The changing relationship between ENSO variability and moisture balance in the continental United States

The El Nino-Southern Oscillation (ENSO) system orchestrates a well-documented suite of climate anomalies worldwide. The details of ENSO's extratropical influence vary among events, but this variability has not been described or diagnosed beyond the past few decades, and previous descriptions have looked at inter-event differences rather than decadal patterns. We use a new tree-ring based drought reconstruction for the continental U.S. and instrumental ENSO indices to document systematic decadal changes in the U.S. drought-ENSO relationship since the late 19th century. Significant ENSO-drought correlation occurs consistently in the southwest U.S., but the strength of penetration of moisture anomalies into the continent varies substantially. The most striking change over the past 130 years is the initiation of a “bipolar” ENSO-drought signature around 1920, producing opposite-sign moisture anomalies in the southwest and mid-Atlantic states. Shifts in teleconnection patterns coincide with variations in the strength of ENSO and in a North Pacific mode.

[1]  M. Hoerling,et al.  Interpretation and Implications of the Observed Inter–El Niño Variability , 1997 .

[2]  Mojib Latif,et al.  A review of ENSO prediction studies , 1994 .

[3]  J. Namias.  Some Causes of United States Drought , 1983 .

[4]  R. Reynolds,et al.  Global surface air temperature in 1995: Return to pre‐Pinatubo level , 1996 .

[5]  K. Trenberth,et al.  Physical Processes Involved in the 1988 Drought and 1993 Floods in North America , 1996 .

[6]  G. McCabe,et al.  DECADAL VARIATIONS IN THE STRENGTH OF ENSO TELECONNECTIONS WITH PRECIPITATION IN THE WESTERN UNITED STATES , 1999 .

[7]  Kevin E. Trenberth,et al.  Progress during TOGA in understanding and modeling global teleconnections associated with tropical sea surface temperatures , 1998 .

[8]  J. Wallace,et al.  A Pacific Interdecadal Climate Oscillation with Impacts on Salmon Production , 1997 .

[9]  Balaji Rajagopalan,et al.  Analyses of global sea surface temperature 1856–1991 , 1998 .

[10]  Kevin E. Trenberth,et al.  On the evolution of the southern oscillation , 1987 .

[11]  Michael Ponater,et al.  On the Roles of Tropical and Midlatitude SSTs in Forcing Interannual to Interdecadal Variability in the Winter Northern Hemisphere Circulation , 1994 .

[12]  Peter W. Glynn,et al.  Eastern Pacific sea surface temperature since 1600 A , 1994 .

[13]  P. Jones,et al.  An Extension of the TahitiDarwin Southern Oscillation Index , 1987 .

[14]  D. Rind.  Latitudinal temperature gradients and climate change , 1998 .

[15]  J. Cole,et al.  Recent Variability in the Southern Oscillation: Isotopic Results from a Tarawa Atoll Coral , 1993, Science.

[16]  M. Ting,et al.  Summertime U.S. Precipitation Variability and Its Relation toPacific Sea Surface Temperature , 1997 .

[17]  Mojib Latif,et al.  Decadal climate variability over the North Pacific and North America: Dynamics and predictability , 1996 .

[18]  K. Trenberth,et al.  Global variations in droughts and wet spells: 1900–1995 , 1998 .

[19]  Neville Nicholls,et al.  Recent apparent changes in relationships between the El Niño-Southern Oscillation and Australian rainfall and temperature , 1996 .

[20]  Edward R. Cook,et al.  Experimental Dendroclimatic Reconstruction of the Southern Oscillation. , 1998 .

[21]  J. Wallace,et al.  ENSO-like Interdecadal Variability: 1900–93 , 1997 .

[22]  E. Sarachik,et al.  Understanding and predicting ENSO , 1995 .

[23]  Malcolm K. Hughes,et al.  Global-scale temperature patterns and climate forcing over the past six centuries , 1998, Nature.

[24]  Dake Chen,et al.  An Improved Procedure for EI Ni�o Forecasting: Implications for Predictability , 1995, Science.

[25]  Henry F. Diaz,et al.  Global climatic anomalies associated with extremes in the Southern Oscillation , 1989 .

[26]  E. Cook,et al.  Drought Reconstructions for the Continental United States , 1999 .