Application of snowcovered area to runoff forecasting in selected basins of the Sierra Nevada, California

The author has identified the following significant results. Direct overlay onto 1:1,000,000 prints takes about one third the time of 1:500,000 zone transfer scope analysis using transparencies, but the consistency of the transparencies reduce the time for data analysis. LANDSAT data received on transparencies is better and more easily interpreted than the near real-time data from Quick Look, or imagery from other sources such as NOAA. The greatest potential for water supply forecasting is probably in improving forecast accuracy and in expanding forecast services during the period of snowmelt. Problems of transient snow line and uncertainties in future weather are the main reasons that snow cover area appears to offer little in water supply forecast accuracy improvement during the peroid snowpack accumulation

Application of satellite imagery to hydrologic modeling snowmelt runoff in the southern Sierra Nevada

There are no author-identified significant results in this report

The use of snowcovered area in runoff forecasts

Long-term snowcovered area data from aircraft and satellite observations have proven useful in reducing seasonal runoff forecast error on the Kern river watershed. Similar use of snowcovered area on the Kings river watershed produced results that were about equivalent to methods based solely on conventional data. Snowcovered area will be most effective in reducing forecast procedural error on watersheds with: (1) a substantial amount of area within a limited elevation range; (2) an erratic precipitation and/or snowpack accumulation pattern not strongly related to elevation; and (3) poor coverage by precipitation stations or snow courses restricting adequate indexing of water supply conditions. When satellite data acquisition and delivery problems are resolved, the derived snowcover information should provide a means for enhancing operational streamflow forecasts for areas that depend primarily on snowmelt for their water supply

Pupillometry, a bioengineering overview

The pupillary control system is examined using a microprocessor based integrative pupillometer. The real time software functions of the microprocessor include: data collection, stimulus generation and area to diameter conversion. Results of an analysis of linear and nonlinear phenomena are presented

Telerobotics: A simulation facility for university research

An experimental telerobotics (TR) simulation suitable for studying human operator (H.O.) performance is described. Simple manipulator pick-and-place and tracking tasks allowed quantitative comparison of a number of calligraphic display viewing conditions. A number of control modes could be compared in this TR simulation, including displacement, rate and acceleratory control using position and force joysticks. A homeomorphic controller turned out to be no better than joysticks; the adaptive properties of the H.O. can apparently permit quite good control over a variety of controller configurations and control modes. Training by optimal control example seemed helpful in preliminary experiments. An introduced communication delay was found to produce decrease in performance. In considerable part, this difficulty could be compensated for by preview control information. That neurological control of normal human movement contains a data period of 0.2 second may relate to this robustness of H.O. control to delay. The Ames-Berkeley enhanced perspective display was utilized in conjunction with an experimental helmet mounted display system (HMD) that provided stereoscopic enhanced views

Climate, irrigation, and land cover change explain streamflow trends in countries bordering the northeast Atlantic

Attribution of trends in streamflow is complex, but essential, in identifying optimal management options for water resources. Disagreement remains on the relative role of climate change and human factors, including water abstractions and land cover change, in driving change in annual streamflow. We construct a very dense network of gauging stations (n = 1,874) from Ireland, the United Kingdom, France, Spain, and Portugal for the period of 1961–2012 to detect and then attribute changes in annual streamflow. Using regression‐based techniques, we show that climate (precipitation and atmospheric evaporative demand) explains many of the observed trends in northwest Europe, while for southwest Europe human disturbances better explain both temporal and spatial trends. For the latter, large increases in irrigated areas, agricultural intensification, and natural revegetation of marginal lands are inferred to be the dominant drivers of decreases in streamflow

Keck-Nirspec Infrared OH Lines: Oxygen Abundances in Metal-Poor Stars Down to [Fe/H] = -2.9

Infrared OH lines at 1.5 - 1.7 um in the H band were obtained with the NIRSPEC high-resolution spectrograph at the 10m Keck Telescope for a sample of seven metal-poor stars. Detailed analyses have been carried out, based on optical high-resolution data obtained with the FEROS spectrograph at ESO. Stellar parameters were derived by adopting infrared flux method effective temperatures, trigonometric and/or evolutionary gravities and metallicities from FeII lines. We obtain that the sample stars with metallicities [Fe/H] < -2.2 show a mean oxygen abundance [O/Fe] ~ 0.54, for a solar oxygen abundance of epsilon(O) = 8.87, or [O/Fe] ~ 0.64 if epsilon(O) = 8.77 is assumed.Comment: To be published in ApJ 575 (August 10

Optimization of Starburst99 for Intermediate-Age and Old Stellar Populations

We have incorporated the latest release of the Padova models into the evolutionary synthesis code Starburst99. The Padova tracks were extended to include the full asymptotic giant branch (AGB) evolution until the final thermal pulse over the mass range 0.9 to 5 solar mass. With this addition, Starburst99 accounts for all stellar phases that contribute to the integrated light of a stellar population with arbitrary age from the extreme ultraviolet to the near-infrared. AGB stars are important for ages between 0.1 and 2 Gyr, with their contribution increasing at longer wavelengths. We investigate similarities and differences between the model predictions by the Geneva and the Padova tracks. The differences are particularly pronounced at ages > 1 Gyr, when incompleteness sets in for the Geneva models. We also perform detailed comparisons with the predictions of other major synthesis codes and found excellent agreement. Our synthesized optical colors are compared to observations of old, intermediate-age, and young populations. Excellent agreement is found for the old globular cluster system of NGC 5128 and for old and intermediate-age clusters in NGC 4038/39. In contrast, the models fail for red supergiant dominated populations with sub-solar abundances. This failure can be traced back to incorrect red supergiant parameters in the stellar evolutionary tracks. Our models and the synthesis code are publicly available as version 5.0 of Starburst99 at http://www.stsci.edu/science/starburst99/.Comment: The revised Starburst99 code discussed in this paper will replace the current version 4.0 on our Starburst99 website by December 31, 2004. Accepted for publication in ApJ; 39 pages, 23 figures, 5 table

Floods: vulnerability, risks and management. A joint report of ETC CCA and ICM

This report describes floods in a European context with the purpose of highlighting factors that contribute to the occurrence and adverse consequences of floods, and possibilities to reduce flood risks from inland waters and rainfall. It includes a discussion on changes in flood patterns and illustrates how different scenarios for climate change may affect vulnerability to floods and flood risks. The report provides illustrative examples of flood risk management from the local to European level

The complex and spatially diverse patterns of hydrological droughts across Europe

This study presents a new data set of gauged streamflow (N = 3,224) for Europe spanning the period 1962–2017. The Monthly Streamflow of Europe Dataset (MSED) is freely available at http://msed.csic.es/. Based on this data set, changes in the characteristics of hydrological drought (i.e., frequency, duration, and severity) were assessed for different regions of Europe. Due to the density of the database, it is possible to delimit spatial patterns in hydrological droughts trend with the greatest detail available to date. Results reveal bidirectional changes in monthly streamflow, with negative changes predominating over central and southern Europe, while positive trends dominate over northern Europe. Temporally, two dominant patterns were noted. The first pattern corresponds to a consistent downward trend in all months, evident for southern Europe. A second pattern was noted over central and northern Europe and western France, with a predominant negative trend during warm months and a positive trend in cold months. For hydrological drought events, results suggest a positive trend toward more frequent and severe droughts in southern and central Europe and conversely a negative trend over northern Europe. This study emphasizes that hydrological droughts show complex spatial patterns across Europe over the past six decades, implying that hydrological drought behavior in Europe has a regional character. Accordingly it is challenging to adopt “efficient” strategies and policies to monitor and mitigate drought impacts at the continental level