• Akima, H., 1970: A new method of interpolation and smooth curve fitting based on local procedures. J. Assoc. Comput. Mach., 17, 589602, https://doi.org/10.1145/321607.321609.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Alory, G., C. Maes, T. Delcroix, N. Reul, and S. Ilig, 2012: Seasonal dynamics of sea surface salinity off Panama: The far eastern Pacific fresh pool. J. Geophys. Res., 117, C04028, https://doi.org/10.1029/2011JC007802.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Balaguru, K., P. Chang, R. Saravanan, L. R. Leung, Z. Xu, M. K. Li, and J. S. Hsieh, 2012: Ocean barrier layers’ effect on tropical cyclone intensification. Proc. Natl. Acad. Sci. USA, 109, 14 34314 347, https://doi.org/10.1073/pnas.1201364109.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bingham, F. M., G. R. Foltz, and M. J. McPhaden, 2010: Seasonal cycles of surface layer salinity in the Pacific Ocean. Ocean Sci., 6, 775787, https://doi.org/10.5194/os-6-775-2010.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bonjean, F., and G. S. Lagerloef, 2002: Diagnostic model and analysis of the surface currents in the tropical Pacific Ocean. J. Phys. Oceanogr., 32, 29382954, https://doi.org/10.1175/1520-0485(2002)032<2938:DMAAOT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Chi, N.-H., R.-C. Lien, and E. A. D′Asaro, 2021: The mixed layer salinity budget in the central equatorial Indian Ocean. J. Geophys. Res. Oceans, 126, e2021JC017280, https://doi.org/10.1029/2021JC017280.

    • Crossref
    • Export Citation
  • Colbo, K., and R. A. Weller, 2009: Accuracy of the IMET sensor package in the subtropics. J. Atmos. Oceanic Technol., 26, 18671890, https://doi.org/10.1175/2009JTECHO667.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cronin, M. F., and M. J. McPhaden, 2002: Barrier layer formation during westerly wind bursts. J. Geophys. Res., 107, 8020, https://doi.org/10.1029/2001JC001171.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cronin, M. F., and W. S. Kessler, 2009: Near-surface shear flow in the tropical Pacific cold tongue front. J. Phys. Oceanogr., 39, 12001215, https://doi.org/10.1175/2008JPO4064.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cronin, M. F., and T. Tozuka, 2016: Near-surface shear flow in the tropical Pacific cold tongue front. Sci. Rep., 9, 28842, https://doi.org/10.1038/srep28842.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cronin, M. F., and Coauthors, 2013: Formation and erosion of the seasonal thermocline in the Kuroshio Extension Recirculation Gyre. Deep-Sea Res. II, 85, 6274, https://doi.org/10.1016/j.dsr2.2012.07.018.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cronin, M. F., N. A. Pelland, S. R. Emerson, and W. R. Crawford, 2015: Estimating diffusivity from the mixed layer heat and salt balances in the North Pacific. J. Geophys. Res. Oceans, 120, 73467362, https://doi.org/10.1002/2015JC011010.

    • Search Google Scholar
    • Export Citation
  • de Boyer Montégut, C., J. Mignot, A. Lazar, and S. Cravatte, 2007: Control of salinity on the mixed layer depth in the World Ocean: 1. General description. J. Geophys. Res., 112, C06011, https://doi.org/10.1029/2006JC003953.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Delcroix, T., A. Chaigneau, D. Soviadan, J. Boutin, and C. Pegliasco, 2019: Eddy-induced salinity changes in the tropical Pacific. J. Geophys. Res. Oceans, 124, 374389, https://doi.org/10.1029/2018JC014394.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dong, S., S. T. Gille, and J. Sprintall, 2007: An assessment of the Southern Ocean mixed layer heat budget. J. Climate, 20, 44254442, https://doi.org/10.1175/JCLI4259.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Drushka, K., J. Sprintall, and S. T. Gille, 2014: Subseasonal variations in salinity and barrier-layer thickness in the eastern equatorial Indian Ocean. J. Geophys. Res. Oceans, 119, 805823, https://doi.org/10.1002/2013JC009422.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Edson, J. B., and Coauthors, 2013: On the exchange of momentum over the open ocean. J. Phys. Oceanogr., 43, 15891610, https://doi.org/10.1175/JPO-D-12-0173.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Fairall, C. W., E. F. Bradley, J. S. Godfrey, G. A. Wick, J. B. Edson, and G. S. Young, 1996: Cool-skin and warm-layer effects on sea surface temperature. J. Geophys. Res., 101, 12951308, https://doi.org/10.1029/95JC03190.

    • Search Google Scholar
    • Export Citation
  • Fairall, C. W., E. F. Bradley, J. E. Hare, A. A. Grachev, and J. B. Edson, 2003: Bulk parameterization of air–sea fluxes: Updates and verification for the COARE algorithm. J. Climate, 16, 571591, https://doi.org/10.1175/1520-0442(2003)016<0571:BPOASF>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Farrar, J. T., 2007: Air-sea interaction at contrasting sites in the eastern tropical Pacific: Mesoscale variability and atmospheric convection at 10°N. PhD thesis, Massachusetts Institute of Technology, 66 pp.

    • Crossref
    • Export Citation
  • Farrar, J. T., and R. A. Weller, 2006: Intraseasonal variability near 10°N in the eastern tropical Pacific Ocean. J. Geophys. Res., 111, C05015, https://doi.org/10.1029/2005JC002989.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Farrar, J. T., and A. J. Plueddemann, 2019: On the factors driving upper-ocean salinity variability at the western edge of the eastern Pacific fresh pool. Oceanography, 32, 3039, https://doi.org/10.5670/oceanog.2019.209.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Farrar, J. T., and Coauthors, 2015: Salinity and temperature balances at the SPURS central mooring during fall and winter. Oceanography, 28, 5665, https://doi.org/10.5670/oceanog.2015.06.

    • Search Google Scholar
    • Export Citation
  • Foltz, G. R., and M. J. McPhaden, 2005: Mixed layer heat balance on intraseasonal time scales in the northwestern tropical Atlantic Ocean. J. Climate, 18, 41684184, https://doi.org/10.1175/JCLI3531.1.

    • Search Google Scholar
    • Export Citation
  • Foltz, G. R., and M. J. McPhaden, 2009: Impact of barrier layer thickness on SST in the central tropical North Atlantic. J. Climate, 22, 285299, https://doi.org/10.1175/2008JCLI2308.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Foltz, G. R., S. A. Grodsky, J. A. Carton, and M. J. McPhaden, 2003: Seasonal mixed layer heat budget of the tropical Atlantic Ocean. J. Geophys. Res., 108, 3146, https://doi.org/10.1029/2002JC001584.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Foltz, G. R., S. A. Grodsky, J. A. Carton, and M. J. McPhaden, 2004: Seasonal salt budget of the northwestern tropical Atlantic Ocean along 38°W. J. Geophys. Res., 109, C03052, https://doi.org/10.1029/2003JC002111.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Girishkumar, M. S., J. Joseph, V. P. Thangaprakash, P. Vijay, and M. J. McPhaden, 2017: Mixed layer temperature budget for the northward propagating summer Monsoon Intraseasonal Oscillation (MISO) in the central Bay of Bengal. J. Geophys. Res. Oceans, 122, 88418854, https://doi.org/10.1002/2017JC013073.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Godfrey, J. S., and E. J. Lindstrom, 1989: The heat budget of the equatorial western Pacific surface mixed layer. J. Geophys. Res., 94, 80078017, https://doi.org/10.1029/JC094iC06p08007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Guimbard, S., N. Reul, B. Chapron, M. Umbert, and C. Maes, 2017: Seasonal and interannual variability of the eastern tropical Pacific Fresh Pool. J. Geophys. Res. Oceans, 122, 17491771, https://doi.org/10.1002/2016JC012130.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hasson, A., J. T. Farrar, J. Boutin, F. Bingham, and T. Lee, 2019: Intraseasonal variability of surface salinity in the eastern tropical Pacific associated with mesoscale eddies. J. Geophys. Res. Oceans, 124, 28612875, https://doi.org/10.1029/2018JC014175.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hsin, Y. C., and B. Qiu, 2012: Seasonal fluctuations of the surface North Equatorial Countercurrent (NECC) across the Pacific basin. J. Geophys. Res., 117, C06001, https://doi.org/10.1029/2011JC007794.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jerlov, N. G., 1976: Marine Optics. 2nd ed. Elsevier Oceanography Series, Vol. 14, Elsevier, 230 pp.

    • Crossref
    • Export Citation
  • Jin, F.-F., J. Boucharel, and I.-I. Lin, 2014: Eastern Pacific tropical cyclone intensified by El Niño delivery of subsurface ocean heat. Nature, 516, 8285, https://doi.org/10.1038/nature13958.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Johnson, E. S., F. Bonjean, G. S. E. Lagerloef, J. T. Gunn, and G. T. Mitchum, 2007: Validation and error analysis of OSCAR sea surface currents. J. Atmos. Oceanic Technol., 24, 688701, https://doi.org/10.1175/JTECH1971.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Katsura, S., and J. Sprintall, 2020: Seasonality and formation of barrier layers and associated temperature inversions in the eastern tropical North Pacific. J. Phys. Oceanogr., 50, 791808, https://doi.org/10.1175/JPO-D-19-0194.1.

    • Search Google Scholar
    • Export Citation
  • Katsura, S., E. Oka, B. Qiu, and N. Schneider, 2013: Formation and subduction of North Pacific tropical water and their interannual variability. J. Phys. Oceanogr., 43, 24002415, https://doi.org/10.1175/JPO-D-13-031.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Katsura, S., H. Ueno, H. Mitsudera, and S. Kouketsu, 2020: Spatial distribution and seasonality of halocline structures in the subarctic North Pacific. J. Phys. Oceanogr., 50, 95109. https://doi.org/10.1175/JPO-D-19-0133.1

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Katsura, S., J. Sprintall, and F. M. Bingham, 2021: Upper ocean stratification in the eastern Pacific during the SPURS-2 field campaign. J. Geophys. Res. Oceans, 126, e2020JC016591, https://doi.org/10.1029/2020JC016591.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kim, S.-B., I. Fukumori, and T. Lee, 2006: The closure of the ocean mixed layer temperature budget using level-coordinate model fields. J. Atmos. Oceanic Technol., 23, 840853, https://doi.org/10.1175/JTECH1883.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kummerow, C., 1998: Beamfilling errors in passive microwave rainfall retrievals. J. Appl. Meteor., 37, 356370, https://doi.org/10.1175/1520-0450(1998)037<0356:BEIPMR>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lee, T., G. Lagerloef, M. M. Gierach, H.-Y. Kao, S. Yueh, and K. Dohan, 2012: Aquarius reveals salinity structure of tropical instability waves. Geophys. Res. Lett., 39, L12610, https://doi.org/10.1029/2012GL052232.

    • Search Google Scholar
    • Export Citation
  • Lindstrom, E. J., J. B. Edson, J. J. Schanze, and A. Y. Shcherbina, 2019: SPURS-2: Salinity processes in the upper-ocean regional study 2. The eastern equatorial Pacific experiment. Oceanography, 32, 1519, https://doi.org/10.5670/oceanog.2019.207.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, X., and H. Zhou, 2020: Seasonal variations of the North Equatorial Current across the Pacific Ocean. J. Geophys. Res. Oceans, 125, e2019JC015895, https://doi.org/10.1029/2019JC015895.

    • Crossref
    • Export Citation
  • Lukas, R., and E. Lindstrom, 1991: The mixed layer of the western equatorial Pacific Ocean. J. Geophys. Res., 96, 33433357, https://doi.org/10.1029/90JC01951.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Masson, S., J.-P. Boulanger, C. Menkes, P. Delecluse, and T. Yamagata, 2004: Impact of salinity on the 1997 Indian Ocean dipole event in a numerical experiment. J. Geophys. Res., 109, C02002, https://doi.org/10.1029/2003JC001807.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Meissner, T., and F. J. Wentz, 2019: SMAP sea surface salinity products, ver. 4.0. PO.DAAC, accessed 21 May 2020, https://doi.org/10.5067/SMP40-3SPCS.

    • Crossref
    • Export Citation
  • Mickett, J. B., Y. L. Serra, M. F. Cronin, and M. H. Alford, 2010: Resonant forcing of mixed layer inertial motions by atmospheric easterly waves in the northeastern tropical Pacific. J. Phys. Oceanogr., 40, 401416, https://doi.org/10.1175/2009JPO4276.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Moisan, J. R., and P. P. Niiler, 1998: The seasonal heat budget of the North Pacific: Net heat flux and heat storage rates (1950–1990). J. Phys. Oceanogr., 28, 401421, https://doi.org/10.1175/1520-0485(1998)028<0401:TSHBOT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Osse, J., S. Stalin, C. Meinig, and H. Milburn, 2015: The PRAWLER, a vertical profiler: Powered by wave energy. Oceans 2015 MTS/IEEE, IEEE, Washington, D.C., 18, https://doi.org/10.23919/OCEANS.2015.7404354.

  • Paulson, C. A., and J. J. Simpson, 1977: Irradiance measurements in the upper ocean. J. Phys. Oceanogr., 7, 952956, https://doi.org/10.1175/1520-0485(1977)007<0952:IMITUO>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pujiana, K., and M. J. McPhaden, 2018: Ocean surface layer response to convectively coupled Kelvin waves in the eastern equatorial Indian Ocean. J. Geophys. Res. Oceans, 123, 57275741, https://doi.org/10.1029/2018JC013858.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ren, L., and S. C. Riser, 2009: Seasonal salt budget in the northeast Pacific Ocean. J. Geophys. Res., 114, C12004, https://doi.org/10.1029/2009JC005307.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ren, L., K. Speer, and E. P. Chassignet, 2011: The mixed layer salinity budget and sea ice in the Southern Ocean. J. Geophys. Res., 116, C08031, https://doi.org/10.1029/2010JC006634.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Reynolds, R. W., T. M. Smith, C. Liu, D. B. Chelton, K. S. Casey, and M. G. Schlax, 2007: Daily high-resolution blended analyses for sea surface temperature. J. Climate, 20, 54735496, https://doi.org/10.1175/2007JCLI1824.1.

    • Search Google Scholar
    • Export Citation
  • Roemmich, D., M. Morris, W. R. Young, and J. R. Donguy, 1994: Fresh equatorial jets. J. Phys. Oceanogr., 24, 540558, https://doi.org/10.1175/1520-0485(1994)024<0540:FEJ>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Saha, A., N. Serra, and D. Stammer, 2021: Growth and decay of northwestern tropical Atlantic barrier layers. J. Geophys. Res. Oceans, 126, e2020JC016956, https://doi.org/10.1029/2020JC016956.

  • Sprintall, J., and M. Tomczak, 1992: Evidence of the barrier layer in the surface layer of the tropics. J. Geophys. Res., 97, 73057316, https://doi.org/10.1029/92JC00407.

    • Search Google Scholar
    • Export Citation
  • Suga, T., K. Motoki, and Y. Aoki, 2004: The North Pacific climatology of winter mixed layer and mode waters. J. Phys. Oceanogr., 34, 322, https://doi.org/10.1175/1520-0485(2004)034<0003:TNPCOW>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Veneziani, M., A. Griffa, Z. Garrafo, and J. A. Mensa, 2014: Barrier layers in the tropical South Atlantic: Mean dynamics and sub-mesoscale effects. J. Phys. Oceanogr., 44, 265288, https://doi.org/10.1175/JPO-D-13-064.1.

    • Search Google Scholar
    • Export Citation
  • Vialard, J., and P. Delecluse, 1998a: An OGCM study for the TOGA decade. Part I: Role of salinity in the physics of the western Pacific fresh pool. J. Phys. Oceanogr., 28, 10711088, https://doi.org/10.1175/1520-0485(1998)028<1071:AOSFTT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Vialard, J., and P. Delecluse, 1998b: An OGCM study for the TOGA decade. Part II: Barrier-layer formation and variability. J. Phys. Oceanogr., 28, 10891106, https://doi.org/10.1175/1520-0485(1998)028<1089:AOSFTT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Wentz, F. J., J. Scott, R. Hoffman, M. Leidner, R. Atlas, and J. Ardizzone, 2015: Remote Sensing Systems Cross-Calibrated Multi-Platform (CCMP) 6-hourly ocean vector wind analysis product on 0.25 deg grid, version 2.0. Remote Sensing Systems, accessed 1 September 2020, http://www.remss.com/measurements/ccmp.

  • Wijesekera, H. W., D. L. Rudnick, C. A. Paulson, S. D. Pierce, W. S. Pegau, J. Mickett, and M. C. Gregg, 2005: Upper ocean heat and freshwater budgets in the eastern Pacific warm pool. J. Geophys. Res., 110, C08004, https://doi.org/10.1029/2004JC002511.

    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., and S. G. H. Philander, 1994: A coupled ocean–atmosphere model of relevance to the ITCZ in the eastern Pacific. Tellus, 46A, 340350, https://doi.org/10.3402/tellusa.v46i4.15484.

    • Search Google Scholar
    • Export Citation
  • Yan, Y., L. Li, and C. Wang, 2017: The effects of oceanic barrier layer on the upper ocean response to tropical cyclones. J. Geophys. Res. Oceans, 122, 48294844, https://doi.org/10.1002/2017JC012694.

    • Search Google Scholar
    • Export Citation
  • Yin, X., J. Boutin, G. Reverdin, T. Lee, N. Martin, and S. Arnault, 2014: SMOS sea surface salinity signatures of tropical instability waves. J. Geophys. Res. Oceans, 119, 78117826, https://doi.org/10.1002/2014JC009960.

    • Search Google Scholar
    • Export Citation
  • Yu, L. S., 2011: A global relationship between the ocean water cycle and near-surface salinity. J. Geophys. Res., 116, C10025, https://doi.org/10.1029/2010JC006937.

    • Search Google Scholar
    • Export Citation
  • Zhurbas, V., and I. S. Oh, 2004: Drifter-derived maps of lateral diffusivity in the Pacific and Atlantic Oceans in relation to surface circulation patterns. J. Geophys. Res., 109, C05015, https://doi.org/10.1029/2003JC002241.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 723 721 36
Full Text Views 268 266 6
PDF Downloads 317 314 8

The Barrier Layer Effect on the Heat and Freshwater Balance from Moored Observations in the Eastern Pacific Fresh Pool

Shota KatsuraaScripps Institution of Oceanography, University of California, San Diego, La Jolla, California

Search for other papers by Shota Katsura in
Current site
Google Scholar
PubMed
Close
,
Janet SprintallaScripps Institution of Oceanography, University of California, San Diego, La Jolla, California

Search for other papers by Janet Sprintall in
Current site
Google Scholar
PubMed
Close
,
J. Thomas FarrarbDepartment of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts

Search for other papers by J. Thomas Farrar in
Current site
Google Scholar
PubMed
Close
,
Dongxiao ZhangcCooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, Seattle, Washington
dNOAA/Pacific Marine Environmental Laboratory, Seattle, Washington

Search for other papers by Dongxiao Zhang in
Current site
Google Scholar
PubMed
Close
, and
Meghan F. CronindNOAA/Pacific Marine Environmental Laboratory, Seattle, Washington

Search for other papers by Meghan F. Cronin in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Formation and evolution of barrier layers (BLs) and associated temperature inversions (TIs) were investigated using a 1-yr time series of oceanic and air–sea surface observations from three moorings deployed in the eastern Pacific fresh pool. BL thickness and TI amplitude showed a seasonality with maxima in boreal summer and autumn when BLs were persistently present. Mixed layer salinity (MLS) and mixed layer temperature (MLT) budgets were constructed to investigate the formation mechanism of BLs and TIs. The MLS budget showed that BLs were initially formed in response to horizontal advection of freshwater in boreal summer and then primarily maintained by precipitation. The MLT budget revealed that penetration of shortwave radiation through the mixed layer base is the dominant contributor to TI formation through subsurface warming. Geostrophic advection is a secondary contributor to TI formation through surface cooling. When the BL exists, the cooling effect from entrainment and the warming effect from detrainment are both significantly reduced. In addition, when the BL is associated with the presence of a TI, entrainment works to warm the mixed layer. The presence of BLs makes the shallower mixed layer more sensitive to surface heat and freshwater fluxes, acting to enhance the formation of TIs that increase the subsurface warming via shortwave penetration.

© 2022 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Shota Katsura, skatsura@ucsd.edu

Abstract

Formation and evolution of barrier layers (BLs) and associated temperature inversions (TIs) were investigated using a 1-yr time series of oceanic and air–sea surface observations from three moorings deployed in the eastern Pacific fresh pool. BL thickness and TI amplitude showed a seasonality with maxima in boreal summer and autumn when BLs were persistently present. Mixed layer salinity (MLS) and mixed layer temperature (MLT) budgets were constructed to investigate the formation mechanism of BLs and TIs. The MLS budget showed that BLs were initially formed in response to horizontal advection of freshwater in boreal summer and then primarily maintained by precipitation. The MLT budget revealed that penetration of shortwave radiation through the mixed layer base is the dominant contributor to TI formation through subsurface warming. Geostrophic advection is a secondary contributor to TI formation through surface cooling. When the BL exists, the cooling effect from entrainment and the warming effect from detrainment are both significantly reduced. In addition, when the BL is associated with the presence of a TI, entrainment works to warm the mixed layer. The presence of BLs makes the shallower mixed layer more sensitive to surface heat and freshwater fluxes, acting to enhance the formation of TIs that increase the subsurface warming via shortwave penetration.

© 2022 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Shota Katsura, skatsura@ucsd.edu
Save