Progress 09/01/08 to 08/31/13
Outputs Target Audience: Targeted researchers addressing hydrologic modeling and energy and mass exchange in natural and managed ecosystems. Results also shared within the academic community through seminars and undergraduate and graduate classes. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? The project entailed participation in the Agro-IBIS modeling workshops and resulted in the training of graduate students in hydrologic modeling, as well as numerous collaborations with other researchers using the Agro-IBIS modeling system How have the results been disseminated to communities of interest? Results have been disseminated through scholarly publications, presentations at professional meetings and workshops. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts What was accomplished under these goals?
To better understand how ecosystems have been perturbed, and how they may change in the future, a basic understanding of exchanges of heat, moisture, and trace gases within the planetary boundary layer is needed along with an understanding of how land management modifies these accordingly. These fluxes are dynamic and responsive to each other, and they combine with land and ocean surface characteristics to influence atmospheric circulation, and large-scale climate patterns. Model and field studies were conducted to advance our understanding of these exchanges as a result of ecosystem perturbations. The Agro-IBIS model was used to examine scenarios of environmental change through the year 2100, and simulations of the recent past (1948-2007) to examine how previous changes in climate, atmospheric CO2, and agricultural management have impacted ecosystem structure and functioning and water and energy exchange. A daily, high-resolution (~8-km), gridded dataset of incoming solar radiation was used to drive the Agro-IBIS model simulations across the Upper Midwest. These data were used along with global datasets of land cover, crop fractional cover and management, soil textural information as a function of soil, transient nitrogen fertilizer use as model drivers for corn, soybeans, and wheat cropping. The results generally show an acceleration of the water cycle in the Upper Mississippi, Missouri, Ohio, and Great Lakes basins, but with significant seasonal and spatial complexity. Over the past 24 years, evapotranspiration has increased in most regions and most seasons, particularly during the fall, which is also a time of pronounced solar brightening. Trends in runoff are characterized by distinct spatial and seasonal variations. Since recent warming has led to a greater fraction of winter precipitation falling as rain rather than snow, spring runoff in some snow-dominated regions has declined significantly since 1984. Other regions show large increases in runoff throughout all seasons, primarily as a result of increased precipitation. Sensitivity experiments show that the water balance is most linearly sensitive to solar radiation and relative humidity, followed by precipitation, air temperature and wind speed. The energy and water balance of a riparian wetland in the Republican River basin in south-central Nebraska, was studied. Due to decreases in streamflow in recent decades in the study area, invasive species such as Phragmites australis have been removed throughout the riparian corridor of the river basin in an effort to reclaim surface water and toreduce consumptive water use from evapotranspiration (ET). The results of the energy budget analysis show that the average ET rate for the wetland during the growing season is 4.4 mm per day, with a maximum rate of 8.2 mm per day occurring which is higher than some values found in previous studies (e.g., 5.0-6.9 mm per day) and is attributed to differences in plant structure/biology, environment, and regional climate. The vegetation phenology and net radiation are the two largest meteorological/vegetation drivers for the seasonal variability in ET. Remote sensing-based estimates of ET were similar to the in-situ energy balance values during full vegetation, and reveal that the ET rates from P. australis are, on average, about 28% (1.18 mm per day) greater than those for native Typha latifolia. Results of the water balance analysis reveal a reasonable correspondence between water level fluctuations and the energy budget-derived estimates of ET. Periods when the two curves do not agree imply influx (outflux) of groundwater early (late) in the growing season. Results suggest that the removal of P. australis from wetlands within the Republican River basin could potentially result in a growing season “water savings” of up to 28% if the native species of T. latifolia replaces the non-native P. australis. If a free water surface replaces P. australis, depending on wind sheltering, a “water loss” or a “water savings” could occur. We conclude that due to the general presence of wind sheltering throughout the riparian corridor of the Republican River basin, this would more likely lead to a small, but tangible amount of “water savings” if replaced by open water. Heat storage rates in the wetland were dominated by changes in water temperature (as compared to soil or canopy heat storage) and comprised a significant portion of the hourly energy balance. On daily mean timescales, changes in the rate of heat storage corresponded to ~13% of the variability in net radiation, while for the season-long average, the heat storage term was found to be essentially negligible. Analysis of the wetland water balance showed seasonal variations in water level that were similar to changes in cumulative water inputs (i.e., precipitation minus ET). In support of the field studies, groundwater was incorporated into Agro-IBIS to simulate riparian and wetland systems; the study also investigated the impact of the introduced genetic lineage of P. australis which grows alongside and out-competes its native counterpart. Gas exchange measurements revealed significant differences between the two lineages. Our results show that native P. australis has a better ability to deal with water fluctuations, water shortages, and warmer temperatures than its introduced counterpart. In contrast, the faster growth rate, higher leaf area and lower water use efficiency of the introduced lineage under cooler temperatures could result in greater carbon assimilation on a whole-plant level, giving invasive P. australis an advantage and leading to further displacement of native communities in water-saturated habitats. In another study, a combination of observed soil temperatures and the Agro-IBIS model was used to investigate how strategic residue management could reduce the risk of rhizome threatening soil temperatures. Historical (1978–2007) reconstruction of extreme minimum 10 cm soil temperatures experienced across the Midwest US and model sensitivity studies quantified the impact of crop residue on soil temperatures. Extreme minimum soil temperatures increased by 2.5C to 6C compared to bare soil when the impact of miscanthus straw thicknesses (1–5 cm) following harvest were simulated. The greatest warming was associated with thicker residue layers. The likelihood of 10 cm soil temperatures reaching -3.5C was greatly reduced with 2– 5 cm of surface residue. However, soil temperatures in portions of the Dakotas, Nebraska, Minnesota, and Wisconsin were colder than -3.5C in 50–80% of all years. These results indicate that a strategic residue management could help increase the likelihood of overwintering of rhizomes (such as those for miscanthus) in the first few years after plant establishment
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2010
Citation:
Soylu, M. E., Istanbulluoglu, E., Lenters, J. D., and Wang, T., 2010. Quantifying the impact of groundwater depth on evapotranspiration in a semi-arid grassland region. Hydrology and Earth System Sciences Discussions, 7:6887-6923. doi:10.5194/hessd-7-6887-2010.
- Type:
Journal Articles
Status:
Published
Year Published:
2010
Citation:
Ryu, J. H., Svoboda, M. D., Lenters, J. D., Tadesse, T., and Knutson, C., 2010. Potential extents for ENSO-driven hydrologic drought forecasts in the United States. Climatic Change, 101(3-4):575-597. doi:10.1007/s10584-009-9705-0.
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Lenters, J. D., Cutrell, G. J., Istanbulluoglu, E., Scott, D. T., Herrman, K. S., Irmak, A., and Eisenhauer, D. E., 2011. Seasonal energy and water balance of a Phragmites australis- dominated wetland in the Republican River basin of south-central Nebraska (USA). Journal of Hydrology, 408, 19-34. doi:10.1016/j.hydrol.2011.07.010.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Herrman, K. S., Scott, D. T., Lenters, J. D., Istanbulluoglu, E., 2012. Nutrient loss following Phragmites australis removal in controlled soil mesocosms. Water, Air, and Soil Pollution. 223(6), 3333-3344. doi:10.1007/s11270-012-1113-9.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Istanbulluoglu, E., Wang, T., Wright, O. M., and Lenters, J. D., 2012. Interpretation of hydrologic trends from a water balance perspective: The role of groundwater storage in the Budyko hypothesis. Water Resources Research. v. 48, W00H16, doi:10.1029/2010WR010100.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Kucharik, C.J., VanLoocke A., Lenters J.D., Motew M.M., 2013. Miscanthus Establishment and Overwintering in the Midwest USA: A Regional Modeling Study of Crop Residue Management on Critical Minimum Soil Temperatures. PLoS ONE 8(7): e68847. doi:10.1371/journal.pone.0068847
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2010
Citation:
Cutrell, G. J., 2010. Seasonal energy and water balance of a Phragmites australis-dominated wetland in the Republican River basin (southwestern Nebraska, USA). Masters Thesis, University of Nebraska-Lincoln, 128 pp
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2010
Citation:
Walters, S. G., 2010. Carbon dynamics in a Phragmites australis invaded riparian wetland. Masters thesis, University of Nebraska-Lincoln, 53 pp
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2012
Citation:
Dong, B. 2012. Impacts of climate change on the surface water balance of the central United States, 1984-2007. Masters Thesis, University of Nebraska-Lincoln
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2012
Citation:
Mykleby, P. 2012. Water and energy balance response of a riparian wetland to the removal of Phragmites australis. Masters Thesis, University of Nebraska-Lincoln
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Progress 10/01/11 to 09/30/12
Outputs OUTPUTS: Together with two graduate students, we have been using the Agro-IBIS model to simulate the impacts of climate variability and change on water resources in the Upper Midwest. One of the graduate students recently completed his thesis, which focused on the impacts of Phragmites australis removal on the surface energy and water balance of a wetland site in south-central Nebraska. A second graduate student also completed his thesis, in which he used the Agro-IBIS model to simulate the surface energy and water balance of the Upper Midwest for the period 1984-2007. The students participated in two land surface hydrology (Agro-IBIS) modeling workshops - one at Iowa State University and the other at the University of Minnesota. PARTICIPANTS: We have two graduate students (Bo Dong, Phillip Mykleby) at the University of Nebraska-Lincoln (UNL) that worked on this project during the past year. Their duties were to analyze field data and perform model simulations and analysis using the Agro-IBIS terrestrial ecosystem model. We have four collaborators at three other academic institutions. This includes Dr. Chris Kucharik from the University of Wisconsin-Madison, Drs. Tracy Twine and Peter Snyder from the University of Minnesota, and Dr. Brian Hornbuckle from Iowa State University. Training has been provided to the two UNL graduate students through coursework and research group meetings. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts Field and growth chamber measurements have allowed us to refine and improve our simulations of the water balance in Agro-IBIS. Results of this study have been published in a student thesis and are also in preparation for submission to a peer-reviewed journal. Participation in Agro-IBIS modeling workshops has resulted in the training of graduate students in hydrologic modeling, as well as numerous collaborations with other researchers using the Agro-IBIS modeling system. Finally, we have graduated two recent M.S. students associated with this project.
Publications
- Herrman, K. S., Scott, D. T., Lenters, J. D., Istanbulluoglu, E. (2012) Nutrient loss following Phragmites australis removal in controlled soil mesocosms. Water, Air, and Soil Pollution. 223(6), 3333-3344. doi:10.1007/s11270-012-1113-9.
- Istanbulluoglu, E., Wang, T., Wright, O. M., and Lenters, J. D. (2012) Interpretation of hydrologic trends from a water balance perspective: The role of groundwater storage in the Budyko hypothesis. Water Resources Research. v. 48, W00H16, doi:10.1029/2010WR010100.
- Soylu, M. E., Lenters, J. D., Istanbulluoglu, E., and Loheide, S. P. (2012) On evapotranspiration and shallow groundwater fluctuations: A Fourier-based improvement to the White method. Water Resources Research, v. 48, W06506, doi:10.1029/2011WR010964.
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Progress 10/01/10 to 09/30/11
Outputs OUTPUTS: Together with three graduate students, we have been working with the Agro-IBIS model to simulate the impacts of climate variability and change on water resources in the Upper Midwest. One of the graduate students recently completed a paper in which groundwater was incorporated into Agro-IBIS to simulate riparian and wetland systems. A second graduate student has completed both field and growth chamber experiments to measure physiological parameters for an invasive plant species (P. australis), which have been incorporated into Agro-IBIS. The third graduate student has completed the calibration of a daily, high-resolution, gridded dataset of incoming solar radiation that is being used to drive the Agro-IBIS model simulations across the Upper Midwest for the entire study period (1948-2007). We participated in two land surface hydrology (Agro-IBIS) modeling workshops - one at the University of Nebraska-Lincoln and the other at the University of Wisconsin-Madison. Participants included three UNL grad students and collaborators from four other universities. PARTICIPANTS: We have three graduate students (Bo Dong, Phillip Mykleby, Evren Soylu) at the University of Nebraska-Lincoln (UNL) that have worked on this project during the past year. Their duties are to analyze field data and perform model simulations and analysis using the Agro-IBIS terrestrial ecosystem model. We have four collaborators at three other academic institutions. This includes Dr. Chris Kucharik from the University of Wisconsin-Madison, Drs. Tracy Twine and Peter Snyder from the University of Minnesota, and Dr. Brian Hornbuckle from Iowa State University. Training has been provided to the three UNL graduate students through coursework and research group meetings. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts The Agro-IBIS modeling results for riparian/wetland systems have been found to compare well with observations (and other models), and this study has now been published in Hydrology and Earth System Science Discussions (an online and open-access EGU journal). The field and growth chamber measurements (as well as the incorporation of groundwater) have allowed us to refine and improve our simulations of the water balance in Agro-IBIS. Publications describing these results are in preparation. The new solar radiation dataset has allowed us to examine trends in cloud cover that are impacting water resources in the U.S. Upper Midwest. Participation in the Agro-IBIS modeling workshops has resulted in the training of graduate students in hydrologic modeling, as well as numerous collaborations with other researchers using the Agro-IBIS modeling system. Finally, we have graduated one Ph.D. student associated with this project, and two more will be graduating in 2012.
Publications
- Soylu, M. E., Lenters, J. D., and Istanbulluoglu, E. (2011) On evapotranspiration and shallow groundwater fluctuations: A Fourier-based improvement to the White method. Water Resources Research. Accepted for publication.
- Lenters, J. D., Cutrell, G. J., Istanbulluoglu, E., Scott, D. T., Herrman, K. S., Irmak, A., and Eisenhauer, D. E. (2011) Seasonal energy and water balance of a Phragmites australis- dominated wetland in the Republican River basin of south-central Nebraska (USA). Journal of Hydrology, 408, 19-34. doi:10.1016/j.hydrol.2011.07.010.
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Progress 09/01/09 to 08/31/10
Outputs OUTPUTS: Together with three graduate students, we have been working with the Agro-IBIS model to simulate the impacts of climate variability and change on water resources in the Upper Midwest. One of the graduate students recently completed a paper in which groundwater was incorporated into Agro-IBIS to simulate riparian and wetland systems. A second graduate student has been collecting field data and planning growth chamber experiments to measure physiological parameters for an invasive plant species (P. australis), which will then be incorporated into Agro-IBIS. The third graduate student is compiling a daily, high-resolution, gridded dataset of incoming solar radiation that will be used to drive the Agro-IBIS model simulations across the Upper Midwest for the entire study period (1948-2007). We participated in two land surface hydrology (Agro-IBIS) modeling workshops - one at Iowa State University and the other at the University of Minnesota. Participants included three UNL grad students and collaborators from five other universities. PARTICIPANTS: We have five graduate students (Gregory Cutrell, Bo Dong, Phillip Mykleby, Evren Soylu, and Steven Walters) and two postdoctoral researchers (Kyle Herrman and Tiejun Wang) at the University of Nebraska-Lincoln (UNL) that have worked on this project during the past year. Their duties are to analyze field data and perform model simulations and analysis using the Agro-IBIS terrestrial ecosystem model. We have five collaborators at four other academic institutions. This includes Dr. Chris Kucharik from the University of Wisconsin-Madison, Drs. Tracy Twine and Peter Snyder from the University of Minnesota, Dr. Brian Hornbuckle from Iowa State University, and Dr. Simon Donner from the University of British Columbia. Training has been provided to the five UNL graduate students and the UNL postdoctoral researchers through coursework and research group meetings. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts The Agro-IBIS modeling results for riparian/wetland systems were found to compare well with observations (and other models), and this study has now been published in Hydrology and Earth System Science Discussions (an online and open-access EGU journal). The field and growth chamber measurements (as well as the incorporation of groundwater) will allow us to refine and improve our simulations of the water balance in Agro-IBIS. Finally, since net radiation is a primary driver of evapotranspiration and other water balance components, it is important that we include a quality solar radiation dataset as one of our model drivers. The new solar radiation dataset will also allow us to examine trends in cloud cover that are impacting water resources in the U.S. Upper Midwest. Participation in the Agro-IBIS modeling workshops has resulted in the training of graduate students in hydrologic modeling, as well as numerous collaborations with other researchers using the Agro-IBIS modeling system.
Publications
- Soylu, M. E., Istanbulluoglu, E., Lenters, J. D., and Wang, T., 2010. Quantifying the impact of groundwater depth on evapotranspiration in a semi-arid grassland region. Hydrology and Earth System Sciences Discussions, 7:6887-6923. doi:10.5194/hessd-7-6887-2010.
- Ryu, J. H., Svoboda, M. D., Lenters, J. D., Tadesse, T., and Knutson, C., 2010. Potential extents for ENSO-driven hydrologic drought forecasts in the United States. Climatic Change, 101(3-4):575-597. doi:10.1007/s10584-009-9705-0.
- Cutrell, G. J., 2010. Seasonal energy and water balance of a Phragmites australis-dominated wetland in the Republican River basin (southwestern Nebraska, USA). Master's Thesis, University of Nebraska-Lincoln, 128 pp.
- Walters, S. G., 2010. Carbon dynamics in a Phragmites australis invaded riparian wetland. Master's thesis, University of Nebraska-Lincoln, 53 pp.
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Progress 09/01/08 to 08/31/09
Outputs OUTPUTS: This report summarizes progress made during the first full year of this Hatch project. Since the initiation of this project on September 1, 2008, significant progress has been made toward the project goals. Accomplishments to date include the following: 1) A high-resolution (~8-km) climate dataset was produced and purchased from ZedX, Inc. for use in our Agro-IBIS model simulations. This dataset covers the entire continental United States (and portions of southern Canada) and includes observations of daily air temperature, precipitation, solar radiation, relative humidity, and wind speed for the period 1948-2007. Preliminary analysis of this new dataset indicates that it provides very reliable estimates of critical atmospheric variables at high enough resolution to be meaningful for regional scale studies, such as the current project. 2) Two new graduate students have been recruited to the University of Nebraska-Lincoln (UNL) to work on the project. Together with an existing third graduate student and a postdoctoral researcher, these individuals are receiving training on the Agro-IBIS model. This is helping to further the education of these individuals and prepare them for making future contributions to the project. 3) An Agro-IBIS workshop was organized and scheduled to be held in Madison, Wisconsin in October of 2009. This workshop will include scientists from the University of Wisconsin-Madison, the University of Minnesota, Iowa State University, and UNL. The objective of the workshop is to explore the various applications that Agro-IBIS is currently being used for, and to share ideas, technical skills, and software for analyzing the data and model outputs. PARTICIPANTS: We have three graduate students (Bo Dong, Phillip Mykleby, and Evren Soylu) and one postdoctoral researcher (Tiejun Wang) at the University of Nebraska-Lincoln (UNL) that are currently working on this project. Their duties are to analyze climatic input data and perform model simulations and analysis using the Agro-IBIS terrestrial ecosystem model. We have three collaborators at two other academic institutions. This includes Dr. Chris Kucharik from the University of Wisconsin-Madison and Drs. Tracy Twine and Peter Snyder from the University of Minnesota. Training has been provided to the three UNL graduate students and the UNL postdoctoral researcher through coursework and research group meetings. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts As we have just completed the first year of the project, there are limited outcomes and impacts to report. The most significant outcome is the availability of the new high resolution climate dataset, which will be useful not only for our model simulations, but also for use in other research projects that require the use of detailed climate observations over the past 60 years. An additional impact of the project is that we are currently training three graduate students in the area of hydroclimatology, and specifically in the use of Agro-IBIS for understanding the impacts of climate variability and change on water resources across the U.S. Upper Midwest.
Publications
- No publications reported this period
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Progress 09/01/07 to 08/31/08
Outputs OUTPUTS: This project was initiated on 9/1/2008, and so there is no progress to report at this time. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts This project was initiated on 9/1/2008, and so there is no progress to report at this time.
Publications
- No publications reported this period
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