SS.KALIKINKAR MAHANTA M.sc 2ND SEMESTER

16ES14DEPARTMENT OF ENVIRONMENTAL

SCIENCES

SUBMITTED BY:-

ATMOSPHERIC BROWN CLOUD

Some Facts About Global Warming:- •  Average sea level around the world rose about 8

inches (20 cm) in the past 100 years.• The global temperature rose a total of 4 to 7

degrees Celsius over about 5,000 years.• The temperature has climbed 0.7 degrees Celsius,

roughly ten times faster than the average rate of ice-age-recovery warming.

• Growing season of crop is lengthening.• About 21,000 species become extinct.• Between 1970 to 2004 Global green house gase

emission have increased by 70%.

Global warming is due to:-• Increase of green house gases.• Increasing of anthropogenic

activities.• More use of Non-renewable

resources• More use of machines• Increasing rate of deforestation.• Depletion of Ozone layer.

One of the Main Source Of Global Warming is SOLAR RADIATION

Clouds play a major role in absorbing or scattering of solar radiation.

CLOUDs:- A visible mass of condensed watery vapour floating in the atmosphere, typically high above the general level of the ground. Containing many air pollutants like Aerosols, Gases ,PM, etc.

TABLE SHOWING TYPES OF CLOUDS

Types of clouds with respect to different altitude:-

Atmospheric Brown Clouds(ABCs):-

•  A layer of air pollution containing aerosols such as soot or dust that absorb as well as scatter incoming solar radiation.

• ABC are widespread layers of brownish haze of air pollutants, such as aerosol particles (black carbon (BC) and non BC), and precursor gases (e.g. CH4, CO, NMVOCs, NOx), which produce aerosols and ozone.

• This layer extends from Earth’s surface to an altitude of roughly 3 km (1.8 miles).

•  The first observations of these phenomena were made in the late 1990s as part of the Indian Ocean Experiment (INDOEX).

• The brownish colour of the cloud is due to absorption of solar radiation at short wavelengths (green, blue, and UV) by organic and black carbon aerosols.

ABCs Hotspots:-

I ) East Asiaii) Indo- Gangetic Plain in South Asiaiii) Southeast Asiaiv) Southern Africav) the Amazon Basin

ABC hotspots are defined as regions where the annual mean anthropogenic aerosol optical depth (AOD) exceeds 0.3 and the percentage of contribution by absorbing aerosols exceeds 10 per cent (absorbing AOD > 0.03).Found in all densely inhabited regions and oceanic regions.

Five regional ABC hotspots around the world have been identified: -

Hotspot’s ABCs

Concentration of ABCs on India and China:-

Composition of ABCs:-• Primarily of Black Carbon and Organic

Carbon.• Copious amounts of tiny particles of soot,

sulphates, nitrates, fly ash and many other pollutants.

• Particles pollutant and hundreds of organic gases and acids.

• Gaseous pollutants that contribute to the formation of ABCs are NOx (nitrogen oxides), SOx(sulfur oxides), VOCs (volatile organic compounds), CO (carbon monoxide), CH4 (methane), and O3 (ozone).

Formation of ABCs due to:-• The combustion of fossil fuels and

biomass.• Absorption of solar radiation by the black

carbon component.• Increase industrialization.• The emissions of NOx .• Inefficient cooking fuels .• Increase population.• Anthropogenic activities.

Effect of ABCs:-• Aerosols in ABC reduce the amount of sunlight

reaching the Earth’s surface by as much as 10 to 15%.• Enhance atmospheric solar heating by as much as

50%.• ABCs mask the greenhouse warming by the surface

dimming.• Enhance the greenhouse gases which warm of the

atmosphere.• ABCs may have masked global warming by as much as

50%.• Accelerated melting of Hindu Kush-Himalayan- Tibetan

glaciers due to black carbon deposition on snow/ice.• 6% decrease in solar energy reaching the surface in

China and India since pre-industrial times

Effects on regional climate:-• Slowing down of the monsoon circulation and

reduction in monsoon rainfall.• Increase strength and frequency of winter and

spring time temperature inversion.• Enhancing the greenhouse warming of the

atmosphere thus contributing to glacier melting.• Impacts on precipitation patterns and water

budgets.• Reduce the amount of snowfall and rainfall every

year.

Effects on Agriculture:-• Increasing ground level ozone and significant loss in

crop yield.• Decrease wheat and rice yield up to 7-8 %.• Decrease the concentration of chlorophyll and

stomata in leaves.• Economic losses were attributed to yield losses of up

to 9% for cereal crops and 23-27 % for soybean.

Effects on Health:-• Cardiovascular and Pulmonary effects leading to

Chronic respiratory problems, hospital admissions and deaths.

• Increases in mortality and morbidity.• indoor: 400,000 deaths a year in India and China

each, and outdoor: up to 500,000 .

ABCs can be controlled by:-• Need to decrease amount of soot, ash and carbon

we release when burn biomass.• Reduce use of automobiles.• Improve technique to reduce emission of NOx,

SOx, CH4, from industry.• Afforestation• Reduce green house gases.

THANK YOU