Stony Brook University ATM 102 Midterm Exam Review

ATM 102 Midterm Review 01 Introduction to Climate and Climate Change Climate: is the broad average of temperature, precipitation, wind direction, and more for a given region. Climate applies to long-term (years and l ...

ATM 102 Midterm Review 01 Introduction to Climate and Climate Change Climate: is the broad average of temperature, precipitation, wind direction, and more for a given region. Climate applies to long-term (years and longer) changes. Weather: is the variability of the same variables on time-scales of hours to weeks. A 1°C temperature change means nothing as far as weather is concerned, but is a very significant change with respect to climate. Earth’s average temperature is 15°C (59°F), and much of the surface ranges between 0° and 30°C (32° and 86°F) Geologic Time: Most climate change occurs on time-scales longer than a human lifetime – we focus on events that last decades, or shorter. Earth is 4.5 billion years old Climate System: -Air, water, ice, land, and vegetation -Things that cause climate to change are referred to as forcing mechanisms, the effect is frequently referred to as the response. Climate Forcing: 1) Tectonic processes – related to the Earth’s internal heat and processes that change the shape of the surface of the earth (mountain building, slow motion of the continents, opening and closing of oceans). Time scales of millions to hundreds of millions years 2) Earth-orbital changes – variations in how our planet orbits the sun affects the amount of solar radiation the planet receives. Time scales of tens to hundreds of thousands of years. 3) Changes in the strength of the Sun – the amount of energy our sun emits is not constant through time. This too affects the amount of solar radiation we receive. Time scales of billions of years to decades. 4) Anthropogenic – the effect of humans on climate. This is a byproduct of industry, agriculture, and other human activities, primarily through greenhouse gases (CO2, CH4), sulfate particles, and soot. Time scales of decades to centuries. Climate Response: -Each part of the climate system responds to forcing with a characteristic response time. -Forcing is slow in comparison to response. If forcing is slow enough, climate tracks the forcing. Ex: Continents moving north or south a rates of centimeters per year. Average continental temperature easily keeps pace. -Forcing is fast in comparison to response. If forcing is too fast, climate barely responds because it can’t respond fast enough. Ex: Total solar eclipse darkens an area for less than an hour – that area’s surface temperature barely changes. - Forcing and response have similar time scales. Never reach equilibrium. Frequency of the forcing determines the magnitude of the response. Ex: much of what actually happens in the real world. Climate forcing and response: -Climate forcing rarely simply turns on and off. -More commonly, changes occur in smoother cycles. -Daily heating and cooling - strongest solar heating at noon, but warmest temperatures occur 3-4 hours later -S