Collaborators needed: data gaps in precipitation and streamflow

All long term datsets contain missing or unusable data (gaps).  While many of these gaps are inevitable, it is not possible to simply omit missing values when calculating solute fluxes from precipitation or streamflow.  The uncertainty associated with gap-filling estimates is not commonly reported or propagated into these  flux estimates.  We hope to characterize the causes of these gaps across sites for both volume and solute chemistry in long-term precipitation and streamflow datasets.  To quantify the uncertainty associate with different gap-filling methods, we will apply them to a series of "fake gaps," and compare the estimates with measured values.

 Weather events can cause gaps in long-term datasets.  (D. Buso)

To do this we need datasets!  We're interested in hearing form potential co-authors with streamflow and precipitation datasets to discuss the frequency and causes of gaps, and how they fill them.  We are especially in need of solute concentration datasets.  We're also interested in hearing from statistically minded individuals with new ideas on how to quantify the uncertainty associated with these gaps.

Please contact Craig See at crsee@syr.edu for more information.

QUEST is now an NSF Research Coordination Network

As of March 2013, Quantifying Uncertainty in Ecosystem Studies (QUEST) is supported by the National Science Foundation as a Research Coordination Network.  The five-year grant will allow the QUEST network to better support activities that advance the application of uncertainty analysis in ecosystem studies.  Efforts will focus on outreach and research on quantifying uncertainty in five topic areas important to ecosystem studies: atmospheric deposition, stream water export, biomass, soils, and ecosystem budgets.

Outreach will target ecosystem scientists through workshops at professional meetings and periodic webinars, each addressing issues in uncertainty in one of the five topic areas listed above.  QUEST has a website at http://www.quantifyinguncertainty.org, which already includes sample code, links to papers, and news announcements.  We will be developing discussion boards, wikis, and tutorials.

QUEST will support efforts to clarify approaches to uncertainty analysis, illustrate its use in evaluating monitoring designs, and address issues of detecting change over time.  QUEST will help to identify problems to be addressed by focus groups in specific topic areas.   The focus groups will produce QUEST funded open-access publications to be made available on the website.  We are also assembling an advisory board of statisticians who will assist in education and collaborate on research projects.

Our goal in the first year is to get the word out and recruit participants.  Please feel free to pass on this announcement, and please send us ideas for other avenues for outreach.

The QUEST Steering Committee:

Ruth Yanai (Coordinator), John Campbell (Information Management), Mark Green (Statistical Coordinator), Chris Daly (Precipitation), Rick Hooper (Streamflow), Jim Clark (Vegetation), Dan Richter (Soils), and Mark Harmon (Ecosystem Budgets)

Email us at QUEST <quantifyinguncertainty@gmail.com> to join our mailing list.

Position as listed filled. Contact us about possible opening for Spring 2014.

Ruth Yanai at the State University of New York College of Environmental Science and Forestry (SUNY-ESF) is recruiting students to start in Fall 2013 or Spring 2014.  We have made progress quantifying uncertainty in estimates of forest biomass and stream loads and are also working on wet deposition and changes in soil storage.  There are currently research opportunities associated with each of these areas. 

In addition to the primary research with QUEST, there are opportunities for involvement in other projects associated with MELNHE (Multi-Element Limitation in Northern Hardwood Ecosystems) in the White Mountains.  MELNHE sites are located at Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook (USFS).  http://www.esf.edu/melnhe

A background in ecology, statistics, and programming would be valuable assets.  Funding will include tuition waiver, stipend, and health insurance, and consist of a combination of research and teaching assistantships.  Please contact Heather Engelman at forestecology@esf.edu if you are interested in applying.  Preference will be given to students available to start with the 2013 summer field season in the White Mountains of New Hampshire.

QUEST Paper in Journal of Forestry

QUEST Authors Ruth Yanai, Carrie Rose Levine, Mark Green, and John Campbell have published an article in this month’s Journal of Forestry titled “Quantifying uncertainty in forest nutrient budgets”

ABSTRACT: Nutrient budgets for forested ecosystems have rarely included error analysis, in spite of the importance of uncertainty to interpretation and extrapolation of the results. Uncertainty derives from natural spatial and temporal variation and also from knowledge uncertainty in measurement and models. For example, when estimating forest biomass, researchers commonly report sampling uncertainty but rarely propagate the uncertainty in the allometric equations used to estimate tree biomass, much less the uncertainty in the selection of which allometric equations to use. Change over time may have less uncertainty than a single measurement, if the measures are consistently biased, as by the use of inaccurate allometric equations or soil sampling techniques. Quantifying uncertainty is not as difficult as is sometimes believed. Here, we describe recent progress in quantifying uncertainty in biomass, soils, and hydrologic inputs and outputs, using examples from the Hubbard Brook Experimental Forest, New Hampshire, USA.

Click here to download the pdf. 

QUEST Workshop at LTER All Scientists Meeting

Members of QUEST held a two hour workshop entitled “Quantifying Uncertainty in Ecosystem Studies” at the 2012 LTER All Scientists Meeting.  The two hour discussion-based workshop started with a round of introductions in which the 40 participants identified their system of study, and the biggest source of uncertainty they face.  The rest of the time was devoted by ten “lightening round” presentations on uncertainty in different ecosystem components (see presenters below).  Each five minute talk was followed up by a group discussion.   We received positive feedback from many of the workshop participants, and a proposal has been submitted for an organized oral session at next years ESA conference in Minneapolis. Full meeting notes are available for download below

List of presenters:

John Campbell:  Intro to QUEST, Participant introductions (what's your biggest uncertainty?)
Harmon:  Intro to sources of uncertainty
Adam Skibbe: Precipitation Uncertainty

Xuesong Zhang: Precipitation Uncertainty
John Battles: Biomass Uncertainty
Mark Green: Streamflow Uncertainty
Ruth Yanai: Uncertainty in Soils
Jeff Taylor: NEON products and their uncertainty
Craig See: Uncertainty in Data Gaps
Carrie Rose Levine: Monitoring Uncertainty

Atmospheric deposition working group meets in Oregon

The LTER synthesis working group on quantifying uncertainty in wet atmospheric deposition convened last week in Oregon.   Participants met May 21-23 at HJ Andrews Experimental Forest to share current research and coordinate future efforts.  The first day included presentations on long-term collection of deposition data, variability in monsoon precipitation (Sevilleta LTER), uncertainty in data gap filling, a hierarchical Bayesian analysis of precipitation patterns, and an analysis of monitoring intensity.  Presentations were followed up with discussion and planning sessions.

The following day included a presentation by Dr. Chris Daly (OSU) on the PRISM model, and the uncertainties associated with large-scale spatiotemporal precipitation estimates and predictions.  The rest of the time was devoted to planning papers and future workshops.  Products coming out of this meeting will include a paper on uncertainty sources in unreplicated measurements (small watersheds), a paper on the effects of monitoring intensity on uncertainty, and a paper on gap filling in long-term hydrologic datasets.  Also coming out of this meeting are plans to host a workshop on uncertainty in ecosystem studies at this year’s LTER All Scientists Meeting in September (more on this when the date is confirmed).  After discussing precipitation for two days, participants were given a rainy tour of HJ Andrews Experimental Forest.

People in attendance: Dr. John Campbell (USFS), Dr. Ruth Yanai (SUNY-ESF), Dr. Shannon LaDeau (Cary Institute), Doug Moore (Sevilleta LTER), Adam Skibbe (Konza LTER), Craig See (SUNY-ESF)
Attending remotely (via video conference call): Dr. Kathleen Weathers (Cary Institute), Mathew Petrie (University of New Mexico), Dr. Mark Green (Plymouth State), Stephanie Laseter (USFS), Dr. Jennifer Knoepp (USFS), Carrie Rose Levine (SUNY-ESF)

Precipitation working group (left to right): John Campbell, Shannon Ladeau, Ruth Yanai, Doug Moore, Craig See

NEON Uncertainty Workshop at ESA 2012

Workshop:  Estimating Uncertainty and Trend Detection in Ecological Data Sets Collected by the National Ecological Observatory Network

Organizers: Jeffery Taylor, Steve Berukoff, Andrew Fox, Katherine Thibault

Description: Ecology is entering a particularly exciting phase, in which the number and availability of long-term data-sets are increasing and the construction of the nation’s first ecological observatory (NEON) has begun. This unprecedented opportunity requires a departure from traditional approaches to ecological data analyses, which have not emphasized uncertainty characterization. New approaches will demand increased proficiency and rigor in both the design of NEON sampling and the analysis of existing and forthcoming long-term ecological data. For example, NEON will collect continental-scale observations of over 500 different ecological variables at 70 sites across the country. Developing a unified approach to estimating uncertainty and detecting trends for all of these data products is therefore a significant challenge faced in the design process. Further development, understanding, and dissemination of the latest statistical techniques for deriving these quantities will both inform
sampling design and equip up-and-coming ecologists with critical skills. This half-day workshop will highlight the underlying mathematical approaches to uncertainty quantification and trend detection and relate these methods to the nationally/internationally accepted standards. Emphasis will be placed on unified approaches to spatio-temporal scaling and the
detection/attribution of long-term trending. The format will consist of 2-3 overview talks, followed by several breakout sessions, and end with a unified synthesis session. Attendees are encouraged to provide feedback and suggest alternative approaches based on their own experience. Lunch will not be provided, but afternoon snacks and refreshments (alcoholic/non-
alcoholic) will be available. NEON will sponsor all costs and the workshop will be free of charge for participants.