AMO-Forced Regional Processes Affecting Summertime Precipitation Variations in the Central United States

Michael C. Veres Department of Earth and Atmospheric Sciences, University of Nebraska at Lincoln, Lincoln, Nebraska

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Qi Hu Department of Earth and Atmospheric Sciences, and School of Natural Resources, University of Nebraska at Lincoln, Lincoln, Nebraska

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Abstract

Numerous previous studies have provided insight into the influence of the Atlantic multidecadal oscillation (AMO) on North American precipitation. However, these studies focused on large-scale processes, and additional studies are needed to gain understanding of local and regional processes that develop in different phases of the AMO and substantiate its influences on precipitation. In this study, the Weather Research and Forecasting (WRF) regional model is used to examine AMO-forced local and regional processes and how they have affected summertime precipitation variation in the central United States.

While moisture transport and convergence by the Great Plains low-level jet have been recognized as necessary conditions for summer precipitation, model simulations show similar low-level moisture flux convergence in the central United States between the cold and warm phases of the AMO. However, there was a strong moistening in the lower troposphere during the AMO cold phase, making the atmosphere more unstable for convection and precipitation. The source of the moisture was found to be a strong positive surface evaporation–precipitation feedback initiated and sustained by increased relative vorticity along a frontal zone. Along the frontal zone, isentropic stretching of the upper-level atmosphere and cyclonic circulation anomalies increased the relative vorticity during the AMO cold phase, providing the dynamic support needed to release the low-level moist instability and produce the increased precipitation. These results indicate that the dynamics of the circulation in the AMO cold phase played key roles to organize regional vorticity processes that further sustained a coupling of precipitation and the surface evaporation and perpetuated the precipitation.

Corresponding author address: Dr. Qi Hu, 707 Hardin Hall, University of Nebraska at Lincoln, Lincoln, NE 68583-0987. E-mail: qhu2@unl.edu

Abstract

Numerous previous studies have provided insight into the influence of the Atlantic multidecadal oscillation (AMO) on North American precipitation. However, these studies focused on large-scale processes, and additional studies are needed to gain understanding of local and regional processes that develop in different phases of the AMO and substantiate its influences on precipitation. In this study, the Weather Research and Forecasting (WRF) regional model is used to examine AMO-forced local and regional processes and how they have affected summertime precipitation variation in the central United States.

While moisture transport and convergence by the Great Plains low-level jet have been recognized as necessary conditions for summer precipitation, model simulations show similar low-level moisture flux convergence in the central United States between the cold and warm phases of the AMO. However, there was a strong moistening in the lower troposphere during the AMO cold phase, making the atmosphere more unstable for convection and precipitation. The source of the moisture was found to be a strong positive surface evaporation–precipitation feedback initiated and sustained by increased relative vorticity along a frontal zone. Along the frontal zone, isentropic stretching of the upper-level atmosphere and cyclonic circulation anomalies increased the relative vorticity during the AMO cold phase, providing the dynamic support needed to release the low-level moist instability and produce the increased precipitation. These results indicate that the dynamics of the circulation in the AMO cold phase played key roles to organize regional vorticity processes that further sustained a coupling of precipitation and the surface evaporation and perpetuated the precipitation.

Corresponding author address: Dr. Qi Hu, 707 Hardin Hall, University of Nebraska at Lincoln, Lincoln, NE 68583-0987. E-mail: qhu2@unl.edu
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  • Arritt, R. W., T. D. Rink, M. Segal, D. P. Todey, C. A. Clark, M. J. Mitchell, and K. M. Labas, 1997: The Great Plains low-level jet during the warm season of 1993. Mon. Wea. Rev., 125, 2176–2192.

    • Search Google Scholar
    • Export Citation
  • Beck, C., J. Grieser, and B. Rudolf, 2005: A new monthly precipitation climatology for the global land areas for the period 1951 to 2000. DWD Climate Status Rep., 181–190.

  • Bell, G. D., and J. E. Janowiak, 1995: Atmospheric circulation associated with the Midwest floods of 1993. Bull. Amer. Meteor. Soc., 76, 681–695.

    • Search Google Scholar
    • Export Citation
  • Bjerknes, J., 1964: Atlantic air-sea interaction. Advances in Geophysics, Vol. 10, Academic Press, 1–82.

  • Bonner, W., 1968: Climatology of the low level jet. Mon. Wea. Rev., 96, 833–850.

  • Dong, B., R. T. Sutton, and A. A. Scaife, 2006: Multidecadal modulation of El Niño–Southern Oscillation (ENSO) variance by Atlantic Ocean sea surface temperatures. Geophys. Res. Lett., 33, L08705, doi:10.1029/2006GL025766.

    • Search Google Scholar
    • Export Citation
  • Enfield, D. B., A. M. Mestas-Nunez, and P. J. Trimble, 2001: The Atlantic multidecadal oscillation and its relation to rainfall and river flows in the continental US. Geophys. Res. Lett., 28, 2077–2080.

    • Search Google Scholar
    • Export Citation
  • Feng, S., R. J. Oglesby, C. M. Rowe, D. B. Loope, and Q. Hu, 2008: Pacific and Atlantic SST influences on medieval drought in North America simulated by Community Atmospheric Model. J. Geophys. Res., 113, D11101, doi:10.1029/2007JD009347.

    • Search Google Scholar
    • Export Citation
  • Feng, S., Q. Hu, and R. J. Oglesby, 2011: Influence of Atlantic sea surface temperature on persistent drought in North America. Climate Dyn., 37, 569–586, doi:10.1007/s00382-010-0835-x.

    • Search Google Scholar
    • Export Citation
  • Frankignoul, C., 1985: Sea-surface temperature anomalies, planetary-waves, and air-sea feedback in the middle latitudes. Rev. Geophys., 23, 357–390.

    • Search Google Scholar
    • Export Citation
  • Gray, S. T., L. J. Graumlich, J. L. Betancourt, and G. T. Peterson, 2004: A tree-ring based reconstruction of the Atlantic multidecadal oscillation since 1567 AD. Geophys. Res. Lett., 31, L12205, doi:10.1029/2004GL019932.

    • Search Google Scholar
    • Export Citation
  • Higgins, R. W., Y. Yao, E. S. Yarosh, J. E. Janowiak, and K. C. Mo, 1997: Influence of the Great Plains low-level jet on summertime precipitation and moisture transport over the central United States. J. Climate, 10, 481–507.

    • Search Google Scholar
    • Export Citation
  • Hoerling, M., and A. Kumar, 2003: The perfect ocean for drought. Science, 299, 691–694.

  • Holton, J. R., 2004: An Introduction to Dynamic Meteorology. 4th ed. International Geophysics Series, Vol. 88, Elsevier Academic Press, 535 pp.

  • Hu, Q., and S. Feng, 2001: Climatic role of the southerly flow from the Gulf of Mexico in interannual variations in summer rainfall in the central United States. J. Climate, 14, 3156–3170.

    • Search Google Scholar
    • Export Citation
  • Hu, Q., and S. Feng, 2007: Decadal variation of the southwest U.S. summer monsoon circulation and rainfall in a regional model. J. Climate, 20, 4702–4716.

    • Search Google Scholar
    • Export Citation
  • Hu, Q., and S. Feng, 2008: Variation of North American summer monsoon regimes and the Atlantic multidecadal oscillation. J. Climate, 21, 2373–2383.

    • Search Google Scholar
    • Export Citation
  • Hu, Q., and S. Feng, 2012: AMO- and ENSO-driven summertime circulation and precipitation variations in North America. J. Climate, 25, 6477–6495.

    • Search Google Scholar
    • Export Citation
  • Hu, Q., S. Feng, and R. J. Oglesby, 2011: Variations in North American summer precipitation driven by the Atlantic multidecadal oscillation. J. Climate, 24, 5555–5570.

    • Search Google Scholar
    • Export Citation
  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437–471.

  • Kerr, R. A., 2000: A North Atlantic climate pacemaker for the centuries. Science, 288, 1984–1986.

  • Kistler, R., and Coauthors, 2001: The NCEP–NCAR 50-Year Reanalysis: Monthly means CD-ROM and documentation. Bull. Amer. Meteor. Soc., 82, 247–267.

    • Search Google Scholar
    • Export Citation
  • Knight, J. R., R. J. Allan, C. K. Folland, M. Vellinga, and M. E. Mann, 2005: A signature of persistent natural thermohaline circulation cycles in observed climate. Geophys. Res. Lett., 32, L20708, doi:10.1029/2005GL024233.

    • Search Google Scholar
    • Export Citation
  • Kushnir, Y., W. A. Robinson, I. Blade, N. M. J. Hall, S. Peng, and R. Sutton, 2002: Atmospheric GCM responses to extratropical SST anomalies: Synthesis and evaluation. J. Climate, 15, 2233–2256.

    • Search Google Scholar
    • Export Citation
  • Latif, M., and T. P. Barnett, 1994: Causes of decadal climate variability over the North Pacific and North America. Science, 266, 634–637.

    • Search Google Scholar
    • Export Citation
  • Lau, N. C., and M. J. Nath, 1994: A modeling study of the relative roles of tropical and extratropical SST anomalies in the variability of the global atmosphere ocean system. J. Climate, 7, 1184–1207.

    • Search Google Scholar
    • Export Citation
  • Lau, N. C., and M. J. Nath, 1996: The role of the “atmospheric bridge” in linking tropical Pacific ENSO events to extratropical SST anomalies. J. Climate, 9, 2036–2057.

    • Search Google Scholar
    • Export Citation
  • Liang, X.-Z., L. Li, A. Dai, and K. E. Kunkel, 2004: Regional climate model simulation of summer precipitation diurnal cycle over the United States. Geophys. Res. Lett., 31, L24208, doi:10.1029/2004GL021054.

    • Search Google Scholar
    • Export Citation
  • McCabe, G. J., M. A. Palecki, and J. L. Betancourt, 2004: Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States. Proc. Natl. Acad. Sci. USA, 101, 4136–4141, doi:10.1073/pnas.0306738101.

    • Search Google Scholar
    • Export Citation
  • Mestas-Nunez, A., and D. B. Enfield, 1999: Rotated global modes of non-ENSO sea surface temperature variability. J. Climate, 12, 2734–2746.

    • Search Google Scholar
    • Export Citation
  • Mo, K. C., J. N. Paegle, and R. W. Higgins, 1997: Atmospheric processes associated with summer floods and droughts in the central United States. J. Climate, 10, 3028–3046.

    • Search Google Scholar
    • Export Citation
  • Mo, K. C., J. E. Schemm, and S. Yoo, 2009: Influence of ENSO and the Atlantic multidecadal oscillation on drought over the United States. J. Climate, 22, 5962–5982.

    • Search Google Scholar
    • Export Citation
  • Namias, J., 1959: Recent seasonal interactions between North Pacific waters and the overlying atmospheric circulation. J. Geophys. Res., 64, 631–646.

    • Search Google Scholar
    • Export Citation
  • Namias, J., 1965: Macroscopic association between monthly mean sea surface temperature and overlying winds. J. Geophys. Res., 70, 2307–2318.

    • Search Google Scholar
    • Export Citation
  • Namias, J., 1969: Seasonal interactions between the North Pacific Ocean and the atmosphere during the 1960s. Mon. Wea. Rev., 97, 173–192.

    • Search Google Scholar
    • Export Citation
  • Namias, J., X. Yuan, and D. R. Cayan, 1988: Persistence of North Pacific sea surface temperature and atmospheric flow patterns. J. Climate, 1, 682–703.

    • Search Google Scholar
    • Export Citation
  • Rasmusson, E. M., 1967: Atmospheric water vapor transport and water balance of North America. I. Characteristics of water vapor flux field. Mon. Wea. Rev., 95, 403–426.

    • Search Google Scholar
    • Export Citation
  • Rudolf, B., and U. Schneider, 2005: Calculation of gridded precipitation data for the global land-surface using in-situ gauge observations. Proc. Second Workshop of the International Precipitation Working Group, Monterey, France, EUMETSAT, 231–247.

  • Rudolf, B., T. Fuchs, U. Schneider, and A. Meyer-Christoffer, 2003: Introduction of the Global Precipitation Climatology Centre (GPCC). Deutscher Wetterdienst Rep., 16 pp.

  • Rudolf, B., C. Beck, J. Grieser, and U. Schneider, 2005: Global precipitation analysis products. DWD Global Precipitation Climatology Centre (GPCC) DWD Internet Publication, 8 pp.

  • Ruiz-Barradas, A., and S. Nigam, 2005: Warm season rainfall variability over the U.S. Great Plains in observations, NCEP and ERA-40 reanalyses, and NCAR and NASA atmospheric model simulations. J. Climate, 18, 1808–1830.

    • Search Google Scholar
    • Export Citation
  • Schubert, S. D., M. J. Suarez, P. J. Pegion, R. D. Koster, and J. T. Bacmeister, 2004: On the cause of the 1930s Dust Bowl. Science, 303, 1855–1859.

    • Search Google Scholar
    • Export Citation
  • Schubert, S. D., and Coauthors, 2009: A U.S. CLIVAR project to assess and compare the responses of global climate models to drought-related SST forcing patterns: Overview and results. J. Climate, 22, 5251–5272.

    • Search Google Scholar
    • Export Citation
  • Seager, R., Y. Kushnir, M. Visbeck, N. Naik, J. Miller, G. Krahmann, and H. Cullen, 2000: Causes of Atlantic Ocean climate variability between 1958 and 1998. J. Climate, 13, 2845–2862.

    • Search Google Scholar
    • Export Citation
  • Skamarock, W. C., J. B. Klemp, J. Dudhia, D. O. Gill, D. M. Barker, W. Wang, and J. G. Powers, 2007: A description of the advanced research WRF version 2. NCAR Tech. Note NCAR/TN-468+STR, 88 pp.

  • Sutton, R. T., and D. L. R. Hodson, 2005: Atlantic Ocean forcing of North American and European summer climate. Science, 309, 115–118, doi:10.1126/science.1109496.

    • Search Google Scholar
    • Export Citation
  • Sutton, R. T., and D. L. R. Hodson, 2007: Climate response to basin-scale warming and cooling of the North Atlantic Ocean. J. Climate, 20, 891–907.

    • Search Google Scholar
    • Export Citation
  • Ting, M. F., and H. Wang, 1997: Summertime U.S. precipitation variability and its relation to Pacific sea surface temperature. J. Climate, 10, 1853–1873.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., and C. J. Guillemot, 1996: Physical processes involved in the 1988 drought and 1993 floods in North America. J. Climate, 9, 1288–1298.

    • Search Google Scholar
    • Export Citation
  • Tuttle, J. D., and C. A. Davis, 2006: Corridors of warm season precipitation in the central United States. Mon. Wea. Rev., 134, 2297–2317.

    • Search Google Scholar
    • Export Citation
  • Veres, M. C., 2011: Atlantic multidecadal oscillation-forced regional summertime precipitation variations in the central United States. M.S. thesis, University of Nebraska Department of Earth and Atmospheric Sciences, 101 pp.

  • Wallace, J. M., 1975: Diurnal variations in precipitation and thunderstorm frequency over the conterminous United States. Mon. Wea. Rev., 103, 406–419.

    • Search Google Scholar
    • Export Citation
  • Wang, C., S. Lee, and D. B. Enfield, 2008: Climate response to anomalously large and small Atlantic warm pools during the summer. J. Climate, 21, 2437–2450.

    • Search Google Scholar
    • Export Citation
  • Wang, H., S. Schubert, M. Suarez, and R. Koster, 2010: The physical mechanisms by which the leading patterns of SST variability impact U.S. precipitation. J. Climate, 23, 1815–1836.

    • Search Google Scholar
    • Export Citation
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