[LTER-mcm-pi] wait... there IS more variability in streamflow since 2002!
Peter Doran
pdoran at lsu.edu
Mon Aug 17 19:09:52 MDT 2015
It was the conductivity I was remembering. This is a lake level
corrected plot for ELB conductivity. Note the variation post flood year.
We can try and update this for Boulder as well.
-Peter
Peter Doran, Professor and John Franks Chair
Department of Geology and Geophysics
E235 Howe Russell Geosciences Complex
Louisiana State University
Baton Rouge, Louisiana, USA 70803
Ph: 225-578-3955
Fx: 225-578-2302
http://geology.lsu.edu/People/Faculty/item73533.html
On 8/17/15 6:16 AM, Peter Doran wrote:
> I seem to recall a difference in the pre and post flood year variability in upper lake temperatures in the analysis we did a few years ago as well. I will check.
>
> Andrew, we can include any met variability analysis to the group in our presentation of the summaries in Boulder. Mike has now created a slot for met which was missing. I'll talk to Maciek when he's in BR this week
>
> -Peter
>
>
>
>> On Aug 16, 2015, at 6:58 PM, Andrew Fountain<andrew at pdx.edu> wrote:
>>
>> Mike,
>>
>> Is the variance higher because the flow is higher after the flood year? Did you do a coefficient of variation analysis?
>>
>> Maciek is working on air temp and soil temp.
>>
>> Andrew
>>
>> On Sun, Aug 16, 2015 at 1:55 PM, Michael Gooseff<michael.gooseff at colorado.edu<mailto:michael.gooseff at colorado.edu>> wrote:
>> Hi all, (greetings from Toolik)
>>
>> 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 variance had gone down in the 2003-2013 period (compared to 1990-2001). My recollection is that this sort of took the wind out of our sails on that discussion.
>>
>> 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 -
>>
>> 1. We fixed an error we found in the calculation of % change of variance from pre- to post-flood.
>> 2. 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) —> doing these 2 steps alone resulted in an increase of variance of 185% in the post-flood vs pre-flood period…
>> 3. However, 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 the result is an increase in variance of 48% in the post-flood period vs. the pre-flood period. 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)
>>
>> So, 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. What are some of the other ecosystem parameters we might evaluate for similar changes?
>> —> 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
>> —> Soil or Air temperature analyses?
>> —> Soil moisture analyses from a long-term plot?
>> —> chl-a in lake photic zone?
>>
>> 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…
>>
>> Talk to you all on Thursday.
>>
>> Cheers
>> -Mike
>>
>>
>> Snip of text: [in the pre-flood period] mean annual streamflow was 0.85 x 106 m3 with a standard deviation of 0.93 x 106 m3 and a variance over this period of 0.86 x 109 m3. The highest annual flows on record were observed in the 2001-02 flow season (total streamflow over 5 x 106 m3). Since this ‘flood year’, mean annual discharge has increased (2003-2013; 1.59 x 106 m3), as has the standard deviation (1.13 x 106 m3) and the variance (1.28 x 109 m3, an increase of 49%).
>> [cid:A5029176-02CE-4C56-8D60-60E7C7B196AD]
>>
>>
>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>> Michael Gooseff, Associate Professor
>> Institute of Arctic and Alpine Research
>> Civil, Architectural, and Environmental Engineering
>> University of Colorado
>> Boulder, CO 80309-0450
>>
>> email: michael.gooseff at colorado.edu<mailto:michael.gooseff at colorado.edu>
>> web: http://goosefflab.weebly.com<http://goosefflab.weebly.com/>
>> phone: 303.735.5333<tel:303.735.5333>
>>
>>
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>>
>>
>>
>> --
>> Andrew G. Fountain
>>
>> Department of Geology
>> Department of Geography
>>
>> Address: FedEx/Shipping Address:
>> ------------------------ --------------------------
>> Department of Geology Department of Geology
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>> Portland, OR 97207-0751 Portland State University
>> USA 1721 SW Broadway
>> Portland, OR 97201
>> Email: andrew at pdx.edu<mailto:andrew at pdx.edu> USA
>> http://www.glaciers.pdx.edu<http://www.glaciers.pdx.edu/>
>> Phone: 503-725-3386
>> Fax: 503-725-3025
>> <A5029176-02CE-4C56-8D60-60E7C7B196AD.png>
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