<p dir="ltr">Really cool mike. That's certainly the general impression.<br>
Is the increase in variance a within year phenomena or interannual?</p>
<div class="gmail_quote">On Aug 16, 2015 4:56 PM, "Michael Gooseff" <<a href="mailto:michael.gooseff@colorado.edu">michael.gooseff@colorado.edu</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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Hi all, (greetings from Toolik)</div>
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I wanted to follow up on a conversation we had a few months ago about the variability in the MDVs since 2002. Recall that Chris shared with us a spreadsheet of annual flow volumes from the Fryxell basin streams, and that the analyses suggested that
<i>variance had gone down in the 2003-2013 period (compared to 1990-2001)</i>. My recollection is that this sort of took the wind out of our sails on that discussion.</div>
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I revisited these analyses in the past week in trying to get some writing and a figure together for the Bioscience paper that Andrew is leading and Chris and I revised the analyses - </div>
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We fixed an error we found in the calculation of % change of variance from pre- to post-flood.</li><li><font face="Calibri,sans-serif">We took out the 2001-02 flood year (to look at ‘before’ and ‘after’, we argue that we shouldn’t lump the flood year in either if we postulate that it is a turning point) —>
</font><span style="color:rgb(0,0,0);font-family:Calibri,sans-serif;font-size:14px"><i>doing these 2 steps alone resulted in an
<u>increase</u> of variance of 185% in the post-flood vs pre-flood period</i></span><font face="Calibri,sans-serif"><i>…</i></font></li><li style="color:rgb(0,0,0);font-family:Calibri,sans-serif;font-size:14px">
<u>However</u>, we had several seasons in each period of poor or no flow estimates because of technical problems with gauges or controls (3 in the pre-flood period (~4%), 7 in the post-flood period (~7%)). Chris came up with some nice correlations to fill
in these gaps (no relationship has an R2 < 0.70), and <i><b>the result is an increase in variance of 48% in the post-flood period vs. the pre-flood period</b></i>. This is (I think) our best analysis of the flow records and indicates increased variance in
the recent decade. (most updated figure inserted below with snip of text)</li></ol>
<div style="font-size:14px">So, <font color="#ff0000"><b>I’d like to suggest that we revisit the notion that our system is becoming more variable as we emerge from the cooling trend as a potential theme for the renewal</b></font>. What are some of the other
ecosystem parameters we might evaluate for similar changes? </div>
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<div style="font-size:14px">—> JP showed us UW PAR data last week that looks like it could be more variable, but will be hard to evaluate with the gaps </div>
<div style="font-size:14px">—> Soil or Air temperature analyses?</div>
<div style="font-size:14px">—> Soil moisture analyses from a long-term plot?</div>
<div style="font-size:14px">—> chl-a in lake photic zone?</div>
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<div style="font-size:14px">If we can demonstrate change in ecosystem temporal trends (the synthesis paper mega plot) and increased variance of some drivers, I think we have an easy sell on the motivation for the proposal…</div>
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<div style="font-size:14px">Talk to you all on Thursday.</div>
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<div style="font-size:14px">Cheers</div>
<div style="font-size:14px">-Mike</div>
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<div><span style="font-size:16px"><b>Snip of text:</b> [in the pre-flood period] </span><span style="font-size:12pt;font-family:Calibri">mean annual streamflow was 0.85 x 10</span><sup style="font-size:14px;font-family:Calibri">6</sup><span style="font-size:12pt;font-family:Calibri">
m</span><sup style="font-size:14px;font-family:Calibri">3</sup><span style="font-size:12pt;font-family:Calibri"> with a standard deviation of 0.93 x 10</span><sup style="font-size:14px;font-family:Calibri">6</sup><span style="font-size:12pt;font-family:Calibri">
m</span><sup style="font-size:14px;font-family:Calibri">3</sup><span style="font-size:12pt;font-family:Calibri"> and a variance over this period of 0.86 x 10</span><sup style="font-size:14px;font-family:Calibri">9</sup><span style="font-size:12pt;font-family:Calibri">
m</span><sup style="font-size:14px;font-family:Calibri">3</sup><span style="font-size:12pt;font-family:Calibri">.</span><span style="font-size:12pt;font-family:Calibri">
</span><span style="font-size:12pt;font-family:Calibri">The highest annual flows on record were observed in the 2001-02 flow season (total streamflow over 5 x 10</span><sup style="font-size:14px;font-family:Calibri">6</sup><span style="font-size:12pt;font-family:Calibri">
m</span><sup style="font-size:14px;font-family:Calibri">3</sup><span style="font-size:12pt;font-family:Calibri">).</span><span style="font-size:12pt;font-family:Calibri">
</span><span style="font-size:12pt;font-family:Calibri">Since this ‘flood year’, mean annual discharge has increased (2003-2013; 1.59 x 10</span><sup style="font-size:14px;font-family:Calibri">6</sup><span style="font-size:12pt;font-family:Calibri">
m</span><sup style="font-size:14px;font-family:Calibri">3</sup><span style="font-size:12pt;font-family:Calibri">), as has the standard deviation (1.13 x 10</span><sup style="font-size:14px;font-family:Calibri">6</sup><span style="font-size:12pt;font-family:Calibri">
m</span><sup style="font-size:14px;font-family:Calibri">3</sup><span style="font-size:12pt;font-family:Calibri">) and the variance (1.28 x 10</span><sup style="font-size:14px;font-family:Calibri">9</sup><span style="font-size:12pt;font-family:Calibri">
m</span><sup style="font-size:14px;font-family:Calibri">3</sup><span style="font-size:12pt;font-family:Calibri">, an increase of 49%).</span><span style="font-size:12pt;font-family:Calibri"> </span></div>
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<div style="font-size:14px">-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-</div>
<div style="font-size:14px">Michael Gooseff, Associate Professor</div>
<div style="font-size:14px">Institute of Arctic and Alpine Research</div>
<div style="font-size:14px">Civil, Architectural, and Environmental Engineering</div>
<div style="font-size:14px">University of Colorado</div>
<div style="font-size:14px">Boulder, CO 80309-0450</div>
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<div style="font-size:14px">email: <a href="mailto:michael.gooseff@colorado.edu" target="_blank">michael.gooseff@colorado.edu</a></div>
<div style="font-size:14px">web: <a href="http://goosefflab.weebly.com/" target="_blank">http://goosefflab.weebly.com</a> </div>
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phone: <a href="tel:303.735.5333" value="+13037355333" target="_blank">303.735.5333</a></div>
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