1 Glaciogenic Cloud Seeding to Increase Orographic Precipitation Bruce A. Boe Director of Meteorology Weather Modification, Inc. Fargo, North Dakota, USA
2 Content and Intent Intention: Present the basic principles of orographic clouds processes. Talk about glaciogenic (ice phase) seeding applied to orographic clouds.
3 Development of Orographic Clouds The first requirement is a topographic barrier, a mountain range. In this example, west is on the left, and east, on the right. We assume zonal (west-to-east) flow will be the typically force cloud development. W IN THE ATMOSPHERE Higher = colder Lower = warmer E
4 W Development of Orographic Clouds If the flow is strong enough, air is forced up and over the mountain barrier, rising, and cooling. Note that in the lee (on the east side), the air descends and warms. IN THE ATMOSPHERE Higher = colder Lower = warmer E
5 Development of Orographic Clouds When the air is sufficiently moist, condensation occurs, and a cloud of tiny water droplets forms. These drops are too small to precipitate. The cloud remains ice-free even at temperatures below 0 C. This supercooling slows the precipitation process. IN THE ATMOSPHERE Higher = colder Lower = warmer
6 Supercooled Water When solid substrates contact the supercooled droplets, they freeze. This accretion builds up on the exposed substrate. This results in aircraft icing. Automobile Radio Antenna
7 C-90 deicing video AIRCRAFT ICING 22
8 AIRCRAFT ICING C-90 deicing video For cloud seeding, supercooled water is good!
9 Development of Orographic Precip Nature commonly begins ice formation at temperatures between -15 to -20 C. This natural process is caused by tiny particles called ice nuclei. APPROXIMATE CLOUD VOLUME CONTAINING SUPERCOOLED LIQUID WATER (SLW) IN THE ATMOSPHERE Higher = colder Lower = warmer. First Ice
10 Development of Orographic Precip Once ice forms, a race begins for the newly-formed ice to grow large enough to precipitate before beginning the descent and warming in the lee. IN THE ATMOSPHERE Higher = colder Lower = warmer GROWTH ZONE. First Ice
11 Development of Orographic Precip Additional ice crystals grow large enough to become snow (and may melt, becoming rain) as they travel beyond the crest. But in the descending, warming cloud, many remain too small to fall. Others melt and evaporate. First Snow or Rain
12 Development of Orographic Precip Cloud seeding provides additional ice nuclei that create ice at warmer temperatures. This causes cloud ice to form sooner, at temperatures as warm as -8 C. (Remember: the natural ice nuclei start to make ice between -15 to -20 o C.) GROWTH ZONE, SEEDED. GROWTH ZONE, UNSEEDED. First Ice, seeding First Ice, not seeded
13 Development of Orographic Precip Precipitation is thus increased because more ice More ice crystals grow large enough to crystals have a better opportunity to grow large become snow as they travel beyond the peak, enough, becoming snow while over the mountain. but in the descending, warming cloud, many are Cloud too seeding small converts to fall. Others supercooled may liquid melt cloud and water into snow, increasing cloud efficiency. This evaporate. cloud water would otherwise often simply pass by. GROWTH ZONE, SEEDED
14 How Do We Seed Effectively?
15 How Do We Seed Effectively? (1) We must recognize when conditions are favorable. Are clouds present? Are they cold enough? Do they contain liquid water? Can seeding agent be delivered effectively?
16 How Do We Seed Effectively? (2) Creation of Ice Nuclei. From the right place - within cloud, or from a location where it will reach supercooled cloud, The right amount, that is, enough to make a difference.
17 How Do We Seed Effectively? (3) Movement from the release points to the supercooled cloud. If the seeding agent (ice nuclei) are not placed directly within the supercooled cloud, nature must transport it. Dispersion dilutes and spreads the seeding agent.
18 How Do We Seed Effectively? (2 and 3) Together these links are often termed TARGETING. Many programs have failed because targeting was poor.
19 How Do We Seed Effectively? (4) As seeding agent enters supercooled cloud (especially between -8 and -20 C), the rate of ice crystal formation and the number of ice crystals increase.
20 How Do We Seed Effectively? (5) The newly-created ice crystals grow, converting the tiny cloud droplets to much larger ice crystals, heavy enough to precipitate.
21 How Do We Seed Effectively? (6) The ice crystals created by seeding are now numerous and precipitating. If our targeting was correct, these crystals will reach the surface as snow, or with warmer temperatures below, rain. If we released enough seeding agent, and there was enough supercooled liquid, precipitation will be increased.
22 How Do We Seed Effectively? (7) Evaluation. Links (1) through (6) may generate more precipitation, but to know how much we must measure it, usually both within and outside of the seeded area, and during seeded and non-seeded periods. The evaluation topic is complex, and not dealt with in this presentation.
23 1. The cloud must contain supercooled liquid water (SLW), so is the cloud cold enough? 2. Is the wind flow over the barrier, not around it? 3. Will there be enough time for the ice produced by seeding to grow large enough to precipitate? If (1) and (2) are TRUE, we must do (3) such that it also will be TRUE. This is targeting. Targeting
24 Targeting GROUND-BASED SEEDING Seeding sites are fixed, that is, not mobile. Multiple sites are required. Site selection is based upon prevailing wind direction(s). The altitude required for the sites depends upon the frequency (how often) and strength of inversion layers, and also the prevalent wind speeds. AIRBORNE SEEDING Seeding can be conducted wherever needed, regardless of wind direction. Flight paths and altitudes are based upon current (real-time) wind directions and speeds. Seeding duration can be limited by the ability of the aircraft to fly in icing conditions.
25 Terrestrial Seeding Seeding sites are fixed, that is, not mobile. Sites, once selected, are usable for a fixed range of seeding directions, for example, southwest through northwest. Sites are also usable for only for a fixed range of wind speeds. If the winds are too weak (A), seeding agent will not reach the cloud SLW quickly. If too strong (B), the snow created by seeding won t have time to grow enough to precipitate on the mountain. A Weak winds B Strong winds..
26 Terrestrial Seeding Seeding sites are fixed, perhaps as shown here. Siting considerations include: Distance from the mountain crest (blue line). Spacing between generators. When wind is strong, spacing must be less because seeding plumes have less time to spread. When wind is weak, spacing can be greater because seeding plumes have much time to spread. If generators are too far from the crest, especially if at low elevations, the chance of seeding agents reaching the SLW can be significantly reduced.
27 Airborne Seeding Seeding paths are flexible, limited only by the mountains themselves. When wind is strong, the clouds are generally broader, so seeding legs are flown at greater distance from the crest (blue line), to allow more time for ice crystal growth. When wind is weak, clouds are narrower, so legs are flown closer. There is no concern about seeding agent being trapped in valleys, as the aircraft fly above any inversions.
28 Which Mode is Better? Terrestrial Requires multiple sites, often at higher elevations. Less expensive, per site. Can be operated steadily for long periods of time (even a day or more). Seedable wind directions are limited. Slow seeding rate, typically 25 grams per hour. Solutions are often burned; pyrotechnics can be used if greater rates are needed. Targeting may be less certain. Airborne Typically only one aircraft per mountain range. (twin-engine, known icing) Can be expensive, especially if using cloud physics and/or aerosol instrumentation. Higher seeding rates necessary because of aircraft speed, typically 35 grams per minute or higher. Pyrotechnics are used, seldom solution. Aircraft may periodically have to stop seeding for short periods to deice the airframe.
29 So which to Use? Both systems can be effective. Selection of effective terrestrial sites and aircraft paths are critically important. This can be improved by numerical modeling. Plume transport can be verified by airborne seeding plume measurements. The best terrestrial sites often are well removed from commercial electrical power, and so must be powered by solar and wind energy, with battery backup. Control is possible via satellite.
30 Opportunity Recognition WHEN ARE CONDITIONS RIGHT? Cloud must contain liquid water [microwave radiometer]. Cloud must be cold enough. [sounding (weather balloon) or aircraft, or numerical modeling.] If ground-based seeding is used, the SLW must be within 1 km above the mountain crest. [difficult to know with certainty] Flow must be over the mountain crest, not around it, at least at the seeding elevation or altitude. [numerical modeling]
31 Even the basics get complicated! CONCLUSIONS Opportunity recognition allows us to begin seeding during favorable conditions. Effective targeting is critical. Airborne and terrestrial-based seeding both have their place. (They can even be used at the same time!) An extensive research project examining this kind of seeding is presently concluding in Wyoming, USA. That evaluation is both statistical (precipitation analysis) and physical (in situ and remote cloud measurements), and numerical modeling. (I cannot discuss results because the project does not conclude until January Ask me then.)
32 Questions? GRACIAS Bruce A, Boe Director of Meteorology Weather Modification, Inc. Fargo, ND USA
What are clouds and how are they formed? Clouds are composed of water droplets and sometimes ice crystals. Clouds form when air that is rich in moisture near the Earth s surface rises higher into the atmosphere,
Idaho Power Company s Cloud Seeding Program Shaun Parkinson, PhD, PE Presentation Overview What is cloud seeding? How we know cloud seeding works Perceptions IPC s cloud seeding program Payette Upper Snake
Lecture 7a: Cloud Development and Forms Why Clouds Form Cloud Types (from The Blue Planet ) Why Clouds Form? Clouds form when air rises and becomes saturated in response to adiabatic cooling. Four Ways
WEATHER AND CLIMATE practice test Multiple Choice Identify the choice that best completes the statement or answers the question. 1. What role does runoff play in the water cycle? a. It is the process in
Aerosol affects on the microphysics of precipitation development in tropical and sub-tropical convective clouds using dual-polarization radar and airborne measurements. Roelof Bruintjes, Sarah Tessendorf,
Chapter 8, Part 1 Precipitation Processes How do droplets grow larger? Cloud contain water droplets, but a cloudy sky does not always mean rain. Cloud Droplets in Equilibrium In equilibrium water molecules
firecatching.blogspot.com Kids.brittanica.com Clouds and fog are physically the same just location is different Fog is considered a stratus cloud at or near the surface What does one see when looking at
Stability and Cloud Development AT350 Why did this cloud form, whereas the sky was clear 4 hours ago? Stability in the atmosphere An Initial Perturbation Stable Unstable Neutral If an air parcel is displaced
In a majority of ice-crystal icing engine events, convective weather occurs in a very warm, moist, tropical-like environment. 22 avoiding convective Weather linked to Ice-crystal Icing engine events understanding
KEY CONCEPT Water falls to Earth s surface as precipitation. BEFORE, you learned Water moves between Earth's surface and the atmosphere Water vapor condenses into clouds NOW, you will learn How precipitation
21 April 2011 The Rundown on Rainmaking Brooke Jones Researcher FDI Global Food and Water Crises Research Programme Summary Australia s susceptibility to drought has affected its farming capacity in the
Lecture 7a: Cloud Development and Forms Why Clouds Form? Clouds form when air rises and becomes saturated in response to adiabatic cooling. Why Clouds Form Cloud Types (from The Blue Planet ) Four Ways
Fog and Cloud Development Bows and Flows of Angel Hair 1 Ch. 5: Condensation Achieving Saturation Evaporation Cooling of Air Adiabatic and Diabatic Processes Lapse Rates Condensation Condensation Nuclei
FOR SUBSCRIBERS ONLY! - TRIAL PASSWORD USERS MAY NOT REPRODUCE AND DISTRIBUTE PRINTABLE MATERIALS OFF THE SOLPASS WEBSITE! 1 NAME DATE GRADE 5 SCIENCE SOL REVIEW WEATHER LABEL the 3 stages of the water
Clouds for pilots Ed Williams http://williams.best.vwh.net/ Clouds are important to pilots! Many of our weather problems are associated with clouds: Fog Thunderstorms Cloud In flight icing Cloud physics
Common Questions and Answers about Cloud Seeding Cloud seeding, often called weather modification, is a scientific process intended to enhance rain and snow, reduce hail damage, and alleviate fog. Current
Air Masses and Fronts Air Masses The weather of the United States east of the Rocky Mountains is dominated by large masses of air that travel south from the wide expanses of land in Canada, and north from
KEY CONCEPT Most clouds form as air rises and cools. BEFORE, you learned Water vapor circulates from Earth to the atmosphere Warm air is less dense than cool air and tends to rise NOW, you will learn How
Cloud Seeding Frequently Asked Questions What is cloud seeding? Cloud seeding is a weather modification technique which involves the introduction of additional particles into suitable clouds to encourage
Cirrus (CI) Detached clouds in the form of delicate white filaments or white patches or narrow bands. These clouds have a fibrous or hair like appearance, or a silky sheen or both. with frontal lifting
CLOUDS Formation & Classification DR. K. K. CHANDRA Department of forestry, Wildlife & Environmental Sciences, GGV, Bilaspur What is Cloud It is mass of tiny water droplets or ice crystals or both of size
SIXTH GRADE WEATHER 1 WEEK LESSON PLANS AND ACTIVITIES WATER CYCLE OVERVIEW OF SIXTH GRADE WATER WEEK 1. PRE: Evaluating components of the water cycle. LAB: Experimenting with porosity and permeability.
Chapter 6: Cloud Development and Forms (from The Blue Planet ) Why Clouds Form Static Stability Cloud Types Why Clouds Form? Clouds form when air rises and becomes saturated in response to adiabatic cooling.
Name: Date: Day/Period: CGC1D1: Interactions in the Physical Environment Factors that Affect Climate Chapter 12 in the Making Connections textbook deals with Climate Connections. Use pages 127-144 to fill
Stability & Cloud Development This chapter discusses: 1. Definitions and causes of stable and unstable atmospheric air 2. Processes that cause instability and cloud development Stability & Movement A rock,
Name: _ Date: LAB: Dew Point and Cloud Formation Adapted from Exploration in Earth Science, The Physical Setting, United Publishing Company, Inc. Introduction: Cumulus clouds are our puffy fair weather
ES 106 Laboratory # 6 MOISTURE IN THE ATMOSPHERE 6-1 Introduction By observing, recording, and analyzing weather conditions, meteorologists attempt to define the principles that control the complex interactions
Weather Unit Exam Pre-Test Questions 7613-1 - Page 1 Name: 1) Equal quantities of water are placed in four uncovered containers with different shapes and left on a table at room temperature. From which
NASA Facts National Aeronautics and Space Administration www.nasa.gov The Importance of Understanding Clouds One of the most interesting features of Earth, as seen from space, is the ever-changing distribution
INDIAN INSTITUTE OF TECHNOLOGY, DELHI DEPARTMENT OF ATMOSPHERIC SCIENCE ASL720: Satellite Meteorology and Remote Sensing TERM PAPER TOPIC: CLOUD CLASSIFICATION Group Members: Anil Kumar (2010ME10649) Mayank
Chapter 6 - Cloud Development and Forms Understanding Weather and Climate Aguado and Burt Interesting Cloud 1 Mechanisms that Lift Air Orographic lifting Frontal Lifting Convergence Localized convective
WEATHER THEORY Temperature, Pressure And Moisture Air Masses And Fronts Weather Theory- Page 77 Every physical process of weather is a result of a heat exchange. The standard sea level temperature is 59
Expert Panel Assessment Snowy Precipitation Enhancement Trial (SPET) Executive Summary In Summary Snowy Hydro Ltd proposes to undertake a six year cloud seeding trial in the Snowy Mountains region of New
JetStream An Online School for Weather Aquifers Aquifers Aquifers 1 3 5 Aquifers Aquifers Aquifers 2 4 6 /atmos/ll_whatacycle_aquifers.pdf There are over 35 lesson plans in the National Weather Service
Analyze Weather in Cold Regions and Mountainous Terrain Terminal Learning Objective Action: Analyze weather of cold regions and mountainous terrain Condition: Given a training mission that involves a specified
Vocabulary and Writing Worksheet 1. Choose the best vocabulary word for each sentence and write it in the blank. dew point evaporation fog gas precipitation relative humidity a. Relative humidity refers
Statement on the Application of Winter Orographic Cloud Seeding For Water Supply and Energy Production Literature Review and Scientific Synthesis on the Efficacy of Winter Orographic Cloud Seeding A Report
Select the be answer on the answer sheet. Please do not make any marks on this te. 1. Weather is be defined as the A. changes that occur in cloud formations from day to day. B. amount of rain or snow that
WORLD METEOROLOGICAL ORGANIZATION WMO DOCUMENTS ON WEATHER MODIFICATION Updated in the meeting of the Expert Team on Weather Modification Research Abu Dhabi, 22-24 March 2010 EXECUTIVE SUMMARY OF THE WMO
Chapter 6 Atmospheric Aerosol and Cloud Processes Spring 2015 Cloud Physics Initiation and development of cloud droplets Special interest: Explain how droplet formation results in rain in approximately
Aircraft Icing FAR 25, Appendix C charts Prof. Dr. Serkan ÖZGEN Dept. Aerospace Engineering, METU Spring 2014 Outline FAR 25 and FAR 29 Appendix C charts Using FAR 25 Appendix C charts Liquid water content
Humidity, Condensation, Clouds, and Fog or Water in the Atmosphere The Hydrologic Cycle Where the Water Exists on Earth Evaporation From the Oceans and Land The Source of Water Vapor for the Atmosphere
Chapter 7 Stability and Cloud Development Atmospheric Stability 1 Cloud Development - stable environment Stable air (parcel) - vertical motion is inhibited if clouds form, they will be shallow, layered
Introduction to Climatology GEOGRAPHY 300 Cloud Development and Forms Tom Giambelluca University of Hawai i at Mānoa LIFTING MECHANISMS 1. Orographic 2. Frontal 3. Convergence 4. Convection Cloud Development
Wintry weather: improved nowcasting through data fusion Arnold Tafferner, Felix Keis DLR Institut für Physik der Atmosphäre (IPA) Wetter&Fliegen Final Colloquium, MAC MUC, 15 March 2012 1 Outline The problem
Assessment Chapter Test A States of Matter MULTIPLE CHOICE Write the letter of the correct answer in the space provided. 1. Boyle s law explains the relationship between volume and pressure for a fixed
Cloud Types Levels Overview: During this project, students learn about different types of clouds and determine which type of cloud is most commonly overhead in their area over a period of four weeks. Objectives:
Education and Outreach Lesson Plan Visit our online activities collection http://education.arm.gov/ Grade levels K 2 Common Covering Clouds Common Covering Clouds Approximate Time 1 1/2 hours, or two 45-minute
Name: Pd: Read and study the following information. After reading complete the review questions. Clouds What are clouds? A cloud is a large collection of very tiny droplets of water or ice crystals. The
DRAFT EXECUTIVE SUMMARY The WYOMING Weather Modification Pilot Program LEVEL II STUDY PREPARED FOR WYOMING WATER DEVELOPMENT COMMISSION 6920 YELLOWTAIL ROAD, CHEYENNE WY 82002 SUBMITTED BY DECEMBER 2014
Cloud Seeding over the Snowy Mountains Presentation to Alpine Resorts Sustainability Forum 1 May 2009 Topics covered by this presentation History of Cloud Seeding over the Snowy Mountains How Cloud Seeding
12 HUMIDITY AND PRECIPITATION In our previous lesson while discussing the composition of the atmosphere, we noted that water vapour, though a minor component, is a very important constituent of the atmosphere.
UNIT 6a TEST REVIEW 1. A weather instrument is shown below. Which weather variable is measured by this instrument? 1) wind speed 3) cloud cover 2) precipitation 4) air pressure 2. Which weather station
Test 2 f14 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Carbon cycles through the Earth system. During photosynthesis, carbon is a. released from wood
These 3 climate graphs and tables of data show average temperatures and precipitation for each month in Victoria, Winnipeg and Whitehorse: Figure 1.1 Month J F M A M J J A S O N D Year Precipitation 139
Chapter Overview CHAPTER 6 Air-Sea Interaction The atmosphere and the ocean are one independent system. Earth has seasons because of the tilt on its axis. There are three major wind belts in each hemisphere.
The Clouds Outside My Window National Weather Service NOAA The Clouds Out My Window Written and illustrated by John Jensenius My window With help from Owlie Skywarn 1 The Clouds Outside My Window Whether
Activity 8 Drawing Isobars Level 2 http://www.uni.edu/storm/activities/level2/index.shtml Objectives: 1. Students will be able to define and draw isobars to analyze air pressure variations. 2. Students
Convec,on, cloud and radia,on Convection redistributes the thermal energy yielding (globally-averaged), a mean lapse rate of ~ -6.5 o C/km. Radiative processes tend to produce a more negative temperature
Cumulifor m clouds develop as air slowly rises over Lake Powell in Utah. Figure 6.1 Dew forms on clear nightswhen objects on the surface cool to a temperature below the dew point. If these beads of water
58 The Causes of Climate R E A D I N G Climates are described by the same conditions used to describe weather, such as temperature, precipitation, and wind. You now know that oceans have an important effect
Climate Models: Uncertainties due to Clouds Joel Norris Assistant Professor of Climate and Atmospheric Sciences Scripps Institution of Oceanography Global mean radiative forcing of the climate system for
NASA Facts National Aeronautics and Space Administration www.nasa.gov The Balance of Power in the Earth-Sun System The Sun is the major source of energy for Earth s oceans, atmosphere, land, and biosphere.
Climate and Climate Change Name Date Class Climate and Climate Change Guided Reading and Study What Causes Climate? This section describes factors that determine climate, or the average weather conditions
August 1999 NF-207 The Earth Science Enterprise Series These articles discuss Earth's many dynamic processes and their interactions Clouds and the Energy Cycle he study of clouds, where they occur, and
Severe Weather A Reading A Z Level T Leveled Book Word Count: 1,775 LEVELED BOOK T SEVERE WEATHER Written by Bruce D. Cooper Illustrated by Cende Hill Visit www.readinga-z.com for thousands of books and
1 Physical Environment: Climate and Biomes EVPP 110 Lecture Instructor: Dr. Largen Fall 2003 2 Climate and Biomes Ecosystem concept physical and biological components of environment are considered as single,
WORLD METEOROLOGICAL ORGANIZATION COMMISSION FOR INSTRUMENT AND METHODS OF OBSERVATION OPAG-UPPER AIR EXPERT TEAM ON REMOTE SENSING UPPER-AIR TECHNOLOGY AND TECHNIQUES First Session Geneva, Switzerland,
CHAPTER 5 Lectures 10 & 11 Air Temperature and Air Temperature Cycles I. Air Temperature: Five important factors influence air temperature: A. Insolation B. Latitude C. Surface types D. Coastal vs. interior
1 Making Aviation Safer: Results of the National Aviation Weather Program s 10-Year Goal to Reduce Weather- Related Accidents by 80 Percent Friends/Partners of Aviation Weather October 9, 2008 Jud Stailey,
The Water Cycle Now You See It, Now You Don t Unit: Salinity Patterns & the Water Cycle l Grade Level: Elementary l Time Required: Introduction - 30 min. - Activity as groups 45min Wrap Up 20 min l Content
Passive and Active Microwave Remote Sensing of Cold-Cloud Precipitation : Wakasa Bay Field Campaign 3 Benjamin T. Johnson,, Gail Skofronick-Jackson 3, Jim Wang 3, Grant Petty firstname.lastname@example.org
February 17 th Video Conference Agenda 8:30 am Video, audio and connection checks 9:00 am Brief intro by mediator, Ellen Holmes, followed by 3 to 5 minute Day in the Life of Presentations from each school.
TUESDAY: air & water & clouds Water, Phase Changes, Clouds How can freezing make something warmer? 'warm air can hold more water' why? How do clouds form? The (extraordinary) properties of Water Physical
FOURTH GRADE WEATHER 1 WEEK LESSON PLANS AND ACTIVITIES WATER CYCLE OVERVIEW OF FOURTH GRADE WATER WEEK 1. PRE: Comparing different reservoirs of water. LAB: Experimenting with surface tension and capillary
Observed Cloud Cover Trends and Global Climate Change Joel Norris Scripps Institution of Oceanography Increasing Global Temperature from www.giss.nasa.gov Increasing Greenhouse Gases from ess.geology.ufl.edu
Name Period 4 th Six Weeks Notes 2015 Weather Radiation Convection Currents Winds Jet Streams Energy from the Sun reaches Earth as electromagnetic waves This energy fuels all life on Earth including the
What the Heck are Low-Cloud Feedbacks? Takanobu Yamaguchi Rachel R. McCrary Anna B. Harper IPCC Cloud feedbacks remain the largest source of uncertainty. Roadmap 1. Low cloud primer 2. Radiation and low
Convection (Walter Glogowski, Chaz Shapiro & Reid Sherman) INTRODUCTION You know from common experience that when there's a difference in temperature between two places close to each other, the temperatures
1. Which single factor generally has the greatest effect on the climate of an area on the Earth's surface? 1) the distance from the Equator 2) the extent of vegetative cover 3) the degrees of longitude