Basin‐scale pCO2 distribution using satellite sea surface temperature, Chl a, and climatological salinity in the North Pacific in spring and summer
V. V. S. S. SarmaToshiro SainoK. SasaokaYukihiro NojiriTsuneo OnoMasao IshiiHisayuki InoueKazuhiko Matsumoto
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Abstract:
An empirical method is presented for the estimation of basin‐scale distribution of partial pressure of carbon dioxide (pCO 2 ) in the North Pacific using satellite‐derived sea surface temperature (SST), chlorophyll‐ a concentrations (chl a ), and climatological sea surface salinity (SSS). In this approach, multiple regression equations were developed to compute mixed layer dissolved inorganic carbon (DIC) based on SST, SSS and Chl a , whereas mixed layer total alkalinity (TA) was linearly regressed with SSS. The DIC‐SST relation exhibited three different slopes at SST < 20°, 20° < SST < 27.5° and SST>27.5°C. Therefore data have been grouped with reference to SST. Regression equations were developed for two seasons (spring and summer). The regression errors for DIC and TA were 10.5 and 5 μmol kg −1 , respectively. The pCO 2 was computed from the estimated DIC and TA using dissociation constants given by Mehrbach et al. (1973), refit by Dickson and Millero (1987). The derived pCO 2 agreed with the shipboard pCO 2 observations within an error of 17–23 μatm. The sensitivity test on the regression equations for DIC estimation indicated that SSS is the most influencing parameter, followed by SST and Chl a . Using the monthly average SST and Chl a fields derived from the Advanced Very High Resolution Radiometer (AVHRR) and SeaWiFS (Sea‐viewing Wide Field of view Sensor), respectively, and climatological SSS, monthly basin‐scale pCO 2 fields were computed. The statistical model derived pCO 2 results are in agreement with underway pCO 2 in the North Pacific. This study strongly suggests that satellite‐based techniques are promising tools for estimation of pCO 2 fields on a basin scale but the associated error bars are larger than required to study anthropogenic carbon uptake by the oceans. Incorporation of more in situ shipboard data may help in refining the estimating equations and reducing the errors further.Keywords:
SeaWiFS
Mixed layer
Advanced very-high-resolution radiometer
Temperature salinity diagrams
SSS*
Advanced Very High Resolution Radiometer (AVHRR) and Sea viewing Wide Field of view Sensor (SeaWiFS) data from January 1998 to June 1999 are used to examine spatial and temporal variability of sea surface temperature (SST) and apparent chlorophyll (AChl) in the Adriatic Sea. Flows long the Albanian coast and the Italian can be distinguished year-round in the monthly averaged AChl, but only in the colder months in the monthly averaged SST's. The AChl averaged fields supply less information on circulation features away from coastal boundaries and where conditions are generally oligotrophic except for the early spring bloom in the Southern Adriatic Gyre. The winter-spring SST and chlorophyll distributions are very different between the two years, particularly in the Northern Adriatic shelf and the Southern Adriatic Gyre. It is hypothesized that this difference may be related to dense water formation that occurs only in the northern and southern Adriatic Seas. The time series of daily SST indicate that dense water formation was favored in 1999 by episodes of cooler winter temperatures in the southern gyre (less than 13.5 degrees Celsius) and on the northern Adriatic shelf. Blooms in 1999 may have been delayed due to surface replacement flows driven by sinking of dense water.
SeaWiFS
Advanced very-high-resolution radiometer
Spring bloom
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Establishment of the temperature-salinity relationship in the ocean has concerned oceanographers for decades because of its importance for understanding ocean circulation. High-resolution measurements in the ocean mixed layer are used to show that temperature and salinity gradients on horizontal scales of 20 meters to 10 kilometers tend to compensate in their effect on density. These observations support the notion of a horizontal mixing in the mixed layer that depends on density gradient.
Mixed layer
Temperature salinity diagrams
Temperature Gradient
Ocean dynamics
Potential temperature
Density gradient
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Pycnocline
Argo
Temperature salinity diagrams
Convective mixing
Forcing (mathematics)
Potential temperature
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Long term Sea Surface Temperature variability and its relation with, chlorophyll (chl) pigment of phytoplankton biomass were investigated using SeaWiFS (Sea-viewing Wide Field of-view Sensor) and AVHRR (Advanced Very High Resolution Radiometer) satellite imagery. SST acquired from AVHRR (1985 to 2009) showed seasonal, annual and interannual variability of temperature. Monthly variability chl from SeaWiFS 1985 to 2009 has also been investigated, Correlation between SST and chl was found to be 78% and significant at P<0.05.
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Advanced very-high-resolution radiometer
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The Space Information Laboratory (SIL) of the Tropical Center for Earth and Space Studies of the University of Puerto Rico at Mayagüez (UPRM) has been collecting and processing satellite data since December of 1996. Satellite imagery from the Advanced Very High Resolution Radiometer (AVHRR) and the Sea viewing Wide Field of view Sensor (SeaWiFS) provides us with a new understanding of phytoplankton dynamics in the Caribbean region. SeaWiFS shows the intrusion of waters into the eastern Caribbean Sea from the Orinoco River during fall and from the Amazon River during spring–summer. Strong coastal upwelling in Venezuela produced by the trade winds during winter–spring is detected with the AVHRR. The satellite data suggest that these seasonal events may play an important role in phytoplankton fertilization of the eastern Caribbean Sea. SeaWiFS and hydrological data are also combined to evaluate the impact of hurricanes on phytoplankton distribution. The development of models for estimation of ocean primary productivity using SeaWiFS and AVHRR data is now in progress.
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Advanced very-high-resolution radiometer
Ocean color
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Temperature salinity diagrams
Ocean dynamics
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Mixed layer
Temperature salinity diagrams
Surface layer
Isothermal process
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Advanced very-high-resolution radiometer
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Advanced very-high-resolution radiometer
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Advanced very-high-resolution radiometer
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