Influence of the Macroclimatic Oscillations in the Gachaneca River Basin Weather Patterns; Boyaca-Colombia

Abstract To study the influence of macroclimatic oscillations in the Gachaneca river basin this work studies the variability of minimum and maximum temperature and standardized precipitation indices in the basin area between the years 1982 and 2015, and evaluated the relation among these variables with El Niño Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), and Quasi-Biennial Oscillation (OCB) by canonical correlation analysis. The results reveal that percentages of variance explained by macroclimatic phenomena in December-February range between 34% and 38%, in March-May between 15% and 20%, in June-August between 15% and 25% and in September- November between 21% and 34%. The most influential phenomenon is ENSO, followed by NAO. During DEF the study area is more exposed to dry events that increase the risk of depletion of water resources due to the warm phase of ENSO. The NAO can indirectly reinforce or mitigate drought events due to its relationship with the magnitude of the trade winds and the variability of the tropical Atlantic that have an impact on the position of the ITCZ and the convective processes of the region.

摘要：为探究加查内卡河流域（Gachaneca river basin）的宏观气候振荡影响，本研究分析了1982至2015年该流域内最低气温、最高气温与标准化降水指数的时空变化特征，并通过典型相关分析，探讨了上述气象变量与厄尔尼诺南方涛动（El Niño Southern Oscillation, ENSO）、北大西洋涛动（North Atlantic Oscillation, NAO）及准两年振荡（Quasi-Biennial Oscillation, OCB）之间的关联。研究结果显示，宏观气候现象在12月至次年2月（DEF）、3月至5月、6月至8月、9月至11月的方差解释率分别为34%~38%、15%~20%、15%~25%及21%~34%。其中影响力最强的气候现象为厄尔尼诺南方涛动（ENSO），其次为北大西洋涛动（NAO）。在12月至次年2月（DEF）期间，受厄尔尼诺南方涛动暖相位影响，研究区域更易遭遇干旱事件，进而提升水资源枯竭的风险。北大西洋涛动（NAO）可通过与信风强度及热带大西洋变率的关联，间接加剧或缓解干旱事件——上述要素会对热带辐合带（Intertropical Convergence Zone, ITCZ）的位置及区域对流过程产生显著影响。