The Characteristics and Variability of Intraseasonal Coastal Kelvin Waves in the Bay of Bengal under Hindcast Conditions and the RCP8.5 Scenario
- 1 July 2022
- journal article
- research article
- Published by American Meteorological Society in Journal of Physical Oceanography
- Vol. 52 (7), 1497-1507
- https://doi.org/10.1175/jpo-d-21-0247.1
Abstract
The characteristics and variability of intraseasonal internal coastal Kelvin waves (CKWs) along the Bay of Bengal (BoB) waveguide are investigated in the context of global warming by employing a regional ocean model. The analyzed period covers 120 years from 1980 to 2099, which includes the historical scenario and the RCP8.5 scenario. CKW information is successfully extracted from the temperature anomalies along the pycnocline by applying a newly developed methodology. The analysis reveals that intraseasonal CKWs in the BoB are highly in accordance with the intraseasonal zonal wind stress in the western equatorial Indian Ocean; the downwelling CKW lags the equatorial intraseasonal westerly winds, and the upwelling CKW lags the equatorial intraseasonal easterly winds. The CKWs significantly affect subsurface characteristics at the eastern BoB boundary, and the weakening of CKWs near the Irrawaddy Delta tip is a general feature occurring in the subsurface. With respect to the long-term scale, the occurrence of significant CKWs is predicted to be more frequent in the future under the high emissions pathway. Remarkably, the monthly climatology of CKWs varies over time; unlike the first two 30-yr analyzed periods, significant CKWs are predicted to mainly occur around August during the last two 30-yr periods due to the corresponding variabilities in the equatorial wind field, suggesting that the BoB characteristics may greatly deviate from the current climatological state. The characteristics and variability of intraseasonal internal coastal Kelvin waves (CKWs) along the Bay of Bengal (BoB) waveguide are investigated in the context of global warming by employing a regional ocean model. The analyzed period covers 120 years from 1980 to 2099, which includes the historical scenario and the RCP8.5 scenario. CKW information is successfully extracted from the temperature anomalies along the pycnocline by applying a newly developed methodology. The analysis reveals that intraseasonal CKWs in the BoB are highly in accordance with the intraseasonal zonal wind stress in the western equatorial Indian Ocean; the downwelling CKW lags the equatorial intraseasonal westerly winds, and the upwelling CKW lags the equatorial intraseasonal easterly winds. The CKWs significantly affect subsurface characteristics at the eastern BoB boundary, and the weakening of CKWs near the Irrawaddy Delta tip is a general feature occurring in the subsurface. With respect to the long-term scale, the occurrence of significant CKWs is predicted to be more frequent in the future under the high emissions pathway. Remarkably, the monthly climatology of CKWs varies over time; unlike the first two 30-yr analyzed periods, significant CKWs are predicted to mainly occur around August during the last two 30-yr periods due to the corresponding variabilities in the equatorial wind field, suggesting that the BoB characteristics may greatly deviate from the current climatological state.Keywords
Funding Information
- National Key Research and Development Plan of China (2021YFF0704002)
- German Ministry for Education and Research (03F0781A)
This publication has 71 references indexed in Scilit:
- Climate and carbon cycle changes from 1850 to 2100 in MPI‐ESM simulations for the Coupled Model Intercomparison Project phase 5Journal of Advances in Modeling Earth Systems, 2013
- Simulated Sea Surface Salinity Variability in the Tropical Indian OceanJournal of Climate, 2010
- Intraseasonal response of the northern Indian Ocean coastal waveguide to the Madden‐Julian OscillationGeophysical Research Letters, 2009
- Madden‐Julian OscillationReviews of Geophysics, 2005
- Seasonal and inter-annual variability of surface circulation in the Bay of Bengal from TOPEX/Poseidon altimetryDeep Sea Research Part II: Topical Studies in Oceanography, 2003
- Dynamical response of equatorial Indian Ocean to intraseasonal winds: Zonal FlowGeophysical Research Letters, 2001
- Seasonal variability of the Bay of Bengal circulation inferred from TOPEX/Poseidon altimetryJournal of Geophysical Research: Oceans, 2000
- Seasonal variability of near‐surface thermal structure and heat budget of the mixed layer of the tropical Indian Ocean from a new global ocean temperature climatologyJournal of Geophysical Research: Oceans, 2000
- Low-Frequency Baroclinic Waves off Coastal BoundariesJournal of Physical Oceanography, 1988
- Coastal-Trapped Waves in a Continuously Stratified OceanJournal of Physical Oceanography, 1976