Teleconnections atmospheric-oceanic (Pacific and Atlantic oceans) modulating the wet and dry summers in the Core North American Monsoon

In recent decades, irregular rainfall has evidenced a number of adverse environmental and socioeconomic effects worldwide. The goal of this study was to analyze the ability of four Regional Climatic Models (RCM's) forced by ERA-Interim to capture the humid and dry extreme monsoons in the Core North American Monsoon (CNAM), considering the oceanic mechanisms of the Pacific and Atlantic. From available databases in the network and for the period 1990-2008, we obtained: 1) average observations (obs mean); after obtaining four sets of observed precipitation data: UDel, CLICOM, GPCP and CRU, 2) from the Coordinated Regional Scale Reduction Experiment (CORDEX) -of North America (NA), four RCM's were obtained forced by ERA-Interim, 3) number and intensity of Pacific hurricanes, and 4) calculation of Caribbean Low Level Jet (CLLJ) anomalies, the Filtered Variance (VF), the Decadal Pacific Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). Two extreme monsoons were selected: one wet (1990) and one dry (2005). To all the data, they were applied the test of normality of Shapiro Wilk. It was calculated a Pearson correlation and a hypothesis test, with a confidence level of 95% (P<0.05) and 99% (P<0.01) between the models, Era-Interim, the observations and oceanic indexes. Regardless of the oceanic indexes, HadGEM3-RA and ERA-Interim were the that better captured precipitation in wet monsoons; And ERA-Interim and Reg1 proved to be better at capturing precipitation for dry monsoons. The 1990 monsoon presented almost twice as much precipitation as the monsoon of 2005. This wet anomaly could be associated with the occurrence of 16 hurricanes near the Gulf of California by 1990, since in 2005, only 7 hurricanes occurred. VF and CLLJ are inversely proportional and are two significant predictors of wet monsoons in the CNAM. ERA-Interim better captures precipitation in extreme wet years. PDO, was significantly and negatively correlated with REMO (Pr = -0.90) and CLLJ (Pr = -0.90), that is to say, REMO has no ability to capture dry monsoons that occur when -PDO (La Niña) and -CLLJ (La Niña) [A RT ÍC UL O RE TR AC TA DO ] Llanes Cárdenas, Omar et al. Nova Scientia, No 19, Vol. 9 (2), 2017. ISSN 2007 – 0705, pp.: 348-371 351 phases are present. The dry events are significantly associated with the occurrence of -PDO (La Niña) phase anomalies and not with the occurrence of -CLLJ (La Niña) phase anomalies. This methodology is an effective alternative to predict extreme hydroclimatic events in CNAM, especially when there is no data from weather stations.