make summary for each lucture

CES 4580, Hurricane Engineering and Global Sustainability MODULE 3 -- ANALYZING THE CHARACTERISTICS OF HURRICANE MULTI-STRESSORS (REF: ‘HURRICANE ALMANAC’ BY BRYAN NORCROSS, ‘DIVINE WIND’ BY KERRY EMANUEL, ‘HURRICANES – CAUSES, EFFECTS, AND THE FUTURE’ BY S.P. LEATHERMAN AND J. WILLIAMS)

Global Warming, Climate Change, and Hurricanes

Global Warming Link to Hurricane Intensity Questioned

Strong Hurricanes Getting Stronger; Warming Is Blamed

Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex, P.M. Midgley (eds.).”IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovern¬mental Panel on Climate Change.” Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp.

Global Warming, Climate Change, and Hurricanes

Hurricane Predictions: El Niño Could Impact Storm Season

https://www.youtube.com/watch?v=d6s0T0m3F8s&index=8&list=P Lygs8D5FNNkg0q6WgBkigmUGRakKG6GnO

Global Warming, Climate Change, and Hurricanes

Are El Niño and La Niña closely related to global warming? El Niño and La Niña are a normal part of the earth’s climate and have likely been occurring for millions of years. Global climate change may affect the characteristics of El Niño and La Niña events, but the research is still ongoing.

Global Warming, Climate Change, and Hurricanes

El Niño refers to the occasional warming of the eastern and central Pacific Ocean around the equator. The warmer water tends to get only 1 to 3 degrees Celsius above the average sea- surface temperatures for that area, although in the very strong El Niño of 1997-98, it reached 5 degrees or more above average in some locations. [El Niño is Spanish for the ‘Christ Child’; warm- water events occurred around Christmas].

La Niña is defined by cooler-than-normal sea-surface temperatures across much of the equatorial eastern and central Pacific.

El Niño and La Niña episodes each tend to last roughly a year, although occasionally they may last 18 months or longer.

Global Warming, Climate Change, and Hurricanes

Ref: The Earth Institute, Columbia University

Global Warming, Climate Change, and Hurricanes

During El Niño events, more air than normal is rising in the atmosphere over the eastern tropical Pacific. Wind blows through the upper levels from the west (from the Pacific) across the tropical Atlantic. Thus one of El Nino’s effects is an increase in upper atmospheric winds blowing from the west across the Caribbean and tropical Atlantic.

Such winds tend to shear apart storms due to increased wind shear. Thus El Niño events are associated with reduced frequency of Atlantic hurricanes.

During La-Nina, air above the tropical Pacific is cooled. The cooled heavy air sinks and this downward suction pulls air from the atmosphere. This enhances wind from the east above the tropical Atlantic, a condition favorable for hurricane development.

Global Warming, Climate Change, and Hurricanes

https://www.climate.gov

Global Warming, Climate Change, and Hurricanes

https://www.climate.gov

Global Warming, Climate Change, and Hurricanes

ENSO (El-Nino Southern Oscillation) phases interact with other climate patterns that influence hurricanes

Another prominent climate factor to influence Atlantic hurricane activity is the Atlantic Multi-Decadal Oscillation (AMO). The warm phase of the AMO is associated with high-activity eras for Atlantic hurricanes, such as has been in place since 1995. Conversely, the cold phase of the AMO is associated with low-activity eras (such as the period 1971-1994).

Global Warming, Climate Change, and Hurricanes

Atlantic Multi-Decadal Oscillation (AMO)

https://www.climate.gov

Global Warming, Climate Change, and Hurricanes

Climate Changes on Three Different Time Scales Affect Atlantic Basin Hurricanes

1. El Nino and La-Nina (warming and cooling of central and eastern Pacific water) -- three to seven year cycle

2. AMO (a slight warming and cooling of the Atlantic Ocean, about 1 degree Faranheit) -- twenty to forty year cycle

3. Global warming (has many effects other than warming temperatures) -- hundreds to thousand of years

Global Warming, Climate Change, and Hurricanes

We are currently in a phase of heightened activity because of natural 60-80 year cycle (AMO) that began around 1995 (may have caused the increased hurricane activities in 1995 and 2005).

Climate change may decrease the temp. change between sea surface and upper troposphere. Climate change may increase the wind shear. So TC activities may reduce due to global warming; however increased sea surface temp. can result in stronger storms.

Global Warming, Climate Change, and Hurricanes

Climate models show: Doubling CO2 in atmosphere should increase tropical ocean temp. from 1°F to 4°F, increasing intensity by 5 to 20 mph (Divine Wind Fig. 32.6 -- effect of hypothetical global warming).

Complex computer models have been used to predict how hurricane frequency would change in response to doubling atmospheric CO2 – some models predict an increase in number of storms while others predict a decrease.

Global Warming, Climate Change, and Hurricanes

Length of accurate records are too short [aircraft reconnaissance (since 1950s) and continuous satellite images (since 1970s) only began in the later part of last century] and evidences are too ambiguous to reach a definitive conclusion on the effect of climate change on hurricane activities and answer the question ‘how global warming might affect hurricane activity.’

Global Warming, Climate Change, and Hurricanes

Thermohaline Circulation

Image courtesy of NASA GSFC

Global Warming, Climate Change, and Hurricanes

Thermohaline (thermo for temp., haline for ocean saltiness) circulation runs the Atlantic conveyor belt, part of a global ocean system in which a continuous flow of upper-level water is drawn from the tropical Atlantic north toward the Pole. There the water cools, sinks, and cycles back to the southern oceans in deepwater currents.

When the system is moving fast, more warm water is transported north, and overall, the Atlantic warms up. A slow cycle yields a cooler ocean. In a warmer world, with melting glaciers, the far North Atlantic would be less salty because of the additional freshwater. This would weaken the circulation (salty water is heavier, and the saltier it is, the faster it sinks in the cold North Atlantic, making circulation go faster).

Slower circulation would cool the North Atlantic ocean because less heat would be transported from south to north. Cooler North Atlantic ocean normally means fewer hurricanes (see slides 27/28 of Module 1).

Global Warming, Climate Change, and Hurricanes

Thermohaline Circulation

-- How would this cooling effect counteract the warming effect?

-- Does it hold off the tipping point?

-- In what unanticipated ways might the climate be disrupted?

-- How do changes in Thermohaline Circulation affect the frequency of El Nino and La Nina?

These are some good questions having no good answers (Ref: Hurricane Almanac).