ATMS 411 Atmospheric Physics [main page] [homework] [2017 notes] [2015 notes][2010 notes].

 


Week 13: 19 November

Homework 5 has been given. It makes heavy use of concepts and equations developed in class.
Bring questions to class about the homework - we'll discuss homework problem hints this week.

Finish quiz Monday:
May use this Mie theory calculator.
A stratiform cloud fills the sky.
The cloud is 1 km thick, and is a water droplet containing cloud composed of a monodispersion of droplets all having radii = 7 microns.
Assume the droplet single scattering albedo is 1 (no absorption of radiation).
The optical depth at 550 nm is τext=τsca=10.


a. What is the size parameter?
b. What scattering regime is this?
c. What is the scattering efficiency factor?
d. What is the asymmetry parameter?
e. What is the number concentration of cloud droplets?
f. What fraction of direct sunlight makes it through this cloud?
g. What fraction of total radiation (diffuse and direct) makes it through this cloud?
h. What fraction is the diffuse radiation to the total radiation coming through this cloud?
i. Would the sun be visible when viewed through this cloud?
j. What is the liquid water path for this cloud?
k. How much water would be collected in a cup of area A swept through the cloud?
(In other words, what is the precipited water in mm, similar to precipitable water vapor).

Continue with chapter 4 radiation transfer presentation.
Multiple scattering between the cloud and ground.
Discuss homework questions.

Bring questions to class about the homework - we'll discuss homework problem hints, Monday and Wednesday. We will look at more topics in Radiation Transfer.

Earth's orbit -- in relation to problems 4.21 and 4.29.

Start Chapters 5 and 6, cloud and aerosol physics. Start reading on chapter 6. We will discuss parts of chapter 5 to help with chapter 6. Cloud microphysics.
Also read this article on cloud and aerosol physics.

 

Related Information:

Layout of the 2 layer problem, and Mathematica treatment of the two layer problem; summary of results.

2 stream model for radiation transfer.

Great journal article on the theory of radiative transfer, with applications.

Journal article on cloud and aerosol physics.

 

 

 

 

Week 12: 12 November

Quiz Thursday:
May use this Mie theory calculator.
A stratiform cloud fills the sky.
The cloud is 1 km thick, and is a water droplet containing cloud composed of a monodispersion of droplets all having radii = 7 microns.
Assume the droplet single scattering albedo is 1 (no absorption of radiation).
The optical depth at 550 nm is τext=τsca=10.



a. What is the size parameter?
b. What scattering regime is this?
c. What is the scattering efficiency factor?
d. What is the asymmetry parameter?
e. What is the number concentration of cloud droplets?
f. What fraction of direct sunlight makes it through this cloud?
g. What fraction of total radiation (diffuse and direct) makes it through this cloud?
h. What fraction is the diffuse radiation to the total radiation coming through this cloud?
i. Would the sun be visible when viewed through this cloud?
j. What is the liquid water path for this cloud?
k. How much water would be collected in a cup of area A swept through the cloud?
(In other words, what is the precipited water in mm, similar to precipitable water vapor).


Continue with chapter 4 radiation transfer presentation.
Demonstrations of multiple scattering.
Single scattering properties of gases, aerosols, and cloud droplets and ice crystals and hydrometeors.
Direct and diffuse beam radiation.
Heating rate due to net flux divergence.

Homework 5 has been given. It makes heavy use of concepts and equations developed in class.

Description of the 2 stream model for radiative transfer; more on forward and backward scatter and asymmetry parameter; reflection and transmission coefficients above an absorbing ground; quiz parts a-g.

 

Wednesday: Review scattering and absorption regimes for single particles; mean free path between scattering events in polydispersions; 2 stream model for total transmitted radiation including direct and diffuse; asymmetry parameter of scattering; single scatter albedo.

 

Summary of scattering regimes

 

 

Related Information:

Northern California fire in photos.

Ira's message.

Sounding from 9 November 2018, and a second view. Discussion of veering and backing winds.

Mie theory calculator: Light scattering, absorption, and extinction and phase function for spherical particles.

UNR Cimel Sunphotometer from the Physics roof.

Refractive index of water and ice for solar and terrestrial wavelengths.

Layout of the 2 layer problem, and Mathematica treatment of the two layer problem; summary of results.

2 stream model for radiation transfer.

Great journal article on the theory of radiative transfer, with applications.

Join the UNR Student Chapter of the American Meteorological Society.

 

 

 

 

 

Week 11: 5 November

Review and look at the results of the "plate" model of the atmosphere (single layer model with solar absorption and infrared active gases.
Continue with chapter 4 radiation transfer presentation.
Single scattering properties of gases, aerosols, and cloud droplets and ice crystals and hydrometeors.
Direct and diffuse beam radiation.
Heating rate due to net flux divergence.

Homework 5 has been given. It will make use of concepts and equations developed in class.

Sun photometry; UNR sun photometer; NASA AERONET; Satellite remote sensing of AOD; Mie Theory; Scattering by non spherical particles.

 

Scattering regimes, Rayleigh, Resonance, and Geom Optics; direct beam calculation; absorption efficiency, cross section, coefficient, and optical depth. Extinction.

 

Rayleigh Scattering and Single Particle Cross Sections for Scattering, Absorption, and Extinction. Went outside to view the polarization of sky light with polarizers.

 

Review of Earth's Astronomical Temperature and 1 layer Model

 

Related Information:

Mie theory calculator: Light scattering, absorption, and extinction and phase function for spherical particles.

UNR Cimel Sunphotometer from the Physics roof.

Refractive index of water and ice for solar and terrestrial wavelengths.

Layout of the 2 layer problem, and Mathematica treatment of the two layer problem.

2 stream model for radiation transfer.

Great journal article on the theory of radiative transfer, with applications.

Join the UNR Student Chapter of the American Meteorological Society.

 


 

 

 

Week 10: 29 October

Thursday's class: More hints on homework and how the atmosphere works from a radiative perspective.
"Plate" model of the atmosphere (single layer model with solar absorption and infrared active gases).

Sketch for problem 4.11cc and single layer model for the atmospheric radiation balance.

 

Sketches for problems aa) and bb), click image for larger version.

Short and longwave radiation features, and parameterization of downwelling longwave

Direct and difffuse radiation, irradiance and radiance, longwave and short wave radiation. Click image for larger version.

Online homework due 28 October 2018. Student presentations for HW4 begin on Wednesday.

We will continue chapter 4, Atmospheric Radiation. Read problem 4.11 (part 1, part 2) now so that you can think about these questions as you read chapter 4.

Demonstration of IR radiation on Monday, talked about the 'plate theory' of the atmosphere.

Related Information:

"Plate" model of the atmosphere (single layer model with solar absorption and infrared active gases).

 

 

 

Week 9: 22 October

We will begin chapter 4, Atmospheric Radiation. Read problem 4.11 (part 1, part 2) now so that you can think about these questions as you read chapter 4.
Homework 4 has been posted. Online homework has been posted.

Thursday class: Solar panel example and top of atmosphere radiation balance. Earth's radiative temperature. Click image for larger version

 

Wednesday class: Blackbody radiation discussion, Wien's displacement law, and Stefan Boltzmann relationship.

 

Tuesday class: Discuss radiation interaction with flat surfaces; trace velocity matching principle (Snell's law) and applications to light and sound.

Tuesday class: Discuss radiation interaction with flat surfaces; trace velocity matching principle (Snell's law) and applications to light and sound.

One related topic is sound propagation in the atmosphere as affected by the thermal structure and winds, from slide 133.

The midterm exam is on Monday October 22nd.
Here are two previous exams to use for style and study. Exam 1. Exam 2.
You can use an equation/note sheet, one side, 8 1/2" by 11", for the exam.
Procedures for obtaining useful quantities from skewT graphs.
The skew T as a gif file is here.
More practice problems with solutions are here. Skew T tutorial is here.
Discussion of the skew T graph and examples.

 

Related Information:

NASA Worldview

AMS Student Chapter Meeting Monday 22 October at 1 pm, all are welcome.

 

 

Week 8: 15 October

The midterm exam is on Monday October 22nd.
Here are two previous exams to use for style and study. Exam 1. Exam 2.
You can use an equation/note sheet, one side, 8 1/2" by 11", for the exam.
Procedures for obtaining useful quantities from skewT graphs.
The skew T as a gif file is here.
More practice problems with solutions are here. Skew T tutorial is here.
Discussion of the skew T graph and examples.

Thursday: Sound propagation in the atmosphere, and skew T practice.
The skew T as a gif file is here.
Work with the 23 April 0Z Reno sounding below.
Read the temperature and dew point off of the Wyoming sounding for the 450 mb and the 400 mb levels.
a) Use this skew T and determine to what pressure the air would have to be lifted above 450 mb to form clouds (LCL for that starting point).
b) What is the relative humidity at the 450 mb level?
c) What are the potential temperatures at the 450 mb and 400 mb levels?
d) Estimate the thickness of the 450 mb - 400 mb level to get dz.

e) What are the dry adiabatic lapse rate, the moist adiabatic lapse rate, and the environmental lapse rate for this layer, and what is the stability classification?
f) What is the equivalent potential temperature at the 450 mb and 400 mb levels?
g) What are the gradients of potential temperature and equivalent potential temperature, Γ=-dθ/dz, and Γ=-dθE/dz and discuss in relation to the stability classification.

Wednesday: Continue discussion of gravity waves and Brunt-Vaisalla frequency starting on slide 111..
Notes: (click image for larger version).

Gravity wave clouds and sounding


Image from 22 April 2017 1:30 pm LST. Reno is midway between lake Tahoe and Pyramid Lake.

See also the movie! Look especially at the latter part of the day. And notice the halos present.


Image in Google Earth to get wavelength.

From here.
The original article is here.

 

Tuesday: Student presentations.
Discussed convective instability,
click image for larger version.

Monday: Student presentations for Homework 3.

Remaining topics of Chapter 3: Brunt-Vaisalla frequency and sound propagation in the atmosphere, starting on slide 111.

 

Related Information:

Gravity wave cloud from NASA Worldview (demonstrate wave clouds, etc, and use for assignments.)

AMS Student Chapter Meeting Monday October 15th at 1 pm , and Undergrad Research Opportunity at UNR

Geostationary satellite imagery and weather maps.

Role of latent heat in our daily lives -- drink can warming due to latent heat release when the can sweats.

 

 

 

 

 

 

Week 7: 8 October

Wednesday class
Reanalysis example for the 500 mb map and the vertical distribution of θ and θE.


400 mb example for comparison with 500 mb level below.


500 mb level example for the time of the sounding on the left.

 

Monday and Tuesday class: worked on assignment 3.
Be sure to come to class early, and work on this.

Goal: obtain the CAPE after calculating the path of the surface air parcel through the atmosphere, e.g. the moist adiabat.

Relationships to interpolate sounding to the LFC pressure, P1 to get the temperature T1 and height z1 at the LFC. This is optional. The rows above and below the new row are from the sounding.

Example calculation from the Lamont Oklahoma case study done in class.

Work on Assignment 3, be sure to make note of your sounding for this assignment so we can work on it in class on Monday.
We'll work on an example from Lamont Oklahoma, the station ID is 74646, example 0z on July 18, 2018.

The midterm exam is coming up during the week of October 15th, exact date to be announced soon, depending on Homework 3.
Here are two previous exams to use for style and study. Exam 1. Exam 2.
You can use an equation/note sheet, one side, 8 1/2" by 11", for the exam.
Procedures for obtaining useful quantities from skewT graphs.
The skew T as a gif file is here.
More practice problems with solutions are here. Skew T tutorial is here.
Discussion of the skew T graph and examples.

 

Related Information:

Gravity wave cloud from NASA Worldview (demonstrate wave clouds, etc, and use for assignments.)

Polar mesospheric clouds, also known as noctilucent clouds.
Bacteria as cloud nuclei.

Kelvin Helmholtz instability and cloud observation and analysis.

AMS Student Chapter Meeting Monday October 15th at 1 pm , and Undergrad Research Opportunity at UNR

Hurricane Michael from GOES imagery.

Geostationary satellite imagery and weather maps.

 

 

 

 

Week 6: 1 October

Thursday notes on how to calculate and graph the LCL, dry, and moist adiabats for use in Assignment 3.

 

Wednesday notes on super saturation and water vapor issues.



Tuesday notes on Chinook winds, air flow over mountain ranges, precipitation on the windward side and lee side hot air.

Tuesday notes on rain shadow effects on downwind temperature

 

Monday notes on using surface wet bulb temperature, air temperature, and pressure to obtain many parameters of the atmosphere: Click image for larger version

 

Online Homework due Sunday night; quiz planned for Monday.
Continue working on the skew T example from T and TwetBulb measurements obtained in class.
Here's the blank SkewT we've been working with.

Things to learn from a dry and wet bulb measurement and a skew T log P graph.
1. Lifting condensation level pressure in mb.
2. Dew point temperature in Celsius.
3. Relative humidity.
4. Potential temperature θ.
5. Wet bulb potential temperature θw.
6. Equivalent potential temperature θE.
7. Water vapor mixing ratio.
8. Saturated water vapor mixing ratio.
9.  Water vapor pressure in mb.
10. Water vapor pressure at saturation in mb.

Next skew T examples are:

a. Air moving over mountain ranges and Chinook winds (problem 3.48 and last slide of presentation).

b. Soundings associated with thunderstorms and large convective available potential energy, concept and calculations starting on slide 62, leading to homework 3.

 

Related Information:

More Skew T practice:
Procedures for obtaining useful quantities from skewT graphs.
The skew T as a gif file is here.
More practice problems with solutions are here. Skew T tutorial is here.
Vapor pressure calculator as a function of temperature.

Interactive Skew T

Final project idea: photograph snow crystals and flakes.

 

 

 

 

Week 5: 24 September

Thursday: Homework due and quiz planned. Thursday started working on the skew T example from T and TwetBulb measurements obtained in class.

Things to learn from a dry and wet bulb measurement and a skew T log P graph.
1. Lifting condensation level pressure in mb.
2. Dew point temperature in Celsius.
3. Relative humidity.
4. Potential temperature θ.
5. Wet bulb potential temperature θw.
6. Equivalent potential temperature θE.
7. Water vapor mixing ratio.
8. Saturated water vapor mixing ratio.
9.  Water vapor pressure in mb.
10. Water vapor pressure at saturation in mb.

 

Tuesday and Wednesday, students present homework problems.

Wednesday class: Air parcels and hot air balloon problem, and saturated adiabatic lapse rate.

Monday class: Stability and potential temperature discussion, click for larger version.

Read chapter 3, Atmospheric Thermodynamics.
We will have several homework assignments from this especially important chapter.
Presentation for chapter 3.
The goals (learning and review objectives)

a. Ideal gas equation applied to dry and moist air.
b. Virtual temperature.
c. Potential temperature.
d. Hydrostatic equation.
e. Increasingly detailed description of the temperature and pressure distribution in the atmosphere.
f. SkewT logP diagrams.
f-g. Relative humidity, absolute humidity.
g. Dew point temperature.
h. Wet bulb temperature.
i. Equivalent potential temperature.
j. Latent heat release and absorption in condensation and evaporation of water.
k. Stability of air parcels.
l. Indices on soundings.
m. Brunt–Väisälä frequency and gravity waves.

Related Information:

Mixing layer height in Reno for 2018 from 0z (afternoon) balloon soundings and use of constant potential temperature in the mixed layer.

Skew T lnP graph showing dry adiabats.

Useful weather maps, including ThetaE.

Forecast weather maps for various pressure levels. And for Northern hemisphere.

Useful constants and facts.

The final project has been posted! Take a look and get started today.

Latent heat dependence on temperature, from here.

Potential temperature and equivalent potential temperature for summer in Barrow and Rochambeau.

Fortran code and example for extracting boundary layer height from balloon soundings, using Theta with height.

Discussion of atmospheric stability in general, to supplement the textbook discussion.

Another discussion of stability, and another.

 

 

 

 

Week 4: 17 September

Class Thursday.

Class Wednesday.

Class Tuesday.

Class Monday. Click for larger version.

Read chapter 3, Atmospheric Thermodynamics.
We will have several homework assignments from this especially important chapter.
Presentation for chapter 3.
The goals (learning and review objectives)

a. Ideal gas equation applied to dry and moist air.
b. Virtual temperature.
c. Potential temperature.
d. Hydrostatic equation.
e. Increasingly detailed description of the temperature and pressure distribution in the atmosphere.
f. SkewT logP diagrams.
f-g. Relative humidity, absolute humidity.
g. Dew point temperature.
h. Wet bulb temperature.
i. Equivalent potential temperature.
j. Latent heat release and absorption in condensation and evaporation of water.
k. Stability of air parcels.
l. Indices on soundings.
m. Brunt–Väisälä frequency and gravity waves.

Related Information:

Skew T lnP graph showing dry adiabats.

Useful weather maps, including ThetaE.

Forecast weather maps for various pressure levels. And for Northern hemisphere.

Hurricane eyewall and air motions.

Useful constants and facts.

The final project has been posted! Take a look and get started today.

El Niño forecast, tropical meteorology.

We celebrate the equinox this week.

NASA worldview look at satellite imagery from the MODIS sensor.

Halo caused by interaction of sunlight with ice crystals in cirrus could. Corona and cloud iridescence are also present. click for larger version.
From Carl Schmitt high in the Peruvian Andes, 2018.

 

 

 

Week 3: 10 September

Thursday class notes, click for larger version.

The final project has been posted! Take a look and get started today.

Wednesday class, we'll look at a presentation together and puzzle over the data set.

Monday and Tuesday class: Add the lapse rate calculation and discuss homework.
Be sure to work on the homework problem 3 between classes.

Notes from Monday, click for larger version.

Where we are headed:
Read chapter 3, Atmospheric Thermodynamics. We will have several homework assignments from this especially important chapter.
Presentation for chapter 3.
The goals (learning and review objectives)

a. Ideal gas equation applied to dry and moist air.
b. Virtual temperature.
c. Potential temperature.
d. Hydrostatic equation.
e. Increasingly detailed description of the temperature and pressure distribution in the atmosphere.
f. SkewT logP diagrams.
f-g. Relative humidity, absolute humidity.
g. Dew point temperature.
h. Wet bulb temperature.
i. Equivalent potential temperature.
j. Latent heat release and absorption in condensation and evaporation of water.
k. Stability of air parcels.
l. Indices on soundings.
m. Brunt–Väisälä frequency and gravity waves.

Related Information:

Atmospheric tides, paper, and website, and a second paper.

Cumulative hurricane tracks from 1985-2005 from NASA.
Ocean surface temperature.
Hurricane winds paper.
Hurricanes as heat engines, and associated article.
Discussion of hurricane intensification and climate.
Can we capture energy from a hurricane?

Sontag competition.

Clouds and Atmospheric Physics
(click images for larger version)

 

 

 

 

 

 

Week 2: 3 September

Tuesday notes. Click on images for larger version.
 

Thursday class: Arrive early if you can, and get started. We'll be working together on analysis for problem 3 of HW1.

Wednesday class: Start Excel and login to your account with your net ID.

Soundings from the equator in the warmest season, and from the north polar region in its coldest season, presentation. Compare and contrast. (Data from Rochambeau French Guiana and Barrow Alaska.)

Set up problem 3 from Homework 1, and work on it in class, total mass per unit area of the layers between UNR and DRI, and between DRI and Slide Mountain, as a time series.

Related Information:

ATMOSPHERIC SCIENCE TALK
Dr. Neil Larue, new Atmospheric Science professor at UNR will give a talk...
Friday, September 7th, from 4 – 4:30 pm "Wildfire Plume Dynamics"
Physics Conference Room, LP 200
All are invited


Data Lister Usage: Change those items listed in red boxes

 

Reno balloon races and sounding from Thursday's class. What recommendations would you give to the balloon pilots?
Click images for larger versions.

 

 

 

 

 

Week 1: 27 August

Thursday notes, sounding values from Antarctica and first model for the pressure variation with height. Click images for larger version

Quiz 1 was held Thursday in class.

 

Discussion on Wednesday, click image for larger version

 

Skew T presentation for in class discussions and as a gif file to be used with Paint.

Homework 1 is due 11 Sept 2018, to be turned in through web campus as well.

Online Homework 1 is due 2 Sept 2017. See webcampus. This is based on MetEd.

Homework for Monday and Tuesday: Read chapter 1.
This class will be one part lecture;
one part active class participation/activity involving atmospheric data from around the world;
and one part study using online modules for atmospheric science education.

Introductions -- each student introduce themselves and give their major.
Syllabus.
Homework. Homework style guide.
Webcampus for online homework assignments/reading.
Weather and geophysical data and models.

Free online Introductory Textbook for Atmospheric Science and local backup.

Overview Presentation: Atmospheric Science relies heavily on measurements and models!
Origin of Atmosphere and Composition presentation chapter 2.
Vertical structure of the atmosphere.

Related Information:

Weather

World record hail stone in Vivian South Dakota. See more on hail.

The Earth's atmosphere is very dynamic (movie 5 fps).

Discussion of baroclinic and barotropic conditions in the atmosphere.

Pittsburgh Spirit Fountain Cloud Physics and coordinate system (click image for larger version.)