Extreme weather events

improving observational capability, extending the record of observations, improve diagnostic process studies, develop models, conducting integrated impact assessments

climate change

process, phenomenon or human activity that may cause loss of life, injury, property damage, social/economic disruption or envtl degradation

chance, high or low, that any hazard will actually cause somebody harm

reflects the conditions of the atmosphere over a short period of time

refers to the average weather/atmospheric patterns over an extended time period

they’ve increased alot

prominent index of drought and measures the cumulative deficit in surface land moisture by incorporating previous precipitation and estimates of moisture drawn into the atmosphere into a hydrological accounting system

increased - concentrated inn heavy events, particularly in the northeast and midwest

accounts for combined strength and duration of tropical storms and hurricanes during a given season by computing theism of squares of the 6 hour maximum sustained surface winds in knots while the storm is above tropical storm intensity -levinson 2005

those lasting 2 days have not increased those lasting less than 2 days have increased a lot - maybe due to better observations

land management and regulatory decisions people building homes at the wildland urban interface

9 weather and climate disaster events with losses exceeding $1 billion each in USA

wet gets wetter, dry gets dryer

reduce meridional temp gradient, impacting speed and waviness of jet stream. jet stream moves further north

moves further north slows becomes more wavy more episodes of severe cold weather

el nino - largest source f climate variability in the instrumental record

Normally, the tropical Pacific Ocean features strong trade winds that blow from east to west - warm water piles up near Indonesia These trade winds bring ocean water with them, which gets heated up by the sun. piles up in the western Pacific. The large warm pool of water near Indonesia causes the air above it to rise, creating rainfall. Meanwhile, back east along South America, frigid water deep down in the ocean gets pulled up closer to the surface — cooling the waters around Peru. sea levels are about half a meter higher in Indonesia than they are in South America. Sea surface temperatures near Indonesia are also about 8°C (or 14.4°F) warmer than near Peru - convective loop

pacific trade winds disrupted every few years. - warm water near Indonesia sloshes back E - thermocline starts sinking - waters near Peru start warming - less rain in sahel region of Africa so less triggering of African easterly waves (seeds for cyclones) This all causes sea surface temperatures in the east and central Pacific to start rising and the trade winds to weaken further - positive feedback el Nino associated with drier weather in places like Australia and Indonesia

boomerang pacific so vast - ENSO system is a major driving force in global climate

cold and dry in california

process f evaluating relative contributions of multiple causal factors to a change or event with assignment of statistical confidence

• those that rely on observational record to determine change in probability and magnitude • those that use model simulations to compare the manifestation of an event in a world of human caused climate change and one without

• diff future warming scenarios • diff models • account for natural ‘random’ variability in earths system