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Rapid Intensification of a Sheared Tropical Storm
OCTOBER 2010 M O L I N A R I A N D V O L L A R O 3869 Rapid Intensification of a Sheared Tropical Storm JOHN MOLINARI AND DAVID VOLLARO Department of Atmospheric and Environmental Sciences, University at Albany, State University of New York, Albany, New York (Manuscript received 10 February 2010, in final form 28 April 2010) ABSTRACT A weak tropical storm (Gabrielle in 2001) experienced a 22-hPa pressure fall in less than 3 h in the presence of 13 m s21 ambient vertical wind shear. A convective cell developed downshear left of the center and moved cyclonically and inward to the 17-km radius during the period of rapid intensification. This cell had one of the most intense 85-GHz scattering signatures ever observed by the Tropical Rainfall Measuring Mission (TRMM). The cell developed at the downwind end of a band in the storm core. Maximum vorticity in the cell exceeded 2.5 3 1022 s21. The cell structure broadly resembled that of a vortical hot tower rather than a supercell. At the time of minimum central pressure, the storm consisted of a strong vortex adjacent to the cell with a radius of maximum winds of about 10 km that exhibited almost no tilt in the vertical. This was surrounded by a broader vortex that tilted approximately left of the ambient shear vector, in a similar direction as the broad precipitation shield. This structure is consistent with the recent results of Riemer et al. The rapid deepening of the storm is attributed to the cell growth within a region of high efficiency of latent heating following the theories of Nolan and Vigh and Schubert. -
Nasa.Gov Determine Their Severity Now Are a Little Less Mysterious
Print Close Related Links January 12, 2004 - (date of web publication) For more information contact: Elvia Thompson A "HOT TOWER" ABOVE THE EYE CAN MAKE HURRICANES Headquarters, Washington STRONGER (Phone: 202/358-1696) They are called hurricanes in the Rob Gutro Atlantic, typhoons in Goddard Space Flight Center, Greenbelt, the West Pacific, Md. and tropical (Phone: 301/286-4044) cyclones worldwide; but wherever these For information about the TRMM Satellite storms roam, the on the Internet, visit: forces that http://trmm.gsfc.nasa.gov determine their http://www.eorc.nasda.go.jp/TRMM severity now are a little less mysterious. NASA scientists, For information about NOAA's National Hurricane Center click here. using data from the Tropical Rainfall For information about Hurricane Measuring Mission Item 1 (TRMM) satellite, Bonnie, click here. have found "hot High resolution image tower" clouds are associated with tropical cyclone intensification. Viewable Images Owen Kelley and John Stout of NASA's Goddard Space Flight Center, Greenbelt, Md., and George Mason University will present their findings at the American Meteorological Society annual meeting in Seattle on Monday, January 12. Caption for Item 1: AN UNUSUALLY DEEP CONVECTIVE TOWER IN Kelley and Stout define a "hot tower" as a rain cloud that reaches at HURRICANE BONNIE AS BONNIE least to the top of the troposphere, the lowest layer of the atmosphere. INTENSIFIED It extends approximately nine miles (14.5 km) high in the tropics. These towers are called "hot" because they rise to such altitude due to This TRMM Precipitation Radar overflight of Hurricane Bonnie shows an 11 mile the large amount of latent heat. -
Statistical Analysis of Sub-Synoptic Meteorological Patterns
ILLINOIS STATE WATER SURVEY ATMOSPHERIC SCIENCES SECTION at the University of Illinois Urbana, Illinois STATISTICAL ANALYSIS OF SUB-SYNOPTIC METEOROLOGICAL PATTERNS by Pieter J. Feteris Principal Investigator Glenn E. Stout Project Director FINAL REPORT National Science Foundation GA-1321 October 15, 1968 CONTENTS Page Introduction 1 Background 1 Objectives 2 Source of data 4 Data editing 4 Problems encountered 8 Acknowledgments 8 Reports written during period of the grants 8 Results of various phases of the work , . 9 Relationships between stability and vertical velocity 9 Influence of windshear on low and medium level convection .... 21 Relationships between synoptic scale flow characteristics and low level circulation patterns 25 Interpretation of the time dependence of the vertical motion field from nephanalyses 34 Feasibility of displaying synoptic data as the time dependence of space averages and standard deviations 40 Summary and conclusions ..... 44 References 46 Appendix A Lightning and rain in relation to sub-synoptic flow parameters, by John W. Wilson and Pieter J. Feteris . 49 Appendix B Computation of kinematic vertical velocities, by Pieter J. Feteris and John W. Wilson 68 Appendix C Synoptic repunch program, by Parker T. Jones III and Robert C. Swaringen 72 INTRODUCTION Background This paper is the last in a series of research reports covering a three-year period during which the National Science Foundation, under Grants GP-5196 and GA-1321, has supported the research. A complete list of reports appears elsewhere in this paper. The first two Progress Reports have dealt mainly with techniques, data preparation, and selected case studies; in this Final Report are presented the results of the past year's efforts. -
Late Holocene Climate Variability in South- Central Chile: a Lacustrine Record of Southern Westerly Wind Dynamics
Late Holocene Climate Variability in South- Central Chile: a Lacustrine Record of Southern Westerly Wind Dynamics. Jonas Vandenberghe ACKNOWLEDGEMENTS First of all, I would like to thanks Prof. Dr. Marc De Batist for the support and supervision of my thesis and for providing this interesting subject as a master thesis project. He was always available for questions and added meaningful corrections and insights on more difficult topics. Special thanks goes to my advisor Willem Vandoorne for his endless support, corrections and answers to my questions in both the lab and during the writing of my thesis. Also I would like to thank other researchers at RCMG especially Maarten and Katrien for very useful explanations and discussions. I am very thankful for the help of all other personel who, directly or indirectly, contributed to this work. Prof. Dr. Eddy Keppens, Leen and Michael from the VUB for their efforts during the carbon and nitrogen isotopic analysis and Rieneke Gielens for her great help with the XRF core scanning at NIOZ. Finally I would like to thank my parents for their support and my girlfriend Celine for coping with me when I was under stress and for providing solutions to all kinds of problems. 1 SAMENVATTING In de laatste decennia was er een opmerkelijke stijging van onderzoek in klimaat reconstructies van de voorbije 1000 jaar. Deze reconstructies moeten een bijdrage leveren aan het begrijpen van de recente klimaatsveranderingen. Klimaatsreconstructies van het laatste millennium kunnen informatie geven over de significantie van deze stijgende trend, de oorzaak van de opwarming en de invloed ervan op andere omgeveingsmechanismes op Aarde. -
Thesis Latent Heating and Mixing Due to Entrainment In
THESIS LATENT HEATING AND MIXING DUE TO ENTRAINMENT IN TROPICAL DEEP CONVECTION Submitted by Clayton J. McGee Department of Atmospheric Science In partial fulfillment of the requirements For the Degree of Master of Science Colorado State University Fort Collins, Colorado Spring 2013 Master’s Committee: Advisor: Susan van den Heever Eric Maloney Richard Eykholt ABSTRACT LATENT HEATING AND MIXING DUE TO ENTRAINMENT IN TROPICAL DEEP CONVECTION Recent studies have noted the role of latent heating above the freezing level in reconciling Riehl and Malkus' Hot Tower Hypothesis (HTH) with evidence of diluted tropical deep convective cores. This study evaluates recent modifications to the HTH through Lagrangian trajectory analysis of deep convective cores in an idealized, high-resolution cloud-resolving model (CRM) simulation. A line of tropical convective cells develops within a high-resolution nested grid whose boundary conditions are obtained from a large-domain CRM simulation approaching radiative-convective equilibrium (RCE). Microphysical impacts on latent heating and equivalent potential temperature (!e) are analyzed along trajectories ascending within convective regions of the high-resolution nested grid. Changes in !e along backward trajectories are partitioned into contributions from latent heating due to ice processes and a residual term. This residual term is composed of radiation and mixing. Due to the small magnitude of radiative heating rates in the convective inflow regions and updrafts examined here, the residual term is treated as an approximate representation of mixing within these regions. The simulations demonstrate that mixing with dry air decreases !e along ascending trajectories below the freezing level, while latent heating due to freezing and vapor deposition increase !e above the freezing level. -
Latent Heating and Mixing Due to Entrainment in Tropical Deep Convection
816 JOURNAL OF THE ATMOSPHERIC SCIENCES VOLUME 71 Latent Heating and Mixing due to Entrainment in Tropical Deep Convection CLAYTON J. MCGEE AND SUSAN C. VAN DEN HEEVER Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado (Manuscript received 13 May 2013, in final form 31 July 2013) ABSTRACT Recent studies have noted the role of latent heating above the freezing level in reconciling Riehl and Malkus’ hot tower hypothesis (HTH) with evidence of diluted tropical deep convective cores. This study evaluates recent modifications to the HTH through Lagrangian trajectory analysis of deep convective cores in an idealized, high-resolution cloud-resolving model (CRM) simulation that uses a sophisticated two-moment microphysical scheme. A line of tropical convective cells develops within a finer nested grid whose boundary conditions are obtained from a large-domain CRM simulation approaching radiative convective equilibrium (RCE). Microphysical impacts on latent heating and equivalent potential temperature (ue) are analyzed along trajectories ascending within convective regions of the high-resolution nested grid. Changes in ue along backward trajectories are partitioned into contributions from latent heating due to ice processes and a re- sidual term that is shown to be an approximate representation of mixing. The simulations demonstrate that mixing with dry environmental air decreases ue along ascending trajectories below the freezing level, while latent heating due to freezing and vapor deposition increase ue above the freezing level. Latent heating contributions along trajectories from cloud nucleation, condensation, evaporation, freezing, deposition, and sublimation are also quantified. Finally, the source regions of trajectories reaching the upper troposphere are identified. -
Convective Towers in Eyewalls of Tropical Cyclones Observed by the Trmm Precipitation Radar in 1998–2001
P1.43 CONVECTIVE TOWERS IN EYEWALLS OF TROPICAL CYCLONES OBSERVED BY THE TRMM PRECIPITATION RADAR IN 1998–2001 Owen A. Kelley* and John Stout TRMM Science Data and Information System, NASA Goddard, Greenbelt, Maryland Center for Earth Observation and Space Research, George Mason University, Fairfax, Virginia Abstract—The Precipitation Radar of the Tropical cyclone. In the mid-1960s, the mesoscale structure Rainfall Measuring Mission (TRMM) is the first surrounding convective towers became a topic of space-borne radar that is capable of resolving the research (Malkus and Riehl 1964). Since the 1980s, detailed vertical structure of convective towers. one mesoscale structure in particular has been studied: During 1998 to 2001, the Precipitation Radar convective bursts, which include multiple convective overflew approximately one hundred tropical towers (Steranka et al. 1986; Rodgers et al. 2000; cyclones and observed their eyewalls. Many Heymsfield et al. 2001). Most papers about convective eyewalls had one or more convective towers in towers and convective bursts are descriptive. In them, especially the eyewalls of intensifying contrast, only a few papers attempted to be predictive, cyclones. A convective tower in an eyewall is such as showing how a convective tower or burst most likely to be associated with cyclone intensi- contributes to tropical cyclone formation (Simpson et al. fication if the tower has a precipitation rate of 2 1998) or intensification (Steranka et al. 1986). mm/h at or above an altitude of 14 km. Alterna- Before the 1997 launch of the Tropical Rainfall tively, the tower can have a 20 dBZ radar reflec- Measuring Mission (TRMM), no dataset existed that tivity at or above 14.5 km. -
Fireline Leadership in the Brave New World of Weather Modification & Modern Wildland Fire Behavior
FIRELINE LEADERSHIP IN THE BRAVE NEW WORLD OF WEATHER MODIFICATION & MODERN WILDLAND FIRE BEHAVIOR Keep Informed on Fire Weather Conditions and Obtain Forecasts Base All Actions on Current and Expected Fire Behavior Unfamiliar with Weather and Local Factors Influencing Fire Behavior LEARNING NEW INDICATORS Fred J. Schoeffler Sheff, LLC January 2008 INTRODUCTION It’s almost ten years ago to the day that I wrote a similar paper and made a similar presentation to my esteemed Hot Shot colleagues. My goal is to hopefully educate you all about a very real, very disturbing phenomenon occurring worldwide on a daily basis. In fact NOAA readily admits to over fifty (50) on-going Weather Modification projects occurring in the United States today. This doesn’t include what “The Government,” the military, and…(others)…are doing. Weather Modification affects us all. I bet it’s safe to say you often look at clouds and think they look artificial or you just know they are not real. The very first Fire Order is “Keep Informed on Fire Weather Conditions and Forecasts.” So by extension, Weather Modification affects us as Fireline Supervisors, because weather influences fire behavior. The most unpredictable element of weather is, of course, the wind. Many of the Weather Modification projects radically affect the wind, especially HAARP, so much of the following information is about other weather and the new indicators you’ll need to watch for. And please note that not all the information presented in this paper deals with “weather modification,” per se. My goal is to show you, among other things, what indicators to look for – in the clouds and in the smoke columns. -
Downloaded 09/30/21 07:50 AM UTC 668 JOURNAL of the ATMOSPHERIC SCIENCES VOLUME 66
MARCH 2009 K U M J I A N A N D R Y Z H K O V 667 Storm-Relative Helicity Revealed from Polarimetric Radar Measurements MATTHEW R. KUMJIAN AND ALEXANDER V. RYZHKOV Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma, and NOAA/OAR/National Severe Storms Laboratory, Norman, Oklahoma (Manuscript received 14 April 2008, in final form 27 August 2008) ABSTRACT The dual-polarization radar variables are especially sensitive to the microphysical processes of melting and size sorting of precipitation particles. In deep convective storms, polarimetric measurements of such processes can provide information about the airflow in and around the storm that may be used to elucidate storm behavior and evolution. Size sorting mechanisms include differential sedimentation, vertical transport, strong rotation, and wind shear. In particular, winds that veer with increasing height typical of supercell environments cause size sorting that is manifested as an enhancement of differential reflectivity (ZDR) along the right or inflow edge of the forward-flank downdraft precipitation echo, which has been called the ZDR arc signature. In some cases, this shear profile can be augmented by the storm inflow. It is argued that the magnitude of this enhancement is related to the low-level storm-relative environmental helicity (SRH) in the storm inflow. To test this hypothesis, a simple numerical model is constructed that calculates trajectories for raindrops based on their individual sizes, which allows size sorting to occur. The modeling results indicate a strong positive correlation between the maximum ZDR in the arc signature and the low-level SRH, regardless of the initial drop size distribution aloft. -
A Vortical Hot Tower Route to Tropical Cyclogenesis
JANUARY 2006 M ONTGOMERY ET AL. 355 A Vortical Hot Tower Route to Tropical Cyclogenesis M. T. MONTGOMERY,M.E.NICHOLLS,T.A.CRAM, AND A. B. SAUNDERS Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado (Manuscript received 5 December 2003, in final form 22 February 2005) ABSTRACT A nonhydrostatic cloud model is used to examine the thermomechanics of tropical cyclogenesis under realistic meteorological conditions. Observations motivate the focus on the problem of how a midtropo- spheric cyclonic vortex, a frequent by-product of mesoscale convective systems during summertime condi- tions over tropical oceans, may be transformed into a surface-concentrated (warm core) tropical depression. As a first step, the vortex transformation is studied in the absence of vertical wind shear or zonal flow. Within the cyclonic vorticity-rich environment of the mesoscale convective vortex (MCV) embryo, the simulations demonstrate that small-scale cumulonimbus towers possessing intense cyclonic vorticity in their cores [vortical hot towers (VHTs)] emerge as the preferred coherent structures. The VHTs acquire their vertical vorticity through a combination of tilting of MCV horizontal vorticity and stretching of MCV and VHT-generated vertical vorticity. Horizontally localized and exhibiting convective lifetimes on the order of 1 h, VHTs overcome the generally adverse effects of downdrafts by consuming convective available po- tential energy in their local environment, humidifying the middle and upper troposphere, and undergoing diabatic vortex merger with neighboring towers. During metamorphosis, the VHTs vortically prime the mesoscale environment and collectively mimic a quasi-steady diabatic heating rate within the MCV embryo. A quasi-balanced toroidal (transverse) circu- lation develops on the system scale that converges cyclonic vorticity of the initial MCV and small-scale vorticity anomalies generated by subsequent tower activity. -
Educator's Guide
Christenberry Planetarium Educator’s Guide ALABAMA SKIES Credit: Hubble Telescope INSIDE: www.samford.edu/departments/planetarium/ • Connections to Education Standards • Preparation Questions • Solar System Breakdown • Synopsis • Glossary of Terms • Classroom Activities 1 Table of Contents FOR THE EDUCATOR Connections to Education Standards…………………….………………….. 2 BEFORE THE SHOW Preparation Questions………………………………………………………… 3 Solar System Breakdown……………………………………………………… 4 AFTER THE SHOW Synopsis…………………………………………………………………………. 6 Classroom Activities……...………………………………………..………..…. 8 Glossary of Terms………………………………………………………………12 Online Resources……………………………………………………………….13 2 Connections to Education Standards Below you will find the national education content standards that we explore in our presentation: NATIONAL EDUCATION CONTENT STANDARDS GRADE CONTENT STANDARD All: Science as a human endeavor K – 4: Objects in the sky Changes in the earth and sky 5 – 8: Motion and forces Earth in the solar system 9 – 12: Motion and forces Interactions of energy and matter Credit: Andrew C. Freeman 3 Preparation Questions What is a Solar System? A solar system is a collection of the planets and their moons in orbit around a star (in our case, the sun). It also includes smaller bodies in the forms of asteroids, meteoroids, comets, and dwarf planets. What is a Galaxy? A system of billions or even trillions of stars along with planets, interstellar Credit: Andrew C. Freeman clouds of gas and dust, and dark matter all held together by gravitational What is the Milky Way? attraction. There are three kinds of galaxies: elliptical, spiral, and irregular. The Milky Way is a barred spiral galaxy that houses our solar system along with How Many Galaxies are There? 100-400 billion stars and at least the There are countless galaxies in the same number of planets. -
1 Orographic Effects on Supercell: Development and Structure
Orographic Effects on Supercell: Development and Structure, Intensity and Tracking Galen M. Smith1, Yuh-Lang Lin1,2,@, and Yevgenii Rastigejev1,3 1Department of Energy and Environmental Systems 2Department of Physics 3Department of Mathematics North Carolina A&T State University March 1, 2016 @Corresponding Author Address: Dr. Yuh-Lang Lin, 302H Gibbs Hall, EES, North Carolina A&T State University, 1601 E. Market St., Greensboro, NC 27411. Email: [email protected]. Web: http://mesolab.ncat.edu Abstract Orographic effects on tornadic supercell development, propagation, and structure are investigated using Cloud Model 1 (CM1) with idealized bell-shaped mountains of various heights and a homogeneous fluid flow with a single sounding. It is found that blocking effects are dominative compared to the terrain-induced environmental heterogeneity downwind of the mountain. The orographic effect shifted the track of the storm towards the the left of storm motion, particularly on the lee side of the mountain, when compared to the track in the case with no mountain. The terrain blocking effect also enhanced the supercells inflow, which was increased more than one hour before the storm approached the terrain peak. This allowed the central region of the storm to exhibit clouds with a greater density of hydrometeors than the control. Moreover, the enhanced inflow increased the areal extent of the supercells precipitation, which, in turn enhanced the cold pool outflow serving to enhance the storm’s updraft until becoming strong enough to undercut and weaken the storm considerably. Another aspect of the orographic effects is that down slope winds produced or enhanced low-level vertical vorticity directly under the updraft when the storm approached the mountain peak.