1. Spatio-temporal analysis of source-sink pairs of precipitation supply in the Amazon River basin Arief Sudradjat, Kaye L. Brubaker, Paul A. Dirmeyer Acknowledgment: NOAA Office of Global Program Grant #GC99-462a “Analysis of Atmospheric Water Cycling” NCAR Scientific Computer Division Grant #35161040

2. Backward- v. forward trajectory analysis: Dynamics and ET: NCEP reanalyses (Kalnay et al. 1996) Precipitation (gridded-observed): Higgins et al. (1996) Dirmeyer and Tan (2001) P ET (Dirmeyer and Brubaker, 1999) (developed in this study) Backward trajectory analysis (backward in time) Forward trajectory analysis (forward in time) time ( t ) A parcel of air: an “imaginary and invisible” balloonlike container of air through solutions of eq.s of mass, momentum, and energy

3. Source-sink regions: September 1979-August 1998 EQ

4. The Amazon River basin: The division line NA SA 15-day Sep Aug P wet = P dry (in total) EQ

5. Tropical North Atlantic Ocean: Sinks of evaporation DJF JJA MAM Self: 17% Amazon: 16% Self: 21% Amazon: 14% Self: 28% Amazon: 5% Africa: 5% Self: 33% Amazon: 8% SON EQ

6. The Amazon River basin: Sources of precipitation DJF: NA (10 majors) Ocean: 50%; NA: 20% Amazon (10 majors): (annual) SA: 26%; NA: 13% TRNA: 18%; TRSA: 14% (Terrestrial: 59%) Anomalies: A v. A R=0.81 A v. TRNA R=0.64 Niño 3.4 index: v. TRNA R=-0.67 v. A R=-0.48 Trend (  =5%) (JJA): TRNA: negative DJF: SA (10 majors) Ocean: 23%; SA: 41% EQ Annual: TRNA: 31% NA: 21% TRSA: 18% (Ocean: 49%; Terrestrial: 48%) Annual: TRSA: 12% TRNA: 10% SA: 39% (Ocean: 23%; Terrestrial: 69%)

7. The Amazon River basin: Sinks of evaporation DJF: A JJA: A EQ

8. The Amazon River basin: Sources’ EOF-1 EQ

9. The Amazon River basin: Sinks’ EOF-1 EQ

10. Conclusion: A should be divided into NA and SA. ITCZ importance in precipitation supply of A. Recycling precipitation is important in precipitation supply of A (annual: 39%; R=0.81). ENSO teleconnections: recycling precipitation and TRNA is reduced (enhanced) during El Niño (La Niña). Implication: The weakening of Amazon-Atlantic atmospheric circulation, consistent with Zeng et al. (1996)?