Electronic Data Collection and Analysis System
Yin Foo, Des; Foley, Margaret
E-Publications; PublicationNT; E-Books; Report ; 39/1992
1992-08-01
Made available via the Publications (Legal Deposit) Act 2004 (NT).
Date:1992-08
English
Power and Water Authority
Darwin
Report ; 39/1992
application/pdf.
Check within Publication or with content Publisher.
https://hdl.handle.net/10070/229024
https://hdl.handle.net/10070/673447
Technical Report WRD92039 Viewed at 15:07:17 on 29/07/2010 Page 183 of 192. (ii) Make the Barometric correction to LDD : First {B} must be recalibrated to the incorrect {L} calib:cation, for which a slope and offset are required. Assume that the Barometr ic changes (max. approx. 70rnm in 6 hours) are reli,tively small and that the recalibration slope and offset for the Barometrically corrected data will be very close to those for the uncorrected data. using the caLibrate routine the slope (m) and offset (C) needed to calibrate {L} to the manuals {Z} can be found (see 2.1, 2.2 above) Assume that this "m" and "C n are reasonably close to those which would recalibrate {BJ to {L} {i.e. assume that the Barometric data {B} is as accurate as the manuals {Z}). As per 2 above, the recalibration must be done using a "True" set ( {T} ), which includes only manual readings at times for "'hich credible Logged data is available, and includes manual readings for a large part of the total DD range. Choose elements of {T} - for this example choose only 4 : When selecting {T) values it is necessary to go through the :set at an expanded scale, so that irregularities can be seen; start at time to, the last recorded zero manual reading before the st.art of Drawdown ( 9: 30: 00 here (mOve, ent I "09:30:00", ent) - the logged value at this time is O.OOlm. Look for next flat part of curve - mOve to 10: 30. Expand Horizontal scale (H) by 10, and vertical (V) by 4