This presentation discusses how heat waves and temperatures have changed over time in Los Angeles, CA. It shows graphs of increasing heat wave frequency and duration, as well as rising average temperatures in LA. Global temperature data is also presented showing worldwide warming. To explain these patterns, the presentation discusses how LA has become more urbanized over the past century due to population growth, leading to increased heat island effects where dense urban areas are warmer than rural surroundings. Side-by-side images of LA from 1877, 1909, and 2002 demonstrate this urban expansion.

1. This presentation was developed with funding from the Center for Multi-Scale
Modeling of Atmospheric Processes (CMMAP) and the National Center for
Atmospheric Research (NCAR). Copyright NESTA
Feeling the Heat

2. Feeling the heat
This presentation is full of data and images to get
you thinking! Discuss as a class the patterns you
see and the reasons for those patterns.
Looking for patterns
Take a look at graph representations of the Los Angeles
heat wave data and the average temperature data. How
have they changed throguh time?
Reasons for patterns
Check out how global climate has changed over time
and compare that with the data from Los Angeles. Take
a look at how Los Angeles has grown through time and
how that has impacted the heat island effect.

3. This graph shows
the number of
heat waves in
Los Angeles, CA
over the past
century. Do you
see a pattern?
How have heat
waves changed
through time?
(Graph from
Tamrazian et al.,
2008)
Looking for patterns

4. This graph shows
the duration of
heat waves in Los
Angeles, CA
(measured in
days.) Has there
been a change
through time?
(Graph from
Tamrazian et al.,
2008)
Looking for patterns

5. Looking for patterns
How has the temperature in Los Angeles changed over time? This
graph shows the average temperature for each year. See a pattern?

6. Warmer city temperatures are partially due to global warming.
This graph shows how Earth’s average temperature has changed.
Reasons for patterns

7. Reasons for patterns
Notice above how the highest temperatures are found in the
most dense part of a city?
The 3 following slides show how LA has changed over time. How
do you think the heat island effect has changed over time? What
was the heat island effect like in 1877, 1909, and 2002?

8. Los Angeles, CA in 1877. East LA is on the left and West LA is
on the right. (Courtesy of the Library of Congress)
Reasons for patterns

9. Los Angeles, CA in 1909. (Courtesy of the Library of Congress)
Reasons for patterns

10. Los Angeles, CA in 2002. This 3-D perspective view was generated
using topographic data and an enhanced color Landsat 5 satellite
image mosaic. Topography is exaggerated one and one-half times.
(Courtesy of NASA/JPL)
Reasons for patterns

11. Population Change in Los Angeles, CA
0
500000
1000000
1500000
2000000
2500000
3000000
3500000
4000000
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Year
NumberofPeople
Reasons for patterns
Population change in Los Angles since 1890. (Data from US
Census Bureau)