High Impact Weather Tornado Ice pellets Wind chill Rain Storm Surge Humidex Snow Hurricane Wind UV Index Blizzard

Hurricanes 30% of global insurance losses related to TCs. Gustav 2002 Fabian 2003 Juan 2003 30% of global insurance losses related to TCs. Since 1899, TCs have claimed ~620 lives in Canada or her waters. Hurricanes Luis 1995 Gabrielle 2001 “The Perfect Storm”1991

Hurricane Juan - 2003

Breeding Grounds for Tropical Cyclones

Hurricanes What's the recipe?

Hurricane recipe Warm ocean temperatures (at least 26.5° C). Unstable atmosphere so hurricanes can grow. Similar wind (speed and direction) from surface to 9 km. At least 500 km from equator.

STAGES OF DEVELOPMENT TROPICAL DISTURBANCE TROPICAL DEPRESSION When a moving area of thunderstorms in the tropics maintains its identity for 24 hours or more, the NHC classifies the weather system as a tropical disturbance. TROPICAL DEPRESSION If the area of thunderstorms becomes organized such that a rotation develops and winds become strong (20 knots or 37 km/h), the system is upgraded to a tropical depression.

STAGES OF DEVELOPMENT TROPICAL STORM If the winds continue to increase, reaching sustained gale strength (34 knots or 63 km/h) the NHC upgrades the system to a tropical storm. While the winds may be tame in comparison with a hurricane, rainfalls of 100-200 mm are not uncommon. The storm is now given a name. HURRICANE Should the winds reach 64 knots (119 km/h) or more, a hurricane is born. There are 5 classes of hurricanes.

5 Hurricane Categories 1 118 - 153 2 154 - 177 3 178 - 210 4 211 - 249 Category Wind Speed (km/h) Description 1 118 - 153 Minimal 2 154 - 177 Moderate 3 178 - 210 Extensive 4 211 - 249 Extreme 5 > 250 Catastrophic

Atlantic Names 2003 2004 2005 2006 2007 2008 Ana Bill Claudette Danny Erika Fabian Grace Henri Isabel Juan Kate Larry Mindy Nicholas Odette Peter Rose Sam Teresa Victor Wanda Alex Bonnie Charley Danielle Earl Frances Gaston Hermine Ivan Jeanne Karl Lisa Matthew Nicole Otto Paula Richard Shary Tomas Virginie Walter Arlene Bret Cindy Dennis Emily Franklin Gert Harvey Irene Jose Katrina Lee Maria Nate Ophelia Philippe Rita Stan Tammy Vince Wilma Alberto Beryl Chris Debby Ernesto Florence Gordon Helene Isaac Joyce Kirk Leslie Michael Nadine Oscar Patty Rafael Sandy Tony Valerie William Andrea Barry Chantal Dean Erin Felix Gabrielle Humberto Ingrid Jerry Karen Lorenzo Melissa Noel Olga Pablo Rebekah Sebastien Tanya Van Wendy Arthur Bertha Cristobal Dolly Edouard Fay Gustav Hanna Ike Josephine Kyle Laura Marco Nana Omar Paloma Rene Sally Teddy Vicky Wilfred

2007 Seasonal Forecasts

50% of the time it verifies in the ranges

But SST was higher than normal for both years! 2005 vs. 2006 2005 >25 named storms 7 major hurricanes 2006 <10 named storms 2 major hurricanes But SST was higher than normal for both years! 6 named storms affected Canadian waters both years. 2006 - El Niño Warm SST but also creates wind shear.

Teaching Resource www.hurricanes.ca

Speaking of hurricanes… What about environmental issues? Climate change. More hurricanes/storms? Sea level rise? Stronger hurricanes/storms? Speaking of hurricanes…there’s a lot of debate over whether or not climate change is causing more and stronger hurricanes/storms. Warmer water…yes! But there are many other ingredients as we just saw. El Nino reduces the # of tropical storms. Let’s talk about climate change. How much is human induced? What can be done? Storm surge? Global warming? Air quality?

Is our climate changing ???

“Warming of the climate system is unequivocal” IPCC Fourth Assessment Report - 2007 Arctic summer sea-ice extent Regionally-average glacier tongue length Toboggan Glacier, Alaska 1909 2000 Photos: US Geological Service, via National Snow and Ice Data Centre

Annual Average Temperature Nova Scotia, 1895-1998 1895-1998 Average 6.3ºC Trend +0.5ºC/century Temperature (ºC) Source of data: Historical Canadian Climate Database1 , courtesy of the Climate Research Branch, Meteorological Service of Canada. This database contains monthly and annual averages of minimum and maximum temperature at 210 Canadian stations. The temperatures at each station have been adjusted to correct for inhomogeneities2 (influences of non-atmospheric events on the temperature record, such as changes in position or type of thermometer, growth of nearby buildings or foliage, etc.) The goal of the adjustment is to produce an internally consistent data set that represents atmospheric temperatures as well as possible.1 Data from two weather stations were used to represent Nova Scotia: Yarmouth and Sydney. These are the only stations in Nova Scotia with records in the database covering the whole period 1895 to 1998. There are six other stations in the database with shorter records, which were not used. Annual average temperature: For each year of the graph, the maximum and minimum temperatures were averaged to calculate the annual average temperature. The two stations were then averaged together. By this procedure, the annual average temperature for these two Nova Scotia stations is 6.3ºC over the period from 1895 to 1998. There is a statistically significant, upward trend of about 0.5ºC per century (with an uncertainty of about ±0.3ºC per century).3 The slope of this linear regression was estimated by Kendall’s tau (the median of all possible slopes between two points), which is considered more accurate than the usual least-squares regression, for serially correlated data such as this temperature series.4 The uncertainty is the 95% confidence interval. It should be noted that much of the increase actually occurred between 1923 and 1953, and temperatures remained above average in most years since the early 1950s. This can be seen by careful inspection of the graph. 1Vincent, L.A., and D. W. Gullett, 1999: Canadian historical and homogeneous temperature datasets for climate change analyses. International Journal of Climatology, vol. 19, no. 13, p.1375-1388. 2Vincent, L.A., 1998: A technique for the identification of inhomogeneities in Canadian temperature series. Journal of Climate, vol. 11, no. 5, p. 1094-1104. 3Trend analysis and graph preparation: Wayne Groszko, Meteorological Service of Canada, Dartmouth, Nova Scotia. 4Zhang, X., L.A. Vincent, W.D. Hogg, and A. Niitsoo, 1999: Temperature and precipitation trends in Canada during the 20th century, submitted to Atmosphere-Ocean, August, 1999. Average of Yarmouth and Sydney Year

Projections of Future Changes in Climate Best estimate for low scenario (B1) is 1.8°C (likely range is 1.1°C to 2.9°C), and for high scenario (A1FI) is 4.0°C (likely range is 2.4°C to 6.4°C).

Hasn’t climate always changed? Yes…but on much slower timescales Continental drift hundreds of millions of years Changes in Earth’s orbit hundreds of thousands of years Enhanced greenhouse effect is now! It is true that the Earth's climate has always changed. In fact, the saying 'the only constant about climate is change' reflects this truth. However, the different factors that can cause climate change operate on very different time scales. Continental drift - the movement of Earth's tectonic plates - has changed the position of land masses on Earth over timescales of hundreds of millions of years, influencing ocean circulation and the formation of major ice sheets. Changes in the earth's orbit around the sun occur on timescales of tens and hundreds of thousands of years, influencing the amount and seasonality of solar radiation the Earth receives. Factors such as these have been instrumental in shaping past climates of Earth, such as the great Ice Ages, or the long warm period that characterized Earth's climate when dinosaurs roamed the world. However, the enhancement of the natural greenhouse effect through human activity is affecting Earth's climate now, will continue to do so in the coming centuries, and is likely to bring about changes in climate that are far more rapid than any experienced in human history. This makes global climate change an issue for citizens of the world today and tomorrow.

Impacts Photos: Top Right… Baker Brook. Credit: Le Madawaska. Top Left: Truro, March 2004. Bottom left: Truro, March 2004. Bottom right: NL

Take Action…ecoAction! www.ec.gc.ca/eco/wycd/school_e.html

QUESTIONS? Links www.weatheroffice.com Skywatchers link Google “Project Atmosphere Environment Canada.” www.hurricanes.ca www.ec.gc.ca/eco/wycd/school_e.html

What about El Niño and hurricanes? Complex process where the winds near the equator blow in the opposite direction than usual. Warm water can drift where it doesn’t normally go, cold water appears where it is normally warm, normally dry areas can get lots of rain, and rainy areas can experience drought. El Niño can create strong winds high in the atmosphere that go in different directions at different speeds. For hurricanes to form, the wind must be blowing in the same direction and at the same speed up to 9,000 metres above the sea. So, El Niño tends to reduce the number of hurricanes that form in the Atlantic.

Other instruments Aerial sounding Stevenson shelter World Meteorological Organization (WMO) standards

Imagine a cork in a stream (flow of atmosphere). TRACK FORECASTING Imagine a cork in a stream (flow of atmosphere). Initial motion and historical paths (climatology). Computer simulations.

Stephen Schneider (Stanford University) "Don't be poor in a hot country, don't live in hurricane alley, watch out about being on the coasts or in the Arctic, and it's a bad idea to be on high mountains with glaciers melting.''   (Associated Press, 07/04/08)

Energy transfers conduction convection radiation All of the atoms remain in their own place, only the energy moves Highly energetic molecules move from one place to another Atoms / molecules emit electromagnetic waves resulting in energy transfer Radiation is the mechanism of energy transfer from the sun to the earth. Heat (energy) is distributed around the earth and atmosphere through convection and conduction.

Changes in temperature are unevenly distributed The pattern of temperature change over Canada and elsewhere is complex. Changes in atmospheric circulation, and hence wind directions, during the past 50 years have caused some regions to warm much more than the hemispheric average of 0.3 C, and others to cool significantly These regional changes may be at least partly related to a long term natural cycle called the Arctic Oscillation Future decades could see a reversal of the pattern, with greater rate of warming in the eastern Arctic than in the west Source: NOAA Change in annual mean 1955 – 2005

PROJECTIONS OF FUTURE CHANGES IN CLIMATE Very likely that hot extremes, heat waves, and heavy precipitation events will continue to become more frequent Likely that future tropical cyclones will become more intense, with larger peak wind speeds and more heavy precipitation less confidence in total numbers Extra-tropical storm tracks projected to move poleward with consequent changes in wind, precipitation, and temperature patterns

Weather and the scientific method… Observation Theory Scientific method refers to a body of techniques for the investigation of phenomena and the acquisition of new knowledge of the natural world, as well as the correction and integration of previous knowledge, based on observable, empirical, measurable evidence, and subject to laws of reasoning. Although specialized procedures vary from one field of inquiry to another, there are identifiable features that distinguish scientific inquiry from other methods of developing knowledge. Scientific researchers propose specific hypotheses as explanations of natural phenomena, and design experimental studies that test these predictions for accuracy. These steps are repeated in order to make increasingly dependable predictions of future results. Theories that encompass whole domains of inquiry serve to bind more specific hypotheses together into logically coherent wholes. This in turn aids in the formation of new hypotheses, as well as in placing groups of specific hypotheses into a broader context of understanding. Among other facets shared by the various fields of inquiry is the conviction that the process must be objective so that the scientist does not bias the interpretation of the results or change the results outright. Another basic expectation is that of making complete documentation of data and methodology available for careful scrutiny by other scientists and researchers, thereby allowing other researchers opportunity to verify results as well as to establish statistical measures of reliability. The scientific method also may involve attempts, if possible and appropriate, to achieve control over the factors involved in the area of inquiry, which may in turn be manipulated to test new hypotheses in order to gain further knowledge. Law