• Adams, D. K., , and A. C. Comrie, 1997: The North American monsoon. Bull. Amer. Meteor. Soc., 78 , 21972213.

  • Barlow, M., , S. Nigam, , and E. H. Berbery, 1998: Evolution of the North American monsoon system. J. Climate, 11 , 22382257.

  • Brito-Castillo, L., , A. V. Douglas, , A. Leyva-Contreras, , and D. Lluch-Belda, 2003: The effect of large-scale circulation on precipitation and streamflow in the Gulf of California continental watershed. Int. J. Climatol., 23 , 751768.

    • Search Google Scholar
    • Export Citation
  • Carleton, A. M., , D. A. Carpenter, , and P. J. Weser, 1990: Mechanisms of interannual variability of the southwest United States summer rainfall maximum. J. Climate, 3 , 9991015.

    • Search Google Scholar
    • Export Citation
  • Castro, C. L., , T. B. McKee, , and R. A. Pielke Sr., 2001: The relationship of the North American monsoon to tropical and North Pacific sea surface temperatures as revealed by observational analyses. J. Climate, 14 , 44494473.

    • Search Google Scholar
    • Export Citation
  • Douglas, A. V., , and P. J. Englehart, 1995: An analysis of the starting date for the summer monsoon in western Mexico and southeast Arizona. Proc. 20th Annual Climate Diagnostics Workshop, Seattle, WA, Climate Prediction Center, 207–211.

  • Douglas, A. V., , and P. J. Englehart, 1996: Variability of the summer monsoon in Mexico and relationships with drought in the United States. Proc. 21st Annual Climate Diagnostics Workshop, Huntsville, AL, Climate Prediction Center, 296–299.

  • Douglas, M. W., , R. Maddox, , K. Howard, , and S. Reyes, 1993: The Mexican monsoon. J. Climate, 6 , 16651677.

  • Englehart, P. J., , and A. V. Douglas, 2001: The role of eastern North Pacific tropical storms in the rainfall climatology of western Mexico. Int. J. Climatol., 21 , 13571370.

    • Search Google Scholar
    • Export Citation
  • Englehart, P. J., , and A. V. Douglas, 2006: Defining intraseasonal rainfall variability within the North American monsoon. J. Climate, 19 , 42434253.

    • Search Google Scholar
    • Export Citation
  • Gochis, D. J., , A. Jimenez, , C. J. Watts, , J. Garatuza-Payan, , and W. J. Shuttleworth, 2004: Analysis of 2002 and 2003 warm-season precipitation from the North American Monsoon Experiment Event Rain Gauge Network. Mon. Wea. Rev., 132 , 29382953.

    • Search Google Scholar
    • Export Citation
  • Gochis, D. J., , L. Brito-Castillo, , and W. J. Shuttleworth, 2007a: Correlations between sea-surface temperatures and warm season streamflow in northwest Mexico. Int. J. Climatol., 27 , 883901.

    • Search Google Scholar
    • Export Citation
  • Gochis, D. J., , C. J. Watts, , J. Garatuza-Payan, , and J. Cesar-Rodriguez, 2007b: Spatial and temporal patterns of precipitation intensity as observed by the NAME Event Rain Gauge Network from 2002 to 2004. J. Climate, 20 , 17341750.

    • Search Google Scholar
    • Export Citation
  • Gutzler, D. S., 2000: Covariability of spring snowpack and summer rainfall across the southwest United States. J. Climate, 13 , 40184027.

    • Search Google Scholar
    • Export Citation
  • Gutzler, D. S., 2004: An index of interannual precipitation variability in the core of the North American monsoon region. J. Climate, 17 , 44734480.

    • Search Google Scholar
    • Export Citation
  • Gutzler, D. S., and Coauthors, 2005: The North American monsoon model assessment project: Integrating numerical modeling into a field-based process study. Bull. Amer. Meteor. Soc., 86 , 14231429.

    • Search Google Scholar
    • Export Citation
  • Higgins, R. W., , and W. Shi, 2000: Dominant factors responsible for interannual variability of the summer monsoon in the southwestern United States. J. Climate, 13 , 759776.

    • Search Google Scholar
    • Export Citation
  • Higgins, R. W., , Y. Yao, , and X. L. Wang, 1997: Influence of the North American monsoon system on the U.S. summer precipitation regime. J. Climate, 10 , 26002622.

    • Search Google Scholar
    • Export Citation
  • Higgins, R. W., , K. C. Mo, , and Y. Yao, 1998: Interannual variability of the U.S. summer precipitation regime with emphasis on the southwestern monsoon. J. Climate, 11 , 25822606.

    • Search Google Scholar
    • Export Citation
  • Higgins, R. W., , Y. Chen, , and A. V. Douglas, 1999: Interannual variability of the North American warm season precipitation regime. J. Climate, 12 , 653680.

    • Search Google Scholar
    • Export Citation
  • Hu, Q., , and S. Feng, 2002: Interannual rainfall variations in the North American summer monsoon region: 1900–98. J. Climate, 15 , 11891202.

    • Search Google Scholar
    • Export Citation
  • Hu, Q., , and S. Feng, 2004: Why has the land memory changed? J. Climate, 17 , 32363243.

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • Liebmann, B., , and D. Allured, 2005: Daily precipitation grids for South America. Bull. Amer. Meteor. Soc., 86 , 15671570.

  • Liebmann, B., and Coauthors, 2004: An observed trend in central South American precipitation. J. Climate, 17 , 43574367.

  • Magaña, V., , J. A. Amador, , and S. Medina, 1999: The midsummer drought over Mexico and Central America. J. Climate, 12 , 15771588.

  • Mapes, B. E., , P. Liu, , and N. Buenning, 2005: Indian monsoon onset and the Americas midsummer drought: Out-of-equilibrium responses to smooth seasonal forcing. J. Climate, 18 , 11091115.

    • Search Google Scholar
    • Export Citation
  • Mechoso, C. R., , A. W. Robertson, , C. F. Ropelewski, , and A. M. Grimm, 2005: Part B: Regional monsoon topics. The American monsoon systems: An introduction. WMO Tech. Doc. 1266 (TMRP Rep. 70), World Meteorological Organization, 197–206.

  • Mesinger, F., and Coauthors, 2006: North American Regional Reanalysis. Bull. Amer. Meteor. Soc., 87 , 343360.

  • Portig, W. H., 1961: Some climatological data of Salvador, Central America. Weather, 16 , 103112.

  • Ropelewski, C. F., , D. S. Gutzler, , R. W. Higgins, , and C. R. Mechoso, 2005: The North American monsoon system. The Global Monsoon System: Research and Forecasts. WMO Tech Doc. WMO TD-1266, Tropical Meteorology Research Program Rep. 70, 207–218.

  • Vera, C., and Coauthors, 2006: Toward a unified view of the American monsoon systems. J. Climate, 19 , 49775000.

  • Wallace, J. M., , C. Smith, , and C. S. Bretherton, 1992: Singular value decomposition of wintertime sea surface temperature and 500-mb height anomalies. J. Climate, 5 , 561576.

    • Search Google Scholar
    • Export Citation
  • Yu, B., , and J. M. Wallace, 2000: The principal mode of interannual variability of the North American monsoon system. J. Climate, 13 , 27942800.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 43 43 14
PDF Downloads 39 39 16

Characteristics of North American Summertime Rainfall with Emphasis on the Monsoon

View More View Less
  • 1 Cooperative Institute for Research in Environmental Sciences, Climate Diagnostics Center, Boulder, Colorado
  • 2 Departament d’Astronomia i Meteorologia, Facultat de Física, Universitat de Barcelona, Barcelona, Spain
  • 3 University of Washington, and Joint Institute for the Study of the Atmosphere and Ocean, Seattle, Washington
  • 4 Research Applications Laboratory, National Center for Atmospheric Research, Boulder, Colorado
  • 5 Cooperative Institute for Research in Environmental Sciences, Climate Diagnostics Center, Boulder, Colorado
© Get Permissions
Restricted access

Abstract

The core region of the North American summer monsoon is examined using spatially averaged daily rainfall observations obtained from gauges, with the objective of improving understanding of its climatology and variability. At most grid points, composite and interannual variations of the onset and end of the wet season are well defined, although, among individual stations that make up a grid average, variability is large. The trigger for monsoon onset in southern and eastern Mexico appears to be related to a change in vertical velocity, while for northwestern Mexico, Arizona, and New Mexico it is related to a reduction in stability, as indicated by a decrease in the lifted index. The wet-season rain rate is a combination of the wet-day rain rate, which decreases with distance from the coast, and the wet-day frequency, which is largest over the Sierra Madre Occidental. Thus the maximum total rate lies slightly to the west of the highest orography. As has been previously noted, onset is not always well correlated with total seasonal precipitation, so in these areas, variations of wet-day frequency and wet-day rain rate must be important. Correlations are small between the wet-day frequency and the wet-day rate, and the former is better correlated than the latter with the seasonal rain rate. Summer rainfall in central to southern Mexico exhibits moderate negative correlations with the leading pattern of sea surface temperature (SST) anomalies in the equatorial Pacific, which projects strongly onto El Niño. The influence of equatorial SSTs on southern Mexico rainfall seems to operate mainly through variability of the wet-day frequency, rather than through variations of the wet-day rain rate.

Corresponding author address: Brant Liebmann, NOAA/ESRL PSD Climate Diagnostics, R/PSD1, 325 Broadway, Boulder, CO 80305-3328. Email: brant.liebmann@noaa.gov

Abstract

The core region of the North American summer monsoon is examined using spatially averaged daily rainfall observations obtained from gauges, with the objective of improving understanding of its climatology and variability. At most grid points, composite and interannual variations of the onset and end of the wet season are well defined, although, among individual stations that make up a grid average, variability is large. The trigger for monsoon onset in southern and eastern Mexico appears to be related to a change in vertical velocity, while for northwestern Mexico, Arizona, and New Mexico it is related to a reduction in stability, as indicated by a decrease in the lifted index. The wet-season rain rate is a combination of the wet-day rain rate, which decreases with distance from the coast, and the wet-day frequency, which is largest over the Sierra Madre Occidental. Thus the maximum total rate lies slightly to the west of the highest orography. As has been previously noted, onset is not always well correlated with total seasonal precipitation, so in these areas, variations of wet-day frequency and wet-day rain rate must be important. Correlations are small between the wet-day frequency and the wet-day rate, and the former is better correlated than the latter with the seasonal rain rate. Summer rainfall in central to southern Mexico exhibits moderate negative correlations with the leading pattern of sea surface temperature (SST) anomalies in the equatorial Pacific, which projects strongly onto El Niño. The influence of equatorial SSTs on southern Mexico rainfall seems to operate mainly through variability of the wet-day frequency, rather than through variations of the wet-day rain rate.

Corresponding author address: Brant Liebmann, NOAA/ESRL PSD Climate Diagnostics, R/PSD1, 325 Broadway, Boulder, CO 80305-3328. Email: brant.liebmann@noaa.gov

Save