1 #====================================================================== |
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2 # L A D C P P R O C . D E F A U L T S |
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3 # doc: Fri Sep 17 09:44:21 2010 |
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4 # dlm: Fri Jul 8 00:06:07 2011 |
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5 # (c) 2010 A.M. Thurnherr |
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6 # uE-Info: 91 16 NIL 0 0 72 0 2 4 NIL ofnI |
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7 #====================================================================== |
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8 |
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9 # default parameters for [mkShearProf] |
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10 |
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11 # NOTES: |
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12 # - defaults are taken: |
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13 # 1) from my current UH processing merge control files |
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14 # 2) from the defaults set in Eric's [merge.c] |
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15 # - the default version in the ANTS bin dir is always loaded |
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16 # - if there is a version in the current processing directory it is loaded |
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17 # afterwards |
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18 # - per-station parameters can be chosed based on $LADCP_file and $CTD_file |
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19 # - for additional notes, see [LADCPproc] |
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20 |
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21 # HISTORY: |
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22 # Sep 17, 2010: - created |
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23 # Dec 9, 2010: - added doc for ASCII CTD file support |
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24 # Jun 15, 2011: - added Svbin_start, Svbin_end |
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25 # Jul 7, 2011: - added BT processing parameters |
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26 |
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27 #---------------------------------------------------------------------- |
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28 # ASCII CTD file support |
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29 #---------------------------------------------------------------------- |
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30 |
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31 # By default, [LADCPproc] reads a standard seabird .cnv file. Alternatively, |
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32 # the CTD data can be supplied in a plain ASCII file. To do so, the following |
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33 # variables must be defined in the setup file (-s). Each variable defines |
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34 # the field (column) number of the corresponding data field. Fields are |
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35 # numbered beginning with 1. |
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36 |
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37 # $CTD_ASCII_sampfreq = 1; ## in Hz |
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38 |
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39 # $CTD_ASCII_press_field = 1; |
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40 # $CTD_ASCII_temp_field = 2; |
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41 # $CTD_ASCII_salin_field = 3; |
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42 # $CTD_ASCII_lat_field = 4; |
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43 # $CTD_ASCII_lon_field = 5; |
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44 |
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45 # The following variable is optional. |
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46 |
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47 # $CTD_ASCII_badval = 999; |
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48 |
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49 #---------------------------------------------------------------------- |
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50 # Backscatter Profile Parameters |
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51 #---------------------------------------------------------------------- |
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52 |
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53 # The output profile of volume-scattering coefficient is calculated |
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54 # from a subset of the bins only. This is based on the observation, |
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55 # from on a single P403 profile, that the volume-scattering coefficient |
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56 # correction of Deines (IEEE 1999) yield similar results only for |
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57 # bins 3-9. |
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58 |
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59 # The seabed-finding routine, on the other hand, uses acoustic |
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60 # backscatter from all bins, as it is possible that the seabed is only |
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61 # seen in the farthest bins. |
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62 |
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63 $Svbin_start = 3; |
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64 $Svbin_end = 9; |
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65 |
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66 #---------------------------------------------------------------------- |
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67 # Bottom Track Parameters |
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68 #---------------------------------------------------------------------- |
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69 |
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70 # First bin to consider when looking for seabed to calculated post- |
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71 # processed BT. NB: For consistency with EF's code, bin 1 is the |
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72 # first bin. |
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73 |
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74 $BT_bin_start = 1; |
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75 |
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76 # CTD depth above seabed where BT search begins |
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77 |
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78 $BT_begin_search_above = 300; |
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79 |
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80 # Maximum allowed spread of bin number where max echo is found. Large values |
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81 # imply sloping seabed and/or large instrument tilt. The default value of |
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82 # 3 is probably too tight. The range spread calculation should be modified |
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83 # to take instrument tilt into consideration. |
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84 |
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85 $BT_max_bin_spread = 3; |
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86 |
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87 # For tricky BT cases, the acoustic backscatter from the seabed can be plotted |
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88 # and the bottom range set manually. This has been found to be very powerful |
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89 # in case of 2011_IWISE yoyo profile 160, where the bottom was around 150m |
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90 # from the lower turning points and where the method of Deines [1999] clearly |
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91 # does not work. |
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92 |
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93 #$BT_min_depth = xxx; |
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94 #$BT_max_depht = xxx; |
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95 |
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96 # Maximum difference between water depth and average distance of echo max., |
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97 # if $BT_min_depth and $BT_max_depth are not set. The stddev of the detected |
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98 # water depth is added To this number. |
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99 |
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100 $BT_max_depth_error = 20; |
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101 |
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102 # Maximum allowed difference between reference-layer w and BT w. Note |
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103 # that this must be relaxed in regions of significant near-bottom |
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104 # vertical velocity, e.g. due to cross-slope currents. |
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105 |
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106 $BT_max_w_difference = 0.03; |
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107 |
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108 #---------------------------------------------------------------------- |
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109 # Shear Processing Parameters |
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110 #---------------------------------------------------------------------- |
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111 |
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112 ## u_bin0, u_bin1, w_bin0, w_bin1: These set the first and |
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113 ## last bin indices used when integrating horizontal and |
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114 ## vertical velocity, respectively. The indices start |
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115 ## from 1 and are inclusive. These parameters do not |
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116 ## affect the calculation of shear. They should specify |
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117 ## a good reference layer (for the calculation of the |
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118 ## barotropic component) such as bins 1 to 4. |
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119 |
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120 $wbin_start = 1; ## These parameters start from 1, not zero |
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121 $wbin_end = 5; |
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122 $ubin_start = 1; |
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123 $ubin_end = 5; |
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124 |
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125 ## sh_bin0, sh_bin1: These are like the above except that |
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126 ## they affect the shear calculation only. They can |
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127 ## normally be left at the default range of 1 to 128 |
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128 ## (disabled). |
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129 |
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130 $shbin_start = 1; |
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131 $shbin_end = $LADCP{N_BINS}; |
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132 |
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133 ## w_ref_bin, w_dif: These control one of the editing |
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134 ## criteria recommended by Fischer and Visbeck, or rather |
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135 ## a modification of it. All velocity data are rejected |
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136 ## below the point at which the vertical velocity |
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137 ## estimate is w_dif larger or smaller than the estimate |
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138 ## in w_ref_bin. I have not found this criterion |
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139 ## helpful. 94/12/22: changed, so that only those points |
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140 ## where w actually deviates from the mean from 0 to w_ref_bin |
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141 ## are flagged. |
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142 |
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143 $w_ref_bin = 10; |
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144 $w_dif = 0.05; |
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145 |
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146 ## wake_hd_dif, wake_ang_min, min_wake_w, n_wake_bins: These control |
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147 ## editing based upon the direction and inclination of the package wake, |
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148 ## calculated from reference layer U,V, and W. wake_hd_dif |
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149 ## sets how close to the heading of the wake must be to |
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150 ## the heading of any beam for interference (in degrees). |
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151 ## wake_ang_min sets the minimum wake angle from the |
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152 ## vertical for interference (in degrees). min_wake_w sets |
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153 ## the minimum package speed required for wake interference |
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154 ## (although upward speed is measured negative, this parameter |
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155 ## is input as a positive value). All three criteria |
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156 ## must be satisfied for the wake flag to be set. n_wake_bins |
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157 ## determines how many bins from the top are removed from a |
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158 ## flagged profile, the default is 1 (top bin only). |
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159 ## Additionally, if the previous ensemble met all |
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160 ## interference criteria, the present ensemble |
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161 ## will be flagged even if the criteria are not met. |
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162 ## Default values are wake_hd_dif=0.0, wake_ang_min=90.0, |
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163 ## and min_wake_w=0.1, which results in no wake editing. |
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164 |
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165 $wake_hd_dif = 0.0; ## set wake editing defaults so that no wake editing |
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166 $wake_ang_min = 90.0; ## occurs |
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167 $min_wake_w = 0.1; |
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168 $n_wake_bins = 1; ## wake editing default - top bin only |
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169 |
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170 ## e_max is the maximum error velocity. An error velocity |
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171 ## greater than e_max will flag the other velocity |
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172 ## components. For the BB with 2-ping ensembles, 0.01 |
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173 ## m/s looks about right for this parameter. It |
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174 ## knocks out the incorrect ambiguity glitches as well |
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175 ## as some smaller but still significant glitches. |
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176 ## Note that for the BB, the PG criteria operate on |
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177 ## percent 4-beam solutions, so PG combined with the |
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178 ## e_max provides a reliable filter against big |
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179 ## glitches. |
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180 ## For the NB with 18-ping ensembles, it is not yet |
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181 ## clear whether there is any benefit in using e_max |
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182 ## at all. To be effective, the value will have to be |
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183 ## small, something like 0.015 or 0.02. Note also |
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184 ## that for the NB, the pg array holds pg counting |
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185 ## both 4-beam and 3-beam solutions, so 3-beam |
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186 ## glitches will slip through the e_max net. |
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187 ## Default is e_max= 10.0, which effectively disables |
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188 ## it. |
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189 |
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190 $e_max = 0.1; |
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191 |
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192 ## min_correlation (BB only) is the minimum correlation, in |
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193 ## counts, for each beam in a given bin. |
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194 |
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195 $min_cor = 70; |
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196 |
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197 ## Shear editing: This requires 2 passes through the |
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198 ## database, one using the option |
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199 ## binned_shear_time_range: |
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200 ## to set the time range for a pass during which the |
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201 ## shear statistics will be calculated on a relatively |
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202 ## coarsely grid by binning rather than interpolation, |
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203 ## then using the usual option |
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204 ## time_range: |
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205 ## for the normal pass in which the results of the |
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206 ## previous pass can be used to flag bad velocity values |
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207 ## based on anomalous shears. The first pass can include |
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208 ## both up and down casts if desired, in which case it |
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209 ## would be followed by a second pass for the up and |
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210 ## downcasts separately. The binned shear statistics are |
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211 ## saved until they are explicitly recalculated with the |
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212 ## "binned_shear_time_range:" option. |
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213 ## The shear editing is controlled by these parameters: |
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214 ## shear_dev_max= x.x, where x.x is a floating point |
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215 ## number giving a threshold in standard |
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216 ## deviations. Any shear component deviating from |
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217 ## the binned mean by more than this times the |
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218 ## local standard deviation will raise a flag. |
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219 ## Suitable values for this parameter are probably |
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220 ## in the range 3-5. Less than 3 is likely to |
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221 ## start trimming too many valid samples, more than |
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222 ## 4 or 5 is likely to do nothing at all. |
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223 ## shear_sum_dev_max= x.x gives a threshold used in |
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224 ## detecting isolated bad velocity points. If the |
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225 ## sum of two successive bad shears (based on |
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226 ## shear_dev_max), divided by the |
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227 ## standard deviation, is LESS THAN this amount, |
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228 ## then the common velocity point is considered to |
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229 ## be an isolated glitch, and it alone is flagged. |
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230 ## Otherwise, both velocity samples contributing to |
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231 ## a flagged shear will be flagged. A reasonable |
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232 ## value for this parameter is probably around 1-2, |
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233 ## but I don't yet have enough experience to be |
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234 ## sure. |
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235 ## Warning: don't forget to reset the first_x=, |
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236 ## first_y=, and first_z= parameters after pass 1 |
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237 ## (with binned_shear_time_range:). If you don't, and |
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238 ## the depths are not in the database, then the depths |
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239 ## will be completely wrong in pass 2 (with |
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240 ## time_range:). You may also want to use a different |
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241 ## output file name for pass 1, so that the binned |
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242 ## shear statistics file will not be overwritten |
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243 ## during pass 2. |
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244 |
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245 $max_shdev = 3.5; ## to disable, set to nan |
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246 $max_shdev_sum = 1.5; |
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247 |
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248 ## previous ping bottom bounce interference editing is controlled by: |
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249 ## clip_margin 0.0 turns off this editing; otherwise, it is the margin in |
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250 ## meters (on each side) by which the calculated range of the |
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251 ## interference is expanded before clipping. A reasonable value would |
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252 ## be something like 32 (2 depth bins). |
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253 |
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254 # NOTES: |
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255 # - default value (90m) taken from comment in merge control files |
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256 # - clipping is disabled if water_depth cannot be determined |
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257 |
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258 $clip_margin = 90; ## default: no previous ping bottom bounce editing |
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259 $first_clip_bin = 1; ## default: apply previous ping clipping to all bins */ |
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260 |
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261 # tilt editing as in Visbeck's code |
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262 |
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263 $max_tilt = 22; # max allowed angle from vertical |
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264 $max_delta_tilt = 4; # max allowed ping-to-ping tilt difference |
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265 |
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266 # On DIMES US2 stations in Drake Passage it was found that the ambiguity velocity had been |
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267 # set too low. It appears, however, that aliased velocities are easy to detect because aliasing |
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268 # causes a large positive velocity to appear as a large negative one, and vice versa. |
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269 # The following defines the maximum allowed discrepancy between the vertical velocity from CTD |
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270 # pressure and the LADCP reference-layer w. This parameter should probably be set to something |
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271 # similar as the ambiguity velocity. |
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272 |
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273 $w_max_err = 2.5; |
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274 |
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275 |
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276 1; |
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