Net Heat Flux Over the Indian Ocean: Trends, Driving Mechanisms, and Uncertainties

2013 ◽  
Vol 10 (4) ◽  
pp. 776-780 ◽  
Author(s):  
S. Rahul ◽  
C. Gnanaseelan
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Driving Mechanisms ◽  
Net Heat Flux ◽  
The Indian Ocean

scholarly journals Annual, Seasonal, and Interannual Variability of Air–Sea Heat Fluxes in the Indian Ocean

2007 ◽  
Vol 20 (13) ◽  
pp. 3190-3209 ◽  
Author(s):  
Lisan Yu ◽  
Xiangze Jin ◽  
Robert A. Weller
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Interannual Variability ◽  
Seasonal Cycle ◽  
Arabian Sea ◽  
Heat Fluxes ◽  
The Other ◽  
Net Heat Flux ◽  
The Indian Ocean ◽  
The Mean

Abstract This study investigated the accuracy and physical representation of air–sea surface heat flux estimates for the Indian Ocean on annual, seasonal, and interannual time scales. Six heat flux products were analyzed, including the newly developed latent and sensible heat fluxes from the Objectively Analyzed Air–Sea Heat Fluxes (OAFlux) project and net shortwave and longwave radiation results from the International Satellite Cloud Climatology Project (ISCCP), the heat flux analysis from the Southampton Oceanography Centre (SOC), the National Centers for Environmental Prediction reanalysis 1 (NCEP1) and reanalysis-2 (NCEP2) datasets, and the European Centre for Medium-Range Weather Forecasts operational (ECMWF-OP) and 40-yr Re-Analysis (ERA-40) products. This paper presents the analysis of the six products in depicting the mean, the seasonal cycle, and the interannual variability of the net heat flux into the ocean. Two time series of in situ flux measurements, one taken from a 1-yr Arabian Sea Experiment field program and the other from a 1-month Joint Air–Sea Monsoon Interaction Experiment (JASMINE) field program in the Bay of Bengal were used to evaluate the statistical properties of the flux products over the measurement periods. The consistency between the six products on seasonal and interannual time scales was investigated using a standard deviation analysis and a physically based correlation analysis. The study has three findings. First of all, large differences exist in the mean value of the six heat flux products. Part of the differences may be attributable to the bias in the numerical weather prediction (NWP) models that underestimates the net heat flux into the Indian Ocean. Along the JASMINE ship tracks, the four NWP modeled mean fluxes all have a sign opposite to the observations, with NCEP1 being underestimated by 53 W m−2 (the least biased) and ECMWF-OP by 108 W m−2 (the most biased). At the Arabian Sea buoy site, the NWP mean fluxes also have an underestimation bias, with the smallest bias of 26 W m−2 (ERA-40) and the largest bias of 69 W m−2 (NCEP1). On the other hand, the OAFlux+ISCCP has the best comparison at both measurement sites. Second, the bias effect changes with the time scale. Despite the fact that the mean is biased significantly, there is no major bias in the seasonal cycle of all the products except for ECMWF-OP. The latter does not have a fixed mean due to the frequent updates of the model platform. Finally, among the four products (OAFlux+ISCCP, ERA-40, NCEP1, and NCEP2) that can be used for studying interannual variability, OAFlux+ISCCP and ERA-40 Qnet have good consistency as judged from both statistical and physical measures. NCEP1 shows broad agreement with the two products, with varying details. By comparison, NCEP2 is the least representative of the Qnet variabilities over the basin scale.

Variability of surface heat flux over the Indian Ocean

2004 ◽  
Vol 42 (3) ◽  
pp. 183-199 ◽  
Author(s):  
Hiroyuki Tomita ◽  
Masahisa Kubota
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Surface Heat Flux ◽  
Surface Heat ◽  
The Indian Ocean

scholarly journals Mechanism of cold water regions observed in winter in the Indian Ocean

MAUSAM ◽  
2021 ◽  
Vol 48 (4) ◽  
pp. 645-656
Author(s):  
MASAHISA KUBOTA ◽  
MORIHERI KAWAGUCHI
Keyword(s):  
Heat Flux ◽  
Arabian Sea ◽  
Cold Water ◽  
The Other ◽  
Sea Surface ◽  
Shortwave Radiation ◽  
Boreal Winter ◽  
Observation Data ◽  
Net Heat Flux ◽  
The Indian Ocean

Two cold sea surface temperature (SST) regions are found in the Arabian Sea in boreal winter. One is located northeast of Madagascar, and another is located in a northern part of Arabian Sea. The mechanism for appearance of the cold water is investigated by using monthly climatological ocean observation data. The cold water found northeast of Madagascar is caused by upwelling owing to Ekman divergence associated with a reversal of wind direction. On the other hand, the decrease in SST in a northern part of Arabian Sea is basically caused by decrease of net heat flux associated with reduced shortwave radiation and increased latent heat flux. These results are consistent with results obtained from a numerical investigation by McCreary and Kundu (1989).    

scholarly journals Correlation between Heat Flux over the Indian Ocean and Rainfalls in Coastal Thailand by Using the MM5 Numerical Model

2013 ◽  
Vol 34 ◽  
pp. 91-98 ◽  
Author(s):  
Phuwieng Prakhammintara ◽  
Absornsuda Siripong ◽  
Dusadee Sukawat
Keyword(s):  
Heat Flux ◽  
Numerical Model ◽  
Indian Ocean ◽  
The Indian Ocean

scholarly journals Variability of Air–Sea Interactions over the Indian Ocean Derived from Satellite Observations

1998 ◽  
Vol 11 (8) ◽  
pp. 1859-1873 ◽  
Author(s):  
Catherine Gautier ◽  
Peter Peterson ◽  
Charles Jones
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Interannual Variability ◽  
Satellite Data ◽  
Large Scale ◽  
Southwest Monsoon ◽  
Seasonal And Interannual Variability ◽  
The Indian Ocean ◽  
The Difference

Abstract Novel ways of monitoring the large-scale variability of the southwest monsoon in the Indian Ocean are presented using multispectral satellite datasets. The fields of sea surface temperature (SST), surface latent heat flux (LHF), net surface solar radiation (SW), precipitation (P), and SW − LHF over the Indian Ocean are analyzed to characterize the seasonal and interannual variability with special emphasis on the period 1988–90. It is shown that satellite data are able to make a significant contribution to the multiplatform strategy necessary to describe the large-scale spatial and temporal variability of air–sea interactions associated with the Indian Ocean Monsoon. The satellite data analyzed here has shown for the first time characteristics of the interannual variability of air–sea interactions over the entire Indian Ocean. Using monthly means of SST, LHF, SW, P, and the difference SW − LHF, the main features of the seasonal and interannual variability of air–sea interactions over the Indian Ocean are characterized. It is shown that the southwest monsoon strongly affects these interactions, inducing dramatic exchanges of heat between air and sea and large temporal variations of these exchanges over relatively small timescale (with regards to typical oceanic timescales). The analyses indicate an overall good agreement between satellite and in situ (ship) estimates, except in the southern Indian Ocean, where ship sampling is minimal, the disagreement can be large. In the latitudinal band of 10°N–15°S, differences in climatological in situ estimates of surface sensible heat flux and net longwave radiation has a larger influence on the net surface heat flux than the difference between satellite and in situ estimates of SW and LHF.

scholarly journals Decadal Sea Level Variations in the Indian Ocean Investigated with HYCOM: Roles of Climate Modes, Ocean Internal Variability, and Stochastic Wind Forcing*

2015 ◽  
Vol 28 (23) ◽  
pp. 9143-9165 ◽  
Author(s):  
Yuanlong Li ◽  
Weiqing Han
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Sea Level ◽  
Surface Heat Flux ◽  
Internal Variability ◽  
Surface Heat ◽  
Wind Forcing ◽  
Sea Level Variability ◽  
The Indian Ocean ◽  
Sea Level Variations

Abstract In this study decadal (≥10 yr) sea level variations in the Indian Ocean (IO) during 1950–2012 are investigated using the Hybrid Coordinate Ocean Model (HYCOM). The solution of the main run agrees well with observations in the western-to-central IO. Results of HYCOM experiments reveal large spatial variations in the mechanisms of decadal sea level variability. Within the tropical IO (north of 20°S), decadal sea level variations achieve maximum amplitude in the south IO thermocline ridge region. They are predominantly forced by decadal fluctuations of surface wind stress associated with climate variability modes, while the impact of other processes is much smaller. The Somali coast and the western Bay of Bengal are two exceptional regions, where ocean internal (unforced) variability has large contribution. Between 28° and 20°S in the subtropical south IO, surface heat flux and ocean internal variability are the major drivers of decadal sea level variability. Heat budget analysis for the upper 300 m of this region suggests that surface heat flux affects regional thermosteric sea level through both local surface heating and heat transport by ocean circulation. In the southwestern IO south of 30°S, where stochastic winds are strong, stochastic wind forcing and its interaction with ocean internal variability generate pronounced decadal variations in sea level. The comprehensive investigation of decadal sea level variability over the IO from an oceanic perspective will contribute to decadal sea level prediction research, which has a high societal demand.

Annual and seasonal variability of net heat flux in the Northern Indian Ocean

2020 ◽  
Vol 41 (17) ◽  
pp. 6461-6483
Author(s):  
Rachel T. Pinker ◽  
Abderrahim Bentamy ◽  
Semyon A. Grodsky ◽  
Wen Chen
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Seasonal Variability ◽  
Northern Indian Ocean ◽  
Net Heat Flux

Impact of the Indian Ocean Dipole on Evolution of the Subsequent ENSO: Relative Roles of Dynamic and Thermodynamic Processes

2021 ◽  
Vol 34 (9) ◽  
pp. 3591-3607
Author(s):  
Zhang Yue ◽  
W. Zhou ◽  
Tim Li
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Southern Oscillation ◽  
La Niña ◽  
Bjerknes Feedback ◽  
Sst Cooling ◽  
La Nina ◽  
The Indian Ocean ◽  
Thermodynamic Processes

AbstractThe complex interaction between the Indian Ocean dipole (IOD) and El Niño–Southern Oscillation (ENSO) is further investigated in this study, with a focus on the impacts of the IOD on ENSO in the subsequent year [ENSO(+1)]. The interaction between the IOD and the concurrent ENSO [ENSO(0)] can be summarized as follows: ENSO(0) can trigger and enhance the IOD, while the IOD can enhance ENSO(0) and accelerate its demise. Regarding the impacts of IOD(0) on the subsequent ENSO(+1), it is revealed that the IOD can lead to anomalous SST cooling patterns over the equatorial Pacific after the winter following the IOD, indicating the formation of a La Niña–like pattern in the subsequent year. While the SST cooling tendency associated with a positive IOD is attributable primarily to net heat flux (thermodynamic processes) from autumn to the ensuing spring, after the ensuing spring the dominant contribution comes from oceanic processes (dynamic processes) instead. From autumn to the ensuing spring, the downward shortwave flux response contributes the most to SST cooling over the central and eastern Pacific, due to the cloud–radiation–SST feedback. From the ensuing winter to the ensuing summer, changes in latent heat flux (LHF) are important for SST cooling, indicating that the release of LHF from the ocean into the atmosphere increases due to strong evaporation and leads to SST cooling through the wind–evaporation–SST feedback. The wind stress response and thermocline shoaling verify that local Bjerknes feedback is crucial for the initiation of La Niña in the later stage.

The Indian Ocean Sea Surface Temperature Warming Simulated by CMIP5 Models during the Twentieth Century: Competing Forcing Roles of GHGs and Anthropogenic Aerosols

2014 ◽  
Vol 27 (9) ◽  
pp. 3348-3362 ◽  
Author(s):  
Lu Dong ◽  
Tianjun Zhou
Keyword(s):  
Twentieth Century ◽  
Heat Flux ◽  
Indian Ocean ◽  
Surface Temperature ◽  
Longwave Radiation ◽  
Sea Surface ◽  
Anthropogenic Aerosols ◽  
Aerosol Effect ◽  
Warming Pattern ◽  
The Indian Ocean

Abstract The Indian Ocean exhibits a robust basinwide sea surface temperature (SST) warming during the twentieth century that has affected the hydrological cycle, atmospheric circulation, and global climate change. The competing roles of greenhouse gases (GHGs) and anthropogenic aerosols (AAs) with regard to the Indian Ocean warming are investigated by using 17 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5). The increasing GHGs are considered to be one reason for the warming. Here model evidence is provided that the emission of AAs has slowed down the warming rate. With AAs, the warming trend has been slowed down by 0.34 K century−1. However, the cooling effect is weakened when only the direct aerosol effect is considered. GHGs and AAs have competed with each other in forming the basinwide warming pattern as well as the equatorial east–west dipole warming pattern. Both the basinwide warming effect of GHGs and the cooling effect of AAs, mainly through indirect aerosol effect, are established through atmospheric processes via radiative and turbulent fluxes. The positive contributions of surface latent heat flux from atmosphere and surface longwave radiation due to GHGs forcing dominate the basinwide warming, while the reductions of surface shortwave radiation, surface longwave radiation, and latent heat flux from atmosphere associated with AAs induce the basinwide cooling. The positive Indian Ocean dipole warming pattern is seen in association with the surface easterly wind anomaly during 1870–2005 along the equator, which is produced by the increase of GHGs but weakened by AAs via direct aerosol effects.

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