Progress 07/01/09 to 06/30/14

Outputs
Target Audience: Target Audience Scientific Research Community Graduate Students Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Opportunities Graduate students were trained during the project to do research and learned technical skills related to surface-atmosphere interactions. The PI advanced knowledge and capabilities by attending national and international conferences, and visiting research laboratories. How have the results been disseminated to communities of interest? Dissemination In addition to peer reviewed publications, some results combined with findings of colleagues appeared in newspapers and science-based web sites. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Accomplishments Wet and dry cycles of the northern Intermountain Region were examined at various time scales. There is a strong cycle of precipitation of about 12 to 15 years, related to the transition of the PDO index of ocean temperatures between its two states. This results in atmospheric changes in the Gulf of Alaska, which bring disturbances and precipitation to the region. Changes in the level of the Great Salt Lake (GSL) integrate larger space and time than point measurements of precipitation. Cycles of lake level changes, stream flow, and precipitation in the watersheds are strongly correlated to variations in the QDO of Pacific Ocean temperatures. It was discovered that there is a cyclical pattern of very wet Junes in northern Utah. This was connected to variations in Pacific Ocean temperatures, at scales of 10-20 years. In order to examine precipitation at longer scales, published tree ring estimates going back about 800 years for a mountain region in NE Utah were used. The data suggest that there are distinct cycles of about 15 years (matching our results), 50 years, and 150 years. The causes and meaning of the apparent 50 and 150 year cycles remain unknown. Eddy covariance measurements were made of evapotranspiration (ET) of irrigated turfgrass. Daily values varied, but were typically about 4 mm. Seasonal totals were over 600 mm, which represent a significant water use. Current irrigation models for turf use a crop coefficient of 0.8, but these results indicated a value closer to 1.0. Results also showed the ET values were greatly affected by winds moving warm and dry air from the surroundings. The project participated in an interdisciplinary study of remote sensing and ET for irrigated cotton in Texas, BEAREX08. The results showed advection of heat increases ET, and is connected to the mixed-layer lying above the surface layer of air. Eddy covariance (EC) measurements of ET the project helped conduct, revealed values significantly less than the large weighing lysimeters. There is not yet general agreement about the meaning of this important finding, but EC measurements passed all tests of reliability and consistency. Measurements of ET and energy balance at the USU Hydrologic Observatory in an alpine meadow in mountains of northern Utah were used to validate a soil-based model for ET made by a fellow researcher for both grass and shrubs. The estimates from soil-based approach using the HYDRUS model compared well with the EC measurements. EC measurements were used to implement a near real time irrigation schedule for applying saline waste-water on grass fields near a power plant. If a suitable set of protocols is followed, the data from the systems can ensure seasonal water application does not exceed ET, and protect the groundwater. Finally, cooperative work has just begun with a Tree Physiologist to examine the feasibility of using tree rings from Utah and Rocky mountain junipers near Logan, UT to estimate both seasonal precipitation and the periodic summer heat waves.

Publications

Progress 01/01/13 to 09/30/13

Outputs
Target Audience: Scientific Research Community Graduate Students Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Graduate students were trained in pertinent science as well as technical and research skills related to surface-atmosphere interactions. The PI advanced knowledge and capabilities by attending national and international conferences, and visiting research laboratories. How have the results been disseminated to communities of interest? Some of results were combined with other findings of colleagues, and appeared in newspapers and web site news items. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The first objective was to quantify frequencies of wet and dry cycles of the northern Intermountain Region. Research showed a strong 12 to 15 year cycle for precipitation. The switch between the wet and dry periods follows a transition of the PDO index of Pacific Ocean between its two states. This results in atmospheric changes in the Gulf of Alaska, which bring disturbances and precipitation to the region. Changes in the level of the Great Salt Lake are useful indicators climate variations as they integrate large integrate larger scales. Cycles of lake level changes, stream flow, and precipitation in the watersheds, are strongly correlated to variations in the QDO of Pacific Ocean temperatures. It was also discovered there is a cyclical pattern of very wet Junes in northern Utah. This was connected to variations in Pacific Ocean temperatures, at scales of 10–20 years. In order to examine precipitation at longer scales, published tree ring estimates going back about 800 years for a mountain region in NE Utah were used. Data suggest there are distinct cycles of about 15 years (matching our earlier results), 50 years, and 150 years. The causes and meaning of the 50 and 150 year cycles remain unknown. The second objective was to quantify the evapotranspiration (ET) of several key ecosystems having critical roles in water resources, and determine the weather and climate properties affecting the ET. Eddy covariance (EC) measurements of ET were conducted over irrigated turfgrass, irrigated agriculture, and an alpine mountain meadow. For turfgrass, daily ET values were typically about 4 mm, and seasonal totals were over 600 mm, which represent a significant water use. Current irrigation models for turf use a crop coefficient of 0.8, but our results indicated a value closer to 1.0. The ET values were greatly affected by winds moving warm and dry air from the surroundings. The project joined an interdisciplinary study of remote sensing and ET for irrigated cotton in Texas, BEAREX08. Results showed advection of heat by wind increases ET, and is connected to the mixed-layer lying above the surface layer. EC values of ET were significantly less than the large weighing lysimeters. There is not yet agreement about the meaning of this important finding, but EC measurements passed all tests of reliability and consistency. Measurements of ET and energy balance at the USU Hydrologic Observatory in an alpine meadow of mountains of northern Utah were used to validate a soil-based model for ET made by a fellow researcher for both grass and shrubs. The estimates from soil-based approach using the HYDRUS model compared well with EC measurements. EC measurements were used to implement a near real time irrigation schedule for applying saline waste-water on grass fields near a power plant. If suitable protocols are followed, data from the systems can ensure seasonal water application does not exceed ET, and protect groundwater. Finally, cooperative work has just begun with a Tree Physiologist to examine the feasibility of using tree rings from Utah and Rocky mountain junipers near Logan, UT to estimate both seasonal precipitation and the periodic summer heat waves.

Publications

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: A large interdisciplinary field study, BEAREX08, examined energy balance and evapotranspiration (ET) for irrigated cotton in an arid environment. Among the issues examined by this CRIS project were: contribution of advection of warm and dry air from arid surroundings on ET; the agreement of the eddy covariance stations with the large weighing lysimeters in the same field. The role of advection of heat on ET included looking at the properties of the mixed layer of air lying above the surface layer. The reliability of eddy covariance estimates of ET was examined by checking how well the energy balance was closed for each site. Previous work at Utah State has documented decadal scale patterns of precipitation in northern Utah, for the period of instrumental observations. In order to extend further back in time, there has been collaboration with other scientists to use local tree rings to estimate previous precipitation values. Data from trees cored in nearby mountains are being analyzed to examine several questions. First, the connections between ring growth and seasonal (intra-annual) precipitation periods, and annual precipitation. Second, what are the effects of hot summer seasons on the annual growth rings, which are superimposed upon any precipitation signal The results will indicate how useful the data will be to estimate precipitation values over the past 500 - 600 years. A new activity connected to the project is to use eddy covariance measurements to estimate ET of several irrigated fields near a power plant. This follows the original study that used older Bowen Ratio stations. These ET estimates are to be used to schedule the irrigation of saline waste water on the fields. Connections continue with the USU hydrological observatory at the mountain ecosystem of the TW Daniels Experimental Forest. Eddy covariance systems for measuring heat, water and CO2 fluxes, continue to operate. It is ensured that the sensors are working and data are stored properly. But the calculations of the flux values have yet to be conducted. These require some additional resources. PARTICIPANTS: Collaborators: Roger Kjelgren, Simon Wang and Scott Jones; Plants, Soils & Climate, USU, Christopher Neale, Civil & Environmental Engineering USU, William Kustas, USDA-ARS Hydrology Laboratory, and John Prueger, National Soil Tilth Laboratory. TARGET AUDIENCES: Applied climate scientists; Surface hydrologists and irrigation scientists studying water balance; Water managers interested in the water resources of the Intermountain Region. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The initial results from the BEAREX08 study are now published. The findings revealed that ET was significantly enhanced by the import of warm and dry air from the mixed-layer. This indicates the much of additional energy came from regional scale sources. The eddy covariance (EC) stations demonstrated rather good energy balance closure values, supporting the reliability of the ET estimates. However, the lysimeter estimates of ET were much larger than the EC stations, especially during afternoon periods of large ET. In order for the lysimeter values to be correct, a very large and unprecedented negative or downward sensible heat flux would be required. This issue is still under investigation. The USU Dendrochronology Lab has produced preliminary tree ring data for a set of Rocky Mountain Junipers near Logan, UT. Ring index values are currently documented for about 450 years of record. Cyclical variations are observed in the rate of annual growth, that are coherent with the observed changes in precipitation measured in Logan. More detailed analyses are being conducted at present. The ET estimates for grass and shrubs have been determined from eddy covariance measurements for several periods of two summers at the TW Daniels Experimental forest. These values are comparing favorably with estimates by another researcher using the soil-based HYDRUS model for ET.

Publications

• French, A. N., Alfieri, J. G., Kustas, W. P., Prueger, J. H., Hipps, L. E., Chavez, J. L., Evett, S. R., Howell, T. A., Gowda, P. H., Hunsaker, D. J., & Thorpe, K. R. 2012. Estimation of surface energy fluxes using surface renewal and flux variance techniques over an advective irrigated agricultural site: Advances in Water Resources, 50: 91-105. (Published).
• Kustas, W. P., Alfieri, J. G., Anderson, M. C., Collaizzi, P., Prueger, J. H., Evett, S. R., Neale, C. M., Hipps, L. E., Chavez, J. L., Copeland, K. S., & Howell, T. A., (2012). Evaluating the two-source energy balance model using local thermal and surface flux observations in a strongly advective irrigated agricultural area: Advances in Water Resources, 50: 120-133. (Published).
• Alfieri, J. G., Kustas, W. P., Prueger, J. H., Hipps, L. E., Evett, S. R., Basara, J. B., Neale, C. M., French, A. N., Collaizzi, P., Agam, N., Cosh, M. H., Chavez, J. L., & Howell, T. A., (2012). On the discrepancy between eddy covariance and lysimetry-based surface flux measurements under strongly advective conditions: Advances in Water Resources, 50: 62-78. (Published).
• Prueger, J. H., Alfieri, J. G., Hipps, L. E., Kustas, W. P., Chavez, J. L., Evett, S. R., Anderson, M. C., French, A. N., Neale, C. M., McKee, L., Hatfield, J. L., Howell, T. A., & Agam, N., (2012). Patch scale turbulence over dryland and irrigated surfaces in a semi-arid landscape under advective conditions during BEAREX08: Advances in Water Resources, 50: 106-119. (Published).
• Neale, C. M., Geli, H. M. E., Kustas, W. P., Alfieri, J., Gowda, P., Evett, S. R., Prueger, J. H., Hipps, L. E., Dulaney, W., Chavez, J. L., French, A. N., & Howell, T. A., (2012). Soil Water Content Estimation using a Remote Sensing Based Hybrid Evapotranspiration Modeling Approach: Advances in Water Resources, 50: 152-161. (Published).
• Alfieri, J., Kustas, W. P., Prueger, J. H., Chavez, J. L., Evett, S. R., Neale, C. M., Anderson, M. C., Hipps, L. E., Kopeland, K. S., Howell, T. A., French, A. N., Dulaney, W., & McKee, L. 2012. A comparison of the eddy covariance and lysimetry-based measurements of the surface energy fluxes during BEAREX08. IAHS. (Published).
• Geli, H. M. E., Neale, C. M., Doyle, W., John, O., Henk, d. B. A. R., W., K., Pack, R. T., & Hipps, L. E., (2012). Improved Scintillometer-Based Estimates of Sensible Heat Flux using LiDAR-Derived Surface Roughness: Journal of Hydrometeorology, 13(4): 1317-1331. (Published).

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: This project participated in a large multi-institutional study of remote sensing, energy balance and evapotranspiration (ET) of irrigated cotton in an arid and windy location in Texas - the so-called BEAREX08 study. The key investigations the project was involved with included the following: The role of the advection of heat from the regional scale arid landscape on ET under these types of conditions. This was approached by connecting measurements and models of both the surface layer near the crop and the deeper layer of atmosphere that is related to the large-scale landscape, called the mixed-layer. The calculations revealed that the ET is significantly enhanced by the import of warm and dry air from the mixed-layer. The study was unique, in that it integrated ground-based ET and energy balance measurements with a tethered balloon and radiosonde measurements of the deeper layer of air. Another experiment performed a comparison of a number of eddy covariance systems placed side by side, in order to estimate uncertainty in the flux estimates due to the inherent variability between identical sensor systems. Collaboration has continued with a project examining ET of Tamarisk trees along the Colorado River in California. The scintillations of a light beam passing above a surface are measured with a scintillometer, and input into equations to estimate the sensible heat flux over the path. When combined with measurements of available energy, it allowed the ET to be estimated for path lengths between 1 and 2 km. Work has begun to document seasonal variations of temperature and precipitation in northern Utah, and any patterns and cycles, such as previously reported for annual precipitation. Previous connections of this project to tree rings used published values for the far NE corner of Utah. - a different hydrology and climate from the Wasatch Front. Collaboration has begun with tree ring measurements in mountains near Logan, UT. Tree ring indices will be integrated with the annual and intra-annual climate data in the region. Response of tree rings to the climate in this region will be examined. Connections continue with the USU studies of hydrology and energy balance of a mountain ecosystem at TW Daniels Experimental Forest. Eddy covariance systems for measuring heat, water and CO2 fluxes, continue to operate. It is ensured that the sensors are working and data are stored properly. But the calculations of the flux values have yet to be conducted. These require some additional resources. PARTICIPANTS: PARTICIPANTS: Collaborators: Roger Kjelgren, Simon Wang and Scott Jones; Plants, Soils & Climate, USU, Christopher Neale, Civil & Environmental Engineering USU, William Kustas USDA-ARS Hydrology Laboratory, and John Prueger, National Soil Tilth Laboratory. TARGET AUDIENCES: Applied Climate scientists; Surface hydrologists and irrigation scientists studying water balance; Water managers interested in the water resources of the Intermountain Region the the West. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The key findings from the BEAREX08 study during the reporting period are now either published or submitted. The mechanism of how advection of warm and dry air enhance the ET were revealed in a better way. Results revealed that ET was significantly enhanced by the import of warm and dry air from the mixed-layer. The study was unique, in that it integrated ground-based ET and energy balance measurements with a tethered balloon and radiosonde measurements of deeper layers of air. Results of the inter-comparison of eddy covariance sensors demonstrated the statistical properties of the variations of flux estimated by each system. The variability increases during conditions when the advection of heat was larger. For the flux of water vapor, or in this case latent heat flux, the variation value was about 27 W m-2. Such information provides quantitative knowledge of the inherent uncertainty of these key research measurements, which will affect interpretation of findings. Findings of the study of ET of Tamarisk, showed that a scintillometer, combined with available energy estimates, could be used to estimate the ET values over paths of one to two km. Agreement with several sets of surface measurements was reasonably good. Such results show the feasibility of using this approach to estimate ET over regions of a few km in size. Preliminary findings of seasonal patterns of precipitation and temperature in northern Utah indicate relationships between the precipitation in winter to that of the following summer, even though atmospheric factors that govern precipitation are quite different between the seasons.

Publications

• No publications reported this period

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: The activities involved the two main aspects of the project: the wet and dry cycles of the Intermountain West; and the evapotranspiration of land surfaces. First, the variations in the precipitation cycles were examined using both the modern instrument record (about 100 years), and published longer-term values derived from tree rings. Various analyses were done to identify the most important cycles that are present in the instrument record. The connections were examined between these cycles and certain variations in ocean temperature patterns, and the dynamics of the upper air flow and location of the jet stream. An extremely wet late spring event in 2009 instigated an analysis of the history and frequency of such events. The historical record for June precipitation at Utah State University was examined, and quantified using time series analyses. The dynamics of ocean temperatures and the flow of air in the Pacific Ocean were examined to document the connections with periodic wet conditions in June. Secondly, the evapotranspiration (ET) of two important surfaces in the Intermountain Region was studied. Experiments were conducted at two sites: an irrigated Kentucky Bluegrass surface near Utah State University, and a mountain meadow at the USU TW Daniels Experimental Forest in the Bear River range in Utah. Eddy covariance stations were run at each site to measure not only the ET, but also the rest of the surface energy balance. The irrigated turf study was designed to determine actual water use by the plants, and to test the current values used in irrigation scheduling of Kentucky Bluegrass. In addition, this project participated in a large USDA study of remote sensing and energy balance of irrigated cotton in a very windy location in Texas, called BEAREX08. During this last year the efforts have been focused on analyses of the large data sets. The biophysical dynamics of the ET in this location were examined, as well as a comparison of the eddy covariance ET values with what are considered the very best lysimeters that were located in the same field. PARTICIPANTS: Collaborators: Paul Johnson, Roger Kjelgren, Scott Jones, Bruce Bugbee Plants, Soils & Climate, USU, Christopher Neale, Civil & Environmental Engineeringg, USU, William Kustas USDA-ARS Hydrology Laboratory, and John Prueger, National Soil Tilth Laboratory. Graduate Student: Lynda Fenton, Plants, Soils & Climate, USU. TARGET AUDIENCES: Climate scientists, both applied and theoretical. Surface hydrologists studying water balance. Analysts and water managers interested in the water resources of the intermountain region. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The extremely wet June in northern Utah prompted a closer look at the historical record at Utah State University (USU), which spans nearly 120 years. A distinct cyclical pattern of wet Junes was quantified, with a return period of 10 - 15 years. In addition, there is a distinct trend of increasing June precipitation at USU. This may be evidence of a trend towards wetter late spring conditions. Several analyses of the data in the upper atmosphere revealed why the month was so wet. The unusual location of a large trough of low pressure near the NW USA in June 2009, was associated with a continuing series of shortwave disturbances or wave trains. The interaction of these waves with moisture convergence over the region led to the large number of significant precipitation events, extending well into what is normally a very dry period. It was discovered that our previously observed approximately 15 year cycle of annual precipitation in northern Utah was connected to the changes in the Pacific Decadal Oscillation (PDO), a flip-flop of temperature patterns in the north vs. tropical Pacific Ocean. The cycle of precipitation is linked to the transition from one phase to another, which was also associated with wave in the Jetstream that produce precipitation events in the region. The published tree ring estimates of precipitation were re-analyzed to reveal patterns. The results went back about 800 years. Three distinct cycles appear, and have time scales of: about 15 years; about 50 years; and about 150 years. The results also show that the 20th Century was by far the wettest of the nearly 800-year record. In addition, very large droughts were common in the record, suggesting the 20th Century precipitation record may not be a good predictor of the future. The water use of Kentucky Bluegrass was determined from the eddy covariance data. The original surface energy fluxes were lower than the measured available energy, as is common to the technique. When the values were forced to match, as often done in the published literature, a new set of ET values was obtained. Daily values varied, but averaged about 4 mm. The seasonal totals for the two years analyzed were somewhat larger than 600 mm. This is a significant value of water use. Current irrigation scheduling models use a crop coefficient for irrigated turf of about 0.8. The results of this study suggested that the actual value is closer to 1.0. The ET was increased when winds were present, which moved warm and dry air from upwind surroundings. The results also showed that the ET was usually limited by available energy during the mornings, but by the saturation deficit of the air and stomatal conductance during the afternoon.

Publications

• Wang, S.-Y., Gillies, R. R., Hipps, L. E., & Jin, J., (2011). A transition-phase teleconnection of the Pacific quasi-decadal oscillation: Climate Dynamics, 36(3-4): 681-693.
• Shih-Yu, W., Hipps, L. E., Gillies, R. R., Xianan, J., & Alan, M. L., (2010). Circumglobal teleconnection and early summer rainfall in the US Intermountain West: Theoretical and Applied Climatology, 102(3-4): 245-252.

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: The project has only been active for 6 months, but some preliminary work had been started before this. The activities have been directed towards two main issues: 1. Identification and quantification of the wet and dry cycles that appear to characterize the climate of much of the Great Basin; 2. Explore the large scale features of the atmosphere and ocean that appear to connect with these cycles. Initial efforts consisted of gathering historical data for ocean temperatures, large-scale atmospheric properties, and measured precipitation. The precipitation records for several stations in northern Utah were combined with large-scale atmospheric and oceanic data from the past 50 years. The connections among the cycles in ocean temperature in various regions of the Pacific Ocean, changes in upper atmosphere and jet stream, and precipitation were examined. In addition, data for historic changes in the level of the Great Salt Lake were used as an integrator of precipitation over a larger region. Analyses were conducted to examine the relationships among lake level, precipitation in the region feeding the lake, and key atmospheric and oceanic features in the Pacific Ocean. The goal was to document if the behavior in key atmosphere and ocean properties is related to later changes in the lake level. Also, the plan was determine the sequence of events and the phase or delay between them. PARTICIPANTS: Collaborators: Paul Johnson, Roger Kjelgren, Scott Jones, Bruce Bugbee Plants, Soils & Climate, USU, Christopher Neale, Civil & Environmental Engineeringg, USU, William Kustas USDA-ARS Hydrology Laboratory, and John Prueger, National Soil Tilth Laboratory. Graduate Student: Lynda Fenton, Plants, Soils & Climate, USU. TARGET AUDIENCES: Climate scientists, both applied and theoretical. Surface hydrologists studying water balance. Analysts and water managers interested in the water resources of the intermountain region. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The first set of analyses conducted for the project demonstrated a link between cycles of precipitation in Northern Utah, and changes in the ocean temperatures in parts of the Pacific Ocean, and properties of the upper air flow. There is a strong 10 -20 year cycle of precipitation in the Intermountain region. A connection was discovered between the Pacific Decadal Oscillilation (PDO) and Intermountain precipitation. The PDO flips between two states, with a cycle also of 10 - 20 years. It was determined that when the PDO transitions between states, the atmospheric circulation changes over the Gulf of Alaska, inducing a synoptic weather pattern bringing more precipitation to the Intermountain region. Interestingly, the changes in the PDO occur about 3 - 4 years ahead of the precipitation response. This implies some possibility of prediction of the wet and dry events of this cycle. Another study has documented quasi-decadal oscillations (QDO) in streamflow, water vapor flux, precipitation and level of the Great Salt Lake. These oscillations were found to be strongly correlated to QDO behavior in the Pacific Ocean temperatures. It was discovered that during transitions in the Pacific QDO from one state to another, the atmospheric circulation pattern over the Gulf of Alaska becomes favorable for increases in precipitation in the watershed region of the lake. This modulates streamflow and ultimately lake level. There is about a 3 year delay between changes in the Pacific QDO and precipitation. In addition, there is another 3 year delay between the changes in precipitation and response of the lake level. These results show how the climate of the region has complex connections with ocean and atmosphere over large distances, and that they are cyclical. The current findings provide more insight into the Intermountain wet and dry cycles.

Publications

• No publications reported this period