Weather + Climate Lectures

If you are looking for a lecture series about weather and climate without any technical prerequisites, then these might be for you.  The following are my lectures from my Blue Planet class at the University of New Mexico.  This class was technically environmental science, but I started out with lectures about weather.  I then transitioned to climate, then climate change.  Then it turns into electricity generation and renewable energy at the end.  So if you are only interested in learning about weather, the first 15 or so are for you.


Lecture 1:  Introduction to the 10 basic cloud types:  cumulus, altocumulus, cirrocumulus, stratocumulus, stratus, altostratus, cirrostratus, cumulonimbus, and cirrus as originally described by Luke Howard in 1802.  I also describe lenticular and mammatus as separate cloud types.  This lecture gets at how to identify the different cloud types and how to discriminate between some that look similar to each other.


Lecture 2:  Humidity is a very complicated and poorly understood subject by the general public.   But to really understand weather, it’s important to have a solid understanding of humidity.  So I have broken down humidity into two lectures.  This first one is about mixing ratio and dew point – both different ways to describe “absolute humidity.”  Relative humidity is the next lecture, but you need to understand absolute humidity first in order to truly grasp what is going on with relative humidity.


Lecture 3:  Relative Humidity is the most common way that humidity is reported to the general public, but few people understand what it is.  In this lecture I go over how relative humidity is calculated and the environmental factors that can change it.


Lecture 3B:  In my experience with students, dew point and relative humidity are especially confusing to them.  So this is a bit of extra lecture using a cool interactive tool from the University of Wisconsin that demonstrates how Dew Point, Relative Humidity, and Temperature are related to each other.


Lecture 4:  Relative Humidity and evaporation are related.  Latent heat is a huge driving force in weather, especially thunderstorms.  Both of these things are related in that evaporation removes latent heat while condensation adds it.  In this lecture I explain how Relative Humidity, evaporation, and latent heat are related.


Lecture 5:  Clouds form when air is cooled to its dew point.  But how does that happen in nature?  In this lecture I demonstrate what happens to an air parcel as it rises up in the atmosphere.  Sometimes you get a cloud, sometimes you don’t.  This lecture is primarily on how cumuloform clouds form.



Lecture 5b:  Some help with determining whether a cloud will form or not.  I’m tracing the formation of thermals from the surface up into the atmosphere and determining if they form clouds or not.  You can download the diagram I am using and do this yourself.


Lecture 6:  This follows what I started in Lecture 5 – namely, what happens if our little parcel of air continues to rise?  If conditions are right, this will lead to cumulonimbus formation and how precipitation forms via the Bergeron Process.  Along with cumulonimbus are a number of hazards that I go over such as downdrafts, microbursts, gust fronts / outflow winds, haboobs, hail formation, etc.  A little bit about tornadoes but I don’t really get into the nitty gritty of tornadoes.  But I do talk about why “tornado alley” exists and how it relates to what I covered in Lecture 5.


Lecture 7:  Air pressure is a big deal in weather ever since Torricelli discovered, in 1643, that there are small variations in air pressure at the surface that change with the weather.  This was the very first time that a scientific instrument could make a prediction about the weather.  Today we use air pressure maps to visualize large weather systems across the world.  I explain the meaning of “sea level pressure” and how it is used in weather analysis.



Lecture 7B:  Maps of sea level pressure can tell you all kinds of things – where air is rising, where air is sinking, the direction of the winds, the relative speeds of the winds, centers of low pressure systems, locations where you might expect to find temperature inversions…all from just measuring air pressure.  This is some extra help with interpreting these maps.  You can download these maps to follow along.



Lecture 8:  The beginning of this lecture is about temperature inversions and the structure of the lower atmosphere.  I go over the troposphere, stratosphere, and the ozone layer.  The stratosphere is the “lid” on Earth’s weather systems.  This includes why mature cumulonimbus often have anvil tops.  After that, the lecture changes to air pollution – particulate matter (including asbestos), Volatile Organic Compounds (VOCs), oxides of nitrogen (NOx), sulfur dioxide (SO2), acid rain, carbon monoxide (CO), ozone, and various iterations of the Clean Air Act and related laws.


Lecture 9:  Fronts are created where giant air masses of different characteristics collide.  When cold air from near the poles collides with warmer air from the subtropical regions, giant storms are created – known as “midlatitude cyclones” or “extratropical cyclones.”  These storms have a predictable series of events when they pass over.  I show Rossby Waves and how the collision of air masses create these storms, then we look for them in satellite imagery.



Lecture 10:  Here I attempt to put together several of the individual components of weather to describe the global atmospheric circulation of the planet.  Cloud types, convection, risking/sinking air, high/low air pressure, fronts, winds….all come together here to make up a sketch of our planet’s circulation.  This includes the Inter-Tropical Convergence Zone (ITCZ), subtropical highs, the westerlies, the easterlies (trades), the polar front, and Hadley Cells.  Then I talk some about the rain shadow / rainout effect and how it can create wet/dry zones on continents.  I show precipitation maps of the USA and New Mexico and explain some of the major precipitation patterns we see.



Lecture 11:  What happens to the global circulation patterns described in Lecture 10 when the seasons change?  That is what is covered here.  We look at how precipitation patterns change seasonally generally around the world and then across the US.  This lecture is where I also introduce climate and how it differs from weather.



Lecture 12:  A good portion of the earth’s human population is subject to a monsoonal circulation and depend on “monsoonal rains” for survival.  But what exactly is a monsoon?  Here I start with an ocean/island breeze system then expand it to a continental scale such as the Indian Monsoon.  Since my original audience was New Mexicans, I focus on the North American Monsoon System (NAMS) and describe how New Mexico’s monsoon circulation starts and stops.



Lecture 13:  El Nino and La Nina are both part of the system called ENSO – which stands for El Nino Southern Oscillation.  In this lecture I talk about how global circulation changes during an El Nino or La Nina.  I focus on how ENSO changes the seasonal weather patterns across the US, though there are effects in many parts of the world that I am ignoring here.



Lecture 14:  Water projects of the southwestern US.  This lecture wouldn’t normally be part of a traditional weather and climate class, but since the politics of water is such a big deal to New Mexico, it was a topic that we studied.  Without “water projects” it would be impossible to support the large population centers we have (Las Vegas, Phoenix, Albuquerque, etc).  The students did a project about the water projects as well.  If you are only interested in learning about weather and climate, you can skip this one.


Lecture 15:  Greenhouse gasses and the greenhouse effect.  How do greenhouse gasses differ than “normal” non-greenhouse gasses?  First I talk about the spectrum of radiation from the sun, including Ultraviolet (UV), visible, and Infrared (IR).  Then I talk about how shortwave and longwave radiation interacts with the Earth, and how the presence of greenhouse gasses changes this.  Are greenhouse gasses good?  Bad?  Necessary?  Then I talk about how we have a system of comparing the relative strength of greenhouse gasses by converting everything to CO2 equivalent.  I do some simple math problems converting different greenhouse gasses to CO2 equivalent.




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