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W. R. Bidlake

Publications and source records attributed to W. R. Bidlake.

9 recordsLinked to original sources
USGS2017

Glacier mass-balance fluctuations in the Pacific Northwest and Alaska, USA

The more than 40 year record of net and seasonal mass-balance records from measurements made by the United States Geological Survey on South Cascade Glacier, Washington, and Wolverine and Gulkana Glaciers, Alaska, shows annual and interannual fluctuations that reflect changes in the controlling climatic conditions at regional and global scales. As the mass-balance record grows in length, it is revealing significant changes in previously described glacier mass-balance behavior, and both inter-glacier and glacier-climate relationships. South Cascade and Wolverine Glaciers are strongly affected by the warm and wet maritime climate of the northeast Pacific Ocean. Their net balances have generally been controlled by winter accumulation, with fluctuations that are strongly related to the Pacific Decadal Oscillation (PDO). Recently, warm dry summers have begun to dominate the net balance of the two maritime glaciers, with a weakening of the correlation between the winter balance fluctuations and the PDO. Non-synchronous periods of positive and negative net balance for each glacier prior to 1989 were followed by a 1989-2004 period of synchronous and almost exclusively negative net balances that averaged -0.8 m for the three glaciers.

Conference Paper↗
USGS2008

Distributed energy balance modeling of South Cascade Glacier, Washington and assessment of model uncertainty

We have developed a physically based, distributed surface energy balance model to simulate glacier mass balance under meteorological and climatological forcing. Here we apply the model to estimate summer ablation on South Cascade Glacier, Washington, for the 2004 and 2005 mass balance seasons. To arrive at optimal mass balance simulations, we investigate and quantify model uncertainty associated with selecting from a range of physical parameter values that are not commonly measured in glaciological mass balance field studies. We optimize the performance of the model by varying values for atmospheric transmissivity, the albedo of surrounding topography, precipitation-elevation lapse rate, surface roughness for turbulent exchange of momentum, and snow albedo aging coefficient. Of these the snow aging parameter and precipitation lapse rates have the greatest influence on the modeled ablation. We examined model sensitivity to varying parameters by performing an additional 103 realizations with parameters randomly chosen over a ??5% range centered about the optimum values. The best fit suite of model parameters yielded a net balance of -1.69??0.38 m water equivalent (WE) for the 2004 water year and -2.10??0.30 m WE up to 11 September 2005. The 2004 result is within 3% of the measured value. These simulations account for 91% and 93% of the variance in measured ablation for the respective years. Copyright 2008 by the American Geophysical Union.

Journal of Geophysical Research F: Earth Surface↗
USGS2007

Evapotranspiration from a bulrush-dominated wetland in the Klamath Basin, Oregon

Growing-season evapotranspiration and surface energy and water balances were investigated for an extensive, bulrush-dominated wetland in the Upper Klamath National Wildlife Refuge of south-central Oregon, a semi-arid region with competing demands for scarce water resources. Turbulent fluxes of sensible and latent heat were measured by eddy covariance for 1.2 to 1.9 days during each of four site visits during late-May to mid-October 1997. Mean daytime latent heat flux and the Bowen ratio ranged from 148 to 178 W m −2 and from 0.38 to 0.51, respectively, during late May, mid-July, and late August site visits. By mid-October, when the plant canopy had senesced, daytime latent heat flux and the Bowen ratio averaged 46 W m −2 and 2.8, respectively. An hourly Penman-Monteith (PM) model that was fitted to the surface-flux data provided values for the surface resistance to water-vapor diffusion that ranged from 78 s m −1 during late August to 206 s m −1 during mid-October. Similarly, a Priestley-Taylor (PT) model provided values for the PT multiplier (a) that ranged from 0.96 during late August to 0.37 during mid-October. The PM and PT models predicted evapotranspiration totals of 560 and 480 mm, respectively, for May 28 to October 12, 1997.

Oregon↗
USGS2002

Evapotranspiration from selected fallowed agricultural fields on the Tule Lake National Wildlife Refuge, California, during May to October 2000

An investigation of evapotranspiration, vegetation quantity and composition, and depth to the water table below the land surface was made at three sites in two fallowed agricultural lots on the 15,800-hectare Tule Lake National Wildlife Refuge in northern California during the 2000 growing season. All three sites had been farmed during 1999, but were not irrigated since the 1999 growing season. Vegetation at the lot C1B and lot 6 stubble sites included weedy species and small grain plants. The lot 6 cover crop site supported a crop of cereal rye that had been planted during the previous winter. Percentage of coverage by live vegetation ranged from 0 to 43.2 percent at the lot C1B site, from approximately 0 to 63.2 percent at the lot 6 stubble site, and it was estimated to range from 0 to greater than 90 percent at the lot 6 cover crop site. Evapotranspiration was measured using the Bowen ratio energy balance technique and it was estimated using a model that was based on the Priestley-Taylor equation and a model that was based on reference evapotranspiration with grass as the reference crop. Total evapotranspiration during May to October varied little among the three evapotranspiration measurement sites, although the timing of evapotranspiration losses did vary among the sites. Total evapotranspiration from the lot C1B site was 426 millimeters, total evapotranspiration from the lot 6 stubble site was 444 millimeters, and total evapotranspiration from the lot 6 cover crop site was 435 millimeters. The months of May to July accounted for approximately 78 percent of the total evapotranspiration from the lot C1B site, approximately 63 percent of the evapotranspiration from the lot 6 stubble site, and approximately 86 percent of the total evapotranspiration from the lot 6 cover crop site. Estimated growing season precipitation accounted for 16 percent of the growing-season evapotranspiration at the lot C1B site and for 17 percent of the growing-season evapotranspiration at the lot 6 stubble and cover crop sites. The ratio of evapotranspiration rate to the reference evapotranspiration rate was strongly correlated with percentage of site coverage by vegetation at the lot C1B and lot 6 stubble sites (correlation coefficient = 0.95, sample size = 6), where percentage of site coverage was determined from quantitative vegetation surveys. It is concluded that evapotranspiration was mediated by the vegetation at all three sites, and that the differences in seasonal timing of evapotranspiration losses were caused by differences in timing of vegetation growth and development and senescence among the sites. Depth to the water table below the land surface at lot C1B ranged from 0.67 meters in early July to greater than 1.39 meters in late August. Depth to the water table at lot 6 ranged from 0.77 meter in late May to greater than 1.40 meters in late August.

Water-Resources Investigations Report↗
USGS1996

Evapotranspiration from areas of native vegetation in west-central Florida

A study was conducted to evaluate the suitability of three micrometeorological methods for estimating evapotranspiration from selected areas of native vegetation in west-central Florida and to estimate annual evapotranspiration from areas having a specific vegetation type. Evapotranspiration was estimated using the methods of energy-balance Bowen ratio (EBBR) and eddy correlation. Potential evapotranspiration was computed using the Penman equation. Field measurements were made intermittently from February 1988 through September 1990. The EBBR method was used to estimate evapotranspiration from unforested and forested sites. A mean-gradient Bowen ratio system was used to measure and average vertical air temperature and vapor-pressure gradients, and the Bowen ratio was computed using the mean air temperature and vapor-pressure gradients. The Bowen ratio estimated in this manner was then used to compute evapotranspiration by the EBBR method. Computations that were based on objective review criteria indicated that the Bowen ratio that was computed using measurements that were made using the mean-gradient Bowen ratio system was not always realistic. During a period of extended operation at a dry prairie site, 9 percent of measured available energy during the daytime occurred when the Bowen ratio obtained using the mean-gradient Bowen ratio system was unrealistic. During 5 out of 14 days of continuous operation at a marsh site, more than 30 percent of measured available energy during the daytime occurred when the Bowen ratio obtained using the mean-gradient Bowen ratio system was unrealistic. One of the primary causes of unrealistic Bowen ratios at the unforested sites was condensation of moisture within the tubing of the mean-gradient Bowen ratio system. Measurements made using the mean-gradient Bowen ratio system at a forested pine flatwood site indicated that vapor-pressure gradients were too weak to be resolved by the system. As a result, the Bowen ratio computed for the forested sites was unreliable when it was obtained using the mean-gradient Bowen ratio system. Direct estimates of sensible and latent heat flux that were computed from eddy correlation measurements were generally insufficient to account for measured available energy at all sites. Analysis of eddy correlation and energy-balance data indicated that the sum of sensible and latent heat fluxes accounted for 68 percent of available energy at dry prairie and marsh sites, 74 percent of available energy at a pine flatwood site, and 45 percent of available energy at a cypress swamp site. Because specific causes of the energy-balance discrepancies could not be quantified, corrections to the direct eddy correlation flux estimates could not be made, and eddy correlation data were combined with other energy-balance data to yield two alternative evapotranspiration estimates. The first alternative evapotranspiration estimate was computed by combining sensible heat flux obtained from eddy correlation with measurements of available energy to compute latent heat flux as the residual of the equation for the surface energy balance. The second alternative evapotranspiration estimate was computed by using direct sensible and latent heat flux estimates that were obtained from eddy correlation measurements to compute the Bowen ratio. The Bowen ratio obtained from eddy correlation measurements was then combined with measurements of available energy to compute evapotranspiration by the EBBR method. Of the three alternative evapotranspiration estimates that were obtained from eddy correlation measurements, the estimate that was computed using the EBBR method, with the Bowen ratio computed from eddy correlation measurements, agreed most strongly with the corresponding evapotranspiration estimate that was computed using the EBBR method with the Bowen ratio obtained from the mean-gradient Bowen ratio system. It is probable that actual evapo-transpiration was within a range defined by the standard eddy correlation computation, which consistently indicated the smallest evapotranspiration, and the energy-balance residual computation, which consistently indicated the largest evapotranspiration. Daily potential evapotranspiration, as computed by the Penman method, and daily evapotranspiration, as computed by the EBBR method, did not seem to correlate with each other at a dry prairie site during late spring and summer; however, the two were correlated with each other at a marsh site during late spring and summer. Evapotranspiration was approximately 57 percent of potential evapotranspiration at the marsh site. The correlation between evapotranspiration and potential evapotranspiration at the marsh site, and the fact that evapotranspiration approached potential evapotranspiration, indicated that the Penman method can be useful for estimating evapotranspiration from marshes in west-central Florida. Annual evapotranspiration estimates were developed for each vegetation type by pooling EBBR and eddy correlation measurements among sites and among the 3 years during which field measurements were made. Three different estimates, which correspond to the three eddy correlation computation methods, were made for each vegetation type. The centric estimates, which were calculated by using the EBBR method with the Bowen ratio obtained from either a mean-gradient system or from eddy correlation measurements, were 1,010 millimeters per year for the dry prairie type, 990 millimeters per year for the marsh vegetation type, 1,060 millimeters per year for the pine flatwood type, and 970 millimeters per year for the cypress swamp type.

Florida↗
USGS1996

Near-surface water balance of an undeveloped upland site in west-central Florida

A study was made to examine the near-surface water balance of a dry prairie site in west-central Florida. The water balance, which was defined on a unit area basis and for a depth of 5.5 meters, was described for the period June 1991 to October 1992. Precipitation during the 498 days of field measurements was 2,245 millimeters. Evapotranspiration, the second largest component, was 1,419 millimeters. Water yield was 808 millimeters and the change in soil water storage was 19 millimeters. Computed vertical water flux was less than 4 percent of evapotranspiration because of the small hydraulic conductivity of a clay layer that began at a depth of 5.5 meters.

Water Supply Paper↗
USGS1996

Simulation of the soil water balance of an undeveloped prairie in west-central Florida

A one-dimensional numerical model was developed to simulate the soil water balance of a densely vegetated prairie site in west-central Florida. Transient simulations of the soil water balance were performed using field-measured soil and vegetation properties. Simulated and measured soil water content generally agreed to within 0.04; however, simulated water storage and recharge were sensitive to air-entry soil-water pressure potential and depth to the water table.

Water Supply Paper↗
USGS1992

Comparative gas exchange characteristics of potted, glasshouse-grown almond, apple, fig, grape, olive, peach and Asian pear

Net photosynthesis ( P n ), dark respiration ( R d ), transpirational flux density (TFD) and leaf conductance ( k l ) on glasshouse-grown plants of almond, apple, fig, grape, olive, peach and Asian pear were examined under various laboratory environmental conditions. Grape and almond had the highest light-saturated photosynthetic rates, greater than 20 μmol CO 2 m −2 s −1 . Apple had the lowest temperature optimum for P n , 20°C. Almond had the highest R d rate between 10 and 50°C, but grape had the highest Q 10 for respiration, a value of 2.5. Apple, olive and grape stomata were most sensitive to the leaf-to-air vapor pressure difference. Apple had the greatest sensitivity of P n to the vapor pressure difference.

Scientia Horticulturae↗