2: Defining Earth's Climate
- Page ID
- 50816
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\( \newcommand{\dsum}{\displaystyle\sum\limits} \)
\( \newcommand{\dint}{\displaystyle\int\limits} \)
\( \newcommand{\dlim}{\displaystyle\lim\limits} \)
\( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)
( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\id}{\mathrm{id}}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\kernel}{\mathrm{null}\,}\)
\( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\)
\( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\)
\( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)
\( \newcommand{\vectorA}[1]{\vec{#1}} % arrow\)
\( \newcommand{\vectorAt}[1]{\vec{\text{#1}}} % arrow\)
\( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vectorC}[1]{\textbf{#1}} \)
\( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)
\( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)
\( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\(\newcommand{\longvect}{\overrightarrow}\)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Introduction
Climate represents the long-term weather pattern in a region, typically averaged over 30 years. While many meteorological factors, such as atmospheric pressure, humidity, wind, etc., determine a region's climate, much of what we experience can be reduced to just temperature and precipitation. Think of a desert – chances are you pictured a hot, dry place. If you imagine a rainforest, it will be warm and wet. In the United States, the regional climate varies considerably, as shown in Figure \(\PageIndex{1}\). The West Coast enjoys plenty of sunshine, but also suffers from wildfires. Midwestern states are known for flat landscapes and fertile soil, which support the agricultural and meat industries. The southeastern states experience year-long hot, humid conditions, while the northeastern states experience humid summers but snowy, cold winters.
A good demonstration of climate would be thinking of your hometown, or the place that you’ve lived in the longest in your life. If you’ve lived in a region for quite a bit of time, you’re probably used to how the weather changes from season to season; when you need an umbrella, jacket, boots, or when you’d prefer shorts and a t-shirt. To define your region’s climate, let’s begin with a few open-ended questions to help you explain the climate of your hometown or the place that you’ve spent most of your life in. For these questions, don’t think of extremes like the day it was 115°F in San Jose; think of what is typical.
- How warm is a typical day during the warmest time of year? What time of year (month or two) does it occur?
- How cold is a typical day during the coldest time of year? What time of year does it occur?
- What time of year (a month or two) do you get the most precipitation? What kind of precipitation (rain, snow, hail, etc.) is typical during that season?
Piecing those questions together, you can get a fairly good description of your hometown’s climate. While a location’s weather can change very rapidly, such as a 25°F temperature drop as a front passes overhead, a location’s climate doesn’t change nearly as quickly. But Earth's climate does change, and it has changed in the past. Archaeologists have found plant fossils from temperate regions, dinosaur fossils in Antarctica, and Woolly mammoths in California. But the natural changes that cause such climate shifts often take tens of thousands, if not millions of years. We’ll talk more about natural climate changes and cycles later in this course. However, in this course, our focus is on a particular type of climate change – Anthropogenic Climate Change – which is defined as the Climate System’s response to human-induced changes in land cover, atmospheric chemistry, and other human alterations. But first, in this investigation, let us examine what climate is and the factors that determine a region's climate.
By the end of this investigation, you should be able to:
- Identify the primary factors that determine a region's climate
- Name the three main climate zones.
- Name the factors that affect a region's precipitation.
Investigation 1 has 23 questions in total, and the list is continuous, carrying over from the first to the last subpages of the investigation.
- 2.1: Factors affecting the Climate
- This page discusses how latitude influences climate and sunlight intensity. Higher latitudes have lower angles of insolation, which disperses solar energy and leads to cooler temperatures, while areas near the Equator receive more direct sunlight, resulting in warmer climates. Earth's axial tilt of 23.5° affects which latitudes get direct sunlight throughout the year, impacting global temperature patterns. Overall, equatorial regions experience more intense sunlight than polar regions.
- 2.2: Climate Zones
- Earth's climate can be divided into three main zones based on latitude and insolation: Tropical, Temperate, and Polar climates, each with distinct temperature characteristics and patterns. Tropical climates have consistent temperatures; Temperate climates experience moderate variations; Polar climates show extreme fluctuations. Local climate variations are also influenced by factors like elevation and proximity to water.
- 2.3: Precipitation
- This page explores the complexity of precipitation variation in various climate zones, highlighting the roles of latitude, ocean currents, and mountains. It explains how latitude influences weather, causing more rain near the Equator and deserts around 30°N & S. Ocean currents impact local climates, with examples like Arica and Rio de Janeiro.
- 2.4: Accessible Descriptions
- This page provides accessible descriptions for the images in the Investigation
Thumbnail: The three main climate zones. Biomes by CK-12 Foundation is licensed under CC BY-SA 3.0.