ATMS 401 Homework [Main Page] [Daily Notes] [Final Project]
Homework style example.
ONLINE ASSIGNMENTS AND DUE DATES FOR ALL ARE GIVEN IN WEBCAMPUS.
Title: Case study of a polar and tropical meteorology: Radiosonde analysis.
Reading: Chapters 1 and 3 and provided links.
Turn in through WebCampus, prepared using Microsoft Word.
We will go through this problem together in class, step by step.Collaboration is encouraged.
Ask questions as needed. Bring your own laptop, or use the classroom computers (save your results to a USB drive, or Google Drive, or
Nevada Box, or OneDrive.) Stay caught up as we progress. The requirement is to obtain the data and interpret it.
Prepare a short report that describes the atmosphere for 12Z, 31 January 2025 for these two locations, Rochambeau French Guiana (SOCA, Station 81405) and Barrow Alaska USA (PABR, Station 70026) using the high spatial resolution sounding data and these assignment tasks.
a. Locations: Use Google Earth to view these two locations, Rochambeau French Guiana (coordinates 4.8222, -52.3653) and Barrow Alaska USA (coordinates 71.2889, -156.7833). Save images of each location and use as figures 1 and 2 in your report.
Include grid lines (turn on with the menu item View:Gridlines) in these images and adjust the magnification so that you can see the Equator and the Tropic of Cancer, and for Barrow the Arctic Circle. Briefly discuss the significance of the Tropic of Cancer and the Arctic circle in general and with respect Rochambeau and Barrow, and the amount of solar radiation they receive seasonally.
b. Skew-T Diagrams: Acquire the png format skew T soundings for PABR and SOCA for this day and time. Make these soundings figures 3 and 4 in your report.
Discuss these soundings. What is the local standard time at each site for the soundings?
Discuss the lapse rate Γ=-dT/dz from the slope of the temperature versus height graph at any point and interpret, along with other feature observed.c. Rochambeau Data: Near equator: Rochambeau French Guiana (get sounding text for SOCA from the Wyoming site.)
Plot pressure and temperature vs height in km as figure 5 in your report, with pressure on the lower x axis, and temperature on the upper one.
Calculate density and plot versus height in km as a separate graph as figure 6.
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d. Barrow Alaska Data: Near north pole: Barrow Alaska (PABR).
Get the text sounding data for PABR from the Wyoming site.
Overlay pressure and temperature vs height in km with the SOCA pressure and temperature in figure 5.
Calculate density and overlay with the SOCA density in figure 6.
Additional problem for ATMS 601 student and extra credit for ATMS 401 students:
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e. Water vapor density: Calculate and graph the water vapor density in grams/m3 for Barrow and overlay with the SOCA water vapor density, as an overlay with figure 6.
Note that water vapor density is the product of density_of_dry_air * w. Discuss.
f. Atmospheric river (AR) related analysis. Transport of water vapor.
Note: To understand the total mass transported by an atmospheric river requires more than 1 isolated balloon sounding. This problem is to aid in understanding the primary quantity needed for the first step, quantifying the transport of water vapor by the wind in a column of the atmosphere.
Calculate the vector Integrated Vapor Transport (IVT) (units of Kg/(m s)) and total precipitable water vapor (PWV) (units of mm) for both Barrow and SOCA.Here is a summary of the relationships needed, repeated in this table.
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The average velocity vector for water vapor transport is equal to the IVT/IWV, where IWV=total integrated water vapor.The purpose is to become familiar with this important concept used to described Atmospheric Rivers.
Here are some notes in OneNote format, and in PDF format.
This research paper describes IVT in Eqs. (1) - (5).
This site describes wind as a vector and its speed and direction.
This site describes operational forecast for atmospheric rivers, and water vapor transport analysis.
g. Solar Radiation: Use this solar position and irradiance calculator (from the National Renewable Energy Lab) to simulate the top of the atmosphere solar irradiance for a detector placed flat on the ground (horizontal detector) every 30 minutes for Jan1 - Dec31, 2025, for SOCA and PABR.
It also known as the "Extraterrestrial Global Horizontal Solar Irradiance (W/m2)". We will use the acronym EGHSI for it.
The results will be a time series of top of atmosphere irradiance values that need to be brought into Excel and plotted. The x-axis will be the day of the year calculated by first combining time and date into a new column, and then using the equation given here.
Make these figures 7a and 7b, on one page for ease of comparison. Discuss these figures in the report.
This image shows the setup for getting numbers for SOCA (change latitude and longitude to get PABR numbers), and this image show which field to use for the irradiance (the temperature and pressure don't matter in the first part).
The Earth's orbital path around the sun is elliptical rather than circular. Note that the solar zenith angle, which is the complement of the solar elevation angle, affects EGHSI more than variation of the Earth-Sun distance as discussed here. This simulation is useful for understanding the Earth's tilt and its effects on seasons, in addition to the variation of irradiance due to the Earth-sun distance. Zooming in the SOCA data to an irradiance range from 1200 to 1400 Watts/m2 shows both the effect of solar zenith angle and the asymmetry for the yearly maximum due to the time of the peak and minimum Earth-sun distance as compared with the time of the solstices.
In summary:
Compare and contrast the difference in the meteorology between these two sites as a function of height in the atmosphere, both near the surface and throughout the atmosphere.
Tip: Use the UNR Writing Center for writing feedback.
Purpose:
Study chapter 1 for an overview of Atmospheric Physics.
Read chapter 1.
1. Do problem 1.6 parts a, c, d, and i from the textbook. Write your answers into the first part of the MSword document you will be turning in for this assignment.
2. Do problem 1.12 from the textbook, being sure to express your answer in degree C per kilometer, and be careful with the sign of the value you find.
Next we'll go to the Amundsen-Scott station in South Pole, Antarctica where radiosonde measurements are sporadically obtained to see if we can find such an extreme lapse rate as in problem 1.12.
Go to the Univ. of Wyoming radiosonde server, and look at monthly data using settings like this for the entire month of August GIF images.
Text values can be obtained by changing the type of plot to Text:list, and will be used as described next.
Choose the day in the month of June, July, or August (your choice of month) of this year that has a lapse rate with a strong surface temperature inversion by quickly scanning the GIF images.
Then acquire the text data and calculate the numeric value of the lapse rate of from the first two rows of data.
Include in your MSword document the GIF image of the sounding you used, and the calculation of the lapse rate.
3. a. Do problem 1.21 from the textbook. This is similar to problem 1.20 from the textbook we will do in class. Show that the air speed is v=(dp⁄dt) RE ⁄ Ps where RE is Earth's radius and Ps is the average surface pressure. Calculate the air speed and use units of mm/second.
Parts b. and c. are associated with the question, what does the data show about average seasonal transport of air across the equator?
Is part a. plausible?
b. Here are graphs of the surface pressure averaged from 1950 - 2019 for Dec/Jan/Feb and for June/July/August.
Discuss the seasonal variation of surface pressure in the Northern hemisphere in summer and winter, locations of highs and lows, and meteorological consequences.
This is discussed an online dynamics textbook near Figure 2.3, the pertinent section is here.
[This data is from NCEP/NCAR. One objective of this problem is to become aware of this data].
[Data from NOAA, Physical Science Laboratory, Monthly/Seasonal Climate Composites]. Historical data is available in another form here.
c. Here is a time series image for this problem, obtained with a web-tool, and this spreadsheet has the details.
Web-based tool for time series development of atmospheric quantities, and intercomparison of reanalysis products.
After looking at the data, is part a. plausible?
Resource for problem 1:
Turbulence and vortex rings in air video to visualize the air motions likely happening in the planetary boundary layer and get an introduction to turbulence.
Resource for problem 2:
Example Python script that acquires the radiosonde data for June, July, and August, calculates the surface lapse rate, plots it as a time series, and finds the day of the minimum. (Generated with CoPilot AI).
Resources for problem 3:
Reanalysis Summary.
Summary of some reanalysis sources.
Site devoted to Reanalysis.
Skew T lnP Practice homework based on the atmosphere of 28 July 2025 at 0Z chosen for its relationship to an intense rainstorm in Reno.
Reno sounding location is 72489 REV (39.56, -119.8). Slidell Louisiana sounding location is 72233 LIX (30.34, -89.83).
Instructions: Place your results from parts 1 through 7 into a Microsoft Word or PDF Document and submit it to Webcampus
You can use OneNote or other programs for doing the homework, just export the assignment as a PDF document.
Download the blank skewT graph with curves marked, or a blank skewT graph to Microsoft Paint, or your favorite image program.
1. From the Reno afternoon sounding text, make a table with the temperature and dewpoint temperature for pressures of mb of 850, 700, 500, 400, and 250 mb. If data is missing at a level, choose the closest value (Local backup).
2. Put these points on the blank skewT graph using Paint, save your skewT image file.
3. Obtain the sounding as a GIF-image for the afternoon, circle the temperature and dewpoint temperature values at the pressures given in part 1. (Local backup).
Compare with your skewT from part 2 with the actual sounding in part 3 to make sure you are understanding these charts.
4. Download the Slidell Louisiana 0Z-GIF image sounding on the same day and discuss the comparison with the Reno sounding. (Local backup).
5.
Make a Google Earth map using the coordinates for each location to help your discussion of the meteorology you would expect for Reno and Slidell.
Google Earth can be downloaded as an application for your device, or used from the web.
6. What are the local daylight savings and local standard times in Reno and Slidell at the time these soundings?
7. Obtain the approximate 1:30 p.m. local time NASA Worldview (MODIS sensor, Aqua satellite Image) and use it to help interpret the meteorological differences.
Resources
Geostationary satellite (GOES West) animation for Nevada and the continental US (Conus) from NASA Worldview 27 July 2025 Reno rainstorm (precip data from the UNR weather station, WRCC).
Some skewT lnP applications and measurements.
Skew T lnP MetEd Module that covers nearly everything, starting with the basics.
How to convert to and from UTC.
Upper air soundings and skewT discussion.
This Python script can be used to plot the balloon trajectories in Google Earth, by creating a .kml file that can be read directly into Google Earth.
Use the "Output Data : Comma Separated Values" to get the data from the high resolution sounding page. Not required but useful.
Time zone in Reno.
World time zone map and Greenwich England.
Current time UTC (Coordinated Universal Time).
World time converter.
Video describing skewT diagrams.
Example of radiosonde errors that can lead to faulty skewT diagrams.
Deliverables:
ATMS 401 in class presentation and turn in presentation in through WebCampus.
ATMS 601 in class presentation, report, and turn in through WebCampus.
Presentations need to be between 15 to 30 minutes long.
Take photographs and/or use other data for the atmosphere, and/or investigate a specific topic we haven't covered in class, or covered lightly (such as the ionosphere, or lightning) and explain the Atmospheric Physics connection. The project topic is not limited to obtaining cloud pictures and explaining them, but can be within the rather broad umbrella of Atmospheric Physics. Please check with me if you have questions or want to talk about resources for the project. Project topics can be chosen to support your BS, MS or PhD research topic though should not be on research you have already accomplished prior to this course.
For observational projects, as an example, you can use photographs or data sources, and can look at a variety of phenomena.
For example, blue sky, sky polarization, coronas, halos, rainbows, lenticular clouds, gravity waves, lightning, water phase clouds, ice phase clouds,
inferring air motions and winds from cloud structures, contrails, vortices in contrails, sky color during pollution events, sky color near the horizon, sky color at sunset looking to the east.
Photographs of the dendritic nature of ice growing on windshields on cold days, the shape and nature of icicles, dew on a moist mornings are also possible topics.
Photographs of snow flakes and snow crystals, here's a discussion.
If you have special hobbies or work, like paragliding or mountaineering, Atmospheric Physics related
aspects can be included in your project.
You can use soundings, satellite images, weather station data, etc, to also help tell the story.
ATMS 401 students will do a presentation. Presentation hints. 7 secrets of great speakers. Teachable moments.
ATMS 601 students will do a presentation and a report. Report format.
Due Dates:
Before Mid Semester: Submit a tentative title and discussion of the topic you would like to work on for this project through WebCampus.
Presentations: Presentations begin on Wednesday the week before prep day. Prep day is on a Wednesday too. Turn in your presentation through webCampus by Tuesday night.
Reports for 601 students: The Sunday after prep day. They can be submitted as a second file through webCampus.
Resources that may help
Gravity wave discussion.
Snow crystal/flake observations.
Cloud identification.
NASA WorldView for satellite imagery. You can add layers for additional information.
National Weather Service balloon soundings, served by the Univ of Wyoming.
Weather station data from the Western Regional Climate Center at DRI. In particular, the UNR weather station.
