Lab4_template_F23
docx
keyboard_arrow_up
School
University of Colorado, Boulder *
*We aren’t endorsed by this school
Course
1070
Subject
English
Date
Dec 6, 2023
Type
docx
Pages
6
Uploaded by ChiefFlowerCapybara13
Lab 4 Report
Name: Frank Diaz Partners: Lucas, Courtney, Stuart_______________ , _______________
Please paste your Excel data and graph below this line. Highlight everything you need in Excel, copy, and then use ‘Paste Special’ to paste as an image (e.g., PNG, PDF, etc.). You can take a screenshot as well and paste it here, but please make sure it is easily viewable by your TA. [EMBED EXCEL DATA / GRAPHS HERE]
Question 1 (5pts):
Consider this situation. Your
elevation angle is 45º with
your balloon directly east rising
at
5 m/s. The horizontal wind is
straight west to east. How fast
will these west winds have to
blow for you to have to reduce
the elevation angle on your
next measurement? Explain
your reasoning.
The wind will have to blow faster than
5 m/s for the angle to be reduced. The
faster the wind the smaller the angle
because the balloon with blow further
away.
Question 2 (15pts):
The scale height of the atmosphere (
H
) is a variable that meteorologists often use to do conversions from altitude to pressure. Scale height of the atmosphere refers to the height one must go to in the atmosphere to achieve
a density or pressure that is roughly 37% of the surface density or pressure. Strictly,
H
is a function of temperature since that influences the changes in density or pressure with height, but for our purposes we can
consider the scale height (
H
) to be a constant 8000 meters
.
The equation to calculate the pressure at a given altitude for the balloon is P
balloon
=
P
sealevel
∙e
(
−
Z
H
)
where P
sealeve
l = 1013mb, H
=8000m, e
is the base of the natural logarithm and is 2.718, and Z
=the balloon’s height above sea level
.
a.
Given that you launched your balloon at 1640m above sea level, calculate the expected pressure at the launch site. Note that you need to calculate (-
Z/H) first, then calculate e
(-Z/H)
, then multiply by 1013mb. Show your calculation.
841.3* 2.718(-1640/8000)
(2.718^-0.205)*841.3= 825.26 mb
b.
How well does this match with the pressure observed by your TA?
This is close to the surface pressure observed by the TA which is 841.3 by a difference of about 16. c.
At what height (in meters) above sea level did you stop tracking your balloon at?
2440 meters is the height we stopped tracking. d. Using the equation given above, at what pressure level did you stop tracking your balloon at? Show your work.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
841.3* 2.718(-2440/8000)
(2.718^-.305)*841.3
746.73 mb
e.
Long’s Peak has an average pressure of 588mb. Was the pressure at your balloon’s highest height higher or lower than the pressure at the top of Long’s Peak? Given this, would your balloon have flown over Long's or would it have hit it?
Our pressure was higher than the Long’s Peak balloon. It would have flown over as the pressure was higher. Question 3 (15pts):
Normally, wind speeds are weakest near the ground (due to friction with trees, hills, building, etc.) and increase with height, but this isn’t always the case.
Find an area of your wind speed vs. height graph where the wind speed changes the most over a 300 meter change in altitude. a.
Which layer did you choose (example: 3000-3300 meters above the surface)?
The greatest speed change is from 1640 to 1940.
b.
Calculate the change in wind speed per meter for this layer. Do this by taking the wind speed at the top of the chosen layer and subtracting the wind speed at the bottom of layer. Then divide this number by 300 meters. Note that you just calculated a measure of vertical ‘spin’ or more simply wind
speed generated shear in the atmosphere. The units are knots/m.
22.2-2.8/300=.06467 knots/m
Find an area of your wind direction vs. height graph where the wind direction changes the most over a 300 meter change in altitude.
c.
Which layer did you choose (example: 2700-3000 meters above the surface)?
1640-1940 the wind direction changes the most d.
Calculate the change in wind direction per meter for this layer. Do this by taking the wind direction (in degrees) at the top of the chosen layer and subtracting the wind direction at the bottom of layer. Then divide this number by 300 meters. Note that you just calculated a value of
horizontal ‘spin’ or more simply directional wind shear in the atmosphere. The units will
be º/m.
247-315/300=-0.226667
e.
Small craft pilots tend to avoid the zones you just identified. Why would this be the case?
In these zones, the wind speed and direction change rapidly which could cause turbulence or dangerous flying. Conclusion Question 1 (10 points):
Give 1 experimental or physical source of error for this lab and explain how it
could be reduced in a subsequent experiment
The physical error could be that we were guessing the altitude and azimuth on the kestrel inaccurately or not exactly at 30 seconds of observation. This could be reduced by being exactly on top of 30 seconds when the observation had to be made. Conclusion Question 2 (10 points):
Give another experimental or physical source of error for this lab and explain
how it could be reduced in a subsequent experiment
The instruments such as the degree dial could not be precise in the experiment. Our dial for measuring degrees could have been more accurate in the experiment to better reduce error. Conclusion Question 3 (5 points):
The pibal balloon system is relatively inexpensive and easy to set up. The limitation is that most people will lose track of the balloon by 15,000 feet above the surface (in very optimal conditions). Identify an area of research, recreation, or emergency response where cheap
low-level wind data would be valuable. How would this data be useful for your chosen application?
Parachuters, gliders, and low-level flying planes could all be examples of recreation that would find this useful as this would help them navigate through changes in wind speed and direction.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help