Seasonal variations of the upper ocean in the western north pacific observed by an argo float

Iwasaka, Naoto; Kobashi, Fumiaki; Kinoshita, Yoshinori; Ohno, Yuko

doi:10.1007/s10872-006-0070-6

Cited by 15 publications

(6 citation statements)

References 19 publications

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“…30; Fig. 3), since this depth is at z ≈ −150 m in the tropical waters of the western North Pacific and west Philippines Sea, which is deeper than the MLD31 (Fig. S9).…”

Section: Resultsmentioning

confidence: 99%

Rainfall-enhanced blooming in typhoon wakes

Lin

Oey

2016

Sci Rep

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Strong phytoplankton blooming in tropical-cyclone (TC) wakes over the oligotrophic oceans potentially contributes to long-term changes in global biogeochemical cycles. Yet blooming has traditionally been discussed using anecdotal events and its biophysical mechanics remain poorly understood. Here we identify dominant blooming patterns using 16 years of ocean-color data in the wakes of 141 typhoons in western North Pacific. We observe right-side asymmetric blooming shortly after the storms, attributed previously to sub-mesoscale re-stratification, but thereafter a left-side asymmetry which coincides with the left-side preference in rainfall due to the large-scale wind shear. Biophysical model experiments and observations demonstrate that heavier rainfall freshens the near-surface water, leading to stronger stratification, decreased turbulence and enhanced blooming. Our results suggest that rainfall plays a previously unrecognized, critical role in TC-induced blooming, with potentially important implications for global biogeochemical cycles especially in view of the recent and projected increases in TC-intensity that harbingers stronger mixing and heavier rain under the storm.

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“…30; Fig. 3), since this depth is at z ≈ −150 m in the tropical waters of the western North Pacific and west Philippines Sea, which is deeper than the MLD31 (Fig. S9).…”

Section: Resultsmentioning

confidence: 99%

Rainfall-enhanced blooming in typhoon wakes

Lin

Oey

2016

Sci Rep

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“…The changes in thermohaline structure recorded by Argo profiles may come from other oceanic processes, such as internal waves, eddies, frontal movements, as well as seasonal variations. For example, Iwasaka et al (2006) revealed the seasonal evolution of the ML in the western North Pacific Ocean by following an Argo float for more than nine months. When using Argo profiles to study ML variations associated with the passage of a typhoon, the background seasonal variability contained in the observations should be taken into account, especially at higher latitudes where such variability is pronounced.…”

Section: Introductionmentioning

confidence: 99%

Typhoon-Induced Variability of the Oceanic Surface Mixed Layer Observed by Argo Floats in the Western North Pacific Ocean

Chen

2012

Atmosphere-Ocean

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This study takes advantage of the newly established observational network of Argo floats to investigate the variability of the oceanic surface mixed layer (ML) in response to typhoons occurring over the period 2000-08 in the western North Pacific Ocean. After removing the background variability due to the seasonal cycle, the regionally averaged ML response is statistically analyzed as a function of the distance from the typhoon centre, the time after typhoon passage, the geographic location, the translation speed of the typhoon and the pre-existing patterns of oceanic circulation. Based on an unprecedented amount of new observational data, our analysis reveals some notable differences between ML temperature and ML depth changes induced by a typhoon, including the delayed response of ML temperature relative to ML depth, the longer restoring time of ML temperature, and the tendency of pre-existing cold-core features to favour ML cooling while warm-core features favour ML deepening.RÉSUMÉ [Traduit par la rédaction] La présente étude tire profit du nouveau réseau de balises d'observation Argo qui étudie la variabilité de la couche de mélange de la surface océanique en réponse aux typhons survenus durant la période 2000-2008 dans l'ouest du Pacifique Nord. Après avoir éliminé la variabilité de fond due au cycle saisonnier, nous faisons une analyse statistique de la réponse de la couche de mélange, moyennée dans une région, en fonction de la distance du centre du typhon, du temps écoulé depuis le passage du typhon, du lieu géographique, de la vitesse de déplacement du typhon et des configurations de circulation océanique préexistantes. En se basant sur une quantité sans précédent de nouvelles données d'observation, notre analyse révèle des différences notables entre les changements de température et de profondeur de la couche de mélange produits par le typhon, y compris la réponse retardée de la température de la couche de mélange par rapport à la profondeur de la couche de mélange, le temps de rétablissement plus long de la température de la couche de mélange et la tendance des caractéristiques de noyaux froids préexistantes à favoriser le refroidissement de la couche de mélange pendant que les caractéristiques de noyaux chauds favorisent l'approfondissement de la couche de mélange.

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“…The paucity of subsurface observations has been partially resolved by Argo floats, which measure profiles of temperature (T) and salinity (S) as they drift in the ocean. The floats provide an unprecedented view of the subsurface ocean, and Argo data is being widely used for basic science as well as applications [e.g., Ravichandran et al , 2004; Iwasaka et al , 2006; Mathews et al , 2007; Krishnamurti et al , 2007]. Riser et al .…”

Section: Introductionmentioning

confidence: 99%

Intraseasonal response of mixed layer temperature and salinity in the Bay of Bengal to heat and freshwater flux

et al. 2010

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[1] Buoy and satellite data show pronounced subseasonal oscillations of sea surface temperature (SST) in the summertime Bay of Bengal. The SST oscillations are forced mainly by surface heat flux associated with the active break cycle of the south Asian summer monsoon. The input of freshwater (FW) from summer rain and rivers to the bay is large, but not much is known about subseasonal salinity variability. We use [2002][2003][2004][2005][2006][2007] observations from three Argo floats with 5 day repeat cycle to study the subseasonal response of temperature and salinity to surface heat and freshwater flux in the central Bay of Bengal. About 95% of Argo profiles show a shallow halocline, with substantial variability of mixed layer salinity. Estimates of surface heat and freshwater flux are based on daily satellite data sampled along the float trajectory. We find that intraseasonal variability of mixed layer temperature is mainly a response to net surface heat flux minus penetrative radiation during the summer monsoon season. In winter and spring, however, temperature variability appears to be mainly due to lateral advection rather than local heat flux. Variability of mixed layer freshwater content is generally independent of local surface flux (precipitation minus evaporation) in all seasons. There are occasions when intense monsoon rainfall leads to local freshening, but these are rare. Large fluctuations in FW appear to be due to advection, suggesting that freshwater from rivers and rain moves in eddies or filaments.

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Seasonal variations of the upper ocean in the western north pacific observed by an argo float

Cited by 15 publications

References 19 publications

Rainfall-enhanced blooming in typhoon wakes

Rainfall-enhanced blooming in typhoon wakes

Typhoon-Induced Variability of the Oceanic Surface Mixed Layer Observed by Argo Floats in the Western North Pacific Ocean

Intraseasonal response of mixed layer temperature and salinity in the Bay of Bengal to heat and freshwater flux

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