Earth Gauge » Oceans

Climate Trivia: El Niño Frequency

kraus — Mon, 08 Mar 2010 15:10:17 +0000

Much of our weather in the United States depends on what is happening in the tropical Pacific Ocean. During an El Niño event, which is happening now, the eastern tropical Pacific is warmer than average. During La Niña events, the eastern tropical Pacific is cooler than average. While South America’s west coast may seem far away, what happens there has been shown to affect weather throughout the United States. El Niño events mean more winter Nor’easters on America’s East Coast. El Niño events also result in a more southerly winter storm track, which means more rain and snow for the Southwest but less for the Pacific Northwest. Hurricane season in the Atlantic is less active during El Niño phases and more active during La Niña phases. An intermediate stage, known as the neutral phase, means more snowfall throughout the Mississippi River basin.

Trivia Question: What phase has been more common over the last 25 years?

a) El Niño
b) La Niña

The correct answer is a. El Niño events have become more common since the mid-1970’s. Duing the 1950’s and 1960’s, La Niña events were more common. See below for a graph of the last 60 years of El Niño (red) and La Niña (blue) event frequency.

Seasons: Winter, Spring, Summer, Fall

Sources: Kim, HM et al. “Impact of Shifting Patterns of Pacific Ocean Warming on North Atlantic Tropical Cyclones.” Science 325 (2009): 77-80 and Twine, TE et al. “Effects of El Niño-Southern Oscillation on the Climate, Water Balance, and Streamflow of the Mississippi River Basin.” Journal of Climate 18 (2005): 4840-4861 and Meehl, GA et al. “Current and Future U.S. Weather Extremes and El Niño.” Geophysical Research Letter 34 (2007) L20704 and Easterling, David. “Observed Climate Variability and Change.” NOAA/National Climatic Data Center. Ashville, NC: 31 January 2007 http://www.ametsoc.org/atmospolicy/documents/Easterling-Observed-Change-Jan-07.pdf and Meehl, GA et al. “Current and Future U.S. Weather Extremes and El Niño.” Geophysical Research Letter 34 (2007) L20704 and Easterling, David. “Observed Climate Variability and Change.” NOAA/National Climatic Data Center. Ashville, NC: 31 January 2007 http://www.ametsoc.org/atmospolicy/documents/Easterling-Observed-Change-Jan-07.pdf.

Climate Number: 2200 Cubic Miles

kraus — Mon, 01 Mar 2010 14:54:42 +0000

Glaciers have a mass balance. Glaciers lose mass by melting during the warm season (primarily the summer months) and gain mass by accumulating snow during the cold season (centered around the winter months). If a glacier accumulates more mass during the cold season than it loses during the warm season, it is said to have a positive mass balance. If it loses more mass than it gains, it is said to have a negative mass balance. Since 1960, it has become more common for glaciers to have negative mass balance years than positive mass balance years, leading to an overall global trend of glacial retreat. It is estimated that since 1960, the world’s glaciers (this does not include the ice sheets on Greenland and Antarctica) have lost about 2200 cubic miles of ice. Because melt water from these glaciers feeds the creeks and rivers that ultimately flow into the ocean, more glacier melt means higher sea levels. About one-third of the recent 3.1 mm average annual sea level rise is due to glacial melt.

For Comparison: An equivalent to 2200 cubic miles of volume is about 36 million Great Pyramids of Giza, or about six million Sears Towers.

Seasons: Winter, Spring, Summer, Fall

Sources: Global Climate Change Impacts in the United States, Thomas R. Karl, Jerry M. Melillo, and Thomas C. Peterson,(eds.). Cambridge University Press, 2009 and Meier, MF et al. “Glaciers Dominate Eustatic Sea-Level Rise in the 21st Century.” Science Express 19 July 2007 / Page 1 / 10.1126/science.1143906.

Climate Number: 73 Terawatts

kraus — Mon, 01 Mar 2010 14:45:37 +0000

The energy moving in both weather systems and through the wires that power your home can be measured in watts. The Sun heats the Earth causing the fluids of the atmosphere and the oceans to move, creating the winds and currents of Earth’s climate. The vast majority of the energy in the climate system moves through the oceans, where currents of warm and cold waters that dwarf even the largest of Earth’s land rivers transport heat and salt to and from the different ocean basins. Compared to other waters in the Arctic, the Barents Sea, which lies to the north of Scandinavia, has a relatively low amount of seasonal sea ice cover. While the northern portion of the sea freezes over with several feet of ice, the southern portion of the sea remains ice free. A current of water from the North Atlantic brings the basin a sufficient amount of warm water to ward off the Arctic ice’s southerly advance. This current moves about 86 terawatts worth of heat into the Barents Sea, and about 13 terawatts leave the sea through other currents. The remaining 73 terawatts is lost into the atmosphere, making what is known as the Barents Sea Opening a major exit, or release point, for the ocean’s heat storage.

For Comparison: It would take about 61,000 1200 megawatt nuclear power plants – about 140 times the number that exist around the world today – to generate 73 terawatts worth of power. This amount of power is almost 30 times the world’s current electrical generation capacity.

Seasons: Winter, Spring

Sources: Smedsrud, LH et al. “Heat in the Barents Sea: transport, storage, and surface fluxes.” Ocean Science 6 (2010): 219-234 and World Nuclear Association. “Nuclear Power in the World Today.” Accessed Online 28 February 2010

Climate Fact: Midwinter Storm Track Suppression

kraus — Mon, 22 Feb 2010 15:15:29 +0000

The temperature/pressure difference between the equatorial regions and the poles is at its maximum during the winter months. The energy this difference generates is thought to power the “storm tracks,” or the bands in the mid-latitudes where east to west traveling storms (cyclonic high and low pressure systems) are most common. The storm track over the Pacific brings the western U.S. ample rainfall for much of the fall, winter and spring seasons. One aspect of Northern Hemisphere winter storm behavior that has been somewhat of a mystery is the midwinter suppression of the Pacific storm track. The maximum latitudinal temperature/pressure difference during winter, which means more power for the storms, is reflected in the Atlantic storm track being at its strongest during the winter months. Over the Pacific, however, the midwinter corresponds to an average decrease in the number and strength of these storms by 20 and 14 percent respectively compared to the fall and spring months. One possible explanation for this suppression is a wintertime drop in the number of atmospheric disturbances that make their way from the mountains of central Eurasia to the Pacific. These disturbances can become the storms that move across the Pacific to North America. The sheer size of the Eurasian landmass means that the wintertime high pressure centers that sit in the middle of the continent are strong enough to push the warmer and competing air masses far to the south and away from the mountains where these warmer air masses can generate the disturbances that can ultimately become the Pacific storms.

Season: Winter

Source: Penny, S et al. “The Source of the Midwinter Suppression in Storminess over the North Pacific.” Journal of Climate 23 (2010): 634-648.

Climate Fact: Under the Sea

kraus — Mon, 22 Feb 2010 15:09:57 +0000

More heat in the Earth system leads to sea level rise through two main processes: thermal expansion and the melting of glacial (land) ice. Over the past 100 years, global sea levels have been rising at a rate of 0.7 inches per decade. Sea level rise impacts include increased coastal erosion, submergence of land surfaces and salt-water intrusion into coastal aquifers, which supply water to some of America’s most populated areas. In Maryland, sea levels around the Chesapeake Bay have been rising at a higher rate compared to global measurements; here, the rate of sea level rise during the 20th century was 1.38 inches per decade. This higher rate is due to local land subsidence – as the global sea level has been rising, the land mass has also been sinking, which increases the rate at which the sea encroaches onto the land. This rapid rise has led to impacts such as the submergence of land in Blackwater Wildlife Refuge. About 8,000 acres of Blackwater Wildlife Refuge that were above water in 1930 are now under the sea. This means that about 150 acres of land are lost to the ocean each year.

Seasons: Winter, Spring, Summer, Fall

Sources: United States. NOAA. National climate data center. “Global warming frequently asked questions: is sea level rising?” NOAA. Web. 7 Sept. 2009 and Douglas, Bruce C. Global Sea level change: determination and interpretation. Chapter 2 Impacts of sea level rise. U.S. National Report to IUGG, 1991-1994. American Geophysical Union, 1995. Web. 8 Sept. 2009. and United States. Fish and Wildlife Service. Wetland restoration. Fish and Wildlife Service, Sept. 2009. Web. 8 Sept. 2009 and United States. Environmental Protection Agency. Climate Change Division. Coastal Sensitivity to Sea-level Rise: A Focus on the Mid-Atlantic Region. EPA, 8 Sept. 2009. Web. 23 Sept. 2009 )

Climate Trivia: Coral Bleaching

espinoza — Mon, 08 Feb 2010 14:04:00 +0000

Some of Earth’s most diverse and colorful ecosystems are shallow-water coral reef ecosystems, which are built on the skeletons of animals called corals. One critical part of these ecosystems, known as zooxanthellae – the single- celled organisms that live in coral skeletons – use their photosynthetic ability to manufacture sugars from the sun, which they give to the corals. This energy, which could be likened to “rent” paid, is necessary to keep the corals alive and the reef ecosystems functioning. Corals need warm waters to survive, which is why they are only found in tropical and subtropical waters. If the water becomes too warm, however, corals “expel” the zooxanthellae and “bleach.” While corals can recover from bleaching events if the exceptionally warm conditions wane, periods of prolonged exposure to these conditions cause the corals to die. When waters in the reefs rise 1.6 degrees Fahrenheit above their long-term monthly averages, they are considered by the National Oceanic and Atmospheric Administration to be in danger of bleaching. El Niño years correspond to elevated sea surface temperatures on a global scale and the El Niño events of 1982-83 and 1997-1998 corresponded to years when coral bleaching was especially widespread.

Trivia Question: During the severe global coral bleaching event of 1998, what percentage of the world’s reef-building corals died?

a. One percent
b. Ten percent
c. 16 percent
d. Less than one percent

The correct answer is c. Sixteen (16) percent of Earth’s corals died during the 1998 bleaching event. Sea surface temperatures in the tropical and sub-tropical Atlantic are the warmest they have been since record keeping began in the 1880’s. The northern hemisphere summer (June, July and August) of 2009 logged the warmest summer global sea-surface temperatures on record.

(Sources: National Oceanic and Atmospheric Administration: NOAA News. “NOAA: Warmest Global Sea Surface Temperatures for August and Summer.” 16 September 2009. Accessed Online 6 February 2010 and Government of Australia: Great Barrier Reef Marine Park Authority. “What is Coral Bleaching?” Accessed Online 6 February 2010 )

Climate Trivia: Ocean vs. Atmosphere Carbon Stocks

espinoza — Mon, 08 Feb 2010 13:56:38 +0000

Carbon is a critical element in the Earth system. Carbon molecules are constantly moving from different states and from reservoir to reservoir. One reservoir is the terrestrial biosphere (the life systems that exist on land), which holds carbon primarily in the form of plant matter and soil. The atmosphere holds carbon in the form of carbon-dioxide gas (CO2) and methane. The oceans also hold carbon, primarily in the form of dissolved CO2 and calcium carbonate. The amount of reactive carbon – carbon in forms that can readily change its chemical state and move from one reservoir to another – in each of these reservoirs is markedly different. The ocean is by far the largest of these three carbon reservoirs.

Trivia Question: The ocean’s carbon reservoir is about how many times the size of the atmosphere’s carbon reservoir?

a. Two times
b. Ten times
c. 25 times
d. More than 60 times

The correct answer is d. The oceans hold more than 60 times the amount of reactive carbon that the atmosphere does.

(Source: Riebesell, U et al. “Sensitivities of marine carbon fluxes to ocean change.” Proceedings of the National Academy of Sciences 49 (2009): 20602-20609)

Climate Trivia: Ocean vs. Atmosphere Heat Capacity

espinoza — Mon, 08 Feb 2010 13:39:51 +0000

Even if the sun’s energy suddenly stopped, Earth would still give off heat for a while. This is because while much of the sun’s energy is reflected back into space, much of the energy that does reach the Earth is “stored” by the atmosphere, the oceans and the land. These bodies gradually release accumulated solar energy back into space in the form of long-wave or infrared radiation. The oceans are an especially complex energy storage system, with an elaborate network of currents that move heat from the surface to the depths and from the tropics to the poles. Water has a higher heat capacity than air, which means it takes far more energy to raise the temperature of a given volume of water than a given volume of air. One consequence of this higher heat capacity is that the oceans store more energy than the surrounding atmosphere.

Trivia Question: The ocean’s heat capacity is approximately how many times larger than that of the surrounding atmosphere?

a. Two times
b. Ten times
c. 100 times
d. 1000 times

The correct answer is d. The oceans hold about 1000 times as much heat as the atmosphere does. Over the past 50 years, the Earth has warmed. During this period, the oceans accumulated about 20 times the amount of heat the atmosphere accumulated.

(Source: Riebesell, U et al. “Sensitivities of marine carbon fluxes to ocean change.” Proceedings of the National Academy of Sciences 49 (2009): 20602-20609)

Climate Number: 100 Million Metric Tons

kraus — Mon, 01 Feb 2010 15:35:39 +0000

In the Southern Ocean around Antarctica, strong winds accompany strong ocean currents that move carbon from the ocean surface to the depths and from the depths to the surface. This ocean is considered to be a “Carbon dioxide (CO2) sink,” or a component of Earth’s climate that takes in more atmospheric CO2 as carbon concentrations in the atmosphere increase. It is also believed to be an important mechanism in the deglaciation process following ice ages, when atmospheric carbon concentrations are low, by “outgassing” more CO2 into the atmosphere than it absorbs. In today’s climate, it is estimated that the Southern Ocean takes in between 100 and 600 million metric tons of carbon ever year.

For Comparison: Americans consume about 100 million metric tons of concrete each year. While this may sound like a huge number, it is small compared to the total amount of CO2 exchange between the oceans and atmosphere each year, which is about 1000 times that amount.

Seasons: Winter, Spring, Summer, Fall

Sources: United Nations Conference on Trade and Development. “Review of Maritime Transport 2004.” Accessed Online 1 February 2010 and Le Quéré, Corinne et al. “Saturation of the Southern CO2 Sink Due to Recent Climate Change.” Science 316 (2007): 1735-1738 and Yuan, X and Martinson, DG. “The Antarctic Dipole and its Predictability.” Geophysical Research Letters 28 (2001): 3609-3612.

Climate Number: Two Watts per Square Meter

kraus — Mon, 01 Feb 2010 15:32:18 +0000

The amount of solar energy Earth receives varies according to the “11-year solar cycle,” which corresponds to a cycle in the frequency and distribution of sunspots on the sun’s surface. The difference in solar energy between high and low points of the solar cycle is about two watts per square meter. About 35 percent of the variation in Earth’s climate since 1600 can be explained directly by shifts in solar forcing. Indirect effects of solar variation are also important and can have pronounced regional effects on climate. For example, the behavior of the El Niño-Southern Oscillation (ENSO), the system of winds and ocean currents that affects temperature distributions in the tropical Pacific Ocean, is believed to be influenced by solar activity. Temperature distributions in the tropical Pacific in turn have noticeable impacts on weather throughout the world, including the strength of the Indian Monsoon; the position of the Northern Hemisphere storm tracks that bring winter and spring precipitation to the United States; and the intensity of the dry season in the Amazon Basin.

For Comparison: The total amount of solar irradiance that reaches Earth varies by two watts per square meter, from 1365 watts per square meter at a low points in the solar cycle to around 1367 watts per square meter at high points – about a 0.1 percent variation. The noticeable effects of the solar cycle, despite the relatively nominal absolute change in solar radiation, illustrate the non-linear nature of Earth’s climate: small changes in certain variables can have large impacts, particularly at regional scales.

Seasons: Winter, Spring, Summer, Fall

Source: Wasco, C and Sharma, A. “Effect of solar variability on atmospheric moisture storage.” Geophysical Research Letters 36 (2009): L03703.

Climate Fact: Arctic Temperature Trend Amplification and the AMO

kraus — Mon, 25 Jan 2010 14:26:27 +0000

Temperature records suggest that the Earth’s surface temperatures warmed during the early part of the 20th century, cooled from the period 1940-1970 and have since been warming. While Arctic temperature trends have corresponded to this general warming and cooling pattern, it has followed these trends more severely. During the warming period from 1910-1940, the Arctic warmed about 5.4 times the rate of the rest of the planet and from 1970-2008 it warmed at about twice the rate. During the cooling period of 1940-1970 it cooled at about nine times the rate of Earth’s average trend. What is behind this temperature trend amplifications in the Arctic? The best explanation is the behavior of the Atlantic Multidecadal Oscillation (AMO), or the periodic 65-year warming and cooling of North Atlantic sea-surface temperatures due to a strengthening and weakening of the ocean currents that bring warm waters from the tropics into the far north. If the Atlantic had a cold anomaly in the far northern regions that was balanced by a warm anomaly in the subtropics, the Arctic would noticeably cool while the rest of the planet would show little or no change in temperature. The coincidence of warm AMO periods (warm waters in the Arctic) and cool AMO periods (cool waters in the Arctic) during periods of global warming and cooling respectively helps to explain why the Arctic has shown such severe warming or cooling trends compared to globally averaged rates.

Seasons: Winter, Spring, Summer, Fall

Source: Chylek, P et al. “Arctic air temperature change amplification and the Atlantic Multidecadal Oscillation.” Geophysical Research Letters 36 (2009): L14801.

Climate Fact: Antarctic Sea Ice

kraus — Wed, 13 Jan 2010 14:42:55 +0000

Much attention has been given to the decline of sea ice over the North Pole, which fell to a September minimum of 1.6 million square miles in 2007, about 40 percent below normal levels. On the other side of the world, the sea ice that extends from Antarctica’s continental ice sheets out over the ocean fluctuates between an average summertime (March) minimum extent of about 1.1 million square miles to an average of 6.9 million miles at the end of winter (September). In contrast to the Arctic ice, the average annual extent of the southern hemisphere ice has actually grown since the late 1970s at a rate of around one percent per decade. This trend has been linked to:

•   Ozone Depletion: The most pronounced rates of ozone depletion have occurred over Antarctica, where the ozone hole forms during the spring months. While the strong westerly winds that “trap” frigid air around the continent during winter make the ozone hole possible, the hole itself works as a feedback by accentuating the pressure difference between the continent and the mid-latitudes of the Southern Hemisphere. This works to strengthen the winds responsible for the ozone hole in the first place.
•   Wind Shifts: The accentuation of the pole to mid-latitude pressure difference linked to ozone depletion has deepened several of the continent’s low pressure zones, strengthening some of the winds that blow from the continent over the ocean during the autumn months. This has led to increases in sea ice over several of Antarctica’s coastal regions.
•   Freshwater on the Ocean Surface: Increased precipitation around Antarctica and melting of the glaciers that sit on the land have led to freshening of the ocean surface waters. This promotes ice formation.

Shifts in the winds have also caused decreases in sea ice extent in some areas of the continent – specifically parts of the Southern Ocean adjacent to the Indian Ocean and the Amundsen-Bellingshausen Sea sectors. These losses have been more than compensated for by gains in other areas.

Seasons: Winter, Spring, Summer, Fall

Source: Turner, J et al. “Non-annular atmospheric circulation change induced by stratospheric ozone depletion and its role in the recent increase in Antarctic sea ice extent.” Geophysical Research Letters 36 (2009): L08502.

Climate Trivia: East Coast Winter Storm Frequency and ENSO

kraus — Mon, 07 Dec 2009 15:59:51 +0000

December is East Coast Winter Storm (ECWS) season. These storms are powered by warm water that flows from the Gulf Stream. The Gulf Stream current flows along the Eastern Seaboard past Florida and the Carolinas before reaching Cape Hatteras, where the warm water heads out into the Atlantic. ECWS’s travel northward along the coast causing high winds and coastal property damage comparable to hurricanes. They also bring heavy snowfall, causing further weather complications. On average, there are 12 ECWS’s during the December to February season, with January being the most active month. One of the best predictors of how intense an ECWS season will be is the ocean temperature along the coast of the southeastern U.S. during the previous summer (Gulf of Mexico temperatures were above average this past summer). The warmer these waters are, the stronger the Gulf Stream generally is and the more active the winter storm season will be. Interestingly, conditions in the eastern tropical Pacific affect ECWS activity as well. What eastern tropical Pacific conditions are most conducive to an active ECWS season?

a)   El Niño conditions (warmer eastern tropical Pacific SSTs)
b)   La Niña conditions (cooler eastern tropical Pacific SSTs)
c)   Neutral Conditions (average eastern tropical Pacific SSTs)

The correct answer is a. More active ECWS seasons tend to coincide with El Niño years. This is in contrast to Atlantic hurricane season trends, as El Niño conditions tend to suppress Atlantic Hurricane formation. Over the second half of the 20th century, the frequency of ECWS events showed little trend, but the storms did become slightly more intense.

Season: Winter

Sources: DeGaetana, AT et al. “Statistical Prediction of Seasonal East Coast Winter Storm Frequency.” Journal of Climate 15 (2002): 1101-1117 and Hirsch, ME et al. “An East Coast Winter Storm Climatology.” Journal of Climate 14 (2001): 882-899 and Eichler, T and Higgins W. “Climatology and ENSO-Related Variability of North American Extratropical Cyclone Activity.” Journal of Climate 19 (2006): 2076-2093 and National Oceanic and Atmospheric Administration: Climate Prediction Center. Accessed Online 7 December 2009 http://www.cpc.ncep.noaa.gov/products/precip/CWlink/stormtracks/eisdiffobs.meta.gif

Climate Trivia: ENSO and Regional Rainfall (Northwest)

kraus — Mon, 07 Dec 2009 15:58:02 +0000

Winter storm season is here. Storms will be blowing in from the Pacific, bringing rainfall to lower elevations and snow to the mountains. This year, the eastern tropical Pacific is in an El Niño phase, meaning that its waters are warmer than average. When the eastern Pacific is in an El Niño phase, the northwestern U.S. can expect:

a)   more than normal rainfall
b)   less than normal rainfall
c)   about average rainfall

The correct answer is b. The Northwest gets less than normal rainfall during El Niño winters and greater than normal rainfall during La Niña winters, when the colder waters in the eastern Pacific cause the Pacific storm track to shift north and hit us. The storm track will spend most of its time south of us this winter, thus giving us below average rainfall through about April.

View a schematic diagram of how El Niño and La Niña events affect wintertime rainfall and temperature: http://www.earthgauge.net/climate-facts-image-library#5. For more information on El Niño, including seasonal forecasts by region, visit: http://www.elnino.noaa.gov/. Learn more about what Northern Hemisphere storm tracks are and how they work: http://www.earthgauge.net/wp-content/CF_Storm%20Tracks.pdf.

Season: Winter

Sources: Eichler, T and Higgins W. “Climatology and ENSO-Related Variability of North American Extratropical Cyclone Activity.” Journal of Climate 19 (2006): 2076-2093 and National Oceanic and Atmospheric Administration: Climate Prediction Center. Accessed Online 7 December 2009 (http://www.cpc.ncep.noaa.gov/products/precip/CWlink/stormtracks/eisdiffobs.meta.gif

Climate Fact: ENSO and Regional Rainfall (South)

kraus — Mon, 07 Dec 2009 15:54:44 +0000

a)   more than normal rainfall and cooler temperatures
b)   less than normal rainfall and warmer temperatures
c)   about normal rainfall and about normal temperatures

The correct answer is a. The South gets more than normal rainfall during El Niño years and less than normal rainfall during La Niña years when the colder waters in the eastern Pacific cause the Pacific storm track to shift north and miss us. During El Niño, not only does the storm track head right for us, it is even stronger than it is during the La Niña phase. Another effect of El Niño is cooler than normal winters in the South from about Texas eastward.

View a schematic diagram of how El Niño and La Niña events affect wintertime rainfall and temperature: http://www.earthgauge.net/climate-facts-image-library#5. For more information on El Niño, including seasonal forecasts by region, visit: http://www.elnino.noaa.gov/. Learn more about what Northern Hemisphere storm tracks are and how they work: http://www.earthgauge.net/wp-content/CF_Storm%20Tracks.pdf.

Seasons: Winter

Climate Trivia: ENSO and Regional Rainfall (Southwest)

kraus — Mon, 07 Dec 2009 15:50:46 +0000

Winter storm season is here. Storms will be blowing in from the Pacific, bringing rainfall to lower elevations and snow to the mountains. This year, the eastern tropical Pacific is in an El Niño phase, meaning that its waters are warmer than normal. When the eastern Pacific is in an El Niño phase, the southwest U.S. can expect:

a)   more than normal rainfall
b)   less than normal rainfall
c)   about normal rainfall

The correct answer is a. The Southwest gets more than normal rainfall during El Niño years and less than normal rainfall during La Niña years when the colder waters in the eastern Pacific cause the Pacific storm track to shift north and miss us. During El Niño, not only does the storm track head right for us, it is even stronger than it is during the La Niña phase. Hopefully, this El Niño winter will give the Southwest some relief from the current dry and drought conditions.

Season: Winter

Climate Number: 122 Petawatts

kraus — Tue, 01 Dec 2009 19:03:33 +0000

What do ceiling fans and tropical cyclones have in common? How about ocean currents and the microwaves that heat your food? Both ceiling fans and tropical cyclones have kinetic energy – energy that an object possesses due to its motion. Ocean currents have kinetic energy as well, and microwaves are powered by electricity that is ultimately generated by the kinetic energy of the turbines that spin at the local power plant. The energy in both weather systems and your power bill can be measured in watts (your power bill is in kilowatt-hours). The energy that drives the world’s weather ultimately originates in the energy the Sun sends to Earth. Air and water are heated as they circulate, giving them a certain amount of kinetic energy. The total amount of energy flowing through the Earth’s climate in the form of wind, ocean currents, atmospheric water vapor, the heat in the soil, etc., is estimated to be 122 Petawatts, or 122 x 1015 Watts.

For Comparison: It would take over 100 million 1,200 Megawatt nuclear power plants to produce 122 Petawatts worth of power. For further comparison, a 1,200 Megawatt plant can power about 650,000 American homes.

Seasons: Winter, Spring, Summer, Fall

Source: Trenberth, KE. “An imperative for climate change planning: tracking Earth’s global energy.” Current Opinion in Environmental Sustainability 1 (2009): 19-27.

Climate Number: 412 million cubic yards per second

kraus — Mon, 30 Nov 2009 16:18:40 +0000

At 27 degrees North and ten miles east of Florida’s Jupiter Inlet, a 50-mile wide current of warm water flows past the Peninsula at an average rate of 412 million cubic yards per second. Known as the Florida Current, this is a critical component of the Gulf Stream, which is in turn a critical component of Earth’s ocean circulation. Without this ocean circulation, the tropics would be too hot and the high latitudes too cold to support life as we know it. When warm ocean waters collide with cold air masses, weather systems form. Because it brings warm waters up from the south, the Florida Current is also responsible for the growth of coral at the relatively high-latitude of the Florida Keys. Without the warm waters of the current, coral – a tropical species –would not be able to survive this far north. First identified by Ponce de Leon in 1513, the flow of the Florida Current varies by about ten percent from its weakest flow to its strongest flow on a period of two to three years.

For Comparison: 412 million cubic yards per second dwarfs the flow of even the largest of Earth’s rivers. The “Mighty Mississippi,” for example, flows past Baton Rogue Louisiana at a rate of less than 17,000 cubic yards per second.

To view a schematic diagram of the Florida Current, visit: http://www.earthgauge.net/climate-facts-image-library#6. The image comes from the National Oceanic and Atmospheric Administration and is in the public domain.

Seasons: Winter, Spring, Summer, Fall

Source: DiNezio, et al. “Observed Interannual Variability of the Florida Current: Wind Forcing and the North Atlantic Oscillation.” Journal of Climate 39 (2009): 721-736.

Climate Fact: Wind, Rain, Tornadoes, Oh My

kraus — Fri, 13 Nov 2009 15:08:28 +0000

Along with heavy rains and high winds, the impacts of landfalling hurricanes and tropical storms also include more tornado formation. The larger the tropical cyclone and the longer it spends over land, the greater the probability that tornadoes will form as the system moves. Since 1995 in the Gulf of Mexico, hurricane strength has increased 35 percent compared to the 16 year period spanning 1948-1964 (considered to be the last active period for hurricanes). This increase in storm strength has corresponded to twice as many tornadoes produced per cyclone.

Seasons: Summer, Fall

Sources: Belanger, JI et al. “Variability in tornado frequency associated with U.S. landfalling tropical cyclones.” Geophysical Research Letters 36 (2009): L17805 and “Tornado Threat Increases As Gulf Hurricanes Get Larger.” ScienceDaily. 10 Sept. 2009. Web. 14 September 2009 .

Climate Fact: SST Changes with Latitude

kraus — Fri, 06 Nov 2009 16:18:01 +0000

In today’s modern Holocene climate, warm surface waters in the tropical oceans gradually transition into the near-freezing surface waters near the poles. During warmer periods of Earth’s distant past, this temperature gradient was far less pronounced. In the early Eocene epoch (56-53 million years ago), average annual temperatures in Siberia and Canada were about 65 degrees Fahrenheit (compared to 32 degrees today) and Earth had no permanent polar ice caps. During this time, there was little temperature difference between waters in the tropics and waters in the mid-latitudes and sub-polar regions. Waters in the sub-polar regions of the southern hemisphere were even warmer than the tropical waters of today – as high as 93 degrees Fahrenheit. Cooler waters could only be found at the poles, with the average annual surface temperature at the North Pole being around 73 degrees Fahrenheit. These high temperatures did not last and over the course of the next 20 million years the mid- and high latitudes cooled. By around 35 million years ago, permanent ice sheets had grown on Antarctica. Temperatures in the tropics, however, remained largely the same, giving us the latitudinal temperature contrasts that characterize today’s climate.

Seasons: Winter, Spring, Summer, Fall

Sources: Bijl, PK et al. “Early Palaeogene temperature evolution of the southwest Pacific Ocean.” Nature 461 (2009): 776-779 and Baez, J. “Temperature.” Department of Mathematics: University of California Riverside. 1 October 2006. Accessed Online 6 November 2009