Assessment of Ground-Based and Aerial Cloud Seeding Using Trace Chemistry

Table 4

Summary of sampling events (excluding snow collected for method development and downwind campaigns).

Storm date	Number of sites sampled	Seeding method^1	Sites sampled	Samples with seeding signal^2	Peak Ag [ppt]	Aircraft AgI released [kg]	Generator AgI released [kg]	Wind speed [m s^−1]^3	Wind direction^3	Min/max temperature [C]^3
Mar 24, 2015	6	Ground	3, 4, 5, 6, 7, 8	44%	21	<0.05	1.4	3.4	W	−3.9/0.6
Apr 5, 2015	2	Ground	3, 6	47%	19	-	1.5	1.3	W	−2.2/1.1
Nov 19, 2015	3	Air & ground	3, 3, 5	0%	2.8	2.1	<0.05	1.3	W	−6.1/−0.6
Dec 4, 2015	3	Ground	3, 5, 6	62%	37	-	2.1	3.8	W	−1.1/0.0
Dec 7, 2015	1	Air & ground	6	20%	14	0.2	0.8	4.2	W	0.0/1.1
Dec 9, 2015	1	Air	6	0%	3.0	0.5	-	4.0	W	0.0/2.2
Dec 10, 2015	1	Air	6	0%	1.7	0.2	-	5.8	SW	−1.1/0.6
Dec 13, 2015	1	Air & ground	5	13%	3.1	2.6	2.4	5.8	S	−2.2/0.0
Dec 19-20, 2015	3	Ground	3, 6, 8	75%	9.5	-	1.2	3.3	SW	−6.7/−5.6
Dec 21, 2015	3	Air & ground	3, 6, 8	73%	80	0.9	5.6	4.9	SW	−6.1/0.0
Jan 28-29, 2016	3	Air	3, 5, 8	0%	2.6	2.0	-	5.1	SW	−3.3/1.1
Feb 18, 2016	4	Ground	2, 3, 5, 10	58%	14	-	1.3	5.0	SW	−2.2/−1.1
Apr 14, 2016	1	Air & ground	6	93%	7.3	1.4	0.4	1.3	SW	−1.1/1.1

A: aircraft; G: ground generator. “Seeding signal” is defined as replicated Ag concentrations greater than 3 ppt and a CEF exceeding 2; ground-level data from NWS station KNST, roughly 15 km east of the Payette River Basin border.