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Salinity fronts in the tropical Pacific Ocean.

Kao HY, Lagerloef GS - J Geophys Res Oceans (2015)

Bottom Line: In the eastern Pacific, we observe a southward extension of the SF in the boreal spring that could be driven by both precipitation and horizontal advection.In the western Pacific, the importance of these newly resolved SF associated with the western Pacific warm/fresh pool and El Niño southern oscillations are also discussed in the context of prior literature.The main conclusions of this study are that (a) Aquarius satellite salinity measurements reveal the heretofore unknown proliferation, structure, and variability of surface salinity fronts, and that (b) the fine-scale structures of the SF in the tropical Pacific yield important new information on the regional air-sea interaction and the upper ocean dynamics.

View Article: PubMed Central - PubMed

Affiliation: Earth and Space Research Seattle, Washington, USA.

ABSTRACT

This study delineates the salinity fronts (SF) across the tropical Pacific, and describes their variability and regional dynamical significance using Aquarius satellite observations. From the monthly maps of the SF, we find that the SF in the tropical Pacific are (1) usually observed around the boundaries of the fresh pool under the intertropical convergence zone (ITCZ), (2) stronger in boreal autumn than in other seasons, and (3) usually stronger in the eastern Pacific than in the western Pacific. The relationship between the SF and the precipitation and the surface velocity are also discussed. We further present detailed analysis of the SF in three key tropical Pacific regions. Extending zonally around the ITCZ, where the temperature is nearly homogeneous, we find the strong SF of 1.2 psu from 7° to 11°N to be the main contributor of the horizontal density difference of 0.8 kg/m(3). In the eastern Pacific, we observe a southward extension of the SF in the boreal spring that could be driven by both precipitation and horizontal advection. In the western Pacific, the importance of these newly resolved SF associated with the western Pacific warm/fresh pool and El Niño southern oscillations are also discussed in the context of prior literature. The main conclusions of this study are that (a) Aquarius satellite salinity measurements reveal the heretofore unknown proliferation, structure, and variability of surface salinity fronts, and that (b) the fine-scale structures of the SF in the tropical Pacific yield important new information on the regional air-sea interaction and the upper ocean dynamics.

No MeSH data available.


The maps of precipitation (left) SSS (middle), and horizontal salinity gradients (right) in the eastern tropical Pacific from January to May. The black contour in Figure 8a shows the 5 mm/day isolines. The black solid and dashed lines in Figures 8b and 6c show the 32.5 and 34.3 psu isohalines, respectively.
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fig08: The maps of precipitation (left) SSS (middle), and horizontal salinity gradients (right) in the eastern tropical Pacific from January to May. The black contour in Figure 8a shows the 5 mm/day isolines. The black solid and dashed lines in Figures 8b and 6c show the 32.5 and 34.3 psu isohalines, respectively.

Mentions: Figure 8 shows the detailed maps of the double ITCZ in precipitation and SSS from January to May. During this time period, a branch of enhanced precipitation forms and grows around 5°S (left panels of Figure 8). In the SSS maps (Figure 8, middle), a fresh pool (<32 psu; black solid contours show the 32 psu isohaline) is present around 80°–90°W and 2°–7°N. In addition, there is a separation of fresh water around 33.5 psu extending southward around 5°S from January to April and then soon dissipates in May. The SF calculated from these SSS maps are strong at the boundaries of the fresh pool and the south boundary of the second ITCZ (right panels of Figure 8). The SF at the boundaries of the fresh pool aligns with the 32.5 psu (black solid contours) and the SF at the south boundary of the second ITCZ aligns well with the 34.3 psu (black-dashed contours).


Salinity fronts in the tropical Pacific Ocean.

Kao HY, Lagerloef GS - J Geophys Res Oceans (2015)

The maps of precipitation (left) SSS (middle), and horizontal salinity gradients (right) in the eastern tropical Pacific from January to May. The black contour in Figure 8a shows the 5 mm/day isolines. The black solid and dashed lines in Figures 8b and 6c show the 32.5 and 34.3 psu isohalines, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508928&req=5

fig08: The maps of precipitation (left) SSS (middle), and horizontal salinity gradients (right) in the eastern tropical Pacific from January to May. The black contour in Figure 8a shows the 5 mm/day isolines. The black solid and dashed lines in Figures 8b and 6c show the 32.5 and 34.3 psu isohalines, respectively.
Mentions: Figure 8 shows the detailed maps of the double ITCZ in precipitation and SSS from January to May. During this time period, a branch of enhanced precipitation forms and grows around 5°S (left panels of Figure 8). In the SSS maps (Figure 8, middle), a fresh pool (<32 psu; black solid contours show the 32 psu isohaline) is present around 80°–90°W and 2°–7°N. In addition, there is a separation of fresh water around 33.5 psu extending southward around 5°S from January to April and then soon dissipates in May. The SF calculated from these SSS maps are strong at the boundaries of the fresh pool and the south boundary of the second ITCZ (right panels of Figure 8). The SF at the boundaries of the fresh pool aligns with the 32.5 psu (black solid contours) and the SF at the south boundary of the second ITCZ aligns well with the 34.3 psu (black-dashed contours).

Bottom Line: In the eastern Pacific, we observe a southward extension of the SF in the boreal spring that could be driven by both precipitation and horizontal advection.In the western Pacific, the importance of these newly resolved SF associated with the western Pacific warm/fresh pool and El Niño southern oscillations are also discussed in the context of prior literature.The main conclusions of this study are that (a) Aquarius satellite salinity measurements reveal the heretofore unknown proliferation, structure, and variability of surface salinity fronts, and that (b) the fine-scale structures of the SF in the tropical Pacific yield important new information on the regional air-sea interaction and the upper ocean dynamics.

View Article: PubMed Central - PubMed

Affiliation: Earth and Space Research Seattle, Washington, USA.

ABSTRACT

This study delineates the salinity fronts (SF) across the tropical Pacific, and describes their variability and regional dynamical significance using Aquarius satellite observations. From the monthly maps of the SF, we find that the SF in the tropical Pacific are (1) usually observed around the boundaries of the fresh pool under the intertropical convergence zone (ITCZ), (2) stronger in boreal autumn than in other seasons, and (3) usually stronger in the eastern Pacific than in the western Pacific. The relationship between the SF and the precipitation and the surface velocity are also discussed. We further present detailed analysis of the SF in three key tropical Pacific regions. Extending zonally around the ITCZ, where the temperature is nearly homogeneous, we find the strong SF of 1.2 psu from 7° to 11°N to be the main contributor of the horizontal density difference of 0.8 kg/m(3). In the eastern Pacific, we observe a southward extension of the SF in the boreal spring that could be driven by both precipitation and horizontal advection. In the western Pacific, the importance of these newly resolved SF associated with the western Pacific warm/fresh pool and El Niño southern oscillations are also discussed in the context of prior literature. The main conclusions of this study are that (a) Aquarius satellite salinity measurements reveal the heretofore unknown proliferation, structure, and variability of surface salinity fronts, and that (b) the fine-scale structures of the SF in the tropical Pacific yield important new information on the regional air-sea interaction and the upper ocean dynamics.

No MeSH data available.