DOCSLIB.ORG

Revival of a Mid-Latitude Explosive Cyclone Calvin A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Revival of a Mid-Latitude Explosive Cyclone Calvin A Meteorology Senior Theses Undergraduate Theses and Capstone Projects 12-1-2017 Climatology of an Explosive Cyclone: Revival of a Mid-Latitude Explosive Cyclone Calvin A. Chaffin Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/mteor_stheses Part of the Meteorology Commons Recommended Citation Chaffin,alv C in A., "Climatology of an Explosive Cyclone: Revival of a Mid-Latitude Explosive Cyclone" (2017). Meteorology Senior Theses. 22. https://lib.dr.iastate.edu/mteor_stheses/22 This Dissertation/Thesis is brought to you for free and open access by the Undergraduate Theses and Capstone Projects at Iowa State University Digital Repository. It has been accepted for inclusion in Meteorology Senior Theses by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Climatology of an Explosive Cyclone: Revival of a Mid-Latitude Explosive Cyclone Calvin A. Chaffin Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa Dr. Mike Chen – Mentor Professor of Geological and Atmospheric Sciences, Dynamic Meteorology Amanda Black – Co-mentor Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa Abstract In 1980, Frederick Sanders and John Gyakum classified the maritime cold season rapidly deepening low pressure system as an explosive cyclone due in part to its intense “bombing” nature. Ever since this phenomenon has been discovered, there have been many, papers, books, and lectures covering the mysterious anomaly. Many scientists attribute the behavior of this weather anomaly to baroclinicity. Baroclinicity is most often conjuncted with vertical shear caused by horizontal temperature gradient leading to the thermal wind in the mean flow. Baroclinicity, coupled with the upper level trough will lead to cyclonic circulation, leading to further amplification of the aloft disturbance, which leads to further intensification. However, not all researchers agree with this theory and suggest that other mechanisms are the cause of this phenomenon. By manually tracking explosively developing low pressure systems through means of NCEP surface analysis charts and OPC products, we are able to determine the forcings behind the low. A key identifier in determining these forcings is whether or not they re-intensify after the initial cyclone decays, leaving behind a residual low that continues to propagate until it redevelops or dissipates entirely. This tells us that baroclinic instability is not involved here and that other forcings are the cause of this intensification. In this study 33 cases of explosive cyclogenesis were collected and analyzed, coming up with 2 cases of reintensification. A revival case and a dissipation case were compared in order to determine what exactly caused on case to dissipate and another to reintensify so long into its life. _____________________________________________________________________________ 1. Introduction & Background varies at latitudes between 12 mb/day at the In 1980, two researchers, Frederick lowest, towards the equator, and up to 28 Sanders and John R. Gyakum, defined a mb/day at the highest around the North Pole rapidly deepening cyclone that dropped 24 (Sanders and Gyakum 1980). Due to the mb over 24 hours (or an average rate of 1 behavior of this rapidly deepening low Bergeron) as an explosive cyclone. The rate pressure system, the phenomenon was at which this explosive deepening is defined properly named the meteorological “bomb” due to its sudden, explosive nature. 1 Seasonally, explosive cyclones are a baroclinicty near the coast of the Atlantic is primarily winter occurrence, however, there near the Gulf Stream. Sea level are other cases of explosive cyclogenesis temperatures were observed, measured, and occurring during other periods. compared to the colder air temperatures Additionally, this phenomena is an almost coming off the coast. These measurements exclusively maritime event, being found in were taken between 15 and 38 degrees many places around the globe at mid- latitude, which is around the Eastern United latitudes including the Northern Pacific States coast (Broccoli and Manabe 1992). Ocean (NPO), Northern Atlantic Ocean The results of this study revealed to us that (NAO), and the Norwegian Sea, just to the pre-storm baroclinic disturbance was name a few. Many researchers have linked to the formation of cyclones just off contributed this to baroclinicity, otherwise the coast of North Carolina and Virginia. known as baroclinic instability(Wang and This relationship doesnt mean that any Rogers 2000). Baroclinic waves are caused cyclones formed will be stronger (Cione et by a balance of static stability and tropical al. 1998). effect stability along with vertical wind Baroclinicity does not just here are shear. Regions of baroclinicity are defined other factors that lead to explosive by polar jets, frontal boundaries indicating cyclonegenesis. Fu et al. (2014) suggests temperature advections, and density that Latent Heat Release (LHR) played an gradients increasing with height important role in a case involving two stage (Pierrehumbert 1984). In order to look at explosive cyclonegenesis development. this we must first track an explosively During the first stage LHR acted against the convective cyclone as it propagates off of intensification of the low pressure system, the Northern Pacific Ocean and reaches its along with the characteristics of dissipation stage defined by Cyclolysis. precipitation such as the intensity, precip Cyclolysis is a process of decay that occurs center, etc. During the second stage when the cold air coming from behind a development, upper level potential vorticity cyclone has overtaken the inflow of warm, forcings were found to play an important moist air, leading it to deteriorate. The role in the development of the explosive process of cyclolysis is most often ignored cyclone. Similarly, in a separate study in most research regarding explosive conducted by Kuwano-Yushida and Asuma cyclones, however it has become an area of (2008), found that latent heat release played interest to some researchers (Grauman et al. an important role in the formation of 2001). cyclones as they affect upper level jets. This Formation was done by studying a control case then removing any latent heat release in the If we take a look over the Atlantic, atmosphere via a “dry run”, results showed we see that the likelihood of an explosively a significant decrease in the disturbance of deepening event increases with the presence upper level jets which led to a decrease in of pre-storm destabilization. Pre-storm the likelihood of formation. A study destabilization is when low level 2 conducted by Riviere and Joly (2005) set attempting to track the residual low of an out to explore the effect Low Frequency already explosively deepened mid-latitude Deformation field has on explosive cyclone to see if it re-intensifies after it has cyclones. Their study concluded that under decayed. If it does re-develop then we will specific spatial restraints, convergence can analyze it to determine whether or not be effected by deformation when upper level baroclinic instability is the primary jets exist over baroclinic regions. When this mechanism. occurs the surface cyclone can intensely 2.Data interact with the upper level disturbances leading to an explosive growth in the Region cyclone. For the focus of this research thesis, Hypothesis and Research Question the regions that will be focused on will be the North Pacific Ocean (NPO), the Despite the abundance of cases over Contiguous United States (CONUS), and the the many years of research, the mechanisms North Atlantic Ocean (NAO). These regions have been chosen for the frequent amount of that contributed to explosive deepening of cyclones and explosive cyclones they mid-latitude cyclones are still very much produce. The NPO was selected for the disputed today. Many researchers believe main region of focus due to its frequent that regions of baroclinicity were output of explosive cyclones, therefore, we responsible for the rapid deepening, used it as the origin for our cases we found. however, not all cases could be explained by This is because the Taiwanese lows this. Other explanations for this rapid propagating out of the South China sea are able to create these explosive lows that form deepening have been proposed, including over the NPO. Additionally, the interannual the location of upper and lower level jets variability of El Nino events, warm water coordinating with one another to create anomalies propogated up into the NPO cyclonic circulation. (Fu et al. (2014), where the colder Sea Surface Temperatures Kuwano and Yashida (2008)). Then, if (SST) resided and led to explosive cyclone baroclinic environments only account for a genesis during the cold season. The natural minority of the explosive cyclones oscillation of El Nino events over this region has led to the increased frequency of these developed, then there must be other forcings events (Chen et al. 1991). Some important responsible for this. In this research paper regions where cyclone genesis occurs are we will be looking to see if baroclinic from the east side of Japan, to just south of instability is the primary mechanism behind Alaska, however, explosive cyclone genesis the genesis of explosive cyclones. To look occurs primarily south of 50 degrees North into this we will be tracking, observing, and over the NPO (Gyakum
Load more

Recommended publications
  • Surface Cyclolysis in the North Pacific Ocean. Part I
    748 MONTHLY WEATHER REVIEW VOLUME 129 Surface Cyclolysis in the North Paci®c Ocean. Part I: A Synoptic Climatology JONATHAN E. MARTIN,RHETT D. GRAUMAN, AND NATHAN MARSILI Department of Atmospheric and Oceanic Sciences, University of WisconsinÐMadison, Madison, Wisconsin (Manuscript received 20 January 2000, in ®nal form 16 August 2000) ABSTRACT A continuous 11-yr sample of extratropical cyclones in the North Paci®c Ocean is used to construct a synoptic climatology of surface cyclolysis in the region. The analysis concentrates on the small population of all decaying cyclones that experience at least one 12-h period in which the sea level pressure increases by 9 hPa or more. Such periods are de®ned as threshold ®lling periods (TFPs). A subset of TFPs, referred to as rapid cyclolysis periods (RCPs), characterized by sea level pressure increases of at least 12 hPa in 12 h, is also considered. The geographical distribution, spectrum of decay rates, and the interannual variability in the number of TFP and RCP cyclones are presented. The Gulf of Alaska and Paci®c Northwest are found to be primary regions for moderate to rapid cyclolysis with a secondary frequency maximum in the Bering Sea. Moderate to rapid cyclolysis is found to be predominantly a cold season phenomena most likely to occur in a cyclone with an initially low sea level pressure minimum. The number of TFP±RCP cyclones in the North Paci®c basin in a given year is fairly well correlated with the phase of the El NinÄo±Southern Oscillation (ENSO) as measured by the multivariate ENSO index.
    [Show full text]
  • Predictability of Explosive Cyclogenesis Over the Northwestern Pacific Region Using Ensemble Reanalysis
    NOVEMBER 2013 K U W A N O - Y O S H I D A A N D E N O M O T O 3769 Predictability of Explosive Cyclogenesis over the Northwestern Pacific Region Using Ensemble Reanalysis AKIRA KUWANO-YOSHIDA Earth Simulator Center, Japan Agency for Marine-Earth Science and Technology, Yokohama, Kanagawa, Japan TAKESHI ENOMOTO Disaster Prevention Research Institute, Kyoto University, Uji, Kyoto, Japan (Manuscript received 1 June 2012, in final form 24 May 2013) ABSTRACT The predictability of explosive cyclones over the northwestern Pacific region is investigated using an en- semble reanalysis dataset. Explosive cyclones are categorized into two types according to whether the region of the most rapid development is in the Sea of Okhotsk or Sea of Japan (OJ) or in the northwestern Pacific Ocean (PO). Cyclone-relative composite analyses are performed for analysis increments (the differences between the analysis and the 6-h forecast) and ensemble spreads (the standard deviations of ensemble members of the analysis or first guess) at the time of the maximum deepening rate. The increment composite shows that the OJ explosive cyclone center is forecast too far north compared to the analyzed center, whereas the PO explosive cyclone is forecast shallower than the analyzed center. To understand the cause of these biases, a diagnosis of the increment using the Zwack–Okossi (Z-O) development equation is conducted. The results suggest that the increment characteristics of both the OJ and PO explosive cyclones are associated with the most important cyclone development mechanisms. The OJ explosive cyclone forecast error is related to a deeper upper trough, whereas the PO explosive cyclone error is related to weaker latent heat release in the model.
    [Show full text]
  • Piecewise Potential Vorticity Diagnosis of a Rapid Cyclolysis Event
    1264 MONTHLY WEATHER REVIEW VOLUME 130 Surface Cyclolysis in the North Paci®c Ocean. Part II: Piecewise Potential Vorticity Diagnosis of a Rapid Cyclolysis Event JONATHAN E. MARTIN AND NATHAN MARSILI Department of Atmospheric and Oceanic Sciences, University of WisconsinÐMadison, Madison, Wisconsin (Manuscript received 19 March 2001, in ®nal form 26 October 2001) ABSTRACT Employing output from a successful numerical simulation, piecewise potential vorticity inversion is used to diagnose a rapid surface cyclolysis event that occurred south of the Aleutian Islands in late October 1996. The sea level pressure minimum of the decaying cyclone rose 35 hPa in 36 h as its associated upper-tropospheric wave quickly acquired a positive tilt while undergoing a rapid transformation from a nearly circular to a linear morphology. The inversion results demonstrate that the upper-tropospheric potential vorticity (PV) anomaly exerted the greatest control over the evolution of the lower-tropospheric height ®eld associated with the cyclone. A portion of the signi®cant height rises that characterized this event was directly associated with a diminution of the upper-tropospheric PV anomaly that resulted from negative PV advection by the full wind. This forcing has a clear parallel in more traditional synoptic/dynamic perspectives on lower-tropospheric development, which emphasize differential vorticity advection. Additional height rises resulted from promotion of increased anisotropy in the upper-tropospheric PV anomaly by upper-tropospheric deformation in the vicinity of a southwesterly jet streak. As the PV anomaly was thinned and elongated by the deformation, its associated geopotential height perturbation decreased throughout the troposphere in what is termed here PV attenuation.
    [Show full text]
  • Explosive Cyclogenesis: a Global Climatology Comparing Multiple Reanalyses
    6468 JOURNAL OF CLIMATE VOLUME 23 Explosive Cyclogenesis: A Global Climatology Comparing Multiple Reanalyses JOHN T. ALLEN,ALEXANDRE B. PEZZA, AND MITCHELL T. BLACK The University of Melbourne, Melbourne, Victoria, Australia (Manuscript received 17 September 2009, in final form 23 August 2010) ABSTRACT A global climatology for rapid cyclone intensification has been produced from the second NCEP reanalysis (NCEP2), the 25-yr Japanese Reanalysis (JRA-25), and the ECMWF reanalyses over the period 1979–2008. An improved (combined) criterion for identifying explosive cyclones has been developed based on preexisting definitions, offering a more balanced, normalized climatological distribution. The combined definition was found to significantly alter the population of explosive cyclones, with a reduction in ‘‘artificial’’ systems, which are found to compose 20% of the population determined by earlier definitions. Seasonally, winter was found to be the dominant formative period in both hemispheres, with a lower degree of interseasonal variability in the Southern Hemisphere (SH). Considered over the period 1979–2008, little change is observed in the frequency of systems outside of natural interannual variability in either hemisphere. Significant statistical differences have been found between reanalyses in the SH, while in contrast the Northern Hemisphere (NH) was characterized by strong positive correlations between reanalyses in almost all examined cases. Spatially, explosive cyclones are distributed into several distinct regions, with two regions in the northwest Pacific and the North Atlantic in the NH and three main regions in the SH. High-resolution and modern reanalysis data were also found to increase the climatology population of rapidly intensifying systems. This indicates that the reanalyses have apparently undergone increasing improvements in consistency over time, particularly in the SH.
    [Show full text]
  • The Effects of Diabatic Heating on Upper
    THE EFFECTS OF DIABATIC HEATING ON UPPER- TROPOSPHERIC ANTICYCLOGENESIS by Ross A. Lazear A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science (Atmospheric and Oceanic Sciences) at the UNIVERSITY OF WISCONSIN - MADISON 2007 i Abstract The role of diabatic heating in the development and maintenance of persistent, upper- tropospheric, large-scale anticyclonic anomalies in the subtropics (subtropical gyres) and middle latitudes (blocking highs) is investigated from the perspective of potential vorticity (PV) non-conservation. The low PV within blocking anticyclones is related to condensational heating within strengthening upstream synoptic-scale systems. Additionally, the associated convective outflow from tropical cyclones (TCs) is shown to build upper- tropospheric, subtropical anticyclones. Not only do both of these large-scale flow phenomena have an impact on the structure and dynamics of neighboring weather systems, and consequently the day-to-day weather, the very persistence of these anticyclones means that they have a profound influence on the seasonal climate of the regions in which they exist. A blocking index based on the meridional reversal of potential temperature on the dynamic tropopause is used to identify cases of wintertime blocking in the North Atlantic from 2000-2007. Two specific cases of blocking are analyzed, one event from February 1983, and another identified using the index, from January 2007. Parallel numerical simulations of these blocking events, differing only in one simulation’s neglect of the effects of latent heating of condensation (a “fake dry” run), illustrate the importance of latent heating in the amplification and wave-breaking of both blocking events.
    [Show full text]
  • A Review of Convective and Artificial Vortices for Power Generation
    A.T. Mustafa et al., Int. J. Sus. Dev. Plann. Vol. 10, No. 5 (2015) 650–665 A REVIEW OF CONVECTIVE AND ARTIFICIAL VORTICES FOR POWER GENERATION A.T. MUSTAFA, H.H. AL-KAYIEM & S.I.U. GILANI Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Malaysia 31750 Tronoh, Perak, Malaysia. ABSTRACT Thermal energy transfer in the atmosphere occurs from a high temperature zone to a low one by means of convective vortices where mechanical energy is produced. There are two ways of driving vertical flow in the core of a vortex: (1) by the direct action of buoyancy acting on hot air and (2) by producing a vertical pressure gradient along the axis of a vortex because of core development involving the lateral spread of the vortex with height. In particular, it indicates that the intensity of convective vortices depends on the depth of the convec- tive layer via thermodynamic efficiency, the enthalpy perturbation across them, and the existence of sources of vorticity. The atmospheric vortex engine (AVE) is a device for producing an artificial vortex. The operation of AVE is based on the fact that the atmosphere is heated from the bottom and cooled at the top. By artificial vortex generation, it is aimed to eliminate the physical solar updraft tower and reduce the capital cost of solar chimney power plants. This paper reviews natural convective vortices and vortex creation via physical prin- ciples of vortex generation. Vortex analysis and modelling are presented. Furthermore, a new model of a solar vortex engine (SVE) is proposed and discussed. An idea on utilizing the solar energy as the heat source for establishing the vortex and operating the SVE model is adopted.
    [Show full text]
  • The Rapid Growth and Decay of an Extratropical Cyclone Over the Central Paci®C Ocean
    358 WEATHER AND FORECASTING VOLUME 19 The Rapid Growth and Decay of an Extratropical Cyclone over the Central Paci®c Ocean JONATHAN E. MARTIN Department of Atmospheric and Oceanic Sciences, University of WisconsinÐMadison, Madison, Wisconsin JASON A. OTKIN Cooperative Institute for Meteorological Satellite Studies, Space Science and Engineering Center, University of WisconsinÐMadison, Madison, Wisconsin (Manuscript received 22 April 2003, in ®nal form 6 November 2003) ABSTRACT The life cycle of a central Paci®c cyclone, characterized by a 48-h interval of rapid ¯uctuation in its intensity, is examined. The cyclone of interest underwent a period of explosive cyclogenesis from 1200 UTC 4 November to 1200 UTC 5 November 1986, followed 12 h later by a period of unusually rapid decay. Output from a numerical simulation of this event, run using the ®fth-generation Pennsylvania State University±National Center for Atmospheric Research (PSU±NCAR) Mesoscale Model (MM5), is used to perform a piecewise potential vorticity (PV) inversion in order to diagnose the life cycle of this unusual cyclone. The analysis reveals that the presence of lower-tropospheric frontogenetic forcing in an environment char- acterized by reduced static stability (as measured by high values of the K index) produced a burst of heavy precipitation during the development stage of the cyclone's life cycle. The associated latent heat release produced a substantial diabatic PV anomaly in the middle troposphere that was, in turn, responsible for the majority of the lower-tropospheric height falls associated with the explosive cyclogenesis. Subsequent height rises during the rapid cyclolysis stage resulted from the northward migration of the surface cyclone into a perturbation geopotential ridge associated with a negative tropopause-level PV anomaly.
    [Show full text]
  • Absorption Abyssal Circulation Acoustic Measurements/Effects
    1 Absorption 2 Abyssal circulation 3 Acoustic measurements/effects 4 Adaptation 5 Adaptive models 6 Advection 7 Aerosols/particulates 8 Aerosol hygroscopicity 9 Aerosol indirect effect 10 Aerosol nucleation 11 Aerosol optical properties 12 Aerosol radiative effect 13 Aerosol-cloud interaction 14 Africa 15 Ageostrophic circulations 16 Agriculture 17 Air pollution 18 Air quality 19 Air quality and climate 20 Air quality and health 21 Air quality forecasts 22 Air quality trends 23 Aircraft observations 24 Airflow 25 Airshed modeling 26 Air-sea interaction 27 Albedo 28 Algorithms 29 Altimetry 30 Amazon region 31 Anelastic models 32 Angular momentum 33 Animal studies 34 Annual variations 35 Annular mode 36 Anomalies 37 Antarctic Oscillation 38 Antarctica 39 Anthropogenic effects/forcing 40 Anticyclones 41 Aqueous-phase chemistry 42 Arctic 43 Arctic Oscillation 44 Artificial intelligence 45 Asia 46 Asymmetry 47 Atlantic Ocean 48 Atmosphere 49 Atmosphere-land interaction 50 Atmosphere-ocean interaction 51 Atmospheric circulation 52 Atmospheric composition 53 Atmospheric electricity 54 Atmospheric oxidation 55 Atmospheric river 56 Australia 57 Automated systems 58 Automatic weather stations 59 Baroclinic flows 60 Baroclinic models 61 Barotropic flows 62 Bayesian methods 63 Behavioral models 64 Bias 65 Biennial oscillation 66 Biofouling 67 Biomass burning 68 Biosphere emissions 69 Biosphere-atmosphere interactions 70 Blocking 71 Boreal meteorology 72 Bottom currents/bottom water 73 Boundary conditions 74 Boundary currents 75 Boundary layer 76
    [Show full text]
  • Extreme Wet Seasons – Their Definition and Relationship with Synoptic-Scale
    Weather Clim. Dynam., 2, 71–88, 2021 https://doi.org/10.5194/wcd-2-71-2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Extreme wet seasons – their definition and relationship with synoptic-scale weather systems Emmanouil Flaounas, Matthias Röthlisberger, Maxi Boettcher, Michael Sprenger, and Heini Wernli Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland Correspondence: Emmanouil Flaounas (emmanouil.fl[email protected]) Received: 30 June 2020 – Discussion started: 8 July 2020 Revised: 24 December 2020 – Accepted: 13 January 2021 – Published: 1 February 2021 Abstract. An extreme aggregation of precipitation on the But interlatitudinal influences are also shown to be impor- seasonal timescale, leading to a so-called extreme wet sea- tant: tropical moisture exports, i.e., the poleward transport son, can have substantial environmental and socio-economic of tropical moisture, can contribute to extreme wet seasons impacts. This study has a twofold aim: first to identify and in the midlatitudes, while breaking Rossby waves, i.e., the statistically characterize extreme wet seasons around the equatorward intrusion of stratospheric air, may decisively globe and second to elucidate their relationship with specific contribute to the formation of extreme wet seasons in the weather systems. tropics. Three illustrative examples provide insight into the Extreme wet seasons are defined independently at every synergetic effects of the four identified weather systems on grid point of ERA-Interim reanalyses as the consecutive 90 d the formation of extreme wet seasons in the midlatitudes, the period with the highest accumulated precipitation in the 40- Arctic and the (sub)tropics.
    [Show full text]
  • The Atmosphere Geog0005
    DEPARTMENT OF GEOGRAPHY The Atmosphere Geog0005 Dr Eloise Marais • Associate Professor in Physical Geography • Atmospheric chemistry modelling • Air quality and human health • Human influence on the atmosphere The Atmosphere • Lecture 1: Weather • Lecture 2: Climate • Lecture 3: Climate Change DEPARTMENT OF GEOGRAPHY Weather Earth geog0005 Weather • Weather is: – the instantaneous state of the atmosphere – We will focus on Earth’s weather (there is also space weather) – what we experience on a daily basis • Type of weather depends on location – latitude, altitude, terrain, water bodies • Climate is long-term average weather Atmospheric Layers Troposphere: Where Earth’s weather occurs ASIDE Key physical concepts Atmospheric Pressure gravitational constant (10 m/s2) Pressure P = ρgh height above surface (m) (Pa, kg/ms2) air density (kg/m3) • Measured in millibars (mb) – 1 mb = 100 Pa = 1 hPa – Average sea level pressure is 1013 mb • Air density decreases with altitude – Most air molecules held tightly to surface (gravity) – Pressure decreases with altitude Reference Frames • A reference frame describes where we look at dynamics from • But the reference frame is moving too (due to Earth’s rotation). This is termed a non-inertial reference frame • Objects in the Earth’s reference frame experience virtual forces related to the movement of the reference frame Inertial vs Non-Inertial Reference Frame Inertial Inertial (static) frame of reference: Black ball appears to move in a straight line Non-inertial Non-inertial (moving) reference frame (observer): Black ball follows a curved path This is due to the Coriolis Force/Effect Coriolis Effect • The Coriolis effect is a quasi-force or fictitious force exerted on a body when it moves in a rotating reference frame: F = ma = m 2W |U| = m 2W n’ • The force F is at 90o angle with respect to the object U.
    [Show full text]
  • Cooperative Institute for Mesoscale Meteorological Studies the University of Oklahoma
    COOPERATIVE INSTITUTE FOR MESOSCALE METEOROLOGICAL STUDIES THE UNIVERSITY OF OKLAHOMA Final Report for Cooperative Agreement NA67RJ0150 July 1, 1996-June 30, 2001 Peter J. Lamb, Director Randy A. Peppler, Associate Director John V. Cortinas, Jr., Assistant Director I. Introduction The University of Oklahoma (OU) and NOAA established the Cooperative Institute for Mesoscale Meteorological Studies (CIMMS) in 1978. Through 1995, CIMMS promoted cooperation and collaboration on problems of mutual interest among research scientists in the NOAA Environmental Research Laboratories (ERL) National Severe Storms Laboratory (NSSL), and faculty, postdoctoral scientists, and students in the School of Meteorology and other academic departments at OU. The Memorandum of Agreement (MOA) between OU and NOAA that established CIMMS was updated in 1995 to include the National Weather Service (NWS). This expanded the formal OU/NOAA collaboration to the Radar Operations Center (ROC) for the WSR-88D (NEXRAD) Program, the NCEP (National Centers for Environmental Prediction) Storm Prediction Center (SPC), and our local NWS Forecast Office, all located in Norman, Oklahoma. Management of the NSSL came under the auspices of the NOAA Office of Oceanic and Atmospheric Research (OAR) in 1999. The Norman NOAA groups at that time became known as the NOAA Weather Partners. Through CIMMS, university scientists collaborate with NOAA scientists on research supported by NOAA programs and laboratories as well as by other agencies such as the National Science Foundation (NSF), the U.S. Department of Energy (DOE), the Federal Aviation Administration (FAA), and the National Aeronautics and Space Administration (NASA). This document describes the significant research progress made by CIMMS scientists at OU and at our NOAA collaborating institutions during the five-year period July 1, 1996-June 30, 2001.
    [Show full text]
  • 16 Tropical Cyclones
    Copyright © 2017 by Roland Stull. Practical Meteorology: An Algebra-based Survey of Atmospheric Science. v1.02 16 TROPICAL CYCLONES Contents Intense synoptic-scale cyclones in the tropics are called tropical cyclones. As for all cyclones, trop- 16.1. Tropical Cyclone Structure 604 ical cyclones have low pressure in the cyclone center 16.2. Intensity & Geographic distribution 605 near sea level. Low-altitude winds also rotate cy- 16.2.1. Saffir-Simpson Hurricane Wind Scale 605 clonically (counterclockwise in the N. Hemisphere) 16.2.2. Typhoon Intensity Scales 607 around these storms and spiral in towards their cen- 16.2.3. Other Tropical-Cyclone Scales 607 ters. 16.2.4. Geographic Distribution and Movement 607 Tropical cyclones are called hurricanes over 16.3. Evolution 608 the Atlantic and eastern Pacific Oceans, the Carib- 16.3.1. Requirements for Cyclogenesis 608 bean Sea, and the Gulf of Mexico (Fig. 16.1). They 16.3.2. Tropical Cyclone Triggers 610 are called typhoons over the western Pacific. Over 16.3.3. Life Cycle 613 the Indian Ocean and near Australia they are called 16.3.4. Movement/Track 615 cyclones. In this chapter we use “tropical cyclone” 16.3.5. Tropical Cyclolysis 616 to refer to such storms anywhere in the world. 16.4. Dynamics 617 Comparing tropical and extratropical cyclones, 16.4.1. Origin of Initial Rotation 617 tropical cyclones do not have fronts while mid-lati- 16.4.2. Subsequent Spin-up 617 tude cyclones do. Also, tropical cyclones have warm 16.4.3. Inflow and Outflow 618 cores while mid-latitude cyclones have cold cores.
    [Show full text]