Free and forced tropical variability: role of the wind-evaporation-sea surface temperature (WES) feedback
The Wind-Evaporation-Sea Surface Temperature (WES) feedback is believedto play an important role in the tropics, where climate variability is governed byatmosphere-ocean coupled interactions. This dissertation reports on studies to distinctlyisolate the WES feedback mechanism over tropical oceans us...
Main Author: | |
---|---|
Other Authors: | , , , |
Format: | Book |
Language: | English |
Published: |
2009
|
Subjects: | |
Online Access: | https://hdl.handle.net/1969.1/ETD-TAMU-3107 |
id |
fttexasamuniv:oai:oaktrust.library.tamu.edu:1969.1/ETD-TAMU-3107 |
---|---|
record_format |
openpolar |
spelling |
fttexasamuniv:oai:oaktrust.library.tamu.edu:1969.1/ETD-TAMU-3107 2023-07-16T04:00:50+02:00 Free and forced tropical variability: role of the wind-evaporation-sea surface temperature (WES) feedback Mahajan, Salil Saravanan, R. Bowman, Kenneth P. Chang, Ping North, Gerald R. 2009-05-15 electronic application/pdf born digital https://hdl.handle.net/1969.1/ETD-TAMU-3107 en_US eng https://hdl.handle.net/1969.1/ETD-TAMU-3107 Tropical Climate Variability Coupled air-sea interactions climate modeling Book Thesis Electronic Dissertation text 2009 fttexasamuniv 2023-06-27T22:55:57Z The Wind-Evaporation-Sea Surface Temperature (WES) feedback is believedto play an important role in the tropics, where climate variability is governed byatmosphere-ocean coupled interactions. This dissertation reports on studies to distinctlyisolate the WES feedback mechanism over tropical oceans using a modiedversion of an NCAR-Community Climate Model (CCM3) thermodynamically coupledto a slab ocean model, where the WES feedback is deliberately suppressed inthe bulk aerodynamic formulation for surface heat uxes. A comparison of coupledintegrations using the modified WES-off CCM3 to those carried out using the standardCCM3 conclusively identifies the role of the WES feedback in enhancing theinter-annual variability over deep tropical oceans and the westward propagation ofthe equatorial annual cycle. An important role for near surface humidity in tropicalclimate variability in enhancing inter-annual variability and in sustaining the equatorialannual cycle is also suggested. Statistical analyses over the tropical Atlanticreveal that the free coupled meridional mode of the Atlantic Ocean is amplified in thepresence of the WES feedback. Similar analyses of coupled model integrations, whenforced with an articial El Ni~no Southern Oscillation (ENSO)-like SST cycle in tropicalPacific, reveal that only in the presence of the WES feedback is the meridionalmode the preferred mode of response of the Atlantic to ENSO forcings. It is also foundthat WES feedback reinforces the tendency of the ITCZ to stay north of the equator over the Atlantic during El-Nino events. Comparative studies between Last GlacialMaximum (LGM) equivalent imposed northern hemispheric sea-ice experiments withthe WES-off model and the standard model indicate a dominant role for the WESfeedback in the southward shift of the ITCZ as indicated by paleo-climate records.However, it is found not to be the sole thermodynamic mechanism responsible for thepropagation of high latitude cold SST anomalies to the tropics, suggesting significantroles for other ... Book Sea ice Texas A&M University Digital Repository |
institution |
Open Polar |
collection |
Texas A&M University Digital Repository |
op_collection_id |
fttexasamuniv |
language |
English |
topic |
Tropical Climate Variability Coupled air-sea interactions climate modeling |
spellingShingle |
Tropical Climate Variability Coupled air-sea interactions climate modeling Mahajan, Salil Free and forced tropical variability: role of the wind-evaporation-sea surface temperature (WES) feedback |
topic_facet |
Tropical Climate Variability Coupled air-sea interactions climate modeling |
description |
The Wind-Evaporation-Sea Surface Temperature (WES) feedback is believedto play an important role in the tropics, where climate variability is governed byatmosphere-ocean coupled interactions. This dissertation reports on studies to distinctlyisolate the WES feedback mechanism over tropical oceans using a modiedversion of an NCAR-Community Climate Model (CCM3) thermodynamically coupledto a slab ocean model, where the WES feedback is deliberately suppressed inthe bulk aerodynamic formulation for surface heat uxes. A comparison of coupledintegrations using the modified WES-off CCM3 to those carried out using the standardCCM3 conclusively identifies the role of the WES feedback in enhancing theinter-annual variability over deep tropical oceans and the westward propagation ofthe equatorial annual cycle. An important role for near surface humidity in tropicalclimate variability in enhancing inter-annual variability and in sustaining the equatorialannual cycle is also suggested. Statistical analyses over the tropical Atlanticreveal that the free coupled meridional mode of the Atlantic Ocean is amplified in thepresence of the WES feedback. Similar analyses of coupled model integrations, whenforced with an articial El Ni~no Southern Oscillation (ENSO)-like SST cycle in tropicalPacific, reveal that only in the presence of the WES feedback is the meridionalmode the preferred mode of response of the Atlantic to ENSO forcings. It is also foundthat WES feedback reinforces the tendency of the ITCZ to stay north of the equator over the Atlantic during El-Nino events. Comparative studies between Last GlacialMaximum (LGM) equivalent imposed northern hemispheric sea-ice experiments withthe WES-off model and the standard model indicate a dominant role for the WESfeedback in the southward shift of the ITCZ as indicated by paleo-climate records.However, it is found not to be the sole thermodynamic mechanism responsible for thepropagation of high latitude cold SST anomalies to the tropics, suggesting significantroles for other ... |
author2 |
Saravanan, R. Bowman, Kenneth P. Chang, Ping North, Gerald R. |
format |
Book |
author |
Mahajan, Salil |
author_facet |
Mahajan, Salil |
author_sort |
Mahajan, Salil |
title |
Free and forced tropical variability: role of the wind-evaporation-sea surface temperature (WES) feedback |
title_short |
Free and forced tropical variability: role of the wind-evaporation-sea surface temperature (WES) feedback |
title_full |
Free and forced tropical variability: role of the wind-evaporation-sea surface temperature (WES) feedback |
title_fullStr |
Free and forced tropical variability: role of the wind-evaporation-sea surface temperature (WES) feedback |
title_full_unstemmed |
Free and forced tropical variability: role of the wind-evaporation-sea surface temperature (WES) feedback |
title_sort |
free and forced tropical variability: role of the wind-evaporation-sea surface temperature (wes) feedback |
publishDate |
2009 |
url |
https://hdl.handle.net/1969.1/ETD-TAMU-3107 |
genre |
Sea ice |
genre_facet |
Sea ice |
op_relation |
https://hdl.handle.net/1969.1/ETD-TAMU-3107 |
_version_ |
1771550072356470784 |