met 4300/5355 severe weatherfaculty.fiu.edu/~hajian/met4300/met4300_swx_lec1.pdf · • severe...
TRANSCRIPT
MET4300/5355SevereWeather
Lecture 1 Introduction
CourseOrganization• Tu/Th11:00AM-12:15 PM,AHC5Rm357•HaiyanJiang,305-348-2984,AHC5Rm371,[email protected]
•OfficeHoursTu12:15-1:15PM,orbyappointment•PreviousGeneralorIntroductiontoMETcourse.•On-linecoursematerialsat:http://faculty.fiu.edu/~hajian/MET4300/MET4300.html
•WxChallenge:LocalmanagerRigobertoOlivera([email protected]),signupbeforeJan20,2019)
Grades:
Grading Factors
Participation(in-class excises) 10%
Term-paper (Graduate) 10%
Exam #1 20%
Exam #2 20%
Final 50%(Under)40% (Graduate)
Total 100%
Absence:
• Needavalidexcuse(in-classexercisesarecountedtowardyourgrade)
Text:
• Severe&HazardousWeather--Anintroduction toHighImpactMeteorology,5th Edition,byRobertRauber, JohnWalsh,andDonnaCharlevoix,Kendall-Hunt,2017. ISBN:9781524931667.Textbookinformationathttps://he.kendallhunt.com/product/severe-and-hazardous-weather-introduction-high-impact-meteorology-0
Textbook:• 27chapters:we’llcover22ofthem
• Specialsections:
1).ListoflearningObjectives2).Checkyourunderstanding3).Testyourunderstanding4).Testyourproblemsolvingskills5).Focusbox(case,advancedtopics,etc.)
Suggestions
• Previewthechapter
• Readthetext,startwithlearningobjectives
• Payattentionto“checkyourunderstanning”questionswhilereading
• ”Answer“Testyourunderstanding”questionsafterreadingthechapter
• “Testyourproblem-solvingskills”
ClassActivities:
• From“ActiveLearningExercises”bookortextbook“testyourproblemsolvingskill”questions
• Dueinclass,counting10%ofyourtotalgrade• NoMake-ups
Exams:
• Total3exams:Exam1,2,andfinal
• Exam1:Feb.7
• Exam2:Mar.28
• Finalexam:Apr.23
• Yourinputaboutexamtime?
CourseFocus:Severe&HazardousWeather
CourseTopics•1/3ofthewholecoursewillcoversomeverybasicmeteorologyconcept(lec1-11;textbookCH1-9)
• Therest:differenttypesofsevere&hazardousweatherincludingleecyclone,northeasters,icestorms,lake-effectsnow,coldwaves,blizzards,mountainsnowstorms,mountainwindstorms,thunderstorms,tornadoes,hailstorms,lightning,anddownbursts.
Whatissevereweather?
• Large,damaginghail(diameter>=1inch)
•Damagingwinds(>=60mph,50kt,or25ms-1)
• Tornado•Oralloftheabove• Strongupdrafts!
SevereWeather=“MESOSCALE”Weather
•Meso=Middle,betweenMacro- andMicro- scale•Orbetween“Synoptic”and“Convective”•ActuallyincludesConvectivescale,too.•Horizontalscaleisdeterminedbysurfacepropertiesornaturalscalesofconvectivesystems
•Verticalscaleisdefinedbythedepthofthetroposphere.
WhatisHazardousWeather?
• Thedefinitionismuchbroaderthansevereweather.•Hazardousweatherincludesalltypesofweatherthathashazardousimpacts.
• Itincludesalmostallscalesofweathersystems,notonlymesoscale.
ScalesofAtmosphericMotion
Scale Length Time
Planetary ~6000 km (Re) Weeks
Synoptic ~ 2000 km days to a week
Meso-α 2000-200 km A day or two
Meso-β 200-20 km A day-hours
Meso-γ 20-2 km Hours-minutes
Convective 5 km – 500m Minutes
Micro < 2 km Minutes-seconds
Orlanski, 1975
METSCALES
PlanetaryWaves
Synoptic-ScaleWeatherin1863
Synoptic-ScaleWeather
Meso- β
Radar, which maps hydrometeors (primarily rainfall) is a key instrument for understanding the mesoscale
Meso-Anticyclone
GustFront
Gustfront:theleadingedgeofcoolairrushingdownandoutfromathunderstorm.
Downslopewind(Chinook,snoweater) isawinddirecteddownaslope,oftenusedtodescribewindsproducedbyprocesseslargerinscalethantheslope.
Suctionvortex arereallysubstructuresofmany,perhapsall,tornadoesbutarenotalwayseasilyvisible.Theseoccur,usually,atthebaseofthetornadovortexwherethetornadomakescontactwiththesurface.
Dustdevil isastrong,well-formed,andrelativelylong-livedwhirlwind,rangingfromsmall(halfametrewideandafewmetrestall)tolarge(morethan10 metreswideandmorethan1000 metrestall).Theprimaryverticalmotionisupward.Dustdevilsareusuallyharmless.
Summary
• Severeweather• Large,damaginghail(20mm,or¾in)• Damagingwinds(50kt,or25ms-1)• Tornado• Oralloftheabove
• Hazardousweather:includeallscalesofweather• Scalesofmotion
• Planetary&synoptic—balanced>2000km• Mesoscale---nonbalanced,2000-2km• Convective—buoyantmotions,5-0.5km(scaleheight)• Microscale---nearsurface<1km