ATM 10 Severe and Unusual Weather - Disc-1 Prof. Richard Grotjahn - UC Davis Canvas
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ATM 10 Severe and Unusual Weather Prof. Richard Grotjahn Disc-1
ATM 10 Severe and Unusual Weather
Fall 2018, MW 12:10-1:00, Giedt 1002
G.E. CREDIT: Science and Engineering; visual, scientific, writing literacies
WEBSITE: http://canvas.ucdavis.edu
INSTRUCTOR: Prof. Richard Grotjahn, 231 Hoagland Hall
Phone: 752-2246; e-mail: grotjahn@ucdavis.edu
Atmospheric Science Program,
Dept. of Land, Air and Water Resources
TAs: Dani Caputi Minmeng Tang
djcaputi@ucdavis.edu mmtang@ucdavis.edu
Office Hours: (W: 10:30-11:30a) (Tu: 11:00a-12:00p)
Location for office hours: 151 Hoagland Hall
DISCUSSION SECTIONS: 12:10-1:00p Thursday 124 Hoagland
1:10-2:00p Thursday 124 Hoagland
12:10-1:00 Friday 124 Hoagland
TEXT: NONE.
Some may want to look at Fry et al. 2010. Some pages are referenced
from it in the course outline. It is OPTIONAL.
ATM 10 Website Shown is 2018 test version; similar to actual
• http://canvas.ucdavis.edu/
• Course postings of lectures,
problem sets, videos and
animations are all folders in the
‘Files’ link.
Homework assignments here
Admin has course syllabus and this
presentation. Note expanded folder.
Lecture notes here
TA discussion notes here
Course Syllabus – Logistics & Grading • Monitor the ‘syllabus’ in the Files, Course Administration folder at the course website: http://canvas.u cdavis.edu/
Course Syllabus - Calendar • Monitor the ‘syllabus’ in the Files, Course Administration folder at the course website: http://canvas.u cdavis.edu/
Optional book; Reading Notes
• What does ‘optional book’ mean?
– You don’t need to buy it.
– You won’t be tested on it, per se.
(Obviously, if a diagram from the book is
shown in lecture you might be asked
about that. Test questions are based on
lecture notes and homework materials.)
• Why mention it?
– The Professor wrote the ‘Extremes’
chapter and will be using some figures
and diagrams from that chapter.
– Some bits and pieces of other chapters Title: Encyclopedia of Weather and
Climate Change: A complete visual guide.
relate to some parts of the lectures Authors: Fry, Graf, Grotjahn,
– The syllabus lists the pages, but you Raphael, Saunders, Whitaker.
don’t have to read the book to do well. ISBN 978-0-520-26101-3
• Is there reading? Yes. Publisher: UC Press
512 pp.
– The lecture notes are the reading!
Course Rules & Suggestions
Some rules:
1. Homework is due by end of lecture on date indicated in syllabus.
Homework turned in after that time receives 0% credit.
2. Homework is submitted on paper to your TA.
1. Do not submit homework as email unless arranged prior with your TA.
2. If there are multiple pages, please staple all pages together.
3. Print out your answers using a word processor:
1. For any written part of an assignment
2. Exceptions:
1. Mathematical calculations can be legibly hand-written
2. Diagrams & charts can be hand-drawn (if clear)
3. Do your own homework.
1. Duplicative homework answers may cause both people to get 0% credit
4. No early or late offerings of midterm
5. Exams are closed book, but you be given equations.
Some suggestions:
1. For more information & updates: routinely check the course website
2. Plan your timing of activities using the syllabus
3. Review the posted lectures after if not before lecture
4. Questions? Ask your TA or the instructor.
5. Check your campus email…our way to alert you to stuff.
Note: To reduce paper usage, homework assignments will not be handed out
(but posted on the course smartsite in the ‘Resources’ heading)
Mini Feedback Forms
Course Overview
• What to expect in lecture:
– powerpoint lecture
– video(s)
– demonstration(s)
– weekly mini feedback form
– weekly turn in of homework
• What to expect in discussion:
– Work through example problem similar to current
homework
– Return of graded assignments, midterm
– Revisit any topic that people missed as noted by the TA
when doing grading
– Revisit topics from lecture identified by students on the
mini feedback form.
Vertical Structure: Atmospheric Layers
ionosphere
Mesopause
• 5 layers based on air properties
Stratopause • 1 is electrically charged
ionosphere
• 4 defined by how air temperature
changes with pressure and
latitude.
• Between layers are key levels.
• Weather & wind differ between
Note the layers.
“orange” • Most “weather” occurs in the
Layer. troposphere.Vertical Structure of Pressure & Density
Gravity pulls gases
toward earth's
surface.
Pressure is weight of
air above. Weight =
mass of air times
acceleration of
gravity.
Whole column of air
at sea level weighs:
The
= 14.7 psi
“orange’
Layer = 1013.25 mb
In space = 29.92 in.Hg.
photo Figure 1.8Why is the line curved?
Red line is curved since:
1. Air below is compressed from the weight of air above.
2. Why? Compression makes:
1. density increase as elevation becomes lower.
2. So, amount of mass in a layer below is > mass in layer the same
depth above.
3. So, pressure difference from top to bottom of a layer increases as
go lower. That is description in words, now consider a picture...Why is the red line curved?
Same layer depths (no comp.) Compressed air
ρ= 1, P=1 ρ= 1 , P= 1
ρ= 1, P=2 ρ= 1.2 , P= 2.2
ρ= 1, P=3 ρ= 1.44 , P= 3.64
ρ= 1, P=4 ρ= 1.73 , P= 5.37
Consider two examples. ρ= 1, P=5 ρ= 2.07 , P= 7.44
Left example: Contents NOT
compressed by layers above; so ρ= 1, P=6 ρ= 2.49 , P= 9.93
density ρ same in each layer. NO compression Let compression
Change of P from top to bottom of so density same in increase density by
each layer is same for each layer. each layer. P change 20% from layer
Pressure at bottom of each layer is is a straight line. above. P change is a
P and P is plotted as pink line. curved line.
Right example: Air layers above
COMPRESS air below; so weight
of air above makes ρ increase for
layers below. More density means
more mass so P change across
layer increases too. P at bottom of
each layer plotted as blue line.Why is the red line curved?
Same layer depths (no comp.) Compressed air
ρ= 1, P=1 ρ= 1 , P= 1
ρ= 1, P=2 ρ= 1.2 , P= 2.2
ρ= 1, P=3 ρ= 1.44 , P= 3.64
ρ= 1, P=4 ρ= 1.73 , P= 5.37
ρ= 1, P=5 ρ= 2.07 , P= 7.44
Left example: Contents NOT
compressed by layers above; so ρ= 1, P=6 ρ= 2.49 , P= 9.93
density ρ same in each layer. NO compression Let compression
Change of P from top to bottom of so density same in increase density by
each layer is same for each layer. each layer. P change 20% from layer
Pressure at bottom of each layer is is a straight line. above. P change is a
P and P is plotted as pink line. curved line.
Right example: Air layers above
COMPRESS air below; so weight
of air above makes ρ increase for
layers below. More density means
more mass so P change across
layer increases too. P at bottom of
each layer plotted as blue line.Why is the red line curved?
Same layer depths (no comp.) Compressed air
ρ= 1, P=1 ρ= 1 , P= 1
ρ= 1, P=2 ρ= 1.2 , P= 2.2
ρ= 1, P=3 ρ= 1.44 , P= 3.64
ρ= 1, P=4 ρ= 1.73 , P= 5.37
Consider two examples. ρ= 1, P=5 ρ= 2.07 , P= 7.44
Left example: Contents NOT
compressed by layers above; so ρ= 1, P=6 ρ= 2.49 , P= 9.93
density ρ same in each layer. NO compression Let compression
Change of P from top to bottom of so density same in increase density by
each layer is same for each layer. each layer. P change 20% from layer
Pressure at bottom of each layer is is a straight line. above. P change is a
P and P is plotted as pink line. curved line.
Right example: Air layers above
COMPRESS air below; so weight
of air above makes ρ increase for
layers below. More density means
more mass so P change across
layer increases too. P at bottom of
each layer plotted as blue line.Clouds • Condensed water vapor: either ice crystals or liquid droplets • Droplets much smaller than raindrops. • Droplets form on a bit of dust, sea salt, etc That bit called a condensation nuclei. • Most clouds form as air rises. • Rising air encounters lower P and T • This leads to our demonstration…
Demo: Clouds in bottles
• Various ways to make
cloud in a bottle:
– Plastic soda bottle with
water and condensation
nuclei inside, compress
(P rises) then let go (P
drops)
– Pump air from (big)
bottle until cloud forms.
• Recall: need
condensation nuclei.
Try a bit of smoke from
match.
• Real clouds have
similar transparency.Severe Weather Stories???
Pre-course Knowledge Assessment • Answer all questions in order to receive full credit. • Unlike all other homework and exams, if you don’t know an answer, just write ‘I don’t know’ or ‘IDK’ to receive full credit on THIS quiz. • Your score will count as extra credit.
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