Thunderstorms, Tornadoes and Lightning
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3. Electrical Structure of Thunderstorm Clouds
3. Electrical Structure of Thunderstorm Clouds 1 Cloud Charge Structure and Mechanisms of Cloud Electrification An isolated thundercloud in the central New Mexico, with rudimentary indication of how electric charge is thought to be distributed and around the thundercloud, as inferred from the remote and in situ observations. Adapted from Krehbiel (1986). 2 2 Cloud Charge Structure and Mechanisms of Cloud Electrification A vertical tripole representing the idealized gross charge structure of a thundercloud. The negative screening layer charges at the cloud top and the positive corona space charge produced at ground are ignored here. 3 3 Cloud Charge Structure and Mechanisms of Cloud Electrification E = 2 E (−)cos( 90o−α) Q H = 2 2 3/2 2πεo()H + r sinα = k Q = const R2 ( ) Method of images for finding the electric field due to a negative point charge above a perfectly conducting ground at a field point located at the ground surface. 4 4 Cloud Charge Structure and Mechanisms of Cloud Electrification The electric field at ground due to the vertical tripole, labeled “Total”, as a function of the distance from the axis of the tripole. Also shown are the contributions to the total electric field from the three individual charges of the tripole. An upward directed electric field is defined as positive (according to the physics sign convention). 5 5 Cloud Charge Structure and Mechanisms of Cloud Electrification Electric Field Change Due to Negative Cloud-to-Ground Discharge Electric Field Change Due to a Cloud Discharge Electric Field Change, kV/m Change, Electric Field Electric Field Change, kV/m Change, Electric Field Distance, km Distance, km Electric field change at ground, due to the Electric field change at ground, due to the total removal of the negative charge of the total removal of the negative and upper vertical tripole via a cloud-to-ground positive charges of the vertical tripole via a discharge, as a function of distance from cloud discharge, as a function of distance from the axis of the tripole. -
Sirocco Manual
SIROCCO INSTALLATION PROPER INSTALLATION IS IMPORTANT. IF YOU NEED ASSISTANCE, CONSULT A CONTRACTOR ELECTRICIAN OR TELEVISION ANTENNA INSTALLER (CHECK WITH YOUR LOCAL BUILDING SUPPLY, OR HARDWARE STORE FOR REFERRALS). TO PROMOTE CONFIDENCE, PERFORM A TRIAL WIRING BEFORE INSTALLATION. Determine where you are going to locate both the 1 rooftop sensor and the read-out. Feed the terminal lug end of the 2-conductor cable through 2 2-CONDUCTOR WIND SPEED the rubber boot and connect the lugs to the terminals on the bottom CABLE SENSOR of the wind speed sensor. (Do NOT adjust the nuts that are already BOOT on the sensor). The polarity does not matter. COTTER PIN 3 Slide the stub mast through the rubber boot and insert the stub mast into the bottom of the wind speed sensor. Secure with the cotter pin. Coat all conections with silicone sealant and slip the boot over the sensor. STRAIGHT STUB MAST Secure the sensor and the stub mast to your antenna 2-CONDUCTOR mast (not supplied) with the two hose clamps. Radio CABLE 4 Shack and similar stores have a selection of antenna HOSE CLAMPS masts and roof mounting brackets. Choose a mount that best suits your location and provides at least eight feet of vertical clearance above objects on the roof. TALL MAST EVE 8 FEET 5 Follow the instructions supplied with the antenna MOUNT VENT-PIPE mount and secure the mast to the mount. MOUNT CABLE WALL CHIMNEY Secure the wire to the building using CLIPS TRIPOD MOUNT MOUNT MOUNT 6 CAULK cable clips (do not use regular staples). -
The Observation of the Lightning Induced Variations in Atmospheric Ions
XV International Conference on Atmospheric Electricity, 15-20 June 2014, Norman, Oklahoma, U.S.A. The Observation of the Lightning Induced Variations in Atmospheric Ions Xuemeng Chen1,*, Hanna E. Manninen1,2, Pasi Aalto1, Petri Keronen1, Antti Mäkelä3, Jussi Paatero3, Tuukka Petäjä1 and Markku Kulmala1 1. Department of Physics, University of Helsinki, Helsinki, Finland 2. Institute of Physics, University of Tartu, Estonia 3. Finnish Meteorological Institute, Helsinki, Finland ABSTRACT: Variations in atmospheric ion concentration were studied in a boreal forest in Finland, with emphasis on the effect of lightning. In general, changes in ion concentrations have diurnal and seasonal patterns. Distinct features were found in ions of different size ranges, namely small ions (0.8 – 1.7 nm) and intermediate ions (1.7 – 7 nm). Preliminary results on two case studies of lightning effect are present, one with rain effect and the other not. Bursts in the concentrations of small ions and intermediate ions were observed in both cases. However, different trends in trace gases were observed for the two cases. Further investigation is needed to reveal the nature of lightning ions and the mechanism in their formation. The work is under progress. INTRODUCTION Atmospheric ions, or air ions, refer to electric charge carriers present in the atmosphere. Distinct features exist in their chemical composition, mass, size as well as number of carried charges. According to Tammet [1998], atmospheric ions can be classified into small or cluster ions, intermediate ions, and large ions based on their mobility (Z) in air, being Z > 0.5 cm2V-1s-1, 0.5 cm2V-1s-1 ≤ Z ≥ 0.03 cm2V-1s-1 and Z< 0.03 cm2V-1s-1, respectively. -
The Error Is the Feature: How to Forecast Lightning Using a Model Prediction Error [Applied Data Science Track, Category Evidential]
The Error is the Feature: How to Forecast Lightning using a Model Prediction Error [Applied Data Science Track, Category Evidential] Christian Schön Jens Dittrich Richard Müller Saarland Informatics Campus Saarland Informatics Campus German Meteorological Service Big Data Analytics Group Big Data Analytics Group Offenbach, Germany ABSTRACT ACM Reference Format: Despite the progress within the last decades, weather forecasting Christian Schön, Jens Dittrich, and Richard Müller. 2019. The Error is the is still a challenging and computationally expensive task. Current Feature: How to Forecast Lightning using a Model Prediction Error: [Ap- plied Data Science Track, Category Evidential]. In Proceedings of 25th ACM satellite-based approaches to predict thunderstorms are usually SIGKDD Conference on Knowledge Discovery and Data Mining (KDD ’19). based on the analysis of the observed brightness temperatures in ACM, New York, NY, USA, 10 pages. different spectral channels and emit a warning if a critical threshold is reached. Recent progress in data science however demonstrates 1 INTRODUCTION that machine learning can be successfully applied to many research fields in science, especially in areas dealing with large datasets. Weather forecasting is a very complex and challenging task requir- We therefore present a new approach to the problem of predicting ing extremely complex models running on large supercomputers. thunderstorms based on machine learning. The core idea of our Besides delivering forecasts for variables such as the temperature, work is to use the error of two-dimensional optical flow algorithms one key task for meteorological services is the detection and pre- applied to images of meteorological satellites as a feature for ma- diction of severe weather conditions. -
PROTECT YOUR PROPERTY from STORM SURGE Owning a House Is One of the Most Important Investments Most People Make
PROTECT YOUR PROPERTY FROM STORM SURGE Owning a house is one of the most important investments most people make. Rent is a large expense for many households. We work hard to provide a home and a future for ourselves and our loved ones. If you live near the coast, where storm surge is possible, take the time to protect yourself, your family and your belongings. Storm surge is the most dangerous and destructive part of coastal flooding. It can turn a peaceful waterfront into a rushing wall of water that floods homes, erodes beaches and damages roadways. While you can’t prevent a storm surge, you can minimize damage to keep your home and those who live there safe. First, determine the Base Flood Elevation (BFE) for your home. The BFE is how high floodwater is likely to rise during a 1%-annual-chance event. BFEs are used to manage floodplains in your community. The regulations about BFEs could affect your home. To find your BFE, you can look up your address on the National Flood Hazard Layer. If you need help accessing or understanding your BFE, contact FEMA’s Flood Mapping and Insurance eXchange. You can send an email to FEMA-FMIX@ fema.dhs.gov or call 877 FEMA MAP (877-336-2627). Your local floodplain manager can help you find this information. Here’s how you can help protect your home from a storm surge. OUTSIDE YOUR HOME ELEVATE While it is an investment, elevating your SECURE Do you have a manufactured home and want flood insurance YOUR HOME home is one of the most effective ways MANUFACTURED from the National Flood Insurance Program? If so, your home to mitigate storm surge effects. -
Hurricane Response Annex Overview Introduction
TABLE OF CONTENTS SECTION I – HURICANE RESPONSE ANNEX OVERVIEW ............................................................... 2 INTRODUCTION .................................................................................................................................................. 3 PLANNING ASSUMPTIONS ................................................................................................................................... 4 COMMUNITY IMPACTS ........................................................................................................................................ 4 SECTION II – CONCEPT OF OPERATIONS ........................................................................................ 5 DEFINING THE HAZARD ...................................................................................................................................... 5 Tropical Cyclones ..................................................................................................................................................... 5 TIMELINES ........................................................................................................................................................... 6 HURRICANE SEASON ...................................................................................................................................... 6 RESPONDER REENTRY HOUR ......................................................................................................................... 7 SECTION III – ROLES & RESPONSIBILITIES -
February 2021 Historical Winter Storm Event South-Central Texas
Austin/San Antonio Weather Forecast Office WEATHER EVENT SUMMARY February 2021 Historical Winter Storm Event South-Central Texas 10-18 February 2021 A Snow-Covered Texas. GeoColor satellite image from the morning of 15 February, 2021. February 2021 South Central Texas Historical Winter Storm Event South-Central Texas Winter Storm Event February 10-18, 2021 Event Summary Overview An unprecedented and historical eight-day period of winter weather occurred between 10 February and 18 February across South-Central Texas. The first push of arctic air arrived in the area on 10 February, with the cold air dropping temperatures into the 20s and 30s across most of the area. The first of several frozen precipitation events occurred on the morning of 11 February where up to 0.75 inches of freezing rain accumulated on surfaces in Llano and Burnet Counties and 0.25-0.50 inches of freezing rain accumulated across the Austin metropolitan area with lesser amounts in portions of the Hill Country and New Braunfels area. For several days, the cold air mass remained in place across South-Central Texas, but a much colder air mass remained stationary across the Northern Plains. This record-breaking arctic air was able to finally move south into the region late on 14 February and into 15 February as a strong upper level low-pressure system moved through the Southern Plains. As this system moved through the region, snow began to fall and temperatures quickly fell into the single digits and teens. Most areas of South-Central Texas picked up at least an inch of snow with the highest amounts seen from Del Rio and Eagle Pass extending to the northeast into the Austin and San Antonio areas. -
Climatic Information of Western Sahel F
Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Clim. Past Discuss., 10, 3877–3900, 2014 www.clim-past-discuss.net/10/3877/2014/ doi:10.5194/cpd-10-3877-2014 CPD © Author(s) 2014. CC Attribution 3.0 License. 10, 3877–3900, 2014 This discussion paper is/has been under review for the journal Climate of the Past (CP). Climatic information Please refer to the corresponding final paper in CP if available. of Western Sahel V. Millán and Climatic information of Western Sahel F. S. Rodrigo (1535–1793 AD) in original documentary sources Title Page Abstract Introduction V. Millán and F. S. Rodrigo Conclusions References Department of Applied Physics, University of Almería, Carretera de San Urbano, s/n, 04120, Almería, Spain Tables Figures Received: 11 September 2014 – Accepted: 12 September 2014 – Published: 26 September J I 2014 Correspondence to: F. S. Rodrigo ([email protected]) J I Published by Copernicus Publications on behalf of the European Geosciences Union. Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion 3877 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Abstract CPD The Sahel is the semi-arid transition zone between arid Sahara and humid tropical Africa, extending approximately 10–20◦ N from Mauritania in the West to Sudan in the 10, 3877–3900, 2014 East. The African continent, one of the most vulnerable regions to climate change, 5 is subject to frequent droughts and famine. One climate challenge research is to iso- Climatic information late those aspects of climate variability that are natural from those that are related of Western Sahel to human influences. -
Severe Thunderstorms and Tornadoes Toolkit
SEVERE THUNDERSTORMS AND TORNADOES TOOLKIT A planning guide for public health and emergency response professionals WISCONSIN CLIMATE AND HEALTH PROGRAM Bureau of Environmental and Occupational Health dhs.wisconsin.gov/climate | SEPTEMBER 2016 | [email protected] State of Wisconsin | Department of Health Services | Division of Public Health | P-01037 (Rev. 09/2016) 1 CONTENTS Introduction Definitions Guides Guide 1: Tornado Categories Guide 2: Recognizing Tornadoes Guide 3: Planning for Severe Storms Guide 4: Staying Safe in a Tornado Guide 5: Staying Safe in a Thunderstorm Guide 6: Lightning Safety Guide 7: After a Severe Storm or Tornado Guide 8: Straight-Line Winds Safety Guide 9: Talking Points Guide 10: Message Maps Appendices Appendix A: References Appendix B: Additional Resources ACKNOWLEDGEMENTS The Wisconsin Severe Thunderstorms and Tornadoes Toolkit was made possible through funding from cooperative agreement 5UE1/EH001043-02 from the Centers for Disease Control and Prevention (CDC) and the commitment of many individuals at the Wisconsin Department of Health Services (DHS), Bureau of Environmental and Occupational Health (BEOH), who contributed their valuable time and knowledge to its development. Special thanks to: Jeffrey Phillips, RS, Director of the Bureau of Environmental and Occupational Health, DHS Megan Christenson, MS,MPH, Epidemiologist, DHS Stephanie Krueger, Public Health Associate, CDC/ DHS Margaret Thelen, BRACE LTE Angelina Hansen, BRACE LTE For more information, please contact: Colleen Moran, MS, MPH Climate and Health Program Manager Bureau of Environmental and Occupational Health 1 W. Wilson St., Room 150 Madison, WI 53703 [email protected] 608-266-6761 2 INTRODUCTION Purpose The purpose of the Wisconsin Severe Thunderstorms and Tornadoes Toolkit is to provide information to local governments, health departments, and citizens in Wisconsin about preparing for and responding to severe storm events, including tornadoes. -
Marine Litter Legislation: a Toolkit for Policymakers
Marine Litter Legislation: A Toolkit for Policymakers The views expressed in this publication are those of the authors and do not necessarily reflect the views of the United Nations Environment Programme. No use of this publication may be made for resale or any other commercial purpose whatsoever without prior permission in writing from the United Nations Environment Programme. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, DCPI, UNEP, P.O. Box 30552, Nairobi, Kenya. Acknowledgments This report was developed by the Environmental Law Institute (ELI) for the United Nations Environment Programme (UNEP). It was researched, drafted, and produced by Carl Bruch, Kathryn Mengerink, Elana Harrison, Davonne Flanagan, Isabel Carey, Thomas Casey, Meggan Davis, Elizabeth Hessami, Joyce Lombardi, Norka Michel- en, Colin Parts, Lucas Rhodes, Nikita West, and Sofia Yazykova. Within UNEP, Heidi Savelli, Arnold Kreilhuber, and Petter Malvik oversaw the development of the report. The authors express their appreciation to the peer reviewers, including Catherine Ayres, Patricia Beneke, Angela Howe, Ileana Lopez, Lara Ognibene, David Vander Zwaag, and Judith Wehrli. Cover photo: Plastics floating in the ocean The views expressed in this report do not necessarily reflect those of the United Nations Environment Programme. © 2016. United Nations Environment Programme. Marine Litter Legislation: A Toolkit for Policymakers Contents Foreword .................................................................................................. -
Analysis of Lightning and Precipitation Activities in Three Severe Convective Events Based on Doppler Radar and Microwave Radiometer Over the Central China Region
atmosphere Article Analysis of Lightning and Precipitation Activities in Three Severe Convective Events Based on Doppler Radar and Microwave Radiometer over the Central China Region Jing Sun 1, Jian Chai 2, Liang Leng 1,* and Guirong Xu 1 1 Hubei Key Laboratory for Heavy Rain Monitoring and Warning Research, Institute of Heavy Rain, China Meteorological Administration, Wuhan 430205, China; [email protected] (J.S.); [email protected] (G.X.) 2 Hubei Lightning Protecting Center, Wuhan 430074, China; [email protected] * Correspondence: [email protected]; Tel.: +86-27-8180-4905 Received: 27 March 2019; Accepted: 23 May 2019; Published: 1 June 2019 Abstract: Hubei Province Region (HPR), located in Central China, is a concentrated area of severe convective weather. Three severe convective processes occurred in HPR were selected, namely 14–15 May 2015 (Case 1), 6–7 July 2013 (Case 2), and 11–12 September 2014 (Case 3). In order to investigate the differences between the three cases, the temporal and spatial distribution characteristics of cloud–ground lightning (CG) flashes and precipitation, the distribution of radar parameters, and the evolution of cloud environment characteristics (including water vapor (VD), liquid water content (LWC), relative humidity (RH), and temperature) were compared and analyzed by using the data of lightning locator, S-band Doppler radar, ground-based microwave radiometer (MWR), and automatic weather stations (AWS) in this study. The results showed that 80% of the CG flashes had an inverse correlation with the spatial distribution of heavy rainfall, 28.6% of positive CG (+CG) flashes occurred at the center of precipitation (>30 mm), and the percentage was higher than that of negative CG ( CG) − flashes (13%). -
North American Notes
268 NORTH AMERICAN NOTES NORTH AMERICAN NOTES BY KENNETH A. HENDERSON HE year I 967 marked the Centennial celebration of the purchase of Alaska from Russia by the United States and the Centenary of the Articles of Confederation which formed the Canadian provinces into the Dominion of Canada. Thus both Alaska and Canada were in a mood to celebrate, and a part of this celebration was expressed · in an extremely active climbing season both in Alaska and the Yukon, where some of the highest mountains on the continent are located. While much of the officially sponsored mountaineering activity was concentrated in the border mountains between Alaska and the Yukon, there was intense activity all over Alaska as well. More information is now available on the first winter ascent of Mount McKinley mentioned in A.J. 72. 329. The team of eight was inter national in scope, a Frenchman, Swiss, German, Japanese, and New Zealander, the rest Americans. The successful group of three reached the summit on February 28 in typical Alaskan weather, -62° F. and winds of 35-40 knots. On their return they were stormbound at Denali Pass camp, I7,3oo ft. for seven days. For the forty days they were on the mountain temperatures averaged -35° to -40° F. (A.A.J. I6. 2I.) One of the most important attacks on McKinley in the summer of I967 was probably the three-pronged assault on the South face by the three parties under the general direction of Boyd Everett (A.A.J. I6. IO). The fourteen men flew in to the South east fork of the Kahiltna glacier on June 22 and split into three groups for the climbs.