate in a coupled model |
topic_facet |
Global runoff NoRiv AMOC Atlantic meridional overturning circulation Research Subject Categories::NATURAL SCIENCES::Earth sciences::Atmosphere and hydrosphere sciences::Oceanography |
description |
In order to study the impact of global runoff, sensitivity experiment (NoRiv) was carried out by shutting down the entire runoff into the ocean for a period of 200 years. The changes in NoRiv, compared to the reference simulation (CR), shows the impact of global runoff (NoRiv minus CR). The evolution of mean ocean SSS in the major ocean basins show that the upper– ocean reached a quasi-stabilized stage in the first 100 years in the NoRiv. Globally, when there is no runoff, the surface ocean turns saltier with the largest increase occurring off the mouths of major river systems. High salinity patches of more than 2 psu are found near the mouths of Amazon, Congo, Ganga–Brahmaputra, Yangtze, etc. The upper–ocean currents distribute the positive salinity anomalies generated near the river mouth of NoRiv to far away regions and open ocean. In accordance with our results using CCSM3.0 model, CESM1.0 also shows that the impact of runoff into the ocean on SSS is significantly higher in the extratropical ocean than in the tropics, though the tropical runoff is considerably higher (Vinayachandran, Jahfer, and Nanjundiah, 2015). Arctic Ocean recorded the highest rise in salinity as the ratio of runoff to the surface area of the basin is highest. The open ocean regions of Pacific exhibited the least change in salinity due to the vastness of the basin. We further analyzed the significance of this rise in SSS on the upper–ocean temperature, air–sea interaction, and rainfall. A saltier ocean in the NoRiv deepens the mixed layer of the upper–ocean owing to the increase in surface density. Though the mean MLD in the NoRiv is found to be deeper than the CR, the SST response to this change in ML is complex. In the simulation without runoff, the northern hemisphere oceans recorded a comparatively higher rise in surface temperature, mostly in the Atlantic Ocean. The change in SST in the NoRiv is primarily due to the weakening of upper–ocean stratification or due to changes in air–sea interaction in the coupled system. The equatorial ... |
author2 |
Vinayachandran, P N Nanjundiah, Ravi S |
format |
Thesis |
author |
Sharif, Jahfer |
author_facet |
Sharif, Jahfer |
author_sort |
Sharif, Jahfer |
title |
Impact of river runoff into the ocean on climate in a coupled model |
title_short |
Impact of river runoff into the ocean on climate in a coupled model |
title_full |
Impact of river runoff into the ocean on climate in a coupled model |
title_fullStr |
Impact of river runoff into the ocean on climate in a coupled model |
title_full_unstemmed |
Impact of river runoff into the ocean on climate in a coupled model |
title_sort |
impact of river runoff into the ocean on climate in a coupled model |
publishDate |
2019 |
url |
https://etd.iisc.ac.in/handle/2005/4378 |
geographic |
Arctic Arctic Ocean Pacific |
geographic_facet |
Arctic Arctic Ocean Pacific |
genre |
Arctic Arctic Ocean |
genre_facet |
Arctic Arctic Ocean |
op_relation |
https://etd.iisc.ac.in/handle/2005/4378 |
op_rights |
I grant Indian Institute of Science the right to archive and to make available my thesis or dissertation in whole or in part in all forms of media, now hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation |
_version_ |
1801373257440428032 |