Seasonal cycles of surface layer salinity in the Pacific Ocean
-
Published:2010-08-24
Issue:3
Volume:6
Page:775-787
-
ISSN:1812-0792
-
Container-title:Ocean Science
-
language:en
-
Short-container-title:Ocean Sci.
Author:
Bingham F. M.,Foltz G. R.,McPhaden M. J.
Abstract
Abstract. The seasonal variability of surface layer salinity (SLS) is examined in the Pacific Ocean between 40° S and 60° N using a variety of data sources. Significant seasonal cycles were found in 5 regions: 1) The western North Pacific, 2) The northeastern North Pacific and Alaska gyre, 3) the intertropical convergence zone (ITCZ), 4) an area of the central North Pacific north of the Hawaiian Islands, 5) the central South Pacific along 10–20° S. Amplitudes range from 0.1 to > 0.5. The largest amplitudes are in the tropical band and the western North Pacific. Maximum salinity is obtained in late (northern) winter in the western North Pacific, late winter and early spring in the northeastern North Pacific, early summer in the ITCZ area, late summer and early fall in the central North Pacific area and (austral) winter in the central South Pacific. Large areas of the Pacific have no significant seasonal variation in SLS. Seasonal variability of evaporation rate, precipitation rate and the difference between them (E-P) were calculated from the OAFlux and Global Precipitation Climatology Project datasets. Typical amplitudes of E-P are 0.1–1 × 10−4 kg m−2 s−1. The seasonal variability of E-P is largely dominated by variability in evaporation in the western North Pacific and precipitation elsewhere. The largest amplitudes are in areas along the edge of the western North Pacific and in the far eastern tropical Pacific around 10° N. Phases in these areas indicate maximum E-P in mid- to late winter in these areas of large amplitude. The closest correspondence between E-P and SLS is in the ITCZ. E-P was combined with seasonal variation of the mixed-layer depth to calculate the freshwater flux forcing term of the SLS balance equation. The term was found to be similar in magnitude and distribution to E-P. Some other terms of the SLS balance were calculated. Horizontal advection was found to have seasonal cycles in a region near the equator. Entrainment was found to be mostly not significant except for a small region along 2.5–7.5° N in the eastern Pacific. Averaged spatially over large areas in the western North Pacific, ITCZ, South Pacific and northern North Pacific, the seasonal cycle is mostly a balance between changes in SLS and E-P, with entrainment and advection playing relatively minor roles. This work highlights the potentially significant role of surface salinity in the hydrologic cycle and in subtropical mode water formation. It can also help to interpret measurements that will soon be available from the Aquarius and SMOS (Soil Moisture and Ocean Salinity) satellite missions.
Publisher
Copernicus GmbH
Subject
Cell Biology,Developmental Biology,Embryology,Anatomy
Reference44 articles.
1. Adler, R. F., Huffman, G. J., Chang, A., Ferraro, R., Xie, P., Janowiak, J., Rudolf, R., Schneider, U., Curtis, S., Bolvin, D., Gruber, A., Susskind, J., Arkin, A., and Nelkin, E.: The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979–Present), J. Hydrometeor., 4, 1147–1167, 2003. 2. Ando, K. and McPhaden, M. J.: Variability of surface layer hydrography in the tropical Pacific Ocean, J. Geophys. Res., 102, 23063–23078, 1997. 3. Antonov, J., Seidov, D., Boyer, T. P., Locarnini, R. A., Mishonov, A. V., and Garcia, H. E.: World Ocean Atlas 2009, Volume 2: Salinity, NOAA NESDIS Report 69, 184 pp., 2010. 4. Berger, M., Camps, A., Font, J., Kerr, Y., Miller, J., Johannssen, J., Boutin, J., Drinkwater, M. R., Skou, N., Floury, N., Rast, M., Rebhan, H., and Attema, E.: Measuring Ocean Salinity with ESA's SMOS Mission, ESA Bull., 111, 113–121, 2002. 5. Bingham, F.: The Formation and Spreading of Subtropical Mode Water in the North Pacific, J. Geophys. Res., 97, 11177–11189, 1992.
Cited by
51 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|