ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-10-26437-2010 VOCALS-CUpEx: the Chilean Upwelling Experiment Garreaud R. D. 1 4 Rutllant J. A. 1 2 Muñoz R. C. 1 Rahn D. A. 1 Ramos M. 2 Figueroa D. 3 Department of Geophysics, Universidad de Chile, Santiago, Chile Center for Advanced Studies in Arid Zones (CEAZA), Facultad de Ciencias del Mar, Universidad Católica del Norte y Universidad de la Serena, Chile Department of Geophysics, Universidad de Concepción, Concepción, Chile Advance Mining Technology Center, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile 05 11 2010 10 11 26437 26472 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/10/26437/2010/acpd-10-26437-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/10/26437/2010/acpd-10-26437-2010.pdf

The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) was a major field experiment conducted in spring of 2008 off southern Peru and northern Chile, aimed at better understanding the coupled climate systems of the southeast Pacific. Because of logistical constrains, the coastal area around 30° S was not sampled during VOCALS-REx. This area not only marks the poleward edge of the subtropical stratocumulus cloud regime (thus acting as a source of transient disturbances) but is also one of the most active upwelling centers and source of surface ocean kinetic energy along the Chilean coast. To fill such an observational gap, a small, brief, but highly focused field experiment was conducted in late spring 2009 in the near-shore region around 30° S. The Chilean Upwelling Experiment (CUpEx) was endorsed by VOCALS as a regional component. <br><br> CUpEx included long-term monitoring, an intensive two-week field campaign and off-shore research flights. Our goal was to obtain an atmospheric/oceanic dataset with enough temporal and spatial coverage to be able to document (a) the mean diurnal cycles of the lower-troposphere and upper-ocean in a region of complex topography and coastline geometry, and (b) the ocean-atmosphere response to the rapid changes in coastal winds from strong, upwelling-favorable southerly winds to relaxed southerlies or even downwelling-favorable northerlies. In this paper we describe the measurement platforms and sampling strategy, and provide an observational overview, highlighting some key mean and transient features.

 References Avissar, R., Holder, H., Abehserra, N., Bolch, M., Canning, P., Magalhaes, J., Walko, R., Novick, K., Katul, G., and Prince, K.: The Duke University Helicopter Observation Platform, B Am. Meteorol. Soc., 90, 939–954, 2009. Beswick, K. M., Gallagher, M. W., Webb, A. R., Norton, E. G., and Perry, F.: Application of the Aventech AIMMS20AQ airborne probe for turbulence measurements during the Convective Storm Initiation Project, Atmos. Chem. Phys., 8, 5449–5463, doi:10.5194/acp-8-5449-2008, 2008. Del-Val, E., Armesto, J., Barbosa, O., Christie, D., Gutiérrez, A., Jones, C., Marquet, P., and Weathers, K.: Rain forest islands in the Chilean semiarid region: fog-dependency, ecosystem persistence and tree regeneration, Ecosystems, 9, 598–608, 2006. Figueroa, D. and Moffat, C.: On the influence of topography in the induction of coastal upwelling along the Chilean coast, Geophys. Res. Lett., 27, 3905–3908, 2000. Garreaud, R. and Muñoz, R.: The low-level jet off the west coast of subtropical South America: Structure and variability, Mon. Weather Rev., 133, 2246–2261, 2005. Garreaud, R., Rutllant, J., and Fuenzalida, H.: Coastal lows along the subtropical west coast of South America: Mean structure and evolution, Mon. Weather Rev., 130, 75–88, 2002. Gonzalez, C., Rutllant J., and Paolini, P.: Frecuencia y Albedo de Estratoc\'umulos Costeros entre 24–32° S. 4to Taller DOCA, Dirección Meteorológica de Chile, Santiago-Chile, 18 y 19 de Octubre de 2007. Hormazabal, S., Shaffer, G., and Leth, O.: Coastal transition zone off Chile, J. Geophys. Res, 109, C01021, doi:10.1029/2003JC001956, 2004. Mechoso, C. M. and Wood, R.: An abbreviated history of VOCALS, Clivar Exchanges, 15, 3–5, 2010. Muñoz, R.: Diurnal cycle of surface winds over the subtropical southeast Pacific, J. Geophys. Res., 113, D13107, doi:10.1029/2008JD009957, 2008. Muñoz, R. and Garreaud, R.: Dynamics of the low-level jet off the west coast of subtropical South America, Mon. Weather Rev., 133, 3661–3677, 2005. Muñoz, R., Garreaud, R., Gallardo, L., Cabello, A., and Rosenbluth, B.: Mejoría del Conocimiento del Recurso Eólico en el Norte y Centro del País, Santiago: Universidad de Chile, 2003. Narváez, D., Navarrete, S., Largier, J., and Vargas, C.: Onshore advection of warm water, larval invertebrate settlement, and relaxation of upwelling off central Chile, Mar. Ecol. Prog. Ser., 309, 159–173, 2006. Nuss, W.: Synoptic-Scale Structure and the Character of Coastally Trapped Wind Reversals, 2010. Painemal, D., Garreaud, R., Rutllant, J., and Zuidema, P.: Southeast Pacific Stratocumulus: High-Frequency Variability and Mesoscale Structures over San Felix Island, J. Appl. Meteorol. Climatol., 49, 463–477, 2010. Rahn, D. A. and Garreaud, R.: Marine boundary layer over the subtropical southeast Pacific during VOCALS-REx – Part 2: Synoptic variability, Atmos. Chem. Phys., 10, 4507–4519, doi:10.5194/acp-10-4507-2010, 2010a. Rahn, D. A. and Garreaud, R.: Marine boundary layer over the subtropical southeast Pacific during VOCALS-REx – Part 1: Mean structure and diurnal cycle, Atmos. Chem. Phys., 10, 4491–4506, doi:10.5194/acp-10-4491-2010, 2010b. Rahn, D., Garreaud, R., and Rutllan, J.: The coastal jet maximum off north-central Chile (30° S), Mon. Weather Rev., in review, 2010. Ramp, S. and Bahr, F.: Seasonal Evolution of the Upwelling Process South of Cape Blanco, J. Phys. Oceanogr., 38, 3–28, 2008. Ramp, S., Paduan, J., Shulman, I., Kindle, J., Bahr, F., and Chavez, F.: Observations of upwelling and relaxation events in the northern Monterey Bay during August 2000, J. Geophys. Res., 110, C07013, doi:10.1029/2004JC002538, 2005. Renault, L., Dewitte, B., Falvey, M., Garreaud, R., Echevin, V., and Bonjean, F.: Impact of atmospheric coastal jet off central Chile on sea surface temperature from satellite observations (2000–2007), J. Geophys. Res, 114, C08006, doi:10.1029/2008JC005083, 2009. Rutllant, J. and Montecinos, V.: Multiscale upwelling forcing cycles and biological response off north-central Chile, Revista Chilena de Historia Natural, 75, 217–231, 2002. Strub, P., Mesias, J., Montecino, V., Rutllant, J., and Salinas, S.: Chapter 10. Coastal ocean circulation off western South America, in: The sea, edited by: Robinson, A. R. and Brink, K. H., Vol 11, J. Wiley & Sons, New York, 273–313, 1998. Tapia, F., Navarrete, S., Castillo, M., Menge, B., Castilla, J., Largier, J., Wieters, E., Broitman, B., and Barth, J.: Thermal indices of upwelling effects on inner-shelf habitats, Prog. Oceanogr., 83, 278–287, 2009. Wentz, F.: A well-calibrated ocean algorithm for special sensor microwave/imager, J. Geophys. Res, 102, 8703–8718, 1997. Wood, R., Bretherton, C., Huebert, B., Mechoso, C., and Weller, R.: The VAMOS Ocean-Cloud-Atmosphere-Land Study (VOCALS): Improving understanding, model simulations, and prediction of the southeast Pacific climate system, Post-VOCALS-Rex Rep, available online at: http://www.eol.ucar.edu/projects/vocals/, 2007. Wood, R., Bretherton, C. S., Mechoso, C. R., Weller, R. A., Huebert, B., Straneo, F., Albrecht, B. A., Coe, H., Allen, G., Vaughan, G., Daum, P., Fairall, C., Chand, D., Gallardo Klenner, L., Garreaud, R., Grados Quispe, C., Covert, D. S., Bates, T. S., Krejci, R., Russell, L. M., de Szoeke, S., Brewer, A., Yuter, S. E., Springston, S. R., Chaigneau, A., Toniazzo, T., Minnis, P., Palikonda, R., Abel, S. J., Brown, W. O. J., Williams, S., Fochesatto, J., and Brioude, J.: The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx): goals, platforms, and field operations, Atmos. Chem. Phys. Discuss., 10, 20769–20822, doi:10.5194/acpd-10-20769-2010, 2010.