lec 7 energy, climate, and weather

heat map

colors represent the magnitude, density, or concentration of values within a dataset

jet stream

area of very fast air movement in the upper atmosphere

jet streams result from

convection cells and the coriolis effect

specific heat capacity

energy required to change the temperature of 1kg of a substance by 1 degree C

specific heat capacity equation

E = mcdT

weather

day-to-day changes in atm conditions

climate

long-term average weather for an area and any departures therefrom

climate determines what we expect from

temperature and precipitation, and what we consider extreme or impossible events

climate drivers

factors that have been shown to influence climate

climate forcings

factors that influence climate change

main determinants of climate stem from

solar energy (temp and precip)

seasons created by

earth's axial tilt

season

period of year defined by specific climatic conditions

climate oscillations

any recurring climate pattern occurring on a range of timescales (not necessarily annual

normal pacific conditions

prevailing winds drive a westward surface current, colder water upwelling replaces it, warmer water collects westward and drives a convection cell, returns high-level air eastward to fuel the recurring surface wind westward

el niño phase

warm water shifts eastward towards SA, convection cell starts more centrally, weakening westward winds and creating a positive feedback

effects of el niño

droughts in Indonesia, floods in SA, subtropical jet stream is enhanced and southern US gets more storms, reduced nutrient upwelling, milder Atlantic hurricane season

la niña phase

normal patterns are enhanced; stronger westward winds, cold waters favor polar jet stream northward, storms track to Canada

la niña effects

more nutrient upwelling, increased Asian monsoon, more severe Atlantic hurricane season

shifts between pacific phases caused by

deep underwater wave-like mass movement, causing system to overshoot its neutral state and flip into the extremes

many climate oscillations cause

short or medium term fluctuations that can add to or mask effects of other forcings

factors in climate spatial variability other than solar radiation

ocean currents, water buffering effect, urban heat island, orography, plant transpiration

surface ocean currents function to

move heat via water transported from equator e.g. Gulf stream → warmer European climate

daytime coastal circulation

warm air above land rises, cooler air from water replaces it → sea breeze

rising air over coast can cool and form clouds and afternoon storms

nighttime coastal circulation

warmer water cools slower than land, so warm air above it rises and brings cooler land air to replace it

orography

high mountain relief forces air upwards, cools and loses moisture to condensation and precipitation