?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=https%3A%2F%2Fepisodesplatform.eu%2Feprints%2F2088%2F&rft.title=A+Graphical+Method+for+Estimation+of%0D%0ABarometric+Efficiency+from+Continuous+Data%E2%80%94%0D%0AConcepts+and+Application+to+a+Site+in+the+Piedmont%2C%0D%0AAir+Force+Plant+6%2C+Marietta%2C+Georgia&rft.creator=Gonthier%2C+Gerard+J.&rft.subject=Other-additional+study&rft.subject=General+about+inducing+technology+types&rft.description=A+graphical+method+that+uses+continuous+water-level+and%0D%0Abarometric-pressure+data+was+developed+to+estimate+barometric%0D%0Aefficiency.+A+plot+of+nearly+continuous+water+level+(on+the%0D%0Ay-axis)%2C+as+a+function+of+nearly+continuous+barometric+pressure%0D%0A(on+the+x-axis)%2C+will+plot+as+a+line+curved+into+a+series+of%0D%0Aconnected+elliptical+loops.+Each+loop+represents+a+barometricpressure%0D%0Afluctuation.+The+negative+of+the+slope+of+the+major%0D%0Aaxis+of+an+elliptical+loop+will+be+the+ratio+of+water-level+change%0D%0Ato+barometric-pressure+change%2C+which+is+the+sum+of+the%0D%0Abarometric+efficiency+plus+the+error.%0D%0AThe+negative+of+the+slope+of+the+preferred+orientation%0D%0Aof+many+elliptical+loops+is+an+estimate+of+the+barometric%0D%0Aefficiency.+The+slope+of+the+preferred+orientation+of+many%0D%0Aelliptical+loops+is+approximately+the+median+of+the+slopes+of%0D%0Athe+major+axes+of+the+elliptical+loops.+If+water-level+change%0D%0Athat+is+not+caused+by+barometric-pressure+change+does+not%0D%0Acorrelate+with+barometric-pressure+change%2C+the+probability%0D%0Athat+the+error+will+be+greater+than+zero+will+be+the+same+as%0D%0Athe+probability+that+it+will+be+less+than+zero.+As+a+result%2C+the%0D%0Anegative+of+the+median+of+the+slopes+for+many+loops+will+be%0D%0Aclose+to+the+barometric+efficiency.%0D%0AThe+graphical+method+provided+a+rapid+assessment+of%0D%0Awhether+a+well+was+affected+by+barometric-pressure+change%0D%0Aand+also+provided+a+rapid+estimate+of+barometric+efficiency.%0D%0AThe+graphical+method+was+used+to+assess+which+wells+at+Air%0D%0AForce+Plant+6%2C+Marietta%2C+Georgia%2C+had+water+levels+affected+by%0D%0Abarometric-pressure+changes+during+a+2003+constant-discharge%0D%0Aaquifer+test.+The+graphical+method+was+also+used+to+estimate%0D%0Abarometric+efficiency.+Barometric-efficiency+estimates+from%0D%0Athe+graphical+method+were+compared+to+those+of+four+other%0D%0Amethods%3A+average+of+ratios%2C+median+of+ratios%2C+Clark%2C+and%0D%0Aslope.+The+two+methods+(the+graphical+and+median-of-ratios%0D%0Amethods)+that+used+the+median+values+of+water-level+change%0D%0Adivided+by+barometric-pressure+change+appeared+to+be+most%0D%0Aresistant+to+error+caused+by+barometric-pressure-independent%0D%0Awater-level+change.+The+graphical+method+was+particularly%0D%0Aresistant+to+large+amounts+of+barometric-pressure-independent%0D%0Awater-level+change%2C+having+an+average+and+standard+deviation%0D%0Aof+error+for+control+wells+that+was+less+than+one-quarter+that+of%0D%0Athe+other+four+methods.%0D%0AWhen+using+the+graphical+method%2C+it+is+advisable+that+more%0D%0Athan+one+person+select+the+slope+or+that+the+same+person+fits+the%0D%0Asame+data+several+times+to+minimize+the+effect+of+subjectivity.%0D%0AAlso%2C+a+long+study+period+should+be+used+(at+least+60+days)%0D%0Ato+ensure+that+loops+affected+by+large+amounts+of+barometricpressure-independent%0D%0Awater-level+change+do+not+significantly%0D%0Acontribute+to+error+in+the+barometric-efficiency+estimate.&rft.publisher=USGS&rft.date=2007-07&rft.type=Reports&rft.type=NonPeerReviewed&rft.identifier=++Gonthier%2C+Gerard+J.++(2007)+A+Graphical+Method+for+Estimation+of+Barometric+Efficiency+from+Continuous+Data%E2%80%94+Concepts+and+Application+to+a+Site+in+the+Piedmont%2C+Air+Force+Plant+6%2C+Marietta%2C+Georgia.++Documentation.+USGS.+++++&rft.relation=https%3A%2F%2Fpubs.usgs.gov%2Fsir%2F2007%2F5111%2Fpdf%2Fsir2007-5111.pdf