Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sweating it out: U.S. cities have 10 more hot nights a year than 40 years ago, Cornell climate researchers discover

27.09.2002


If you think that summers are getting hotter, you could be right -- depending on where you live. Summers are heating up if you live in or near any major U.S. city. But in rural areas, temperatures have remained relatively constant.



"What surprised me was the difference in the extreme temperature trends between rural and urban areas," says Arthur T. DeGaetano, Cornell associate professor of earth and atmospheric sciences, who reviewed temperature trends from climate-reporting stations across the United States over the past century and examined data from the last 40 years in greater detail. "I expected maybe a 25 percent increase for the urban areas compared to the rural ones. I didn’t expect a 300 percent increase across the U.S."

Because of population growth in urban and suburban areas over the past four decades, particularly in major East Coast cities, there are more hot summer nights than ever, says DeGaetano. "This means that cities and the suburbs may be contributing greatly to their own heat problems," he says. "Greenhouse gases could be a factor, but not the one and only cause. There is natural climate variability, and you tend to see higher temperatures during periods of drought."


Working with Robert J. Allen, a researcher in earth and atmospheric sciences, he found that urban areas across the United States now have an average of 10 more very warm nights a year than they did 40 years ago. In rural areas there was an average increase of only three warm nights a year in the same period.

The growth was the lowest in the central United States, with only two more very warm nights. West of the Rocky Mountains the increase has been about five nights. DeGaetano explains this disparity by the fact that there are simply fewer urban areas in these regions.

DeGaetano classifies a warm night as 70 degrees Fahrenheit in the Eastern, Southern and Midwestern United States. In the Southwest, he says, 80 degrees would be considered a warm night and 70 degrees would be considered cool.

The research article, "Trends in Twentieth-Century Temperature Extremes in the United States," describes average temperature increases for all cities and rural areas across the United States. It will be published in a forthcomingJournal of Climate . It was supported by grants from NASA and from the National Oceanic and Atmospheric Administration.

Since the beginning of the 20th century almost three-fourths of the climate-reporting stations examined in the study have shown an increase in the number of very warm nights. DeGaetano says that the decade of the 1960s stands out as a transition between a period that was relatively stable and cool, and the sharp increase in warm nights that has occurred in recent decades. "You would not expect such a change in the number of very warm nights to occur by chance. We saw a statistically significant shift," he explains.

Climate-reporting stations located in urban areas often are indicators of the huge growth around them. In Manhattan, for example, the station is located in Central Park, which was surrounded by a highly developed urban area even a century ago. Thus that station did not show the wild fluctuations recorded in cities such as Miami and Los Angeles, which have grown exponentially over the past 100 years.

In very warm periods throughout the past century, drought has been a factor. "Warm temperature trends in the past century across the United States are strongly influenced by the peaks in warm maximum and warm minimum temperature extremes during the 1930s and to some extent the 1950s. And these peaks tend to coincide with widespread drought," says DeGaetano.

Blaine P. Friedlander, Jr. | EurekAlert!

More articles from Earth Sciences:

nachricht NASA analyzes Tropical Cyclone Cristina's water vapor concentration
09.07.2020 | NASA/Goddard Space Flight Center

nachricht In the Arctic, spring snowmelt triggers fresh CO2 production
06.07.2020 | San Diego State University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The spin state story: Observation of the quantum spin liquid state in novel material

New insight into the spin behavior in an exotic state of matter puts us closer to next-generation spintronic devices

Aside from the deep understanding of the natural world that quantum physics theory offers, scientists worldwide are working tirelessly to bring forth a...

Im Focus: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

X-ray scattering shines light on protein folding

10.07.2020 | Life Sciences

Looking at linkers helps to join the dots

10.07.2020 | Materials Sciences

Surprisingly many peculiar long introns found in brain genes

10.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>