The Urban Heat Island of San Antonio, Texas | Chapter 02 | Current Perspectives to Environment and Climate Change Vol. 2
This study aims to investigate the
urban heat island (UHI) effect of San Antonio, Texas (USA), and its temporal
changes over the time period 1991-2010. It is an extension of previous work
that used historical air temperature data from 1946 to 1990. The study was
designed to compare 20 years of daily air temperature records (1991-2010) of
San Antonio, Texas (USA), with three small surrounding communities; New
Braunfels, Poteet, and Boerne. These towns are all within 50 kilometers of San
Antonio and have contemporary temperature records. Temperature differences
between San Antonio and the surrounding communities indicate changes in the
thermal environment due to urbanization. The results are as follows. The daily
UHI intensity in autumn and winter is increasing and decreases in the spring
and summer seasons. Autumn is the only season where the daily UHI intensity
increased and spring is the only season where it decreased during the years
1991-2010. The results for Poteet and Boerne were generally similar. In June
during 1997 to 2010, the daily UHI intensity in San Antonio is increasing at an
average rate of 0.8°C/decade relative to New Braunfels. These results are
generally consistent with previous studies. The authors report the first
tentative discovery of San Antonio’s Subsurface UHI. Aquifer well water
temperatures show annual intensity variations (lows of -0.1°C in the winter and
highs of 2.2°C in the summer), with a growth rate of about 0.4°C/decade.
Diurnal variations show maximum intensity of 2.3°C in the late afternoon and
minimum of 0.4°C at night after midnight. Ozone concentrations in the summer
show a positive correlation with temperature at a rate of 2.7 ppb/°C, implying
an ozone increase of 4.3 ppb/decade due to the UHI effect. A physical model of
the urban environment is described that is under development to aid in
interpreting the results and for city planning. Mitigation strategies as
applied to San Antonio are briefly discussed, including green roofs, and urban
trees and other natural vegetation. In conclusion, despite mitigating
influences, San Antonio continues to have an increasing UHI effect. However,
further work is needed to connect to the previous study from 1946 to 1990 and
update to the present to strengthen this conclusion.
Author(s) Details
Dr. Daniel C. Boice
Founder & Principal
Astronomer
Scientific Studies and
Consulting, 171 Harmon Drive, San Antonio, TX, 78209 USA.
Michelle E. Garza
Stormwater Analyst,
Environmental Sciences
San Antonio River Authority,
100 E. Euclid Ave., San Antonio, TX 78238 USA.
Ms. Susan E. Holmes
Applied Mathematician,
Physical Sciences
Indigo Elements, LLC, Unit
6010 Box 147, DPO, AE 09825 USA.
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