Research and development technique for estimating airflow and diffusion parameters in connection with the Atmospheric Water Resources Program: annual report

September 1970.CER70-71MMO-JEC-LOG23.Period September 2, 1969 to June 30, 1970.Includes bibliographical references.Atmospheric Water Resources Research, Bureau of Reclamation, Contract No. 14-06-D-6842

Research and development technique for estimating airflow and diffusion parameters related to the Atmospheric Water Resources Program: final report

Period September 1969 to September 1971.CER71-72MMO-JEC-LOG20.Includes bibliographical references

Delivery of nucleating materials to cloud systems from individual ground generators

CER69-70LOG-JEC-MMO24.February 1968.Includes bibliographical references (pages 40-42).Presented to the Bureau of Reclamation Third Skywater Conference on the Production and Delivery of Cloud Nucleating Materials February 14-16, 1968.Delivery of nucleating materials to cloud systems from individual ground generators can play an important role in the beneficial modification of orographic cloud systems. Substantial evidence from the Colorado State University mountain study at Climax is presented to show that ground-released seeding materials do under some weather situations in fact enter the mountain cloud systems and produce changes in the precipitation. Evidence is also presented to show that under other weather situations seeding materials are not carried to the proper clouds at a place and time to be of value. A discussion of atmospheric transport mechanisms is presented to serve as a basis for understanding the motions of seeding materials once released from a ground source. The approaches, or directions, for further research are discussed. This includes consideration of the coagulation problem in the vicinity of the generator site. The use of wind tunnel modeling, which can provide basic information and specific results for specific areas, is emphasized

Research and development technique for estimating airflow and diffusion parameters in connection with the Atmospheric Water Resources Program : final report

CER69-70JEC-LOG-MMO-11.August 1969.Includes bibliographical references (pages 47-48).Period March 15, 1968 to June 30, 1969 Atmospheric Water Resources Research Bureau of Reclamation Contract No. 14-06-D-6455.A stably stratified atmospheric boundary layer was simulated in a wind tunnel and utilized to determine radioactive krypton dispersion patterns over a 1:9600 scale model of the Eagle River Valley and topography surrounding Climax, Colorado. Geometric, dynamic, and thermal similarity are considered, primarily, for barostromatic airflow. Similarity criteria for transport and dispersion are considered also. This is the first time that a barostromatic airflow produced by cooling with dry ice has been documented by temperature and velocity profile measurements. Field Gata indicate that airflow and temperature characteristics over the model are approximately similar to a prototype storm. Dispersion measurements were taken by using sources representative of field ground sources. Model and field measurements confirm that seeding nuclei are reaching the target area from the present existing ground sources. Limited field measurements of ice nuclei concentrations at Chalk Mountain show a variation of 5 to 300 part./liter or XU/Q ~ 1 x 10 -9m-2 to 68 x 10-9m-2. Concentration values deduced from radioactive gas measurements over the model show values within the same range but closer to the optimum values indicated by present cloud physics models, i.e., XU/Q ~ 15 to 18 x 10-9m-2. The barostromatic airflow model indicated that topography plays an important role in determining the downwind direction of the particulate plume.Under contract no. 14-06-D-6455

Research and development technique for estimating airflow and diffusion parameters in connection with the Atmospheric Water Resources Program: interim report

CER70-71MMO78.Period September 2, 1970 to February 28, 1971.Includes bibliographical references (pages 38-39).Atmospheric Water Resources Research, Bureau of Reclamation, Contract No. 14-06-0-6842.This report presents a summary of the research and tentative findings on the use of scaled topographic models and laboratory techniques to study the transport and dispersion of cloud seeding material over mountainous terrain. Three mountainous areas along the continental divide have been selected by the Bureau of Reclamation for such studies. Each area has cloud seeding programs in progress

UWB Propagation through Walls

The propagation of ultra wide band (UWB) signals through walls is analyzed. For this propagation studies, it is necessary to consider not only propagation at a single frequency but in the whole band. The UWB radar output signal is formed by both transmitter and antenna. The effects of antenna receiving and transmitting responses for various antenna types (such as small and aperture antennas) are studied in the frequency as well as time domain. Moreover, UWB radar output signals can be substantially affected due to electromagnetic wave propagation through walls and multipath effects

The METCRAX II Field Experiment: A Study of Downslope Windstorm-Type Flows in Arizona\u2019s Meteor Crater

The second Meteor Crater Experiment (METCRAX II) was conducted in October 2013 at Arizona\u2019s Meteor Crater. The experiment was designed to investigate nighttime downslope windstorm 12type flows that form regularly above the inner southwest sidewall of the 1.2-km diameter crater as a southwesterly mesoscale katabatic flow cascades over the crater rim. The objective of METCRAX II is to determine the causes of these strong, intermittent, and turbulent inflows that bring warm-air intrusions into the southwest part of the crater. This article provides an overview of the scientific goals of the experiment; summarizes the measurements, the crater topography, and the synoptic meteorology of the study period; and presents initial analysis results

Root functioning, tree water use and hydraulic redistribution in Quercus suber trees: a modeling approach based on root sap flow

Mediterranean evergreen oaks have to survive a long summer drought. Roots may play a relevant role under these conditions. We studied their structure and function in a mature Quercus suber L. tree in central Portugal. The root system was mapped till the lowest water table level (4.5 m depth). Xylem anatomy was analyzed in a vertical profile belowground. Sap flow was continuously monitored for 1.5 yrs in the stem and roots of this intensively studied tree (heat field deformation method) and in the stem of four trees (Granier method), in relation to environmental variables and predawn leaf water potential. The sources of water uptake were assessed by stable isotope analyses in summer. Results showed a dimorphic root system with a network of superficial roots linked to sinker roots, and a taproot diverting into tangles of deep fine roots submerged for long periods, with parenchyma aerenchyma. Transpiration was not restricted in summer due to root access to groundwater. The isotopic d18O signature of twig xylem water was similar to that of groundwater in the dry season. Two functional types of superficial roots were identified: shallow connected and deep connected roots. A modeling approach was built considering that each superficial root was linked to a sinker, with part of the root deep connected (between the stem and the sinker) and part shallow connected (between the sinker and topsoil). This conceptual framework simulated tree stem sap flow from root sap flow with a high efficiency (R2 = 0.85) in four plot trees. On an annual basis, soil water and groundwater contributions were 69.5% and 30.5% of stem flow, respectively. Annual hydraulic lift and hydraulic descent were 0.9% and 37.0% of stem flow, respectively. The trees maximize the exploitation of the environmental resources by using the topsoil water during most of the year, and groundwater together with hydraulic lift (nutrient supply) in the dry summer. This study shows that a dimorphic root system, with roots reaching groundwater, is an efficient strategy of Q. suber trees to cope with seasonal drought. Knowledge of the functional behavior of Q. suber trees under shallow water table conditions may contribute to the definition of better adapted management practices and to anticipate their responses to climate chang