Raw data: Unreported Characteristics of the North American Monsoon
Raw data for "Unreported Characteristics of the North American Monsoon".
The North American Monsoon (NAM) in southern Arizona continues to be a topic of interest to ecologists, climatologists, and citizens as well as the triggers and characteristics of plant growth and reproduction in relation to the onset of the monsoon. In researching the onset of the North American Monsoon (NAM) in south-central Arizona relative to the phenology of Saguaro cactus (Carnegiea gigantea) and other Sonoran Desert species we identified interesting and previously unreported features in a rainfall dataset from 33 stations located in Pima and Pinal Counties, Arizona, from 1990-2022. We present preliminary descriptive analyses of monsoon onset, monsoon precipitation, annual precipitation, and proportion of annual station precipitation received during the monsoon. Onset was measured by the first day from 1 June to 30 September with precipitation ≥10 mm. Tests indicate no overall trend in the time series. Spatial correlation and correlation analyses across the station datasets are reported. Generalized Additive Models (GAMs) identified sinusoidal waves and provided frequency and amplitude estimates to be calculated in Sinusoidal Regression Models (SRMs). Features found in the monsoon onset dataset were also found in monsoon, annual, and proportion of monsoon in annual precipitation although in approximately mirror-image. Relationships are weak to moderate. GAM explain 5-19% of deviance and the sinusoidal regression R2 scores range from 0.04-0.26. The data exhibit a pattern in which troughs have relatively low variance and encompass fewer years than the crests which exhibit greater dispersion and temporally predominate. We suggest a possible explanation for this. Further research using our monsoon onset criteria should be done in other NAM domain regions. If the sinusoidal wave can be found elsewhere, it may be that the details of the wave will suggest an origin or teleconnections to global-scale climate phenomena, though, as yet it is unexplained.
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