Fargo, ND, United States
Fargo, ND, United States

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Boe B.A.,Weather Modification Inc. | Heimbach J.A.,University of North Carolina at Asheville | Krauss T.W.,Krauss Weather Services Inc. | Xue L.,U.S. National Center for Atmospheric Research | And 2 more authors.
Journal of Applied Meteorology and Climatology | Year: 2014

Part I of this paper presents the results from a series of plume-tracing flights over the Medicine Bow and Sierra Madre Ranges in south-central Wyoming. These flights, conducted during February and early March of 2011, were part of the Wyoming Weather Modification Pilot Project. Effective targeting of ground-based silver iodide plumes to supercooled clouds has long been a problem for winter orographic cloud-seeding projects. Surface-based ice nucleus (IN) measurements made at a fixed location near the Medicine Bow Range target area had confirmed the effective transport of IN plumes in many cases, but not all. Airborne plume tracing, undertaken to further illuminate the processes involved, provided additional insight into the plume behavior while providing physical measurements that were later compared with large-eddy-simulation modeling (Part II). It was found that the plumes were most often encountered along the flight paths set out in the experimental designs and, in the absence of convection, appear to be mostly confined to the lowest 600m above the highest terrain. All passes above 600mabove ground level revealed IN concentrations greater than background levels, however. An estimate of IN flux measured over the Medicine Bow Range was approximately 85% of that produced by the five ground-based IN generators active at the time. © 2014 American Meteorological Society.


Tessendorf S.A.,U.S. National Center for Atmospheric Research | Boe B.,Weather Modification Inc. | Geerts B.,University of Wyoming | Manton M.J.,Monash University | And 2 more authors.
Bulletin of the American Meteorological Society | Year: 2015

The 20th Conference on Planned and Inadvertent Weather Modification held in Phoenix from 6-8 january, 2015, discussed winter orographic cloud-seeding research and operations. Cloud modeling research in particular has been aided by greatly increased computational capabilities, as well as the development of a silver iodide cloud-seeding parameterization in the Weather Research and Forecasting (WRF) model. On the logistical and public relations front, funding and improving public per?ception of cloud seeding were identified as continual challenges. Moreover, there needs to be continuity in the management of these projects in order to maintain consistent, well-designed operations. The Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) field program has been proposed as a collaboration among several of the panelists to the National Science Foundation in order to collect cutting-edge in situ and remote sensing measurements within winter orographic clouds seeded from the air and from the ground. A sustained experiment is really needed for this to happen, and therefore the panelists suggested the need for a well-instrumented watershed as a test bed that would be maintained for many years.


Krauss T.W.,Weather Modification Inc. | Sin'kevich A.A.,Voeikov Main Geophysical Observatory | Burger R.,University of Witwatersrand | Veremei N.E.,Voeikov Main Geophysical Observatory | And 2 more authors.
Russian Meteorology and Hydrology | Year: 2011

Changes are analyzed of a Cb cloud characteristics due to its merging with feeder clouds, on the data on a long-living Cb cloud in Saudi Arabia on July 4, 2008. Continuous radar and satellite observations of the cloud are carried out during 6 h. The Cb cloud development is also numerically simulated using a nonstationary 11/2 model. It is found that the processes of Cb cloud merging with feeder clouds developing in its vicinities affect significantly the Cb cloud development. This impact demonstrates itself in longer duration of the Cb cloud life span, increasing top height, reflectivity, precipitation duration and intensity. Modification of the feeder clouds can accelerate their development, which eventually can affect notably the Cb cloud. © 2011 Allerton Press, Inc.


Xue L.,U.S. National Center for Atmospheric Research | Chu X.,University of Wyoming | Rasmussen R.,U.S. National Center for Atmospheric Research | Breed D.,U.S. National Center for Atmospheric Research | And 2 more authors.
Journal of Applied Meteorology and Climatology | Year: 2014

A numerical modeling study has been conducted to explore the ability of the Weather Research and Forecasting (WRF) model-based large-eddy simulation (LES) with 100-m grid spacing to reproduce silver iodide (AgI) particle dispersion by comparing the model results with measurements made on 16 February 2011 over theMedicineBowMountains inWyoming. Xue et al.'s recently developed AgI cloud-seeding parameterization was applied in this study to simulate AgI release from ground-based generators. Qualitative and quantitative comparisons between the LES results and observed AgI concentrations were conducted.Analyses of turbulent kinetic energy (TKE) features within the planetary boundary layer (PBL) and comparisons between the 100-m LES and simulations with 500-m grid spacing were performed as well. The results showed the following: 1) Despite the moist bias close to the ground and above 4kmAGL, the LES with 100-m grid spacing captured the essential environmental conditions except for a slightly more stable PBL relative to the observed soundings. 2) Wind shear is the dominantTKE productionmechanism inwintertime PBL over complex terrain and generates a PBL of about 1000-m depth. The terrain-induced turbulent eddies are primarily responsible for the vertical dispersion of AgI particles. 3) The LES-simulated AgI plumes were shallow and narrow, in agreement with observations. The LES overestimated AgI concentrations close to the ground, which is consistent with the higher static stability in the model than is observed. 4) Non-LES simulations using PBL schemes had difficulty in capturing the shear-dominant turbulent PBL structure over complex terrain in wintertime. Therefore, LES of wintertime orographic clouds with grid spacing close to 500m or finer are recommended. © 2014 American Meteorological Society.


Krauss T.W.,Weather Modification Inc. | Sin'kevich A.A.,Voeikov Main Geophysical Observatory | Veremei N.E.,Voeikov Main Geophysical Observatory | Dovgalyuk Y.A.,Voeikov Main Geophysical Observatory | And 2 more authors.
Russian Meteorology and Hydrology | Year: 2011

Basing on airmass motion trajectory calculations over the Arabian Peninsula on April 10, 2008, it can be assumed that in the lower and middle troposphere, zones with increased air moisture exist due to air inflow from the Red Sea. As a result, mesoscale volumes of dry and moist air are neighboring, though large-scale field is comparatively homogeneous with low humidity. In the mesoscale zones, intense thunderstorm and hailstorm Cb clouds developed, whose characteristics and evolution are studied in the paper. Continuous radar observations of the clouds are carried out during 5 hours. Numerical simulation of the cloud evolution is performed with nonstationary 1.5-dimensional model. It is noted that under the mentioned atmospheric conditions, in the area under consideration, heavy rain and hail from the Cb clouds are observed. The main factors of their origination are high thermal instability of the atmosphere and moist air inflow from outside. © 2011 Allerton Press, Inc.


Krauss T.W.,Weather Modification Inc. | Sin'kevich A.A.,Voeikov Main Geophysical Observatory | Veremei N.E.,Voeikov Main Geophysical Observatory | Dovgalyuk Y.A.,Voeikov Main Geophysical Observatory | And 2 more authors.
Russian Meteorology and Hydrology | Year: 2011

Development of a long-living Cb cloud in the desert part of Saudi Arabia on April 10, 2008 is analyzed. Continuous satellite and radar observations of the cloud are carried out during five hours. Numerical modeling of the cloud is performed using a nonstationary 1.5-dimensional model. Data on the Cb cloud and its anvil development dynamics are obtained. It is shown that the anvil characteristics differ significantly in the zone of its formation directly over the cloud and when moving away from it. It is pointed out that the radar underestimates the anvil sizes. Estimation of precipitation rate from the cloud under study by means of satellite and radar measurements is compared against the results of numerical modeling. It is found that precipitation rate could reach 100 mm/h. The radar estimates of the precipitation rate are significantly overstated, which is, in this case, due to presence of large hail particles. © 2011 Allerton Press, Inc.


Sinkevich A.A.,Voeikov Main Geophysical Observatory | Crauss T.W.,Weather Modification Inc.
Russian Meteorology and Hydrology | Year: 2010

The results of experiments to enhance precipitation in Saudi Arabia by Weather Modification Inc. (USA) are presented. Statistical analysis of radar measurements indicates that there are significant changes in cloud characteristics and an increase in precipitation due to seeding. © 2010 Allerton Press, Inc.


Krauss T.W.,Weather Modification Inc. | Sin'kevich A.A.,Voeikov Main Geophysical Observatory | Ghulam A.S.,Presidency of Meteorology and Environment
Russian Meteorology and Hydrology | Year: 2012

Considered is a case of the cumulonimbus cloud development in the southwestern part of Saudi Arabia with a very high precipitation intensity. The height of the cloud top amounted to 14 km and the radar reflectivity, to 60 dBZ. Carried out is the comparison of remote methods of measuring the intensity of precipitation from the cloud under study: the radar (using the relationship between the reflectivity and precipitation intensity) and satellite IR-radiometric (based on the results of sounding with the SEVERI radiometer installed at the Meteosat-8 satellite) methods. A split-window technique was used for detecting the position of the cloud top from the radiometric observations. The analysis enabled to select the best relationships for estimating the precipitation intensity from the data of radar and satellite measurements. The computations based on these relationships correspond most closely to the ground-based measurements with the precipitation gage. © 2012 Allerton Press, Inc.


Krauss T.W.,Weather Modification Inc. | Sin'kevich A.A.,Voeikov Main Geophysical Observatory | Ghulam A.S.,Presidency of Meteorology and Environment
Russian Meteorology and Hydrology | Year: 2012

Presented are the results of radar investigations of cloud merger during their natural cycle of development and after the seeding. The observations were carried out in the southwest of the Kingdom of Saudi Arabia in 2008. It is revealed that the merging was observed under conditions of very unstable atmosphere, when the convective available potential energy exceeded 3000 J/kg. The cloud merger impacts significantly their development. The most considerable changes due to the cloud merging were observed for the cloud mass and precipitation flow increased as a result of this process by two or three times. It is discovered that the impact of the merger of clouds on their characteristics exceeds significantly the effect of seeding carried out for the feeder clouds. © 2012 Allerton Press, Inc.

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