Morrow, R. M., Ohman, M. D., Goericke, R., Kelly, T. B., Stephens, B. M., & Stukel, M. R. (2018). CCE V: Primary production, mesozooplankton grazing, and the biological pump in the California Current Ecosystem: Variability and response to El Niño. Deep Sea Research Part I: Oceanographic Research Papers , 140 , 52–62.
Abstract: Predicting marine carbon sequestration in a changing climate requires mechanistic understanding of the processes controlling sinking particle flux under different climatic conditions. The recent occurrence of a warm anomaly (2014-2015) followed by an El Nino (2015-2016) in the southern sector of the California Current System presented an opportunity to analyze changes in the biological carbon pump in response to altered climate forcing. We compare primary production, mesozooplankton grazing, and carbon export from the euphotic zone during quasi-Lagrangian experiments conducted in contrasting conditions: two cruises during warm years – one during the warm anomaly in 2014 and one toward the end of El Nino 2016 – and three cruises during El Ninoneutral years. Results showed no substantial differences in the relationships between vertical carbon export and its presumed drivers (primary production, mesozooplankton grazing) between warm and neutral years. Mesozooplankton fecal pellet enumeration and phaeopigment measurements both showed that fecal pellets were the dominant contributor to export in productive upwelling regions. In more oligotrophic regions, fluxes were dominated by amorphous marine snow with negligible pigment content. We found no evidence for a significant shift in the relationship between mesozooplankton grazing rate and chlorophyll concentration. However, massspecific grazing rates were lower at low-to-moderate chlorophyll concentrations during warm years relative to neutral years. We also detected a significant difference in the relationship between phytoplankton primary production and photosynthetically active radiation between years: at similar irradiance and nutrient concentrations, productivity decreased during the warm events. Whether these changes resulted from species composition changes remains to be determined. Overall, our results suggest that the processes driving export remain similar during different climate conditions, but that species compositional changes or other structural changes require further attention.
Kvaleberg, E. (2004). Generation of Cold Core Filaments and Eddies Through Baroclinic Instability on a Continental Shelf . Ph.D. thesis, Florida State University, Tallahassee, FL.
Abstract: The formation of cold core filaments on an idealized continental shelf is investigated using a numerical model to simulate the ocean's response to surface cooling. A horizontal density gradient forms because of uneven buoyancy loss due to the sloping bottom, and this gradient induces an alongshelf current in thermal wind balance, that in time becomes unstable. As the instabilities grow, filaments, and later eddies, are generated so that dense water near the coast is mixed offshore. Scaling arguments of the filament wavelength indicate that the current is baroclinically unstable, and an analytical model of the frontal expansion with time is in very good agreement with the simulations. This study was inspired by satellite observations of sea surface temperature on the West Florida Shelf during the winter months, in which it is clearly seen that cold core filaments extend from a thermal front. Numerical experiments are therefore designed to allow for reliable comparisons with conditions in this region.
Rousset, C., Houssais, M. - N., & Chassignet, E. P. (2009). A multi-model study of the restratification phase in an idealized convection basin. Ocean Modelling , 26 (3-4), 115–133.
Griffies, S. M., Biastoch, A., Böning, C., Bryan, F., Danabasoglu, G., Chassignet, E. P., et al. (2009). Coordinated Ocean-ice Reference Experiments (COREs). Ocean Modelling , 26 (1-2), 1–46.
Glinton, M. R., Gray, S. L., Chagnon, J. M., & Morcrette, C. J. (2017). Modulation of precipitation by conditional symmetric instability release. Atmospheric Research , 185 , 186–201.
Shinoda, T., Kiladis, G. N., & Roundy, P. E. (2009). Statistical representation of equatorial waves and tropical instability waves in the Pacific Ocean. In Atmospheric Research (Vol. 94, pp. 37–44).
Huang, B., Hu, Z. - Z., Kinter, J. L., Wu, Z., & Kumar, A. (2012). Connection of stratospheric QBO with global atmospheric general circulation and tropical SST. Part I: methodology and composite life cycle. Clim Dyn , 38 (1-2), 1–23.
Hart, R. E., Maue, R. N., & Watson, M. C. (2007). Estimating Local Memory of Tropical Cyclones through MPI Anomaly Evolution. Mon. Wea. Rev. , 135 (12), 3990–4005.
Ali, M. M., Bhat, G. S., Long, D. G., Bharadwaj, S., & Bourassa, M. A. (2013). Estimating Wind Stress at the Ocean Surface From Scatterometer Observations. IEEE Geosci. Remote Sensing Lett. , 10 (5), 1129–1132.
