Meteorology and Atmospheric Physics

, Volume 123, Issue 1–2, pp 1–15 | Cite as

Observations of the marine boundary layer under a cutoff low over the southeast Pacific Ocean

  • David A. Rahn
Original Paper


Stratocumulus is often present offshore of Peru and northern Chile and exists at the top of a cool, moist and well-mixed marine boundary layer (MBL) under a marked temperature inversion maintained by large-scale subsidence. The subtropical MBL and stratocumulus has been the focus of many recent studies, but mid-latitude systems can exert a strong influence. However, this connection is not well established due to debatable model results and few in situ measurements south of 20°S. During a 2-week field campaign in August 2011 at Robinson Crusoe Island (~700 km offshore at 33.6°S), radiosondes were launched to observe the response of the MBL to mid-latitude synoptic forcing. During the observation period a broad, slow-moving cutoff low (COL) passed over the region. Other observations include COSMIC GPS, infrared satellite imagery, TRMM radar reflectivity, and operational radiosondes from the Chilean weather service. A numerical simulation is included to diagnose the synoptic features. The inversion prior to the COL was maintained and lifted above 5 km as the COL passed over the island. Soon after the COL center passed the island, the MBL top did not descend or reform near the surface and then deepen, but rather an inversion reformed at ~2.7 km. Using a variety of datasets, the height of the reformation of the inversion is related to the cloud top height of the scattered shallow cumulus convection under the COL, which coincides with the level of maximum convergence of the vertical velocity.


Global Position System Brightness Temperature Temperature Inversion Vertical Wind Shear Marine Boundary Layer 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This project was supported by the Chilean Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT) 3110100 and New Faculty Startup funds at KU. Thanks to José Rutllant, Carlos Parra of the Dirección Meteorológica de Chile, and Rosa Zamora for their help during the field campaign on RCI. Roberto Rondanelli helped with processing the satellite data. I also thank two anonymous reviewers for their comments.


  1. Allen G, Coe H, Clarke A, Bretherton C, Wood R, Abel SJ, Barrett P, Brown P, George R, Freitag S, McNaughton C, Howell S, Shank L, Kapustin V, Brekhovskikh V, Kleinman L, Lee Y-N, Springston S, Toniazzo T, Krejci R, Fochesatto J, Shaw G, Krecl P, Brooks B, McMeeking G, Bower KN, Williams PI, Crosier J, Crawford I, Connolly P, Allan JD, Covert D, Bandy AR, Russell LM, Trembath J, Bart M, McQuaid JB, Wang J, Chand D (2011) South East Pacific atmospheric composition and variability sampled along 20°S during VOCALS-Rex. Atmos Chem Phys 11:5237–5262. doi: 10.5194/acp-11-5237-2011 CrossRefGoogle Scholar
  2. Anthes RA, Bernhardt PA, Chen Y, Cucurull L, Dymond KF, Ector D, Healy SB, Ho SP, Hunt DC, Kuo YH, Liu H, Manning K, McCormick C, Meehan TK, Randel WJ, Rocken C, Schreiner WS, Sokolovskiy SV, Syndergaard S, Thompson DC, Trenberth KE, Wee TK, Yen NL, Zhang Z (2008) The COSMIC/FORMOSAT-3 mission: early results. Bull Am Meteorol Soc 89:313–333. doi: 10.1175/BAMS-89-3-313 CrossRefGoogle Scholar
  3. Bretherton CS, Park S (2009) A new moist turbulence parameterization in the Community Atmosphere Model. J Clim 22:3422–3448CrossRefGoogle Scholar
  4. Chand D, Hegg DA, Wood R, Shaw GE, Wallace D, Covert DS (2010) Source attribution of climatically important aerosol properties measured at Paposo (Chile) during VOCALS. Atmos Chem Phys 10:10789–10801. doi: 10.5194/acp-10-10789-2010 CrossRefGoogle Scholar
  5. de Szoeke SP, Fairall CW, Wolfe DE, Bariteau L, Zuidema P (2010) Surface flux observations on the southeastern tropical Pacific Ocean and attribution of SST errors in coupled ocean–atmosphere models. J Clim 23:4152–4174CrossRefGoogle Scholar
  6. Field PR, Wood R (2007) Precipitation and cloud structure in midlatitude cyclones. J Clim 20:233–254CrossRefGoogle Scholar
  7. Fuenzalida HA, Sanchez R, Garreaud RD (2005) A climatology of cutoff lows in the Southern Hemisphere. J Geophys Res 110:D18101. doi: 10.1029/2005JD005934 CrossRefGoogle Scholar
  8. Garreaud R, Fuenzalida H (2007) The influence of Andes on cutoff lows: a modeling study. Mon Weather Rev 135:1596–1613CrossRefGoogle Scholar
  9. Garreaud RD, Rutllant J, Quintana J, Carrasco J, Minnis P (2001) CIMAR-5: a snapshot of the lower troposphere over the subtropical southeast Pacific. Bull Am Meteorol Soc 82:2193–2207CrossRefGoogle Scholar
  10. Garreaud RD, Rutllant JA, Muñoz RC, Rahn DA, Ramos M, Figueroa D (2011) VOCALS-CUpEx: the Chilean upwelling experiment. Atmos Chem Phys 11:2015–2029CrossRefGoogle Scholar
  11. Guo P, Kuo Y-H, Sokolovskiy SV, Lenschow DH (2011) Estimating atmospheric boundary layer depth using COSMIC radio occultation data. J Atmos Sci 68(8):1703–1713. doi: 10.1175/2011JAS3612.1 CrossRefGoogle Scholar
  12. Hill EF, Browning KA (1987) Case study of a persistent mesoscale cold pool. Meteorol Mag 116:297–309Google Scholar
  13. Iacono MJ, Delamere JS, Mlawer EJ, Shephard MW, Clough SA, Collins WD (2008) Radiative forcing by long-lived greenhouse gases: calculations with the AER radiative transfer models. J Geophys Res 113:D13103CrossRefGoogle Scholar
  14. Janjic ZI (2000) Comments on “Development and evaluation of a convection scheme for use in climate models.” J Atmos Sci 57:3686CrossRefGoogle Scholar
  15. Janjić ZI (1994) The step-mountain eta coordinate model: further developments of the convection, viscous sublayer and turbulence closure schemes. Mon Weather Rev 122:927–945CrossRefGoogle Scholar
  16. Jones CR, Bretherton CS, Leon D (2011) Coupled vs. decoupled boundary layers in VOCALS-Rex. Atmos Chem Phys 11:7143–7153. doi: 10.5194/acp-11-7143-2011 CrossRefGoogle Scholar
  17. Keyser D, Shapiro MA (1986) A review of the structure and dynamics of upper level frontal zones. Mon Weather Rev 114:452–499CrossRefGoogle Scholar
  18. Klein SA, Hartmann DL (1993) The seasonal cycle of low stratiform clouds. J Clim 6:1587–1606CrossRefGoogle Scholar
  19. Kummerow C, Barnes W, Kozu T, Shiue J, Simpson J (1998) The Tropical Rainfall Measuring Mission (TRMM) sensor package. J Atmos Ocean Technol 15:809–816CrossRefGoogle Scholar
  20. Leon DC, Wang Z, Liu D (2008) Climatology of drizzle in marine boundary layer clouds based on 1 year of data from CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). J Geophys Res 113:D00A14. doi: 10.1029/2008JD009835 CrossRefGoogle Scholar
  21. Ma CC, Mechoso CR, Robertson AW, Arakawa A (1996) Peruvian stratus clouds and the tropical Pacific circulation: a coupled ocean-atmosphere GCM study. J Clim 9:1635–1645CrossRefGoogle Scholar
  22. Matsumoto SK, Ninomiya K, Hasegawa R, Miki Y (1982) The structure and role of a subsynoptic cold vortex on the heavy precipitation. J Meteorol Soc Jpn 60:339–353Google Scholar
  23. Mechem DB, Kogan YL, Schultz DM (2010a) Large-eddy observation of post-cold-frontal continental stratocumulus. J Atmos Sci 67:3368–3383. doi: 10.1175/2010JAS3389.1 CrossRefGoogle Scholar
  24. Mechem DB, Kogan YL, Schultz DM (2010b) Large-eddy simulation of post-cold-frontal continental stratocumulus. J Atmos Sci 67:3835–3853. doi: 10.1175/2010JAS3467.1 CrossRefGoogle Scholar
  25. Mechoso CR, Robertson AW, Barth N, Davey MK, Delecluse P, Gent PR, Ineson S, Kirtman B, Latif M, Le Treut H, Nagai T, Neelin JD, Philaner SGH, Polcher J, Schopt PS, Stockdale T, Suarez MJ, Terray L, Thual O, Tribbia JJ (1995) The seasonal cycle over the tropical Pacific in coupled ocean-atmosphere general circulation models. Mon Weather Rev 123:2825–2838CrossRefGoogle Scholar
  26. Painemal D, Garreaud R, Ruttlant J, Zuidema P (2010) Southeast Pacific stratocumulus: high-frequency variability and mesoscale structures over San Felix Island. J Appl Meteorol Climatol 49:463–477CrossRefGoogle Scholar
  27. Palmén E, Newton CW (1969) Atmospheric circulation systems: their structure and physical interpretation. Academic Press, New YorkGoogle Scholar
  28. Pleim JE (2006) A simple, efficient solution of flux–profile relationships in the atmospheric surface layer. J Appl Meteorol Climatol 45:341–347CrossRefGoogle Scholar
  29. Pleim JE, Xiu A (2003) Development of a land-surface model. Part II: data assimilation. J Appl Meteorol 42:1811–1822CrossRefGoogle Scholar
  30. Rahn DA, Garreaud R (2010a) 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 CrossRefGoogle Scholar
  31. Rahn DA, Garreaud R (2010b) 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 CrossRefGoogle Scholar
  32. Reboita MS, Nieto R, Gimeno L, da Rocha RP, Ambrizzi T, Garreaud R, Krüger LF (2010) Climatological features of cutoff low systems in the Southern Hemisphere. J Geophys Res 115:D17104. doi: 10.1029/2009JD013251 CrossRefGoogle Scholar
  33. Rutllant JA, Muñoz RC, Garreaud RD (2013) Meteorological observations in the Northern Chilean coast during VOCALS-REx. Atmos Chem Phys Discuss 12:22783–22811. doi: 10.5194/acpd-12-22783-2012 CrossRefGoogle Scholar
  34. Sandu I, Stevens B (2011) On the factors modulating the stratocumulus to cumulus transitions. J Atmos Sci 68:1865–1881CrossRefGoogle Scholar
  35. Sinclair VA, Belcher SE, Gray SL (2010) Synoptic controls on boundary-layer characteristics. Bound-Lay Meteorol 134:387–409. doi: 10.1007/s10546-009-9455-6 CrossRefGoogle Scholar
  36. Skamarock WC, Klemp JB, Dudhia J, Gill DO, Barker DM, Wang W, Powers JG (2008) A description of the advanced research WRF version 3, NCAR Tech Note, NCAR/TN–475+STRGoogle Scholar
  37. Stull RB (1988) An introduction to boundary layer meteorology. Kluwer Academic, New YorkCrossRefGoogle Scholar
  38. Thompson G, Field PR, Rasmussen RM, Hall WD (2008) Explicit forecasts of winter precipitation using an improved bulk microphysics scheme. Part II: implementation of a new snow parameterization. Mon Weather Rev 136:5095–5115CrossRefGoogle Scholar
  39. Wood R, Mechoso CR, Bretherton CS, Weller RA, Huebert B, Straneo F, Albrecht BA, Coe H, Allen G, Vaughan G, Daum P, Fairall C, Chand D, Gallardo Klenner L, Garreaud R, Grados C, Covert DS, Bates TS, Krejci R, Russell LM, de Szoeke S, Brewer A, Yuter SE, Springston SR, Chaigneau A, Toniazzo T, Minnis P, Palikonda R, Abel SJ, Brown WOJ, Williams S, Fochesatto J, Brioude J, Bower KN (2011) The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx): goals, platforms, and field operations. Atmos Chem Phys 11:627–654. doi: 10.5194/acp-11-627-2011 CrossRefGoogle Scholar
  40. Wyant MC, Bretherton CS, Rand HA, Stevens DE (1997) Numerical simulations and a conceptual model of the stratocumulus to trade cumulus transition. J Atmos Sci 54:168–192CrossRefGoogle Scholar
  41. Wyant MC, Wood R, Bretherton CS, Mechoso CR et al (2009) The PreVOCA experiment: modeling the lower troposphere in the Southeast Pacific. Atmos Chem Phys Discuss 9:23909–23953CrossRefGoogle Scholar
  42. Xiao H, Wu C-M, Mechoso CR (2011) Buoyancy reversal, decoupling and the transition from stratocumulus to shallow cumulus topped marine boundary layers. Clim Dyn 37(5–6):971–984CrossRefGoogle Scholar
  43. Xie F, Wu DL, Ao CO, Mannucci AJ, Kursinski ER (2012) Advances and limitations of atmospheric boundary layer observations with GPS occultation over southeast Pacific Ocean. Atmos Chem Phys 12:903–918CrossRefGoogle Scholar
  44. Xiu A, Pleim JE (2001) Development of a land surface model. Part I: application in a mesoscale meteorological model. J Appl Meteorol 40:192–209CrossRefGoogle Scholar
  45. Zuidema P, Painemal D, de Szoeke S, Fairall C (2009) Stratocumulus cloud-top height estimates and their climatic implications. J Clim 22:4652–4666CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Wien 2013

Authors and Affiliations

  1. 1.Atmospheric Science Program, Department of GeographyUniversity of KansasLawrenceUSA

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