scholarly journals Review of Wintertime Orographic Cloud Seeding

1986 ◽  
Vol 43 ◽  
pp. 87-104 ◽  
Author(s):  
Robert D. Elliott
Keyword(s):  
Scientific Literature ◽  
Doppler Radar ◽  
Cloud Seeding ◽  
Weather Modification ◽  
The Past ◽  
Orographic Clouds ◽  
The 1960S ◽  
Orographic Cloud ◽  
Microwave Radiometers ◽  
Seeding Effects

Abstract This review provides a sketchy background of orographic weather modification activities prior to the 1960s, followed by a more critical review of major orographic projects carried out and reported in the scientific literature during the past 25 years. In the earlier of these major projects, evaluation of results had been based largely upon comparisons of seeded and nonseeded precipitation experimental units stratified by various sounding-derived parameters in an attempt to amplify the physical significance of the seeding effects within various sub-types of orographic clouds. The later major projects are still underway with no final evaluations having been presented. However, a wealth of significant data analyses have been reported that provide important insights into the various natural and seeding precipitation mechanisms. Much of this is attributable to the new observational tools in use, which include airborne and ground microphysical sensors, doppler radar, and microwave radiometers.

scholarly journals Review of Advances in Precipitation Enhancement Research

2019 ◽  
Vol 100 (8) ◽  
pp. 1465-1480 ◽  
Author(s):  
Andrea I. Flossmann ◽  
Michael Manton ◽  
Ali Abshaev ◽  
Roelof Bruintjes ◽  
Masataka Murakami ◽  
...  
Keyword(s):  
Convective Cloud ◽  
Cloud Seeding ◽  
Weather Modification ◽  
Catchment Scale ◽  
Cloud Systems ◽  
The Past ◽  
Expert Team ◽  
Orographic Cloud ◽  
Water Catchment ◽  
Precipitation Enhancement

AbstractThis paper provides a summary of the assessment report of the World Meteorological Organization (WMO) Expert Team on Weather Modification that discusses recent progress on precipitation enhancement research. The progress has been underpinned by advances in our understanding of cloud processes and interactions between clouds and their environment, which, in turn, have been enabled by substantial developments in technical capabilities to both observe and simulate clouds from the microphysical to the mesoscale. We focus on the two cloud types most commonly seeded in the past: winter orographic cloud systems and convective cloud systems. A key issue for cloud seeding is the extension from cloud-scale research to water catchment–scale impacts on precipitation on the ground. Consequently, the requirements for the design, implementation, and evaluation of a catchment-scale precipitation enhancement campaign are discussed. The paper concludes by indicating the most important gaps in our knowledge. Some recommendations regarding the most urgent research topics are given to stimulate further research.

scholarly journals Collaboration via co-authorship trends in Government of Canada forestry research

2020 ◽  
Vol 96 (01) ◽  
pp. 77-84
Author(s):  
Heather MacDonald ◽  
Daniel W. McKenney ◽  
Kaitlin DeBoer
Keyword(s):  
Longitudinal Analysis ◽  
Scientific Literature ◽  
Forest Service ◽  
Citation Data ◽  
The Past ◽  
Publication Record ◽  
Government Of Canada ◽  
The 1960S ◽  
Citation Databases ◽  
Number Of Authors

As part of its long history, the Canadian Forest Service (CFS) has a mandate to collaborate and share its scientific research. Publishing peer-reviewed scientific literature is an important part of this process. Using a database of CFS publications over the past fifty years, we highlight the continuing publication record of this sector of the Canadian government. The average number of authors reported in the CFS bookstore increased from 1.4 authors per article in the 1960s and 1.5 in the 1970s to just under five authors per publication from 2010 to 2018. Our work also illustrates challenges with longitudinal analysis of citation databases. In particular, use of a popular citation database resulted in significantly fewer articles authored by one person, and significantly more articles with twenty or more authors compared to the publicly available CFS “bookstore” of publications. Based on our findings, we outline a number of recommendations for use of citation data to inform collaboration research.

Quantifying snowfall from orographic cloud seeding

2020 ◽  
Author(s):  
Katja Friedrich ◽  
Kyoko Ikeda ◽  
Sarah Tessendorf ◽  
Jeffrey French ◽  
Robert Rauber ◽  
...  
Keyword(s):  
Water Management ◽  
Silver Iodide ◽  
Management Strategy ◽  
Radar Reflectivity ◽  
Cloud Seeding ◽  
Straight Line ◽  
Orographic Clouds ◽  
Increasing Demand ◽  
Orographic Cloud ◽  
Water Management Strategy

<p>Cloud seeding has been used as one water management strategy to overcome the increasing demand for water despite decades of inconclusive results on the efficacy of cloud seeding. In this study snowfall accumulation from glaciogenic cloud seeding is quantified based on snow gauge and radar observations from three days in January 2017, when orographic clouds in the absent of natural precipitation were seeded with silver iodide (AgI) in the Payette basin of Idaho during the Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE). On each day, a seeding aircraft equipped with AgI flares flew back and forth on a straight-line flight track producing a zig-zag pattern representing two to eight lines of clouds visible through enhancements in radar reflectivity. As these seeding lines started to form precipitation, they passed over several snow gauges and through the radar observational domain. For the three cases presented here, precipitation gauges measured increases between 0.05-0.3 mm as precipitation generated by cloud seeding pass over the instruments. A variety of relationships between radar reflectivity factor and liquid equivalent snowfall rate were used to quantify snowfall within the radar observation domain. For the three cases, snowfall occurred within the radar observational domain between 25 -160 min producing a total amount of water generated by cloud seeding ranging from 123,220 to 339,540 m3 using the best-match Ze-S relationship. Uncertainties in radar reflectivity estimated snowfall are provided by considering not only the best-match Ze-S relationship but also an ensemble of Ze-S relationships based on the range of coefficients published from previous studies and then examining the percentile of snowfall estimates based on all of the Ze-S relationships within the ensemble. Considering the interquartile range and 5<sup>th</sup>/95<sup>th</sup> percentiles, uncertainties in total amount of water generated by cloud seeding can range between 20-45% compared to the best-math estimates. These results provide new insights towards understanding how cloud seeding impacts precipitation and its distribution across a region.</p>

Hypotheses for the Climax Wintertime Orographic Cloud Seeding Experiments

1986 ◽  
Vol 43 ◽  
pp. 105-108 ◽  
Author(s):  
Lewis O. Grant
Keyword(s):  
Hypothesis Testing ◽  
Remotely Sensed ◽  
Cloud Seeding ◽  
Statistical Experiments ◽  
Orographic Clouds ◽  
Orographic Cloud

Abstract The hypothesis used for the initial Climax wintertime cloud seeding experiment and for subsequent Climax replication-type experiments are described and briefly discussed. More recent physical studies of Colorado orographic clouds and seeding hypotheses are briefly summarized. These later tests and studies of orographic cloud seeding hypotheses emphasized direct and remotely sensed cloud and precipitation measurements utilizing instrumentation and modeling capabilities not available during the Climax statistical experiments. The conclusions suggested from the hypothesis testing, considering both the statistical experiments and the later physical studies, are summarized.

A Transformational Approach to Winter Orographic Weather Modification Research: The SNOWIE Project

2019 ◽  
Vol 100 (1) ◽  
pp. 71-92 ◽  
Author(s):  
Sarah A. Tessendorf ◽  
Jeffrey R. French ◽  
Katja Friedrich ◽  
Bart Geerts ◽  
Robert M. Rauber ◽  
...  
Keyword(s):  
Silver Iodide ◽  
Supercooled Liquid ◽  
Cloud Seeding ◽  
Remotely Sensed Data ◽  
Weather Modification ◽  
Before And After ◽  
Orographic Clouds ◽  
Seeding Material ◽  
Airborne Sensors

AbstractThe Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) project aims to study the impacts of cloud seeding on winter orographic clouds. The field campaign took place in Idaho between 7 January and 17 March 2017 and employed a comprehensive suite of instrumentation, including ground-based radars and airborne sensors, to collect in situ and remotely sensed data in and around clouds containing supercooled liquid water before and after seeding with silver iodide aerosol particles. The seeding material was released primarily by an aircraft. It was hypothesized that the dispersal of the seeding material from aircraft would produce zigzag lines of silver iodide as it dispersed downwind. In several cases, unambiguous zigzag lines of reflectivity were detected by radar, and in situ measurements within these lines have been examined to determine the microphysical response of the cloud to seeding. The measurements from SNOWIE aim to address long-standing questions about the efficacy of cloud seeding, starting with documenting the physical chain of events following seeding. The data will also be used to evaluate and improve computer modeling parameterizations, including a new cloud-seeding parameterization designed to further evaluate and quantify the impacts of cloud seeding.

Wintertime Orographic Cloud Seeding—A Review

2019 ◽  
Vol 58 (10) ◽  
pp. 2117-2140 ◽  
Author(s):  
Robert M. Rauber ◽  
Bart Geerts ◽  
Lulin Xue ◽  
Jeffrey French ◽  
Katja Friedrich ◽  
...  
Keyword(s):  
Supercooled Water ◽  
Mountain Range ◽  
Target Area ◽  
Cloud Seeding ◽  
Cloud Systems ◽  
The Past ◽  
Precipitation Efficiency ◽  
Focus On Results ◽  
Orographic Cloud ◽  
Modern Instrumentation

AbstractThis paper reviews research conducted over the last six decades to understand and quantify the efficacy of wintertime orographic cloud seeding to increase winter snowpack and water supplies within a mountain basin. The fundamental hypothesis underlying cloud seeding as a method to enhance precipitation from wintertime orographic cloud systems is that a cloud’s natural precipitation efficiency can be enhanced by converting supercooled water to ice upstream and over a mountain range in such a manner that newly created ice particles can grow and fall to the ground as additional snow on a specified target area. The review summarizes the results of physical, statistical, and modeling studies aimed at evaluating this underlying hypothesis, with a focus on results from more recent experiments that take advantage of modern instrumentation and advanced computation capabilities. Recent advances in assessment and operations are also reviewed, and recommendations for future experiments, based on the successes and failures of experiments of the past, are given.

scholarly journals Evaluating Winter Orographic Cloud Seeding: Design of the Wyoming Weather Modification Pilot Project (WWMPP)

2014 ◽  
Vol 53 (2) ◽  
pp. 282-299 ◽  
Author(s):  
Daniel Breed ◽  
Roy Rasmussen ◽  
Courtney Weeks ◽  
Bruce Boe ◽  
Terry Deshler
Keyword(s):  
Sample Size ◽  
Statistical Significance ◽  
Pilot Project ◽  
Cloud Seeding ◽  
Weather Modification ◽  
South Central ◽  
Design Choice ◽  
Wide Range ◽  
Orographic Cloud ◽  
Size Estimates

AbstractAn overview of the Wyoming Weather Modification Pilot Project (WWMPP) is presented. This project, funded by the State of Wyoming, is designed to evaluate the effectiveness of cloud seeding with silver iodide in the Medicine Bow and Sierra Madre Ranges of south-central Wyoming. The statistical evaluation is based on a randomized crossover design for the two barriers. The description of the experimental design includes the rationale behind the design choice, the criteria for case selection, facilities for operations and evaluation, and the statistical analysis approach. Initial estimates of the number of cases needed for statistical significance used historical Snow Telemetry (SNOTEL) data (1987–2006), prior to the beginning of the randomized seeding experiment. Refined estimates were calculated using high-resolution precipitation data collected during the initial seasons of the project (2007–10). Comparing the sample size estimates from these two data sources, the initial estimates are reduced to 236 (110) for detecting a 10% (15%) change. The sample size estimates are highly dependent on the assumed effect of seeding, on the correlations between the two target barriers and between the target and control sites, and on the variance of the response variable, namely precipitation. In addition to the statistical experiment, a wide range of physical studies and ancillary analyses are being planned and conducted.

scholarly journals Estimating the Fraction of Winter Orographic Precipitation Produced under Conditions Meeting the Seeding Criteria for the Wyoming Weather Modification Pilot Project

2015 ◽  
Vol 54 (6) ◽  
pp. 1202-1215 ◽  
Author(s):  
Jaclyn M. Ritzman ◽  
Terry Deshler ◽  
Kyoko Ikeda ◽  
Roy Rasmussen
Keyword(s):  
Climate Model ◽  
Dynamical Downscaling ◽  
Winter Precipitation ◽  
State Legislature ◽  
Atmospheric Conditions ◽  
Cloud Seeding ◽  
Weather Modification ◽  
Orographic Clouds ◽  
Glaciogenic Seeding ◽  
The Impact

AbstractAnnual precipitation increases of 10% or more are often quoted for the impact of winter orographic cloud seeding; however, establishing the basis for such values is problematic for two reasons. First, the impact of glaciogenic seeding of candidate orographic storms has not been firmly established. Second, not all winter precipitation is produced by candidate “seedable” storms. Addressing the first question motivated the Wyoming state legislature to fund a multiyear, crossover, randomized cloud-seeding experiment in southeastern Wyoming to quantify the impact of glaciogenic seeding of wintertime orographic clouds. The crossover design requires two barriers, one randomly selected for seeding, for comparisons of seeded and nonseeded precipitation under relatively homogeneous atmospheric conditions. Addressing the second question motivated the work here. The seeding criteria—700-hPa temperatures ≤−8°C, 700-hPa winds between 210° and 315°, and the presence of supercooled liquid water—were applied to eight winters to determine the percent of winter precipitation that may fall under the seeding criteria. Since no observational datasets provide precipitation and all of the atmospheric variables required for this study, a regional climate model dynamical downscaling of historical data over 8 years was used. The accuracy of the model was tested against several measurements, and the small model biases were removed. On average, ~26% of the time between 15 November and 15 April atmospheric conditions were seedable over the barriers in southeastern Wyoming. These seedable conditions were accompanied by precipitation ~12%–14% of the time, indicating that ~27%–30% of the winter precipitation resulted from seedable clouds.

Sign in / Sign up

Export Citation Format

Share Document