Quality assessment of Redsox-1 LADCP current profiles ====================================================== Hartmut Peters, 4/4/02 Executive 3-sentence summary: The RSX1 LADCP current profiles are good to +- 3 cm/s or better on average. Some identifiable profiles have larger uncertainty. The chief cause of problem cases is excessive, non-random noise in the raw shear data. Profiles with and without reference to GPS navigation data are treated separately. The data quality is assessed by means of comparing LADCP current data with independent data. Profile plots are found in /os5/redsox/Ladcp/Plot/rsx1-hres (rsx1nnn.ladcp.epsi). The downcasts of casts 10 and 63 were declared 'bad,' as was highres file no1 of # 10. These are not included in any of the comparisons below. 1) 'Nav'-reference vs. 'bottom track' reference ----------------------------------------------- During the processing, LADCP velocity profiles are adjusted to velocity data from bottom tracking. Thereafter, a further barotropic shift is applied to adjust the LADCP profiles to the navigation data. Ideally, this adjustment should be zero. Uncertainties are a combination of uncertainties in the water column data and the bottom track data. Results for the adjustment to 'nav'; data im m/s: component mean standard minimum maximum number of deviation profiles --------------------------------------------------------------------- ubt -0.00559947 0.0286181 -0.138463 0.107261 136 vbt 0.000125062 0.0257422 -0.0550269 0.14557 136 The rms profile-average velocity deviations between LADCP and SADCP are 0.023 / 0.019 m/s for u and v, respectively, for nav-referenced LADCP data. The rms deviations go up to 0.046 / 0.041 m/s for bottom-referenced LADCP velocities. n=148. The following lists the 'nav' adjustment for individual profiles. Large values indicate problems with the data. Values in excess of +- 10 cm/s have been highlighted. Note that a number of casts have no bottom track and are not included below. The data are(in 'gpl'-format) in /os5/redsox/Ladcp/Rsx1/Gpl/rsx1.nav.tish-2. CAST ubt vbt -------------------------- 51.000 -0.033 0.041 83.000 0.002 -0.023 87.000 -0.019 0.011 88.000 -0.026 -0.030 90.000 -0.006 -0.008 91.000 0.003 -0.010 92.000 -0.028 0.019 95.000 -0.003 0.000 97.000 -0.020 0.016 98.000 0.009 0.005 99.000 -0.022 -0.026 100.000 -0.021 -0.014 102.000 0.008 0.002 103.000 -0.012 -0.013 104.000 -0.011 -0.010 105.000 0.018 -0.030 106.000 -0.016 0.006 107.000 -0.008 -0.004 108.000 -0.005 0.001 109.000 0.000 -0.011 110.000 0.001 -0.004 111.000 0.009 -0.022 112.000 -0.027 -0.005 113.000 0.029 0.001 114.000 0.017 -0.017 115.000 0.007 -0.009 116.000 0.017 -0.008 117.000 -0.018 -0.020 118.000 -0.021 -0.012 119.000 -0.016 -0.014 120.000 -0.003 -0.003 121.000 0.009 0.008 122.000 -0.030 0.004 123.000 -0.028 0.035 124.000 0.006 -0.007 125.000 0.003 0.010 126.000 0.107 0.044 ^^^^^^ 127.000 0.016 -0.018 128.000 -0.027 0.029 129.000 0.012 -0.015 130.000 0.001 -0.011 131.000 0.012 0.029 132.000 0.031 -0.006 133.000 0.014 0.015 134.000 0.015 0.012 135.000 -0.014 -0.021 136.000 -0.012 -0.007 137.000 0.020 -0.055 138.000 0.022 -0.017 139.000 -0.023 -0.004 140.000 -0.003 -0.008 141.000 0.001 0.021 142.000 0.021 -0.015 143.000 -0.033 -0.027 144.000 -0.008 -0.008 145.000 0.028 -0.008 146.000 -0.020 -0.013 147.000 -0.007 -0.002 148.000 -0.005 -0.005 149.000 -0.012 -0.010 150.000 0.049 0.010 151.000 0.013 0.003 152.000 -0.011 -0.016 153.000 0.009 0.004 154.000 -0.011 -0.003 155.000 0.013 -0.012 156.000 0.018 0.013 157.000 0.009 -0.001 158.000 -0.029 -0.007 159.000 0.002 -0.012 161.000 -0.054 0.004 162.000 -0.002 -0.025 163.000 0.008 -0.003 164.000 -0.023 0.047 165.000 -0.016 0.010 166.000 0.002 0.001 167.000 -0.011 -0.009 168.000 0.011 -0.004 169.000 -0.014 0.018 170.000 -0.020 0.031 171.000 -0.006 0.013 172.000 0.024 0.007 173.000 0.006 -0.021 174.000 0.014 0.036 175.000 -0.004 -0.025 176.000 -0.021 -0.047 177.000 0.008 -0.001 178.000 -0.051 -0.026 179.000 -0.008 -0.023 180.000 -0.007 -0.000 181.000 -0.009 -0.011 182.000 -0.032 0.004 183.000 0.008 0.002 185.000 -0.031 -0.016 186.000 -0.017 -0.038 187.000 0.025 -0.008 188.000 -0.042 -0.040 189.000 -0.032 0.011 190.000 0.005 -0.008 191.000 -0.041 0.000 192.000 -0.007 0.054 193.000 0.006 -0.013 194.000 0.016 0.000 195.000 -0.008 0.023 196.000 -0.013 0.034 197.000 -0.006 -0.003 198.000 0.020 -0.042 199.000 0.004 -0.011 201.000 -0.046 -0.028 202.000 0.008 -0.017 203.000 0.018 0.013 204.000 0.072 0.047 205.000 0.009 0.003 206.000 -0.029 0.003 207.000 0.025 -0.029 209.000 -0.014 0.016 210.000 0.020 -0.026 211.000 -0.036 0.050 212.000 -0.024 -0.001 213.000 0.043 0.023 214.000 -0.018 -0.034 215.000 -0.128 0.146 ^^^^^^ ^^^^^^ 216.000 -0.002 0.011 217.000 0.042 -0.006 218.000 0.022 0.031 219.000 -0.020 -0.002 222.000 -0.041 -0.041 223.000 -0.003 0.018 224.000 -0.019 -0.010 225.000 0.017 -0.006 229.000 -0.138 0.011 ^^^^^^ 230.000 -0.038 -0.003 235.000 -0.077 0.106 ^^^^^^ 236.000 -0.040 0.047 237.000 0.001 0.013 238.000 -0.022 0.020 Cast # 215 has been examined closely. The problem lies with the u-shear component of the raw data. The profile plot in rsx1215.ladcp.epsi shows that the LADCP velocity profile neither matches the bottom track well nor the ship ADCP. Conceivably, the profile could be improved somewhat by forcing a fit to the bottom track at the bottom and to the SADCP at the top with a linear correction in between. Such being rather ad-hoc, it has not been done. 2) LADCP vs. SADCP, 'nav' casts ------------------------------- The following summarizes profile-mean velocity differences between SADCP and LADCP in m/s. component mean standard minimum maximum number of deviation profiles --------------------------------------------------------------------- du 0.000429149 0.0234866 -0.087817 0.0877005 148 dv 0.00489245 0.0189053 -0.0677372 0.0560225 148 The individual profile-mean data are as follows. For possible problem cases, data in excess of +- 5 cm/s should be examined. The data are generated by the script cmp.ls.nav.rsx1.x in /os5/redsox/Ladcp/Scripts. CAST du dv -------------------------------- 25.000 -0.021 0.004 51.000 -0.003 0.044 83.000 -0.008 0.011 87.000 -0.005 -0.001 88.000 -0.006 0.013 90.000 0.003 -0.011 91.000 -0.001 0.009 92.000 0.025 -0.008 93.000 0.003 -0.015 94.000 -0.015 0.010 95.000 -0.009 -0.003 96.000 -0.003 -0.011 97.000 -0.005 -0.006 98.000 0.007 0.009 99.000 -0.008 0.014 100.000 0.006 0.007 102.000 -0.008 -0.012 103.000 0.011 0.001 104.000 0.004 0.009 105.000 0.013 0.010 106.000 -0.011 0.008 107.000 -0.022 -0.030 108.000 -0.001 -0.028 109.000 0.029 -0.005 110.000 -0.005 -0.014 111.000 0.017 -0.005 112.000 -0.019 -0.007 113.000 0.043 0.003 114.000 0.027 0.001 115.000 0.019 -0.000 116.000 0.026 -0.022 117.000 0.017 -0.011 118.000 -0.026 0.010 119.000 -0.018 -0.016 120.000 0.015 0.028 121.000 -0.009 -0.004 122.000 -0.004 -0.018 123.000 0.007 0.006 124.000 0.016 0.030 125.000 -0.011 0.017 126.000 -0.074 -0.006 ^^^^^^ 127.000 -0.010 0.013 128.000 0.029 0.015 129.000 -0.003 -0.003 130.000 -0.009 -0.025 131.000 0.005 0.013 132.000 0.037 0.013 133.000 0.010 -0.016 134.000 -0.010 0.036 135.000 -0.016 0.011 136.000 -0.010 0.032 137.000 -0.043 0.056 ^^^^^^ 138.000 0.012 0.028 139.000 0.018 0.017 140.000 0.010 0.030 141.000 -0.007 0.015 142.000 0.003 0.016 144.000 -0.007 0.005 145.000 -0.014 0.008 146.000 0.021 0.012 147.000 0.013 0.006 148.000 0.027 -0.011 149.000 0.012 -0.017 150.000 -0.007 -0.026 151.000 0.008 -0.004 152.000 0.019 -0.010 153.000 0.014 -0.010 154.000 0.013 0.023 155.000 -0.007 0.017 156.000 0.003 -0.011 157.000 -0.011 0.007 158.000 0.020 -0.004 159.000 -0.011 -0.002 160.000 0.013 0.005 161.000 -0.036 -0.036 162.000 -0.006 0.013 163.000 0.007 -0.007 164.000 0.013 0.006 165.000 -0.003 0.022 166.000 0.009 0.029 167.000 -0.005 0.010 168.000 0.014 0.027 169.000 0.011 0.001 170.000 -0.008 0.007 171.000 -0.007 -0.007 172.000 -0.006 0.002 173.000 -0.001 -0.023 174.000 -0.010 0.011 175.000 0.012 0.020 176.000 -0.003 -0.002 177.000 -0.018 -0.028 178.000 -0.088 -0.027 ^^^^^^ 179.000 -0.038 0.018 180.000 -0.025 -0.018 181.000 -0.012 -0.004 182.000 0.035 0.002 183.000 -0.005 0.006 184.000 0.012 0.018 185.000 -0.020 0.036 186.000 0.018 0.029 187.000 0.012 0.001 188.000 -0.031 0.013 189.000 0.012 0.027 190.000 -0.013 -0.001 191.000 0.032 0.005 192.000 0.007 -0.017 193.000 0.003 0.030 194.000 -0.021 0.010 195.000 -0.026 -0.038 196.000 -0.001 0.021 197.000 0.005 -0.003 198.000 -0.000 0.032 199.000 0.002 -0.003 201.000 0.029 -0.002 202.000 0.007 -0.003 203.000 -0.023 0.005 204.000 -0.037 -0.021 205.000 -0.019 0.001 206.000 -0.005 0.001 207.000 -0.008 0.043 208.000 -0.001 0.009 209.000 -0.013 0.024 210.000 -0.006 0.023 211.000 0.024 0.026 212.000 0.007 0.009 213.000 -0.015 -0.011 214.000 -0.013 -0.004 215.000 0.082 -0.068 ^^^^^^ ^^^^^^ 216.000 0.007 -0.001 217.000 -0.027 0.012 218.000 -0.018 -0.025 219.000 0.072 -0.010 220.000 -0.002 0.023 221.000 -0.065 0.055 222.000 -0.010 0.020 223.000 0.000 0.014 224.000 -0.000 0.008 225.000 -0.001 -0.006 226.000 0.027 0.050 ^^^^^^ 227.000 0.012 -0.004 228.000 0.048 0.018 229.000 0.088 0.027 ^^^^^^ 230.000 0.017 -0.019 234.000 0.045 0.023 235.000 -0.021 0.019 236.000 0.010 0.008 237.000 -0.046 0.011 238.000 -0.025 0.032 A different way of looking at the LADCP vs. SADCP 'nav' data is by considering all individual velocity data points (instead of profile averages): component mean standard minimum maximum number of deviation data --------------------------------------------------------------------- du 0.000240576 0.0289354 -0.136281 0.147805 5779 dv 0.00477374 0.0269133 -0.0983247 0.232563 5779 3) 'No-nav' down/up comparison ------------------------------ Ideally, downcast and upcast velocity profiles should be matched closely. The downcast velocity data of # 10 and # 63 were declared bad and should not be used. The statistics of the down/up profile average differences are as follows. The data are generated by cmp.downup.rsx1.x in /os5/redsox/Ladcp/Scripts. component mean standard minimum maximum number of deviation profiles ---------------------------------------------------------------------- du 0.00341746 0.0315907 -0.12306 0.117196 70 dv -0.00484738 0.0423578 -0.137579 0.16543 70 The individual profile-average velocity differences down/up are as follows. Values in excess of +- 7 cm/s are marked. CAST du dv -------------------------- 3.000 -0.010 0.070 ^^^^^^ 4.000 -0.003 0.040 5.000 -0.015 -0.012 7.000 0.006 -0.014 8.000 -0.005 -0.077 ^^^^^^ 9.000 0.061 0.042 11.000 -0.013 -0.036 12.000 -0.022 -0.004 13.000 -0.015 0.016 14.000 0.045 -0.017 15.000 -0.006 0.008 16.000 0.004 0.022 17.000 -0.017 0.023 18.000 0.043 -0.016 19.000 0.008 -0.027 20.000 -0.006 -0.011 21.000 0.004 0.007 22.000 -0.000 0.008 23.000 0.005 -0.007 24.000 -0.001 -0.003 26.000 0.081 -0.020 ^^^^^^ 27.000 -0.007 0.011 28.000 0.032 -0.005 29.000 0.035 -0.076 ^^^^^^ 30.000 -0.123 0.165 ^^^^^^ ^^^^^^ 31.000 0.019 0.056 32.000 -0.006 -0.017 33.000 0.003 0.002 35.000 0.026 -0.138 ^^^^^^ 38.000 0.117 -0.113 ^^^^^^ ^^^^^^ 39.000 -0.004 -0.076 ^^^^^^ 40.000 0.009 -0.094 ^^^^^^ 41.000 -0.038 -0.033 42.000 -0.022 0.087 ^^^^^^ 43.000 -0.013 -0.004 44.000 0.002 -0.000 45.000 -0.022 0.045 49.000 -0.003 0.022 52.000 -0.042 0.009 53.000 -0.016 0.017 54.000 0.017 0.011 55.000 -0.021 0.005 56.000 0.043 0.019 57.000 0.031 0.008 59.000 0.017 -0.012 60.000 -0.020 -0.018 61.000 -0.006 -0.004 62.000 -0.010 -0.003 64.000 0.000 0.004 65.000 -0.013 -0.019 66.000 0.025 0.031 67.000 0.008 0.018 68.000 -0.059 -0.057 69.000 0.024 -0.018 70.000 0.001 -0.014 71.000 0.007 0.015 72.000 0.006 -0.012 73.000 -0.009 -0.035 74.000 0.002 -0.002 75.000 -0.000 -0.008 76.000 -0.003 -0.005 77.000 0.007 -0.010 78.000 -0.007 -0.041 79.000 0.008 -0.015 80.000 0.059 -0.008 82.000 0.057 0.007 84.000 -0.015 -0.008 85.000 -0.002 0.017 86.000 0.004 -0.039 101.000 -0.004 -0.001 The statistics of the individual down/up velocity differences (rather than profile-average) follow: component mean standard minimum maximum number of deviation data ---------------------------------------------------------------------- du 0.00375966 0.0510221 -0.319299 0.319619 3213 dv -0.00342876 0.0612119 -0.462881 0.343854 3213 4) 'No-nav' LADCP / SADCP comparison ------------------------------------ The script cmp.ls.no-nav.rsx1.x generates the following cast-average LADCP/SADCP velocity differences. LADCP data are the mean of downcast and upcast unless one of them was declared bad. component mean standard minimum maximum number of deviation casts ---------------------------------------------------------------------- du 0.00156792 0.0524695 -0.286989 0.14024 81 dv -0.00264986 0.0250311 -0.0877326 0.0623404 81 The list of individual cast-average data follows. The 4 casts with velocity differences in excess of +- 10 cm/s seem to be having problems with the SADCP profiles. Data in excess of +- 7 cm/s have been marked. CAST du dv ----------------------------- 3.000 0.095 0.043 ^^^^^^ 4.000 -0.032 0.036 5.000 0.008 0.045 7.000 -0.009 0.013 8.000 -0.005 0.006 9.000 -0.022 -0.006 10.000 0.003 -0.008 11.000 0.019 -0.021 12.000 0.026 -0.012 13.000 0.013 -0.004 14.000 0.001 -0.033 15.000 0.021 0.001 16.000 -0.021 0.052 17.000 -0.017 -0.000 18.000 0.041 -0.060 19.000 -0.043 -0.028 20.000 -0.072 -0.030 ^^^^^^ 21.000 -0.037 -0.015 22.000 0.140 -0.088 ^^^^^^ ^^^^^^ 23.000 -0.060 0.028 24.000 -0.287 -0.010 ^^^^^^ 26.000 -0.077 -0.048 ^^^^^^ 27.000 0.009 -0.017 28.000 0.080 -0.049 ^^^^^^ 29.000 0.000 0.007 30.000 0.088 0.040 ^^^^^^ 31.000 0.004 0.037 32.000 -0.000 0.062 33.000 -0.029 0.021 34.000 0.002 -0.012 35.000 -0.021 -0.032 36.000 0.042 -0.008 37.000 0.010 -0.030 38.000 -0.173 0.007 ^^^^^^ 39.000 0.006 0.032 40.000 -0.002 0.011 41.000 -0.028 0.017 42.000 0.003 -0.013 43.000 -0.047 0.007 44.000 0.109 -0.028 ^^^^^^ 45.000 0.045 -0.016 46.000 0.048 -0.020 47.000 0.041 0.018 48.000 0.030 0.005 49.000 0.045 -0.011 50.000 0.018 0.008 52.000 -0.013 0.010 53.000 0.006 -0.005 54.000 0.023 -0.010 55.000 0.018 -0.016 56.000 -0.034 0.000 57.000 -0.011 -0.009 58.000 0.017 -0.026 59.000 -0.002 0.004 60.000 0.027 0.001 61.000 0.029 -0.002 62.000 0.003 0.017 63.000 0.037 0.012 64.000 -0.002 0.003 65.000 0.000 0.006 66.000 -0.002 -0.026 67.000 0.006 -0.012 68.000 0.006 -0.016 69.000 0.001 -0.008 70.000 -0.002 -0.001 71.000 0.003 0.003 72.000 -0.006 -0.015 73.000 -0.010 -0.017 74.000 -0.003 -0.008 75.000 -0.005 -0.004 76.000 0.002 0.002 77.000 -0.001 -0.004 78.000 0.070 0.001 ^^^^^^ 79.000 0.021 0.001 80.000 -0.004 -0.028 81.000 -0.038 -0.021 82.000 -0.012 0.044 84.000 0.034 -0.004 85.000 0.001 -0.001 86.000 -0.009 0.039 101.000 0.011 -0.021