Editorial Type:
Article
Article Type:
Research Article

Low Cloud Type over the Ocean from Surface Observations. Part II: Geographical and Seasonal Variations

Joel R. Norris Department of Atmospheric Sciences, University of Washington, Seattle, Washington

Search for other papers by Joel R. Norris in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Mar 1998
DOI:
https://doi.org/10.1175/1520-0442(1998)011<0383:LCTOTO>2.0.CO;2
Page(s):
383–403
Restricted access

Abstract

Synoptic surface cloud observations primarily made by volunteer observing ships are used to construct global climatologies of the frequency of occurrence of individual low cloud types over the ocean for daytime during summer and winter seasons for the time period 1954–92. This essentially separates the previous S. Warren et al. “stratus,” “cumulus,” and “cumulonimbus” climatologies into their constituent cloud types. The different geographical and seasonal distributions of low cloud types indicate that each type within the Warren et al. categories is associated with different meteorological conditions. Hence, investigations based on individual low cloud types instead of broader categories will best identify the processes and variability in meteorological parameters responsible for observed variability in cloudiness. The present study is intended to provide a foundation for future investigations by documenting the climatological distributions of low cloud type frequency and demonstrating the physical consistency with expected patterns of boundary layer structure, advection, surface divergence, and synoptic activity over the global ocean.

Further analyses are conducted to examine in greater detail transitions in low cloud type and related boundary layer processes in the eastern subtropical North Pacific, eastern equatorial Pacific, and western North Pacific during summer. Maxima in the climatological frequencies of stratocumulus, cumulus-with-stratocumulus, and cumulus occur progressively equatorward over eastern subtropical oceans, consistent with an increasing decoupled boundary layer. This transition is also observed north of the equatorial cold tongue, but advection over colder SST on the southern side of equatorial cold tongue sometimes produces an absence of low cloudiness. A transition between cumuliform low cloud types to the south and stratiform low cloud types to the north occurs over the region of strong SST gradient in the western North Pacific, and during summer the maximum frequency of stratus associated with precipitation is collocated with the region of strong SST gradient.

* Current affiliation: National Center for Atmospheric Research, Boulder, Colorado.

Corresponding author address: Joel R. Norris, NCAR/ASP, P.O. Box 3000, Boulder, CO 80307-3000.

Abstract

Synoptic surface cloud observations primarily made by volunteer observing ships are used to construct global climatologies of the frequency of occurrence of individual low cloud types over the ocean for daytime during summer and winter seasons for the time period 1954–92. This essentially separates the previous S. Warren et al. “stratus,” “cumulus,” and “cumulonimbus” climatologies into their constituent cloud types. The different geographical and seasonal distributions of low cloud types indicate that each type within the Warren et al. categories is associated with different meteorological conditions. Hence, investigations based on individual low cloud types instead of broader categories will best identify the processes and variability in meteorological parameters responsible for observed variability in cloudiness. The present study is intended to provide a foundation for future investigations by documenting the climatological distributions of low cloud type frequency and demonstrating the physical consistency with expected patterns of boundary layer structure, advection, surface divergence, and synoptic activity over the global ocean.

Further analyses are conducted to examine in greater detail transitions in low cloud type and related boundary layer processes in the eastern subtropical North Pacific, eastern equatorial Pacific, and western North Pacific during summer. Maxima in the climatological frequencies of stratocumulus, cumulus-with-stratocumulus, and cumulus occur progressively equatorward over eastern subtropical oceans, consistent with an increasing decoupled boundary layer. This transition is also observed north of the equatorial cold tongue, but advection over colder SST on the southern side of equatorial cold tongue sometimes produces an absence of low cloudiness. A transition between cumuliform low cloud types to the south and stratiform low cloud types to the north occurs over the region of strong SST gradient in the western North Pacific, and during summer the maximum frequency of stratus associated with precipitation is collocated with the region of strong SST gradient.

* Current affiliation: National Center for Atmospheric Research, Boulder, Colorado.

Corresponding author address: Joel R. Norris, NCAR/ASP, P.O. Box 3000, Boulder, CO 80307-3000.

Save
Cover Journal of Climate
Journal of Climate

  • Arking, A., 1991: The radiative effects of clouds and their impact on climate. Bull. Amer. Meteor. Soc.,72, 795–813.

  • Bond, N. A., 1992: Observations of planetary boundary-layer structure in the eastern equatorial Pacific. J. Climate,5, 699–706.

  • Bretherton, C. S., 1992: A conceptual model of the stratocumulus-trade-cumulus transition in the subtropical oceans. Preprints, Proc. 11th Int. Conf. on Clouds and Precipitation, Vol. I, Montreal, PQ, Canada, Amer. Meteor. Soc., 374–377.

  • ——, and R. Pincus, 1995: Cloudiness and marine boundary layer dynamics in the ASTEX Lagrangian experiments. Part I: Synoptic setting and vertical structure. J. Atmos. Sci.,52, 2707–2723.

  • ——, and W. C. Wyant, 1997: Moisture transport, lower-tropospheric stability, and decoupling of cloud-topped boundary layers. J. Atmos. Sci.,54, 148–167.

  • ——, P. Austin, and S. T. Siems, 1995: Cloudiness and marine boundary layer dynamics in the ASTEX Lagrangian experiments. Part II: Cloudiness, drizzle, surface fluxes, and entrainment. J. Atmos. Sci.,52, 2724–2735.

  • Curry, J. A., E. E. Ebert, and G. F. Herman, 1988: Mean and turbulence structure of the summertime Arctic cloudy boundary layer. Quart. J. Roy. Meteor. Soc.,114, 715–746.

  • Deser, C., and J. M. Wallace, 1990: Large-scale atmospheric circulation features of warm and cold episodes in the tropical Pacific. J. Climate,3, 1254–1281.

  • ——, J. J. Bates, and S. Wahl, 1993: The influence of sea surface temperature gradients on stratiform cloudiness along the equatorial front in the Pacific Ocean. J. Climate,6, 1172–1180.

  • Goerss, J. S., and C. E. Duchon, 1980: Effect of ship heating on dry-bulb temperature measurements in GATE. J. Phys. Oceanogr.,10, 478–479.

  • Hahn, C. J., S. G. Warren, J. London, R. L. Jenne, and R. M. Chervin, 1988: Climatological data for clouds over the globe from surface observations. Carbon Dioxide Information Analysis Center Rep. NDP-026, Oak Ridge National Laboratory, Oak Ridge, TN, 54 pp. [Available from Carbon Dioxide Analysis Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6335.].

  • ——, ——, and ——, 1995: The effect of moonlight on observation of cloud cover at night, and application to cloud climatology. J. Climate,8, 1429–1446.

  • ——, ——, and ——, 1996: Edited synoptic cloud reports from ships and land stations over the globe, 1982–1991. Carbon Dioxide Information Analysis Center Rep. NDP026B, 45 pp. [Available from Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6335.].

  • Hanson, H. P., 1991: Marine stratocumulus climatologies. Int. J. Climatol.,11, 147–164.

  • Haraguchi, P. Y., 1968: Inversions over the tropical eastern Pacific Ocean. Mon. Wea. Rev.,96, 177–185.

  • Hartmann, D. L., M. E. Ockert-Bell, and M. L. Michelsen, 1992: The effect of cloud type on Earth’s energy balance: Global analysis. J. Climate,5, 1281–1304.

  • Herman, G., and R. Goody, 1976: Formation and persistence of summertime Arctic stratus clouds. J. Atmos. Sci.,33, 1537–1553.

  • Hoskins, B. J., H. H. Hsu, I. N. James, M. Masutani, P. D. Sardeshmukh, and G. H. White, 1989: Diagnostics of the global atmospheric circulation based on ECMWF analyses 1979–1989. WCRP-27, WMO/TD No. 326., WMO, 219 pp.

  • Houze, R. A., 1993: Cloud Dynamics. Academic Press, 573 pp.

  • Klein, S. A., and D. L. Hartmann, 1993: The seasonal cycle of low stratiform clouds. J. Climate,6, 1587–1606.

  • ——, ——, and J. R. Norris, 1995: On the relationship among low-cloud structure, sea surface temperature, and atmospheric circulation in the summertime northeast Pacific. J. Climate,8, 1140–1155.

  • Lilly, D. K., 1968: Models of cloud-topped mixed layers under a strong inversion. Quart. J. Roy. Meteor. Soc.,94, 292–309.

  • Mitchell, T. P., and J. M. Wallace, 1992: The annual cycle in equatorial convection and sea surface temperature. J. Climate,5, 1140–1156.

  • Neiburger, M., D. S. Johnson, and C.-W. Chien, 1961: Studies of the Structure of the Atmosphere over the Eastern Pacific Ocean in Summer. Vol. 1, The Inversion over the Eastern North Pacific Ocean. University of California Press, 94 pp.

  • Norris, J. R., 1998: Low cloud type over the ocean from surface observations. Part I: Relationship to surface meteorology and the vertical distribution of temperature and moisture. J. Climate,11, 369–382.

  • ——, and C. B. Leovy, 1994: Interannual variability in stratiform cloudiness and sea surface temperature. J. Climate,7, 1915–1925.

  • Orville, R. E., and R. W. Henderson, 1986: Global distribution of midnight lightning: September 1977 to August 1987. Mon. Wea. Rev.,114, 2640–2653.

  • Petty, G. W., 1995: Frequencies and characteristics of global oceanic precipitation from shipboard present-weather reports. Bull. Amer. Meteor. Soc.,76, 1593–1616.

  • Rossow, W. B., and R. A. Schiffer, 1991: ISCCP cloud data products. Bull. Amer. Meteor. Soc.,72, 2–20.

  • Rozendaal, M. A., C. B. Leovy, and S. A. Klein, 1995: An observational study of diurnal variations of marine stratiform cloud. J. Climate,8, 1795–1809.

  • Schubert, W. H., J. S. Wakefield, E. J. Steiner, and S. K. Cox, 1979:Marine stratocumulus convection. Part II: Horizontally inhomogeneous solutions. J. Atmos. Sci.,36, 1308–1324.

  • Wallace, J. M., T. P. Mitchell, and C. Deser, 1989: The influence of sea-surface temperature on surface wind in the eastern equatorial Pacific: Seasonal and interannual variability. J. Climate,2, 1492–1499.

  • Warren S. G., C. J. Hahn, J. London, R. M. Chervin, and R. L. Jenne, 1988: Global distribution of total cloud cover and cloud type amounts over the ocean. NCAR/TN-317+STR, Boulder, CO, 42 pp. plus 170 maps. [Available from NCAR, P.O. Box 3000, Boulder, CO 80307.].

  • Woodruff, S. D., R. J. Slutz, R. L. Jenne, and P. M. Steurer, 1987: A Comprehensive Ocean–Atmosphere Data Set. Bull. Amer. Meteor. Soc.,68, 1239–1250.

  • WMO, 1974: Manual on codes. WMO Publ. 306, WMO.

  • ——, 1975: Manual on the observation of clouds and other meteors. WMO Publ. 407, WMO, 155 pp.

  • Wyant, M. C., C. S. Bretherton, H. A. Rand, and D. E. Stevens, 1997:Numerical simulations and a conceptual model of the stratocumulus to trade cumulus transition. J. Atmos. Sci.,54, 168–192.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 1420 853 46
PDF Downloads 445 99 9