Tuesday July 16, 2019
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Increase green cover to mitigate urban heat : NASA

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By NewsGram Staff Writer

Washington:  Providing a solution to the recent problem of rising urban heat, a recently conducted study by NASA explained how increasing the green cover can help cities to a great extent.

Cheetal_(spotted_deer)_at_Van_Vihar_National_Park

Using multiple satellites’ observations, researchers found that areas in the US covered in part by concrete surfaces had a summer temperature 1.9 degrees Celsius higher than surrounding rural areas.

In winter, the temperature difference was 1.5 degrees Celsius higher in urban areas.

At the human level, a rise of one degrees Celsius can raise energy demands for air conditioning in the summer from five to 20 percent.

“This has nothing to do with greenhouse gas emissions. It is in addition to the greenhouse gas effect. This is the land use component only,” said Lahouari Bounoua, research scientist at NASA’s Goddard Space Flight Centre in Greenbelt, Maryland.

The urban heat island effect occurs primarily during the day when urban impervious surfaces absorb more solar radiation than the surrounding vegetated areas, resulting in a few degrees temperature difference.

The urban area has also lost the trees and vegetation that naturally cool the air.

“Anywhere in the US, small cities generate less heat than mega-cities,” Bounoua said.

The reason is the effect vegetation has on keeping a lid on rising temperatures.

“The amount and type of vegetation plays a big role in how much the urbanisation changes the temperature,” added research scientist and co-author Kurtis Thome.

As a by-product of photosynthesis, leaves release water back into the atmosphere in a process called evapotranspiration, which cools the local surface temperature the same way that sweat evaporating off a person’s skin cools them off.

Trees with broad leaves have more pores to exchange water than trees with needles, and so have more of a cooling effect.

“So even though 0.3 degrees Celcius may seem like a small difference, it still may have impact on energy use,” Bounoua said, especially when urban heat island effects are exacerbated by global temperature rises due to climate change.

Understanding the tradeoffs between urban surfaces and vegetation may help city planners in the future mitigate some of the heating effects, the authors noted in a paper that appeared in the journal Environmental Research Letters.

(With inputs from IANS)

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Incredible Full Moon Falls on 50th Anniversary of NASA’s Apollo 11

The partial lunar eclipse will occur during the full moon beginning Tuesday night

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Full Moon, Anniversary, NASA
The moon is seen during a lunar eclipse known as the "Super Blood Wolf Moon," in Manaus, Brazil, Jan. 21, 2019. VOA

The last lunar eclipse of the year will take place this week, allowing stargazers from large swathes of the globe to catch a glimpse of the celestial phenomena.

The partial lunar eclipse will occur during the full moon beginning Tuesday night, and will be visible in South America, Europe, Africa, Asia and Australia. The only region that will miss out on viewing the eclipse entirely is North America.

A lunar eclipse occurs when there is an alignment of the moon, the sun and the Earth. It can only happen during a full moon, because that is the only time the moon can be directly opposite of the sun in Earth’s sky.

The upcoming alignment will result in a partial lunar eclipse because the moon will be slightly askew from a direct line with Earth’s shadow.

Full Moon, Anniversary, NASA
The last lunar eclipse of the year will take place this week, allowing stargazers from large swathes of the globe to catch a glimpse of the celestial phenomena. Pixabay

This lunar eclipse will come two weeks after a total eclipse of the sun was visible over South America. This follows a typical astronomical pattern of lunar eclipses occurring within two weeks of a solar eclipse.

The last lunar eclipse took place in January 2019 and was visible from both Americas as well as parts of Europe and Africa. The next lunar eclipse will not take place until next year, however all four eclipses in 2020 will only be penumbral eclipses, which are much weaker than partial or full eclipses.

During penumbral eclipses, the moon passes through the weakest shadow cast by Earth and often does not visibly darken to the naked eye.

There won’t be another total lunar eclipse until May 2021.

Also Read- India Aborts Launch of Spacecraft Intended to Land on Far Side of Moon

Apollo anniversary

Tuesday’s lunar eclipse will be seen by stargazers at different times around the globe. Viewers in South America will be the first to see Earth’s shadow touch the moon’s surface when the moon is rising in the sky around sunset July 16, while watchers in Asia and Australia will see the moon in eclipse as it sets around sunrise July 17.

Interestingly, this celestial event falls on the anniversary of another lunar happening: July 16 is the 50th anniversary of the Apollo 11 rocket launch, which first landed humans on the moon. (VOA)