55 2160 McElroy, Tom;Midwinter, Clive;Barton, David;Hall, Bob;Kerr, James;Wardle, David ENVIRONMENT CANADA, Dowsview, Ontario, CANADA M3H 5T4 (416) 739-4630 Brewer Ozone Spectrophotometer data at Moffett Field ( 37.42, 122.58) STRAT 1 1 1996 02 03 1996 02 03 0 13 elapsed time in UT seconds from 0000 hours on the day given in DATE Station name 9 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 99 99 99 999 999 999 999 999 999 hour minute second airmass ozone [DU] (Dobson Units) ozone error [DU] (Dobson Units) SO2 [DU] (Dobson Units) SO2 error [DU] (Dobson Units) Number of data points in row 9 0 1 1 1 1 1 1 1 1 1 99 9999 999 999 99999 999 999 999 999 number of observations instrument number station latitude (degrees) station longitude (degrees) station elevation (m) daily mean O3 [DU] (Dobson Units) daily mean O3 error [DU] (Dobson Units) daily mean SO2 [DU] (Dobson Units) daily mean SO2 error [DU] (Dobson Units) 1 *** preliminary data *** 16 The Brewer Ozone Spectrophotometer is a 15-cm focal-length, modified Ebert-Fastie spectrograph which makes rapid, time-multiplexed measurements in the UV-B region of the solar spectrum. A typical direct sun observation is the average of 5 separate observations. If the standard deviation of the measurements is less than 2 DU, the measurement is taken as acceptable. If the standard deviation is larger, it is interpreted as indicating variability of the solar intensity, i.e.: clouds or other optical attenuation. Each of the five ozone measurements which contributes to the average value are composed of 40 short observation samples. A cycle of 2 samples on each of the five wavelengths takes place in about 1.2 seconds. The usual measurement of 20 cycles takes under 30 seconds. Daily averages are calcluted using all good observations and are reported as the last line in the data table. Moffett Field 2 009 37.42 122.58 0.0 317.5 0.0 -4.0 0.0 74892 20 48 12 1.700 317.5 0.9 -4.0 0.4 5 75407 20 56 47 1.710 310.6 4.7 0.2 2.8 5