Atmospheric circulation features associated to Argentinean Andean rivers discharge variability

• Published in: Geophysical research letters Vol. 35; no. 1; pp. L01805 - n/a
• Main Authors: Araneo, Diego C., Compagnucci, Rosa H.
• Format: Journal Article
• Language: English
• Published: American Geophysical Union 01.01.2008; Blackwell Publishing Ltd
• Subjects: Atmospheric Processes; Atuel River; Brackish; Chubut River; Climate change and variability; Freshwater; General circulation; Hydroclimatology; Hydrology; Marine; Argentina, Chubut, Chubut R; PSW, Argentina; IS, Pacific; PSW, Antarctic Ocean, Drake Passage; Australia; AS, South Atlantic; PSW, Argentina, Chubut; Atuel River; Chubut River
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2007GL032427

Winter atmospheric circulation patterns and their relationship to runoff variability in the Atuel and Chubut rivers of Argentina are analyzed. The most important atmospheric low levels condition associated with high (low) Atuel discharges is the weakening (strengthening) of the mean atmospheric flow, while the same feature is displaced 5° southward for Chubut. At high levels, results suggest the existence of a NW‐SE direction wave pattern extending from Australia to the South Atlantic, favoring positive (negative) pressure anomalies West of the Drake Passage, which deflect the storm tracks northward (southward) and hence increase (decrease) precipitations and subsequent Atuel discharges. In contrast, Chubut discharges are mainly controlled by a shorter wave pattern along the subtropical Pacific, which zonally crosses South America. This pattern helps to maintain low (high) pressure anomalies off the Chilean coast at the upper‐river basin latitude for high (low) Chubut runoffs.