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Variations of the Great Plains Precipitation and Its Relationship with Tropical Central-Eastern Pacific SST. Song Yang. NOAA’s Climate Prediction Center. X. Ding and D. Zheng. Hong Kong Polytechnic University, China. Li et al. (2004): Precip and ENSO, AO, NAO, PDO, NP, …. GL. PNW. NE. MW.
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Variations of the Great Plains Precipitation and Its Relationship with Tropical Central-Eastern Pacific SST Song Yang NOAA’s Climate Prediction Center X. Ding and D. Zheng Hong Kong Polytechnic University, China
Li et al. (2004): Precip and ENSO, AO, NAO, PDO, NP, … GL PNW NE MW IM GP OV MA SC SE SW GC
Li et al. (2004): Precip and ENSO DJF JJA Y Y Y Y Y Y Y Y Y Y Y MAM SON Y Y Y Y Y Y Y Y Y Y Y Y
Issues of Interest Time-frequency features especially the dominant time scales of the variability of GP precipitation Effect of multi-scale oscillating signals on the variability of GP precipitation Relationship between tropical Pacific SST and GP precipitation especially its time-frequency feature and seasonality
Data and Methods DATA Precipitation from CRU TS 2.0 Product: 1901-2000 (Mitchell et al. 2004) NOAA Extended Reconstructed SST (Smith and Reynolds 2003) METHODS* Wavelet analysis Least squares analysis Multi-stage filtering Leap-step time series analysis Coherence and correlation analyses Multiple moving-window method Monte Carlo significance test *For details, see Ding et al. (2002) and Yang et al. (2004)
May 1957 June 1988 131.9 55.8 14.3 -6.5 -4.0 7.4 35.9 25.8 8.6 0.6 -7.2 8.9 Subseasonal Semiannual Annual Biennial Interannual
8 Yrs 0.7 1.2 Yrs 4 2.5 4.5 5.3
2.5 Yrs 10 Yrs 7.5 Yrs 10 2.2 Yrs 5 Yrs 4.5 8
Summary • The variability of GP precipitation is characterized by strong annual, followed by semiannual signals. Interannual and interdecadal signals are also evident, especially the interannual signals in large precipitation anomalies. • In the case of positive (negative) precipitation anomaly, non-seasonal signals are in phase with (out of phase to) the seasonal signals. • NINO3.4 SST has a strong relationship with the GP precipitation, especially in summer. Significant SST-precipitation relationships occur on semiannual timescale in the 1950s, annual timescale in 1940s-50s, and interannaul timescales in 1910s, 1940s, and 1980s (especially the biennial timescale).