011030 Notes on comparisons Files AA-041015-1520.txt and BB-041015-1520.txt contain identical data. I interpret this as data from a single disdrometer. time period 1520 to 2230, within the 433 minute sample AA and BB had 421 minutes of rain > 0 mm/hr, CC had 423 minutes and DD had 420 minutes so very similar time periods of rain Table of sums of n# values for time period 1520 to 2230 Sum AA Sum BB Sum CC Sum DD CC/AA DD/AA n1 5026.00 5026.00 4321.00 5536.00 0.86 1.10 n2 10805.00 10805.00 9515.00 11674.00 0.88 1.08 n3 12710.00 12710.00 12627.00 13431.00 0.99 1.06 n4 15466.00 15466.00 15813.00 16056.00 1.02 1.04 n5 11939.00 11939.00 11745.00 11894.00 0.98 1.00 n6 15637.00 15637.00 14943.00 14698.00 0.96 0.94 n7 13681.00 13681.00 13842.00 13427.00 1.01 0.98 n8 6616.00 6616.00 7036.00 6837.00 1.06 1.03 n9 3265.00 3265.00 3464.00 3403.00 1.06 1.04 n10 2369.00 2369.00 2359.00 2244.00 1.00 0.95 n11 2381.00 2381.00 2549.00 2298.00 1.07 0.97 n12 676.00 676.00 793.00 699.00 1.17 1.03 n13 190.00 190.00 190.00 149.00 1.00 0.78 n14 85.00 85.00 91.00 65.00 1.07 0.76 n15 45.00 45.00 35.00 27.00 0.78 0.60 n16 19.00 19.00 8.00 16.00 0.42 0.84 n17 4.00 4.00 2.00 3.00 0.50 0.75 n18 2.0 2.0 1.0 3.0 0.5 1.5 n19 0 0 0 0 NA NA n20 0 0 0 0 NA NA Major concerns are with values that are more than 10% from those of AA disdrometer when number of total drops is > 200 * for CC disdrometer, n1 and n2 are more than 10% off value of AA. Since there are a large number of drops present at this size I consider this difference significant, and indicating a loss of sensitivity to drop sizes in n1 and n2 classes *for CC disdrometer n12 drops is 117% of value for AA, this seems also a problem perhaps indicating n12 size range is shifted to slightly smaller sizes Less significant since total number of drops is < 200 but perhaps also of concern. * for DD disdrometer, n13, n14, n15, and n16 seems less sensitive to large drops or size sensitivity is shifter to larger sizes * for CC disdrometer small number of n16 size drops is troubling as it is less than half measured by other instruments