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 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 Quantifying snowfall from orographic cloud seeding

2020 ◽  
Vol 117 (10) ◽  
pp. 5190-5195 ◽  
Author(s):  
Katja Friedrich ◽  
Kyoko Ikeda ◽  
Sarah A. Tessendorf ◽  
Jeffrey R. French ◽  
Robert M. Rauber ◽  
...  
Keyword(s):  
Climate Change ◽  
Population Growth ◽  
Arid Regions ◽  
Temporal Evolution ◽  
Cloud Seeding ◽  
Cloud Systems ◽  
Physically Based ◽  
Statistical Approaches ◽  
Orographic Cloud ◽  
Precipitation Gauge

Climate change and population growth have increased demand for water in arid regions. For over half a century, cloud seeding has been evaluated as a technology to increase water supply; statistical approaches have compared seeded to nonseeded events through precipitation gauge analyses. Here, a physically based approach to quantify snowfall from cloud seeding in mountain cloud systems is presented. Areas of precipitation unambiguously attributed to cloud seeding are isolated from natural precipitation (<1 mm h−1). Spatial and temporal evolution of precipitation generated by cloud seeding is then quantified using radar observations and snow gauge measurements. This study uses the approach of combining radar technology and precipitation gauge measurements to quantify the spatial and temporal evolution of snowfall generated from glaciogenic cloud seeding of winter mountain cloud systems and its spatial and temporal evolution. The results represent a critical step toward quantifying cloud seeding impact. For the cases presented, precipitation gauges measured increases between 0.05 and 0.3 mm as precipitation generated by cloud seeding passed over the instruments. The total amount of water generated by cloud seeding ranged from 1.2 × 105 m3 (100 ac ft) for 20 min of cloud seeding, 2.4 × 105 m3 (196 ac ft) for 86 min of seeding to 3.4 x 105 m3 (275 ac ft) for 24 min of cloud seeding.

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 Multiscale Aspects of Convective Systems Associated with an Intraseasonal Oscillation over the Indonesian Maritime Continent

2006 ◽  
Vol 134 (6) ◽  
pp. 1682-1696 ◽  
Author(s):  
Yoshiaki Shibagaki ◽  
Toyoshi Shimomai ◽  
Toshiaki Kozu ◽  
Shuichi Mori ◽  
Yasushi Fujiyoshi ◽  
...  
Keyword(s):  
Intraseasonal Oscillation ◽  
Convective Precipitation ◽  
Cloud System ◽  
Mountain Range ◽  
Horizontal Scale ◽  
Maritime Continent ◽  
Cloud Systems ◽  
Convective Systems ◽  
Cloud Clusters ◽  
Orographic Cloud

Abstract Multiscale aspects of convective systems over the Indonesian Maritime Continent in the convectively active phase of an intraseasonal oscillation (ISO) during November 2002 are studied using Geostationary Meteorological Satellite infrared data and ground-based observational data from X-band rain radar, equatorial atmosphere radar, L-band boundary layer radar, and upper-air soundings at Koto Tabang (KT; 0.20°S, 100.32°E; 865 m above mean sea level), West Sumatera, Indonesia. In the analysis period, four super cloud clusters (SCCs; horizontal scale of 2000–4000 km), associated with an ISO, are seen to propagate eastward from the eastern Indian Ocean to the Indonesian Maritime Continent. The SCCs are recognized as envelopes of convection, composed of meso-α-scale cloud clusters (MαCCs; horizontal scale of 500–1000 km) propagating westward. When SCCs reach the Indonesian Maritime Continent, the envelopes disappear but MαCCs are clearly observed. Over Sumatera, the evolution and structure of a distinct MαCC is closely related to the organization of localized cloud systems with a diurnal cycle. The cloud systems are characterized by westward-propagating meso-β-scale cloud clusters (MβCCs; horizontal scale of ∼100 km) developed in eastern Sumatera, and an orographic cloud system formed over a mountain range in western Sumatera. Ground-based observations further revealed the internal structure of the orographic cloud system around KT. A meso-β-scale convective precipitation system with eastward propagation (E-MβCP; horizontal scale of ∼40 km) is found with the formation of the orographic cloud system. This is associated with a low-level wind change from easterly to westerly, considered to be local circulation over the mountain range. The E-MβCP also indicates a multicell structure composed of several meso-γ-scale convective precipitation systems (horizontal scale of &lt;10 km) with multiple evolution stages (formation, development, and dissipation).

Introduction to Cell Membranes at Molecular Resolution

1978 ◽  
Vol 36 (3) ◽  
pp. 497-502
Author(s):  
R.J. Barrnett
Keyword(s):  
Cell Membranes ◽  
International Federation ◽  
Mountain Range ◽  
Cellular Membranes ◽  
Short History ◽  
Biological Organization ◽  
Macromolecular Assemblies ◽  
The Past

This subject, is like observing the panorama of a mountain range, magnificent towering peaks, but it doesn't take much duration of observation to recognize that they are still in the process of formation. The mountains consist of approaches, materials and methods and the rocky substance of information has accumulated to such a degree that I find myself concentrating on the foothills in the foreground in order to keep up with the advance; the edifices behind form a wonderous, substantive background. It's a short history for such an accumulation and much of it has been moved by the members of the societies that make up this International Federation. My panel of speakers are here to provide what we hope is an interesting scientific fare, based on the fact that there is a continuum of biological organization from biochemical molecules through macromolecular assemblies and cellular membranes to the cell itself. Indeed, this fact explains the whole range of towering peaks that have emerged progressively during the past 25 years.

scholarly journals Exploring the past of Mavrovouni forest in the Pindus Mountain range (Greece) using tree rings of Bosnian pines

Trees ◽  
2021 ◽  
Author(s):  
Anastasia Christopoulou ◽  
Nikolaos M. Fyllas ◽  
Barbara Gmińska-Nowak ◽  
Yasemin Özarslan ◽  
Margarita Arianoutsou ◽  
...  
Keyword(s):  
Fire History ◽  
Ring Width ◽  
Severe Drought ◽  
Mountain Range ◽  
Degree Days ◽  
Mature Trees ◽  
The Past ◽  
Natural Agent ◽  
Fire Ignition ◽  
Animal Grazing

Abstract Key message Long Bosnian pine chronologies from different mountains are shaped by different climatic parameters and can help identify past drought events and reconstruct landscape histories. Abstract We developed a 735-year-long Pinus heldreichii chronology from the southern distribution limit of the species, expanding the available database of long Bosnian pine chronologies. Tree-ring growth was mainly positively correlated with growing degree days (GDD: r1950–2018 = 0.476) while higher temperatures during both winter and growing season also enhanced growth (TWT: r1950–2018 = 0.361 and TGS: 0.289, respectively). Annual precipitation, during both calendar and water years, had a negative but weaker impact on annual tree growth. The newly developed chronology correlates well with chronologies developed from the neighboring mountains. The years with ring width index (RWI) lower than the average were found to correspond to cool years with dry summers. Still, the newly developed chronology was able to capture severe drought events, such as those in 1660, 1687, and 1725. Several old living trees had internal scars presumably caused by fires. Therefore, old mature trees could be used for fire history reconstruction in addition to climate reconstruction. Although the presence of lightning scars indicates an important natural agent of fire ignition, human activities associated with animal grazing could also be an underlying reason for fires in the region.

Soft Power Effectiveness: Problem of Evaluation

2015 ◽  
pp. 48-58
Author(s):  
E. Kharitonova
Keyword(s):  
Soft Power ◽  
Point Of View ◽  
State Agencies ◽  
Practical Application ◽  
Theoretical Understanding ◽  
Policy Makers ◽  
The Past ◽  
Focus On Results ◽  
Need To Evaluate ◽  
Power Concept

The article focuses on the task of measuring and evaluating a state's soft power. While the soft power concept developed by Joseph Nye is currently widely accepted and used, its theoretical understanding and practical application remains challenging. Both international relations scholars and those responsible for soft power in governmental and non-state agencies are looking for the tools to assess their work and the country's standing in the world in terms of soft power. As the author of the concept and other researchers noted, evaluation and measurement may be difficult due to the number of influencing factors including the use of hard power that can overshadow soft power efforts, and also because soft power efforts can bring results only in a distant period of time. However, in response to the researchers' and policy makers' need to evaluate, measure and compare soft power related parameters, a number of international ratings evolved during the past several years, such as various ratings of soft power, nation brands, countries' reputation and presence. At the same time, such rankings have several weaknesses. First of all, they present mainly the western point of view which focuses on the parameters important for western audiences and may overlook characteristics important for other, non-western cultures. They also may be subjective due to financial reasons. Besides that, while some of the ratings aim to evaluate resources or assets of nations' soft power, other focus on results like influence or reputation. Evaluation of instruments used to enhance a country's soft power and their effectiveness is also important. In many cases, even significant resources of soft power do not guarantee strong positions in this context. Comparing certain countries' positions in different ratings helps to understand a country's standing in terms of soft power, identify strong sides and analyze whether a state's soft power potential transforms into the desired outcomes.

scholarly journals Simulation of the aerosol effect on the microphysical properties of shallow stratocumulus clouds over East Asia using a bin-based meso-scale cloud model

2010 ◽  
Vol 10 (10) ◽  
pp. 23449-23495 ◽  
Author(s):  
I.-J. Choi ◽  
T. Iguchi ◽  
S.-W. Kim ◽  
S.-C. Yoon ◽  
T. Nakajima
Keyword(s):  
East Asia ◽  
Liquid Water ◽  
Cloud Model ◽  
Atmospheric Condition ◽  
Meteorological Condition ◽  
Sensitivity Factor ◽  
Target Area ◽  
Precipitation Efficiency ◽  
Microphysical Properties ◽  
Meso Scale

Abstract. A bin-based meso-scale cloud model has been employed to explore the aerosol influence on the cloud microphysical properties and precipitation efficiency of shallow stratocumulus in East Asia in March 2005. We newly constructed aerosol size distributions and hygroscopicity parameters for five aerosol species that reproduced observed aerosol and cloud condensation nuclei (CCN) number concentrations in the target period, and thereby used in model simulation of the cloud microphysical properties and precipitation efficiency. It is found that the simulated results were satisfactorily close to the satellite-based observation. Significant effects of aerosols as well as of the meteorological condition were found in the simulated cloud properties and precipitation as confirmed by comparing maritime and polluted aerosol cases and by a sensitivity test with interchanging the aerosol conditions for two cases. Cloud droplets in the polluted condition tended to exhibit relatively narrower cloud drop spectral widths with a bias toward smaller droplet sizes than those in maritime condition, supporting the dispersion effect. The polluted aerosol condition also had a tendency of thinner and higher cloud layers than maritime aerosol condition under relatively humid meteorological condition, possibly due to enhanced updraft. In our cases, vertical structures of cloud droplet number and size were affected predominantly by the change in aerosol conditions, whereas in the structures of liquid water content and cloud fraction were influenced by both meteorological and aerosol conditions. Aerosol change made little differences in cloud liquid water, vertical cloud structure, and updraft/downdraft velocities between the maritime and polluted conditions under dry atmospheric condition. Quantitative evaluations of the sensitivity factor between aerosol and cloud parameters revealed a large sensitivity values in the target area compared to the previously reported values, indicating the strong aerosol-cloud interaction.

Exploring high-mountain limnic faunas: discovery of a novel endemic bivalve species (Sphaeriidae : Pisidium) in the Nepal Himalayas

2016 ◽  
Vol 30 (6) ◽  
pp. 588 ◽  
Author(s):  
Ulrich Bößneck ◽  
Catharina Clewing ◽  
Christian Albrecht
Keyword(s):  
New Species ◽  
Molecular Phylogenetics ◽  
Nuclear Data ◽  
Elevational Gradient ◽  
Shell Morphology ◽  
High Mountain ◽  
Mountain Range ◽  
Field Surveys ◽  
The Past ◽  
A New Species

High-mountain regions are known to harbour considerable biodiversity, although it is not all well known. The terrestrial fauna of the world’s largest mountain range, the Himalayas, has been moderately well studied, but this is not the case with the limnic fauna, and especially molluscs. During intensive malacozoological field surveys conducted over the past 20 years, the bivalve family Sphaeriidae has been studied in Nepal along an elevational gradient from 100 to 4010 m above sea level (a.s.l.). Here we describe a new species of Sphaeriidae, Pisidium alexeii, sp. nov., based on comprehensive molecular phylogenetics, anatomy and shell morphology. The species can be clearly distinguished from all other sphaeriid species occurring in Nepal. A molecular phylogeny based on mitochondrial and nuclear data inferred the oriental biogeographical affinity of the new species. The species is ecologically restricted and only occurs at a few sites between 1010 and 1700 m a.s.l. A review and updated checklist of the sphaeriid fauna of Nepal is provided and biodiversity and biogeographical patterns are discussed.

A new species of Ischnocnema Reinhardt and Lütken, 1862 (Anura: Brachycephalidae) of the I. lactea species series from southeastern Brazil

Zootaxa ◽  
2019 ◽  
Vol 4706 (4) ◽  
pp. 531-545 ◽  
Author(s):  
PEDRO P. G. TAUCCE ◽  
BÁRBARA F. ZAIDAN ◽  
HUSSAM ZAHER ◽  
PAULO C. A. GARCIA
Keyword(s):  
New Species ◽  
Dorsal Surface ◽  
Lateral View ◽  
Southeastern Brazil ◽  
Medium Size ◽  
Advertisement Call ◽  
Mountain Range ◽  
The Past ◽  
A New Species ◽  
High Support

We describe a new species of Ischnocnema from the Serra da Bocaina mountain range, state of São Paulo, southeastern Brazil, based on morphological, bioacoustic, and mtDNA data. The new species is retrieved with high support values within the I. lactea species series as the sister species of I. spanios. Ischnocnema bocaina sp. nov. is characterized by its medium size (18.6–19.0 mm), a smooth venter, a rounded snout in dorsal view and acuminate in lateral view, a slightly expanded subgular, single vocal sac, a round and whitish, poorly-developed glandular-appearing nuptial pad on the dorsal surface of the thumb, and a nonpulsed advertisement call with 9 to 18 notes. We raise to 38 the number of Ischnocnema species, the 12th described in the past 10 years.

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