аЯрЁБс>ўџ 46ўџџџ3џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџьЅС%` №П:bjbj"x"x .@@: џџџџџџЄююююююю & сь> > > > > > > > `bbbbbb$Эh5~†ю" > > " " †юю> > ›      " Ію> ю> `  " `    :”,юю> 2 €лwh8Щ Ш Р `Б0сЪRГо ЌГГюD> "`   x Œ –> > > ††Š > > > с" " " " „†„†ююююююџџџџ University of Nebraska-Lincoln Data Screening and Gap Filling Procedures Study Sites: Mead, Nebraska Data Screening Procedures Four steps are used in screening flux data. Stationarity: We accept our net ecosystem CO2 exchange (NEE) data following criteria discussed in Foken and Wichura (1996; Tools for quality assessment of surface-based flux measurements. Ag. For. Meteo., 78, 83-105). The criteria are relaxed during the non-growing season as fluxes are substantially smaller. Statistical filtering: This screening includes removing fluxes when kurtosis or standard deviations of either the scalar and velocity fluctuations are outside predetermined limits based on the literature. Other Quality Control: Periods when sensors were being calibrated or when flow rates were unacceptable are deleted. Nighttime Calm Winds: Nighttime NEE data are accepted when mean horizontal wind speed, U > 2.5m/s (this corresponds to a u* of approximately 0.25 m/s). This limit was determined from 3 years of data where integrated NEE was gap filled after imposing different thresholds of U. Gap Filling Procedures Growing season, Daytime: – Screened net ecosystem CO2 exchange (NEE) during a 5 day window (day to be gap filled Б2 days) are plotted with corresponding incident photosynthetically active radiation (PAR) data. A hyperbolic light response curve is fit to the data. The resulting regression parameters are used to fill in missing daytime NEE for that day only. The 5 day window then slides down to the next day and the procedure is repeated. Growing season, Nighttime: A Б2 week window of screened night NEE is bin-averaged into 6 different ranges of air temperature (bins are 3oC wide). A Q10 relationship is fit for each night where there is sufficient data to get a “good fit” (sufficiently high r2). To obtain an estimate for each night, the Q10 and Rref values obtained from regression are smoothed using a 5 day running filter (NEE = Rref*Q10(T-Tref)/10; Tref = 0oC). Where there are large gaps in screened nighttime data, the Q10 and Rref values are interpolated. The Q10 and Rref values are then used with daytime air temperatures to obtain Re estimates during the day. Non-growing season, Daytime and Nighttime: Daily averages of screened NEE data are plotted against the corresponding soil temperature. A Q10 relationship of all data combined for the entire non-growing season period (fall through spring) is determined. To gap fill a missing hour, the Rref is calculated from the daily average of screened NEE data. These Q10 and Rref factors are then used to gap fill missing hours. 1Ief€„…‰Š” ЁЅКЛМНЦклцщъ   ! # ' ‡ Я н ф х ћ I M S c y ™ Б В Д К Щ & ( 2 L Q  ‰ Œ Ђ Ѓ Н О  - < = @ W e љђюђљђътокожюожокожожожЮжожожококЪожокожокЦкжожкожожкожкжожкОкжкЦжЦотЖhЇ1hh" 5hЦGнhЦGнH*hIРhX ІhCAњhˆ9hH*hˆ9hhЦGнhх8phЇ1hhЇ1h>*h" hCAњ hЇ1hhЇ1h hЇ1hh" FIef€Ўц Д ( > ? @ W “”89:їїїђђэххххђђђђђђђђђу & Fgdх8pgdх8pgd" $a$gdˆ9h:§e f n o r ‹ Œ Ѕ б д љ  ! " a { !",.0›œЃЉЋFHNQ›ЄЇЈЉЋГЖЙМРСУФХЦфї  -/њђњюътъюъюъюъюъюђњђњъюъкъювюЪювюТюОЖОВЊЅВЊВ•В‘юОюъювюТювh^N5hX ІhX ІH*hH|>hH|>H* hX ІH*hX ІhX ІH*hX Іhq-0hH|>H*hH|>hq-0h" H*hЉbсh" H*hБ2yh" H*hБ2yhЇ1hH*hCAњhЇ1hH*hЇ1hh" hЇ1hh" 5 hЇ1h59/58>?@C”ІЇНОПРућ!D“ВДЗЛдћ§:ќєќ№ќ№ќшушоќкќкќвќкќкќвќкќвќвќh" h" H*hх8p hх8p5 hЇ1h5hЇ1hh" 5hЇ1hhq-0h" H*h" ,1hАа/ Ар=!А"А# $ %ААаАа а†œ@@ёџ@ " NormalCJ_HaJmH sH tH DAђџЁD Default Paragraph FontRiѓџГR  Table Normalі4ж l4жaі (k@єџС(No ListH™ђH Ї1h Balloon TextCJOJQJ^JaJ: џџџџIef€ЎцД(>?@W“”8 9 < ˜0€€˜0€€˜0€€˜0€€˜0€€˜0€€˜ 0€€˜ 0€€˜ 0€€˜ 0€€˜0€€˜0€€˜0€€˜0€€˜0€€˜0€€˜0€€˜0€€˜0€€˜0€€Ief€ЎцД(>?@W“”8 9 < š0€€˜0€€˜0€€˜0€€˜0€€š0€€€š 0€€€š 0€€š 0€€š 0€€X‘0 0 л}`Ї1hˆ9hх8pX ІIРЦGнCAњџ@€ППЊюПП: @џџUnknownџџџџџџџџџџџџG‡z €џTimes New Roman5€Symbol3& ‡z €џArial5& ‡za€џTahoma"qˆ№аhFкЪ&лЪ&лЪ&t†Д†Д!№ ДД245 5 2ƒQ№HX)№џ?фџџџџџџџџџџџџџџџџџџџџџ" 2џџUNL Gap Filling Proceduresasuyker1asuyker1  ўџр…ŸђљOhЋ‘+'Гй0œ˜ Фаф№ќ  , L X d p|„Œ”фUNL Gap Filling Procedures asuyker1Normal asuyker15Microsoft Office Word@И{4@Р{V8Щ@Е#=8Щ@и+rh8Щ†ДўџеЭеœ.“—+,љЎ0 hp˜ Ј АИРШ а їфUniversity of Nebraska5 ' UNL Gap Filling Procedures Title ўџџџўџџџ !"ўџџџ$%&'()*ўџџџ,-./012ўџџџ§џџџ5ўџџџўџџџўџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџRoot Entryџџџџџџџџ РF€Lwh8Щ7€Data џџџџџџџџџџџџ1TableџџџџЧWordDocumentџџџџ.SummaryInformation(џџџџџџџџџџџџ#DocumentSummaryInformation8џџџџџџџџ+CompObjџџџџџџџџџџџџqџџџџџџџџџџџџўџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџўџ џџџџ РFMicrosoft Office Word Document MSWordDocWord.Document.8є9Вq