FIG 6.

Summary of trends in ice-nucleating particle (INP) data with source ecoregion and physical, chemical, and microbiological properties of the precipitation. Ecoregions as depicted in Fig. 4 are outlined by black solid lines. (a) Key for INP concentrations in the ecoregion for panels b to g and Pearson correlation coefficents for panel h are shown. (b to g) Ecoregions that correlated significantly with total_{−5 to −11} (b), total_{−11 to −14} (c), bio_{−5 to −10} (d), bio_{−11 to −12} (e), bio_{−13 to −14} (f), and bac_{−5 to −10} (g) INP concentrations are shown. (h) Heat plot of Pearson correlation coefficients between INP concentrations and various precipitation measurements, as follows (units): cell abundance (cells liter⁻¹ precipitation); conductivity (cond.; μS cm⁻¹); chloride, sodium, nitrate, and sulfate (μM); DOC, dissolved organic carbon (parts per million); C1, PARAFAC component C1 (Raman units [R.U.]); C2, PARAFAC component C2 (A.U.); and C3, PARAFAC component C3 (A.U.).