#======================================================================
# S V E L _ C O R R E C T I O N S . P L
# doc: Thu Dec 30 01:35:18 2010
# dlm: Mon Jun 29 11:02:08 2020
# (c) 2010 A.M. Thurnherr
# uE-Info: 22 74 NIL 0 0 72 0 2 4 NIL ofnI
#======================================================================
# HISTORY:
# Dec 30, 2010: - created
# Oct 5, 2011: - sscorr_w temporarily disabled
# - re-enabled
# Oct 26, 2011: - BUG? in calc_binDepth() on very shallow station 38 in
# 2010 Gom Spill data set the uplooker code did not stop
# at the surface, requiring additon of another test
# Mar 4, 2014: - added support for missing TILT (PITCH/ROLL)
# May 12, 2016: - removed unused lines of code
# May 18, 2016: - removed assumption of 1500m/s soundspeed setting
# - made sscorr_w return nan on undef'd input vel
# May 24, 2016: - calc_binDepths() -> binDepths()
# - added caching to binDepths
# Jun 29, 2020: - renamed sscorr_w to remove conflict with RDI_Coords.pl
# NOTES:
# In an effort to track down the scale bias, NBP0901 stn 160 was reprocessed with various
# simplified soundspeed correction methods:
# 1) no sscorr: bias is depth dependent and disappears btw 2500 and 3000m
# 2) simplified (dBin/dADCP): very similar to full correction, esp. when dBin is used
# 3) hacked correction (1450m/s vs 1500m/s assumed soundspeed) => bias largely disappears
sub sscorr_LADCP_w($$$$$) # sound-speed correction for w
{ # see RDI Coord. Trans. manual sec. 4.1, ...
my($wObs,$wCTD,$ssADCP,$dADCP,$dBin) = @_; # but there is an error: the ^2 applies to the []
return nan unless numberp($wObs);
my($tanSqBeamAngle) = tan(rad($LADCP{BEAM_ANGLE}))**2;
$dADCP = int($dADCP); # @sVelProf is binned to 1m
$dBin = int($dBin);
while (!numberp($sVelProf[$dADCP])) { $dADCP--; } # skip gaps & bottom of profile
while (!numberp($sVelProf[$dBin ])) { $dBin--; }
my($Kn) = sqrt(1 + (1 - $sVelProf[$dBin]/$sVelProf[$dADCP])**2 * $tanSqBeamAngle);
return ($wObs*$sVelProf[$dBin]/$ssADCP - $wCTD) / $Kn; # full correction
}
sub binDepths($) # see RDI Coord Trans manual sec. 4.2
{
my($ens) = @_;
return @{$LADCP{ENSEMBLE}[$ens]->{BIN_DEPTHS}} # cached result
if (@{$LADCP{ENSEMBLE}[$ens]->{BIN_DEPTHS}});
my(@bindz); # if not cached => calculate
# if the following assertion fails, the entire code needs to be searched for
# each call of calc_binDepths() needs to be protected by a test
die("ensemble $ens") unless defined($LADCP{ENSEMBLE}[$ens]->{TILT});
my($tanSqBeamAngle) = tan(rad($LADCP{BEAM_ANGLE}))**2;
my($curdz) = 0; # calc avg sndspeed btw transducer & 1st bin
$curdz-- until numberp($sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)]);
my($avgss) = my($ADCPss) = $sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)];
my($sumss) = my($nss) = 0;
if ($LADCP{ENSEMBLE}[$ens]->{XDUCER_FACING_UP}) {
while ($curdz >= -$LADCP{DISTANCE_TO_BIN1_CENTER}*cos(rad($LADCP{ENSEMBLE}[$ens]->{TILT}))) {
if (numberp($sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)])) {
$sumss += $sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)]; $nss++;
}
$curdz--;
}
} else {
while ($curdz <= $LADCP{DISTANCE_TO_BIN1_CENTER}*cos(rad($LADCP{ENSEMBLE}[$ens]->{TILT}))) {
if (numberp($sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)])) {
$sumss += $sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)]; $nss++;
}
$curdz++;
}
}
$avgss = $sumss/$nss if ($nss>0);
my($Kn) = sqrt(1 + (1 - $avgss/$ADCPss)**2 * $tanSqBeamAngle);
$bindz[0] = $LADCP{ENSEMBLE}[$ens]->{XDUCER_FACING_UP} ?
- $LADCP{DISTANCE_TO_BIN1_CENTER}*$Kn*$avgss/$LADCP{ENSEMBLE}[$ens]->{SPEED_OF_SOUND}*cos(rad($LADCP{ENSEMBLE}[$ens]->{TILT})) :
+ $LADCP{DISTANCE_TO_BIN1_CENTER}*$Kn*$avgss/$LADCP{ENSEMBLE}[$ens]->{SPEED_OF_SOUND}*cos(rad($LADCP{ENSEMBLE}[$ens]->{TILT}));
for (my($bin)=1; $bin<=$LADCP_lastBin-1; $bin++) {
$sumss = $nss = 0;
if ($LADCP{ENSEMBLE}[$ens]->{XDUCER_FACING_UP}) {
while ($curdz >= $bindz[$bin-1]-$LADCP{BIN_LENGTH}*cos(rad($LADCP{ENSEMBLE}[$ens]->{TILT}))) {
last unless (int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz) >= 0);
if (numberp($sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)])) {
$sumss += $sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)]; $nss++;
}
$curdz--;
}
} else {
while ($curdz <= $bindz[$bin-1]+$LADCP{BIN_LENGTH}*cos(rad($LADCP{ENSEMBLE}[$ens]->{TILT}))) {
if (numberp($sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)])) {
$sumss += $sVelProf[int($LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH}+$curdz)]; $nss++;
}
$curdz++;
}
}
$avgss = $sumss/$nss if ($nss > 0); # otherwise, leave avgss as is
$Kn = sqrt(1 + (1 - $avgss/$ADCPss)**2 * $tanSqBeamAngle);
$bindz[$bin] = $LADCP{ENSEMBLE}[$ens]->{XDUCER_FACING_UP} ?
$bindz[$bin-1] - $LADCP{BIN_LENGTH}*$Kn*$avgss/$LADCP{ENSEMBLE}[$ens]->{SPEED_OF_SOUND}*cos(rad($LADCP{ENSEMBLE}[$ens]->{TILT})) :
$bindz[$bin-1] + $LADCP{BIN_LENGTH}*$Kn*$avgss/$LADCP{ENSEMBLE}[$ens]->{SPEED_OF_SOUND}*cos(rad($LADCP{ENSEMBLE}[$ens]->{TILT}));
}
for (my($i)=0; $i<@bindz; $i++) { # cache result
$LADCP{ENSEMBLE}[$ens]->{BIN_DEPTHS}[$i] = $LADCP{ENSEMBLE}[$ens]->{CTD_DEPTH} + $bindz[$i];
}
return @{$LADCP{ENSEMBLE}[$ens]->{BIN_DEPTHS}}; # return result
}
1;