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Binod Pokharel
,
Bart Geerts
, and
Xiaoqin Jing

1. Introduction Water is vital for humanity and the environment. Water availability is limited yet demand is expected to continue to rise. Limited resources and increasing demand have prompted an interest in the feasibility of augmenting the water supply by means of cloud seeding. The most researched and widely practiced method of advertent weather modification aimed at precipitation enhancement in the western United States is the glaciogenic seeding of cold-season orographic clouds (e

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Anthony E. Morrison
,
Steven T. Siems
,
Michael J. Manton
, and
Alex Nazarov

1. Introduction The practice of cloud seeding has remained a point of contention in the scientific community for over half of a century. Early laboratory experiments were able to readily demonstrate precipitation enhancement mechanisms through the conversion of supercooled water to ice by the introduction of suitable ice nuclei ( Schaefer 1946 ), and these laboratory experiments were followed by a field demonstration on individual clouds by Kraus and Squires (1947) . However, the extension of

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Robert M. Rauber
,
Bart Geerts
,
Lulin Xue
,
Jeffrey French
,
Katja Friedrich
,
Roy M. Rasmussen
,
Sarah A. Tessendorf
,
Derek R. Blestrud
,
Melvin L. Kunkel
, and
Shaun Parkinson

1. Introduction The U.S. population more than doubled from 1950 to 2010 and shifted from rural to urban areas ( U.S. Census Bureau 2010 ). Southern and western states experienced the greatest population increase, resulting in concurrent expansion of public water supply systems. In response to increased demands and limits on water supplies, western communities have sought additional water sources through technologies such as cloud seeding, and/or have instituted water-conservation measures to

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Daniel Rosenfeld
,
Duncan Axisa
,
William L. Woodley
, and
Ronen Lahav

1. Introduction This study examines the spreading and dilution of seeded hygroscopic aerosols from two perspectives—their impacts on cloud drop size distribution (DSD) and how that might affect the precipitation forming processes. Before describing the experiments, we briefly state the physical background. Hygroscopic seeding for rain enhancement in convective clouds is aimed at accelerating autoconversion (i.e., the conversion of cloud water to precipitation). This was reviewed extensively by

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Katja Friedrich
,
Jeffrey R. French
,
Sarah A. Tessendorf
,
Melinda Hatt
,
Courtney Weeks
,
Robert M. Rauber
,
Bart Geerts
,
Lulin Xue
,
Roy M. Rasmussen
,
Derek R. Blestrud
,
Melvin L. Kunkel
,
Nicholas Dawson
, and
Shaun Parkinson

1. Introduction Mountain snowpack is a natural reservoir recharged annually by winter snowfall. Seeding of orographic clouds to increase snowpack and water supplies for agricultural, energy, and municipal applications has been pursued for nearly 70 years (Rauber et al. 2019). During cloud seeding, silver iodide (AgI) aerosols are injected into clouds of supercooled liquid water (SLW) converting droplets into ice particles, which subsequently fall out as snow ( Ludlam 1955 ). Advances in

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Bart Geerts
and
Robert M. Rauber

A brief history of cloud seeding to increase precipitation Attempts at weather modification have a long and colorful history ( Haupt et al. 2018 ). Both Zeus in the Greek mythology and the Dragon King in ancient Chinese culture are rain gods. Many ancient societies conducted elaborate rituals as a means of pleading with the gods for favorable weather. Across history, many bright minds have tried a variety of methods to enhance precipitation in the face of droughts. In the late 1940s, a

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Scott Knowles
and
Mark Skidmore

1. Introduction The objective of this paper is to conduct an evaluation of the North Dakota Cloud Modification Project (NDCMP). With origins dating back to the early 1950s, the NDCMP has evolved over the years, but its objectives have remained consistent: reduce local damage incurred by summertime hailstorms and increase beneficial precipitation. Initially, only ground-based cloud-seeding generators were used in a grassroots effort to protect crops in North Dakota. Later, with the founding of

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Thomas Mazzetti
,
Bart Geerts
, and
Lulin Xue

1. Introduction In arid regions, there has long been an interest in the enhancement of precipitation through cloud seeding ( Haupt et al. 2019 ). A method commonly used in the western United States and elsewhere is the glaciogenic seeding of orographic clouds in the cold season ( http://www.nawmc.org/ ). These mountains are targeted because the region is relatively arid and water supply is largely derived from the high-elevation snowpack. Interest in cloud seeding to enhance precipitation

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Yoav Benjamini
,
Amir Givati
,
Pavel Khain
,
Yoav Levi
,
Daniel Rosenfeld
,
Uri Shamir
,
Ayal Siegel
,
Assaf Zipori
,
Baruch Ziv
, and
David M. Steinberg

1. Introduction Cloud seeding has been studied for more than 70 years as a means for increasing rainfall or snow precipitation. If successful, seeding is a cost-effective procedure and experiments continue to examine its efficacy. French et al. (2018) presented the scientific basis for the potential of cloud seeding in orographic regions, using both radar measurements and airborne cloud probes to obtain data illustrating the effects of glaciogenic seeding. Dong et al. (2020 , 2021

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Lulin Xue
,
Akihiro Hashimoto
,
Masataka Murakami
,
Roy Rasmussen
,
Sarah A. Tessendorf
,
Daniel Breed
,
Shaun Parkinson
,
Pat Holbrook
, and
Derek Blestrud

1. Introduction Freshwater is becoming one of the most stressed and in-demand natural resources given the rapidly increasing human population. The need for water provides motivation to find solutions other than drilling wells, digging canals, and building reservoirs. Cloud seeding is one method being pursued in many locations around the world. Since the first proof-of-concept experiment on glaciogenic seeding of nonprecipitating supercooled stratus clouds by dry ice ( Schaefer 1946 ) and the

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