Limited time offer 20% OFF StudySoup Subscription details

ECU - AS 1300 - Class Notes - Week 5

Created by: Rachel Notetaker Elite Notetaker

ECU - AS 1300 - Class Notes - Week 5

This preview shows pages 1 - 2 of a 3 page document. to view the rest of the content
background image Week 5     9/18-9/21 Relative Humidity(RH) – ratio of water vapor in the air to water vapor in 
air at saturation
Actual Vapor Pressure          Saturation Vapor Pressure Dew point: located on bottom left corner on a weather map o If ground cools to dew point temperature, dew forms (change of  water vapor to liquid: condensation o If the surface dew point temperature is below 0C, frost forms  (change of water vapor to solid: deposition) Humidity – the water in the air doesn’t evaporate so it sticks to surfaces 
(i.e. your skin)
Relative humidity is related to 2 things: o How much water vapor is in the air?
o How much water vapor can be in the air? (change of liquid to 
water vapor: evaporation) Temperature – average kinetic energy of molecules 
(determines how much water vapor is in the air)
Higher temperature=more water vapor/more 
Higher temperature = more water molecules can “escape” 
(evaporate) from liquid to air
Saturation- when air is full of water vapor o Ex: leave a lid on a jar of water it traps the  water vapor which creates saturation Evaporation rate=condensation rate  Fog- when air is saturated and condensation occurs 
(gas to liquid) only if there are condensation nuclei 
for water molecules to stick on to 
o Condensation is more likely when air is cool         Sea salt, dust, smoke: is needed to help  water       vapor turn to liquid Saturation vapor pressure – amount of water vapor that can be in the air As temp rises, saturation vapor pressure increases At higher temps there can be more water vapor in the air o How can we make the air unsaturated? o Increase the temp...more liquid water molecules can  enter the air 1%– 4% water vapor in the air air pressure – related to the amount of air above your head/weight of 
the air (the sum of the pressures of each gas in the air)
pressure – the force exerted by the air per unit area from the  weight of the column of air above o troposphere = more air pressure Actual Vapor Pressure- the “weight” of water vapor Q: How do you lower the Relative Humidity (RH)? RH = 
100% x
background image Week 5     9/18-9/21 Remove water vapor from the air (at constant temp) - lowers actual 
vapor pressure
Raise temp – increases saturation vapor pressure (heat the air to 
make it less humid)
Clouds and Stability Recap: Cool the air to the dew point temperature = clouds Air near the surface cools at night to the dew point temperature = fog
       Both require condensation nuclei Stability – how we know whether air will cool to form clouds Concept of stability- will air rise or sink?
o Make observations:
Lapse rate of the environment: a measurement of the 
temperature with height (change of temperature as you 
move up in the atmosphere)
Environmental lapse rate – actual temperature profile “Sounding”     measured with a radiosonde (on a weather  balloon) Temperature Pressure Relative humidity Wind speed Wind direction *REMEMBER: Dew point less than the temperature = low humidity Stable equilibrium – will return to its original state o Ex: push a ball up a hill it comes back Unstable equilibrium – will not return to original state o Ex: push a ball up a hill it rolls down away from you Will air rise (cool) and form a cloud or will it return back to where it started? *REMEMBER: air rises – expands and cools; air sinks – compresses and 
If rising air is: Dry air-no condensation
Adiabatic – no heat exchange with surroundings
dry     adiabatic lapse rate - as air rises temperature 
-10C per 1000m moist air- condensation in a cloud
o latent heat added to air in the cloud
    adiabatic lapse rate- as air rises temperature  decreases:  -6C per 1000m

This is the end of the preview. Please to view the rest of the content
Join more than 18,000+ college students at East Carolina University who use StudySoup to get ahead
School: East Carolina University
Department: Atmosphere Sciences
Course: Weather and Climate
Professor: Thomas Rickenbach
Term: Fall 2015
Tags: relative, humidity, Unstable, and stable
Name: ATMO/GEOG 1300: Weather & Climate - week 5
Description: This week we learned about relative humidity and how to calculate if a cloud is stable or unstable.
Uploaded: 09/21/2017
3 Pages 10 Views 8 Unlocks
  • Better Grades Guarantee
  • 24/7 Homework help
  • Notes, Study Guides, Flashcards + More!
Join StudySoup for FREE
Get Full Access to ECU - ATMO 1300 - Class Notes - Week 5
Join with Email
Already have an account? Login here
Log in to StudySoup
Get Full Access to ECU - ATMO 1300 - Class Notes - Week 5

Forgot password? Reset password here

Reset your password

I don't want to reset my password

Need help? Contact support

Need an Account? Is not associated with an account
Sign up
We're here to help

Having trouble accessing your account? Let us help you, contact support at +1(510) 944-1054 or

Got it, thanks!
Password Reset Request Sent An email has been sent to the email address associated to your account. Follow the link in the email to reset your password. If you're having trouble finding our email please check your spam folder
Got it, thanks!
Already have an Account? Is already in use
Log in
Incorrect Password The password used to log in with this account is incorrect
Try Again

Forgot password? Reset it here