Meteorology and Climatology

© Jones & Bartlett Learning, LLC CHAPTER© 1 Jones Introduction & Bartlett to Climatology Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT MeteorologyFOR SALE and Climatology OR DISTRIBUTION Scales in Climatology Subﬁelds of Climatology Climatic Records and Statistics Summary © Jones & Bartlett Learning, LLCKey Terms © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONReview Questions NOT FOR SALE OR DISTRIBUTION Questions for Thought CHAPTER 2 Atmospheric Structure and Composition © Jones & Bartlett Learning, LLC Origin of the Earth© Jonesand Atmosphere & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Atmospheric CompositionNOT FOR SALE OR DISTRIBUTION Faint Young Sun Paradox Atmospheric Structure Summary Key Terms © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Review Questions NOT FOR SALE OR DISTRIBUTION NOT QuestionsFOR SALEfor Thought OR DISTRIBUTION

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Desert: © Denis Burdin/Shutterstock;NOT Supercell: FOR © Minerva SALE Studio/Shutterstock; OR City: ©DISTRIBUTION Mrs_ya/Shutterstock.

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© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION CHAPTER 1 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC IntroductionNOT FOR SALE OR DISTRIBUTION to ClimatologyNOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION CHAPTER AT A GLANCE

■ Meteorology and Climatology ■ Scales in Climatology © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ■ Subﬁelds of Climatology NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION ■ Climatic Records and Statistics ■ Summary ■ Key Terms ■ Review Questions © Jones■ Questions & Bartlett for Thought Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

limatology may be described as the scienti c part of the system that is covered by liquid water is study of the behavior of the atmosphere— termed the hydrosphere; it is considered by those in © Jones & Bartlettthe Learning, thin gaseous LLC layer surrounding Earth’s© Jones the & elds Bartlett of oceanography, Learning, hydrology, LLC and limnology Csurface—integrated over time. Although this de nition (the study of lakes). e region comprising frozen NOT FOR SALEis certainly OR DISTRIBUTION acceptable, it fails to capture fully the scopeNOT FORwater SALE in all OR its formsDISTRIBUTION (glaciers, sea ice, surface and of climatology. Climatology is a holistic science that subsurface ice, and snow) is known as the cryosphere incorporates data, ideas, and theories from all parts of and is studied by those specializing in glaciology, as the Earth–ocean–atmosphere system, including those well as specialized physical geographers, geologists, inuenced by humans,© Jones into & an Bartlett integrated Learning, whole to LLCand oceanographers. e© biosphere,Jones & whichBartlett crosscuts Learning, LLC explain atmosphericNOT properties. FOR SALE OR DISTRIBUTIONthe lithosphere, hydrosphere,NOT FORcryosphere, SALE and OR atmo DISTRIBUTION- e Earth–ocean–atmosphere system may be di- sphere, includes the zone containing all life forms vided into a number of zones, with each traditionally on the planet, including humans. e biosphere is studied by a separate scienti c discipline. e part examined by specialists in the wide array of life sci- of© theJones solid &Earth Bartlett nearest Learning, to the surface LLC (to a depth ences, ©along Jones with & physical Bartlett geographers, Learning, geologists, LLC of perhaps 100 km) is called the lithosphere and is and other environmental scientists. studiedNOT FOR by geologists, SALE geophysicists,OR DISTRIBUTION geomorphologists, eNOT atmosphere FOR SALE is the OR component DISTRIBUTION of the sys- soil scientists, vulcanologists, and other practitioners tem studied by climatologists and meteorologists. of the environmental and agricultural sciences. e Holistic interactions between the atmosphere and

3 © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION.

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© Jones TABLE& Bartlett 1.1 Examples Learning, of Interactions LLC Between the Atmosphere© Jones and the &Other Bartlett “Spheres” Learning, and Impacts LLCon Thermal NOT FORReceipt/Climate SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Sphere Interacting with Atmosphere Example of a Potential Impact © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Lithosphere NOT FORLarge SALE volcanic OR eruptions DISTRIBUTION can create a dust and soot cloud thatNOT can reduce FOR the SALE receipt OR DISTRIBUTION of solar radiation, cooling the global atmosphere for months or years.

Hydrosphere Changes in ocean circulation can cause global atmospheric circulation shifts that produce warming in some regions and cooling in others. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC CryosphereNOT FOR SALE OR MeltingDISTRIBUTION of polar ice caps can cause extra heatingNOT at FORthe surface SALE where OR ice DISTRIBUTION was located because bare ground reﬂ ects less of the solar energy incident upon the surface than ice.

Biosphere Deforestation increases the amount of solar energy received at the surface and alters © Jones & Bartlett Learning, LLCatmospheric chemistry by© returning Jones carbon & Bartlett dioxide stored Learning, in living plantLLC matter to NOT FOR SALE OR DISTRIBUTIONthe atmosphere. NOT FOR SALE OR DISTRIBUTION

each combination of the “spheres” are important ▸ TABLE 1.1 Meteorology and Climatology contributors to the climate© Jones ( & Bartlett), at scales Learning, from LLC © Jones & Bartlett Learning, LLC local to planetary. us, climatologists must draw on e two atmospheric sciences, meteorology and cli- NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION knowledge generated in several natural and some- matology, are inherently linked. Meteorology is the times social scienti c disciplines to understand the study of weather—the overall instantaneous condition processes at work in the atmosphere. Because of its of the atmosphere at a certain place and time. Weather holistic nature of atmospheric properties over time is described through the direct measurement of par- and space,© Jones climatology & Bartlett naturally Learning, falls into the LLC broader ticular atmospheric© Jones properties & Bartlett such Learning,as temperature, LLC disciplineNOT of FORgeography. SALE OR DISTRIBUTION precipitation,NOT humidity, FOR wind SALE direction, OR DISTRIBUTION wind speed, Over the course of this book we shall see that these cloud cover, and cloud type. e term “weather” refers processes can be complex. e e ects of some of these to tangible aspects of the atmosphere. A quick look or interactions cascade up from local to planetary scales, walk outside may be all that is needed to describe the and the e ects of others tend to cascade down the weather of your location. Of course, these observations © Jonesvarious & Bartlett scales to Learning, ultimately aLLC ect individual locations © Jonesmay be compared& Bartlett with Learning, the state of LLC the atmosphere at NOT FORover SALE time. OR e processes DISTRIBUTION are so interrelated with other NOTother FOR locations, SALE which OR inDISTRIBUTION most cases is di erent. spheres and with other scales that it is o en di cult to Because meteorology deals with direct and speci c generalize by saying that any particular impact begins measurements of atmospheric properties, discussion at one component of the system or side of the scale and of weather centers on short-duration time intervals. proceeds to another. © Jones & Bartlett Learning,Weather LLC is generally discussed© over Jones time spans & Bartlett of a few Learning, LLC We can state that theNOT scope FOR of climatology SALE OR is broad. DISTRIBUTION days at most. How is the weatherNOT today? FOR How SALE does this OR DISTRIBUTION It has also expanded widely from its roots in ancient compare with the weather we had yesterday? What will Greece. e term “climatology” is derived from the the weather be like tomorrow or toward the end of the Greek word “klima,” which means “slope,” and re ects week? All of these questions involve short-term analysis the early idea that distance from the equator alone of atmospheric properties for a given time and place. So (which© causes Jones di &erences Bartlett in the Learning, angle or slope LLC of the meteorology ©involves Jones only & theBartlett present, Learning, the immediate LLC Sun in NOTthe sky) FOR drove SALE climate. OR DISTRIBUTIONe second part of the past, and the NOTnear future. FOR SALE OR DISTRIBUTION word is derived from “logos,” de ned as “study” or But a much more important component of meteo- “discourse.” Modern climatology seeks not only to rology is the examination of the forces that create the describe the nature of the atmosphere from location atmospheric properties being measured. Changes in the © Jonesto & location Bartlett over Learning, many di erent LLC time scales but also to © Jonesmagnitude & Bartlettor direction Learning, of these forces LLC over time and NOT FORexplain SALE why OR particular DISTRIBUTION attributes occur and change NOTchanges FOR in SALE the internal OR DISTRIBUTION properties of the matter being over time and to assess the potential impacts of those a ected by these forces create di erences in weather changes on natural and social systems. conditions over time. Although many meteorologists

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© Jones & Bartlettare not directly Learning, involved LLC with forecasting these changes,© Jones want & Bartlettto know how Learning, many days LLC on average exceed 1.5 cm meteorology is the only natural science in which a (0.6 in.) of rain in October because October rains are NOT FOR SALE OR DISTRIBUTION NOT FOR SALEprimary OR goal DISTRIBUTION is to predict future conditions. Weather problematic for any crop harvested during that month. forecasting has improved greatly with recent technological We can say then that both meteorologists and cli- enhancements that allow for improved understanding matologists study the same atmospheric processes but of these forces, along with improved observation, data with three primary and important di erences. First, the collection, and modeling© Jones of the & atmosphere.Bartlett Learning, Currently, LLCtime scales involved are© di Jones erent. &Meteorologists Bartlett Learning, are LLC weather forecastsNOT produced FOR by SALEthe National OR DISTRIBUTION Weather primarily concerned withNOT features FOR of theSALE atmosphere OR DISTRIBUTION at Service in the United States are accurate for most loca- a particular time and place—the “weather”—whereas tions over a period of approximately 72 hours. climatologists study the long-term patterns and trends By contrast, climate refers to the state of the at- of those short-term features—the “climate.” Second, mosphere© Jones for & a Bartlettgiven place Learning, over time. It LLC is important to meteorologists© Jones are &more Bartlett concerned Learning, with the processesLLC note that climatologists are indeed concerned with the for their own sake, while climatologists consider the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION same atmospheric processes that meteorologists study, long-term implications of those processes. ird, cli- but the scope is di erent. Meteorologists may study the matology is inherently more intertwined with processes processes for their own sake, while climatologists study happening not only in the atmosphere but also in the the processes to understand the long-term consequences other “spheres” because the interactions between the © Jones & Bartlettof those Learning,processes. Climatology, LLC therefore, allows© us Jones atmosphere & Bartlett and Learning, the other spheres LLC are more likely to NOT FOR SALEto study OR atmospheric DISTRIBUTION processes and their impactsNOT far FORhave SALE important OR consequences DISTRIBUTION over longer, rather than beyond present-day weather. shorter, time scales. is is particularly true if those ere are three properties of climatic data to consider: processes occur over large areas, because the impacts normals, extremes, and frequencies. ese are used usually take longer to develop in such cases. For in- to gauge the state© of Jones the atmosphere & Bartlett over Learning,a particular LLCstance, if the Great Lakes© Jones were to & totally Bartlett evaporate, Learning, LLC time period as compared with atmospheric conditions such a process would necessarily take place over a long NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION over a similar time period in the past. Normals refer to time period. e di erence in water level in the Great average weather conditions at a place. Climatic normals Lakes between today and tomorrow would not cause are typically calculated for 30-year periods and give a much impact on tomorrow’s weather as compared view of the type of expected weather conditions for a with today’s. A meteorologist would not need to take location© Jones through & Bartlett the course Learning, of a year. For LLC example, cli- this atmosphere–hydrosphere© Jones & Bartlett interaction Learning, into LLC account matologicallyNOT FOR SALEnormal conditionsOR DISTRIBUTION in Crestview, Florida, when consideringNOT FOR tomorrow’s SALE OR weather. DISTRIBUTION However, the are hot and humid during the summer and cool but not di erence in water content between the Great Lakes cold in winter. over centuries is more likely to have a noticeable and Two places could have the same average conditions dramatic impact on climate during that time period. but with di erent ranges of those conditions, in the Interactions between the atmosphere and other spheres, © Jones & Bartlettsame way Learning, that two students LLC who both have an average© Jones such & Bartlettas in this example, Learning, thus LLCmust be considered when NOT FOR SALEof 85% OR in DISTRIBUTIONa class may not have acquired that averageNOT FORevaluating SALE climate. OR DISTRIBUTION by earning the same score on each graded assignment. Regardless of the di erences between meteorology erefore, extremes are used to describe the maximum and climatology, it is important to recognize that the and minimum measurements of atmospheric variables distinction between the two is becoming increasingly that can be expected© toJones occur at& a Bartlett certain place Learning, and time, LLCblurred over time. A successful© Jones climatologist & Bartlett should Learning, have LLC based on a long periodNOT of FOR observations. SALE OR For example,DISTRIBUTION a a rm grounding in theNOT laws FORof atmospheric SALE OR physics DISTRIBUTION temperature of 0°C (32°F) at Crestview in April would and chemistry that dictate the instantaneous behavior fall outside of the range of expected temperatures. of the atmosphere. An e ective meteorologist should Finally, frequencies refer to the rate of incidence recognize the importance of patterns over time and of a particular phenomenon at a particular place over the impacts of those and other patterns on the Earth– a© long Jones period & of Bartlett time. Frequency Learning, data areLLC o en impor- ocean–atmosphere© Jones & system. Bartlett Learning, LLC tantNOT for FOR risk assessment,SALE OR engineering, DISTRIBUTION or agricultural eNOT holistic FOR perspective SALE ofOR climatology DISTRIBUTION also carries applications. For instance, the frequency of hailstorms over to include interactions between the atmosphere in a city is a factor in determining a homeowner’s insur- and social systems. e impact of people on their en- ance premium. Or if an engineer designs a culvert to vironment is a theme in climatology that has become © Jones & Bartlettaccommodate Learning, 8 cm (3 in.)LLC of rain in a 5-hour period© but Jones more & Bartlett prevalent Learning,in recent years. LLC It is being increasingly NOT FOR SALEthat frequency OR DISTRIBUTION is exceeded an average of two times NOTper FORrecognized SALE ORthat DISTRIBUTIONmany features of the human condi- year, this rate of failure may or may not be acceptable tion are related to climate. is is especially true of to the citizens a ected by the culvert. A farmer may climatic “extremes” and “frequencies,” because it is the

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© Jones“abnormal” & Bartlett events, Learning, and conditions LLC exceeding certain © Jonesto weeks. & Entire Bartlett tropical Learning, cyclone systems LLC and midlatitude thresholds, that generally cause the greatest impact on (frontal) cyclones with their associated fronts fall into NOT FOR SALE OR DISTRIBUTION NOT FORindividuals SALE andOR society.DISTRIBUTION the synoptic scale. Because these phenomena are quite frequent and directly a ect many people, the synoptic scale is perhaps the most studied spatial scale in the ▸ Scales in Climatology atmospheric sciences. © Jones & Bartlett Learning, LLCFinally, we can also study and© Jones view climate & Bartlett over an Learning, LLC Just as temporal scale is NOTimportant, FOR climatology SALE OR also DISTRIBUTION in- entire hemisphere or even the NOTentire FORglobe. SALE is repre- OR DISTRIBUTION volves the study of atmospheric phenomena along many sents the largest spatial scale possible and is termed the di erent spatial scales. ere is usually a direct relationship planetary scale, because it encompasses atmospheric between the size of individual atmospheric phenomena phenomena on the order of 10,000 to 40,000 km (6000 and the time scale in which that phenomenon occurs to 24,000 mi). Because in general the largest spatial FIGURE© 1.1 Jonesmicroscale & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ( ). e represents the smallest of systems operate over the longest time scales, it is no NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION all atmospheric scales. Phenomena that operate along this surprise then that planetary-scale systems operate over spatial scale are smaller than 0.5 km (0.3 mi) and typically temporal scales that span weeks to months. Examples last from a few seconds to a few hours. A tiny circulation of planetary-scale systems include the broad wavelike between the underside and the top of an individual leaf ow in the upper atmosphere and the major latitudinal © Jonesfalls & intoBartlett this category, Learning, as does LLC a tornado funnel cloud, © Jonespressure & and Bartlett wind beltsLearning, that encircle LLC the planet. local scale NOT FORand SALE everything OR between. DISTRIBUTION A larger scale is the , NOT FOR SALE OR DISTRIBUTION which operates over areas between about 0.5 and 5 km (0.3 to 3 mi)—about the size of a small town. A typical ▸ Subﬁ elds of Climatology thunderstorm falls into this spatial scale. e next spatial scale is the mesoscale, which Climatology can be divided into several sub elds, some involves systems that operate© Jones over areas & Bartlett between Learning,about of LLC which correspond to certain© scalesJones of &analysis. Bartlett For Learning, LLC 5 and 100 km (3 to 60 mi)NOT and FORtypically SALE last from OR aDISTRIBUTION few instance, the study of the microscaleNOT processes FOR SALE involving OR DISTRIBUTION hours to a few days. Such systems include those you interactions between the lower atmosphere and the local may have encountered in earlier coursework, such as the surface falls into the realm of boundary-layer climatol- mountain/valley breeze and land/sea breeze circulation ogy. is sub eld is primarily concerned with exchanges systems,© clusters Jones of &interacting Bartlett thunderstorms Learning, LLCknown as in energy, matter© Jones (especially & Bartlett water), and Learning, momentum LLC mesoscaleNOT convective FOR SALE complexes, OR aDISTRIBUTION related phenomenon near the surface.NOT Physical FOR processes SALE canOR become DISTRIBUTION complex associated with cold fronts termed “mesoscale convective in the near-surface “boundary layer” for two reasons. systems,” and the central region of a hurricane. First, the decreasing e ect of friction from the surface Moving toward larger phenomena, we come to the upward complicates the motion of the atmosphere and synoptic scale, a spatial scale of analysis that functions involves signi cant transfer of momentum downward to © Jonesover & Bartlettareas between Learning, 100 and 10,000 LLC km (60 to 6000 mi). © Jonesthe surface. & Second,Bartlett the Learning, most vigorous LLC exchanges of energy NOT FORSystems SALE of this OR size DISTRIBUTION typically operate over periods of days NOTand FOR moisture SALE occur OR in DISTRIBUTIONthis layer because solar radiant

Atmospheric © Jones & Bartlett Learning, LLC © planetaryJones w&av Bartlettes Learning, LLC 106 NOT FOR SALE OR DISTRIBUTION Midlatitude cycloneNOT FOR SALE OR DISTRIBUTION Hurricane 105 Land/sea breeze 4 10 Thunderstorm Tornado 103 © Jones & Bartlett DustLearning, devil LLC © Jones & Bartlett Learning, LLC NOT102 FORTurbulence SALE OR in an DISTRIBUTION urban city street NOT FOR SALE OR DISTRIBUTION Microturbulence Temporal Scale (seconds) Temporal 101 Micro Local Meso Synoptic Planetary 100 © Jones & Bartlett.00001 Learning,.0001 LLC.001 .01 .1 ©1 Jones10 & Bartlett100 Learning,1,000 10,000 LLC100,000 NOT FOR SALE OR DISTRIBUTION SpatialNOT Scale FOR (km) SALE OR DISTRIBUTION

FIGURE 1.1 Spatial–temporal relationships for selected atmospheric features.

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© Jones & Bartlettenergy striking Learning, the ground LLC warms it greatly and rapidly© Jones climatology & Bartlett necessarily Learning, involves LLC the explanation of compared with the atmosphere above it and because process, whereas regional climatology may not. NOT FOR SALE OR DISTRIBUTION NOT FOR SALEthe source OR DISTRIBUTIONof water for evaporation is at the surface. e study of climate can extend to times before the Boundary-layer climatology may be further subdivided advent of the instrumental weather record. is sub eld into topics that examine surface–atmosphere interactions of climatology is termed paleoclimatology and involves in mountain/alpine regions, urban landscapes, or various the extraction of climatic data from indirect sources. vegetated land covers.© Jones & Bartlett Learning, LLC i s proxy evidence may© includeJones human& Bartlett sources Learning, such LLC Physical climatologyNOT FOR is related SALE to ORboundary-layer DISTRIBUTION as books, journals, diaries,NOT newspapers, FOR SALE and OR artwork DISTRIBUTION climatology in that it studies energy and matter. However, to gain information about preinstrumental climates. it di ers in that it emphasizes the nature of atmospheric However, the eld primarily focuses on biological, energy and matter themselves at climatic time scales, geological, geochemical, and geophysical proxy sources, rather© Jones than the& Bartlettprocesses involvingLearning, energy, LLC matter, and such as ©the Jones analysis & of Bartlett tree rings, Learning, fossils, corals, LLC pollen, momentum exchanges only in the near-surface atmo- ice cores, striations in rocks, and sediment deposited NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION sphere. Some examples include studies on the causes of annually on the bottoms of lakes (varves). lightning, atmospheric optical e ects, microphysics of Bioclimatology is a diverse sub eld that includes cloud formation, and air pollution. Although meteorol- the interaction of living things with their atmospheric ogy has traditionally emphasized this type of work to environment. Agricultural climatology is the branch of © Jones & Bartletta greater Learning,extent than climatology,LLC climatologists have© Jones bioclimatology & Bartlett thatLearning, deals with LLC the impact of atmospheric NOT FOR SALEcontributed OR DISTRIBUTION to our understanding of these phenomena.NOT FORproperties SALE and OR processes DISTRIBUTION on living things of economic Furthermore, the convergence of meteorology and cli- value. Human bioclimatology is closely related to the matology as disciplines will likely lead to more overlap life sciences, including biophysics and human physiology. in these topics of research in the future. Applied climatology is di erent in its orientation Hydroclimatology © Jones involves & Bartlett the processes Learning, (at all LLCfrom the other sub elds© of Jonesclimatology. & Bartlett While the Learning, oth- LLC spatial scales) of interaction between the atmosphere and ers seek to uncover causes of various aspects of climate, NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION near-surface water in solid, liquid, and gaseous forms. applied climatology is primarily concerned with the ef- is sub eld analyzes all components of the global hy- fects of climate on other natural and social phenomena. drologic cycle. Hydroclimatology interfaces especially is sub eld may be further subdivided. One area of closely with the study of other “spheres,” including the focus involves attempts to improve the environment. lithosphere,© Jones &cryosphere, Bartlett andLearning, biosphere, LLC because water Examples© Jonesinclude &using Bartlett climatic Learning, data to create LLC more isNOT present FOR in all SALE of these OR spheres DISTRIBUTION and interactions readily e cientNOT architectural FOR SALE and engineering OR DISTRIBUTION design, generat- occur between them. ing improvements in medicine, and understanding the Another sub eld of climatology is dynamic cli- impact of urban landscapes on the natural and human matology, which is primarily concerned with general environment. Other examples involve the possibility of atmospheric dynamics—the processes that induce at- modifying the physical atmosphere to suit particular © Jones & Bartlettmospheric Learning, motion. Most LLC dynamic climatologists work© Jones human & Bartlett needs, such Learning, as with the LLC practice of cloud seed- NOT FOR SALEat the OR planetary DISTRIBUTION scale. is di ers from the sub NOT eld FORing ,SALE which attemptsOR DISTRIBUTION to extract the maximum amount of synoptic climatology, which is also concerned of precipitation from clouds in water-scarce regions. with the processes of circulation but is more region- In general, each sub eld overlaps with others. We ally focused and usually involves more practical and cannot fully understand processes and impacts relevant speci c applications© Jonesthan those & Bartlettdescribed Learning,in the more LLCto any sub eld without touching© Jones on & aspects Bartlett important Learning, LLC theoretical area ofNOT dynamic FOR climatology. SALE OR According DISTRIBUTION to for others and at least oneNOT other FOR nonclimatology SALE OR DISTRIBUTIONeld. climatologist Brent Yarnal, synoptic climatology “studies For example, an agricultural climatologist interested the relationships between the atmospheric circulation in the e ect of windbreaks to reduce evaporation rates and the surface environment of a region.” He goes on in an irrigated eld must understand the near-surface to state that, “because synoptic climatology seeks to wind pro le and turbulent transfer of moisture, along explain© Jones key &interactions Bartlett betweenLearning, the atmosphereLLC and with soil© andJones vegetation & Bartlett properties. Learning, LLC surfaceNOT FOR environment, SALE OR it has DISTRIBUTION great potential for basic NOT FOR SALE OR DISTRIBUTION and applied research in the environmental sciences.” ▸ Climatic Records and Statistics Synoptic climatology may act as a keystone that links studies of atmospheric dynamics with applications in Because climatology deals with aggregates of weather © Jones & Bartlettvarious other Learning, disciplines. LLC © Jonesproperties, & Bartlett statistics Learning, are used LLC to reduce a vast array NOT FOR SALESynoptic OR DISTRIBUTION climatology is similar in some waysNOT to FORof recorded SALE ORproperties DISTRIBUTION into one or a few understand- regional climatology, a description of the climate of able numbers. For instance, we could calculate the a particular region of the surface. However, synoptic daily mean temperature—the average temperature

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© Jonesfor & the Bartlett entire day—for Learning, yesterday LLC at a particular location © Jonesa particular & Bartletttime period. Learning, Extremes are LLC o en given on the through a number of methods. First, we could take nightly news to give a reference point to the daily recorded NOT FOR SALE OR DISTRIBUTION NOT FORall recordedSALE OR temperatures DISTRIBUTION throughout the day, add temperatures. We might hear that the high temperature them together, and then divide by the total number of for the day was 33°C (92°F), but that was still 5 C° (8 F°) observations. lower than the “record high” of 38°C (100°F) recorded A much simpler (but less accurate) method of calculat- on the same date in 1963. As long as our recorded atmo- ing the daily mean temperature© Jones is actually & Bartlett the one Learning,that is spheric LLC properties are within the© extremes, Jones we& Bartlettknow that Learning, LLC used: A simple average isNOT calculated FOR from SALE the maximum OR DISTRIBUTION the atmosphere is operating withinNOT the FOR expected SALE range OR DISTRIBUTION and minimum tem peratures recorded for the day. is of conditions. When extremes are exceeded or nearly method is the most common because in the days before exceeded, then the atmosphere may be considered to be computers were used to measure and record temperature, behaving in an “anomalous” manner. e frequency with special ©thermometers Jones & Bartlettthat operated Learning, on the principle LLC of a which extreme© events Jones occur & Bartlett is also important. Learning, Speci LLC - “bathtub ring” were able to leave a mark at the highest and cally, if extreme events occur with increasing frequency, NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION lowest temperature experienced since the last time that the environmental, agricultural, epidemiological, and the thermometer was reset. Each day, human observers economic impacts will undoubtedly increase. could determine the maximum and minimum temperature Why are climatic records important? During the for the previous 24 hours, but they would not know any 1980s and 1990s the rather elementary notion that © Jonesof &the Bartlett other temperatures Learning, that LLC occurred over that time © Jonesclimate changes& Bartlett over timeLearning, was absorbed LLC by the general NOT FORspan. SALE For most OR of DISTRIBUTIONthe period of weather records, we knew NOTpublic. FOR Before SALE that OR time DISTRIBUTION many people thought that cli- only the maximum and minimum daily temperatures. mate remained static even though weather properties Of course, the numerical average calculated by the varied considerably around the normals (averages). maximum–minimum method di ers somewhat from With heightened understanding of weather processes the one obtained by taking© Jonesall hourly & temperatures Bartlett Learning, and came LLC the realization that climate© Jones varies considerably& Bartlett Learning, LLC dividing by 24. Even though we have automated systems as well. Climatic calculations and the representation NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION now that can measure and record temperatures every of climate for a given place over time became exceed- second, we do not calculate mean daily temperatures ingly important and precise. e problems associated using this more accurate method because we do not want with the calculation of various atmospheric properties to change the method of calculating the means in the still existed, however, and the methods of calculating middle© of Jonesour long-term & Bartlett weather Learning, records. What LLC would these properties© Jones could have & Bartlett far-reaching Learning, implications LLC happenNOT if the temperaturesFOR SALE began OR DISTRIBUTIONto rise abruptly at the on such endeavorsNOT asFOR environmental SALE OR planning, DISTRIBUTION hazard same point in the period of record that the method of assessment, and governmental policy. calculating the mean temperature changed? We would With today’s technology we would assume that not know whether the “change” represented an actual calculating a simple average temperature for Earth, change in climate or was just an artifact of a change for instance, would be easy. However, data biases and © Jonesin & the Bartlett method Learning,of calculating LLC the mean temperature. © Jonesmethodological & Bartlett di erences Learning, complicate LLC matters. Many NOT FOR SALEBut what OR about DISTRIBUTION that average temperature? Is it actually NOTof these FOR issues SALE have OR been DISTRIBUTION mathema tically corrected in meaningful? Let’s say that yesterday we recorded a high recorded data. Given the corrections, it is generally temperature of 32°C (90°F) and a low of 21°C (70°F). Our accepted that Earth’s average annual temperature has calculated average daily temperature would be about 27°C risen by about 0.85 C° (1.53 F°) since the widespread (80°F). is number would© Jones be used & to Bartlett simply describe Learning, instrumental LLC record began in 1880.© Jones & Bartlett Learning, LLC and represent the temperatureNOT of FOR the day SALE for our OR location. DISTRIBUTION Another factor that complicatesNOT theFOR interpretation SALE OR DISTRIBUTION But the temperature was likely to have been 27°C (80°F) of the observed warming is the increasingly urban only during two short periods in the day, once during location of many weather stations as urban sprawl in- the mid-day hours when climbing toward the maximum fringes on formerly rural weather stations. Early in the and again as temperatures decreased through the late twentieth century many weather stations in the United a ernoon.© Jones So the term & Bartlett “average temperature” Learning, is LLC actually a States and elsewhere© Jones were & located Bartlett on the Learning, fringe of major LLC rather abstractNOT FOR notion. SALE Most averages OR DISTRIBUTION or climatic “normals” cities. is wasNOT especially FOR trueSALE toward OR the DISTRIBUTION middle part are abstract notions, but the advantage from a long-term of the century with the construction of major airports (climatic) perspective is that they provide a “mechanism” far from the urban core. Weather observations could for analyzing long-term changes and variability. be recorded at the airport in a relatively rural, undis- © Jones & “Extremes”Bartlett areLearning, somewhat diLLC erent. As we saw earlier in © Jonesturbed location. & Bartlett As cities Learning, grew, however, LLC these locations NOT FORthis SALEchapter, ORclimatic DISTRIBUTION extremes represent the most unusual NOTbecame FOR swallowed SALE OR up byDISTRIBUTION urban areas. is instituted conditions recorded for a location. For example, these considerable bias into long-term records as arti cial heat may represent the highest or lowest temperatures during from urban sources, known as the urban heat island,

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FIGURE 1.2 Location of global surface observations at various years. Courtesy of Kevan Hashemi. © 2015. Retrieved from: www.hashemifamily.com/Kevan/Climate/#Global%20Surface. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION became part of the climatic record. Various properties, arrival of satellite monitoring and recording technology, such as the abundance of concrete that absorbs solar because the representation of surface and atmospheric energy e ectively, the absence of vegetation and water properties was greatly limited to shipping lanes. surfaces,© Jones and & the Bartlett generation Learning, of waste LLCheat by human Even© recordsJones taken & Bartlett with rather Learning, sophisticated LLC weather activitiesNOT FOR contribute SALE to OR the DISTRIBUTIONheat island. e urban heat stationsNOT may be FOR biased SALE and complicated OR DISTRIBUTION to some degree island provides an excellent example of how humans by rather simple issues. Foremost among these are sta- can modify natural climates and can complicate the tion moves. Moving a station even a few meters may calculation and analysis of “natural” climatic changes. ultimately bias long-term recordings as factors such as In addition, the long-term recordings themselves di ering surface materials and solar exposure occur. Also © Jones & Bartlettmay be plagued Learning, by other LLC problems. Consider that most© Jones of ¬e Bartlett is time of Learning, observation LLC bias, which involved data NOT FOR SALEweather OR records DISTRIBUTION for the world are con ned to more-NOT FORbias SALE based on OR the DISTRIBUTION time of day when measurements are developed countries and tend to be collected in, or near, recorded at di erent stations. Finally, systematic biases and population centers. Developing countries, rural areas, changes in the instrumentation may cause inaccuracies and especially the oceans are poorly represented in in measurements. e result of these, and a host of other the global weather© database, Jones particularly& Bartlett in Learning, the earlier LLCbiases, is that considerable© dataJones “correction” & Bartlett is required. Learning, LLC part of the recordNOT (FIGURE FOR 1.2). SALE Oceans OR comprise DISTRIBUTION over Both the biases and the correctionNOT FOR methods SALE fuel OR debate DISTRIBUTION 70% of the planet’s surface, yet relatively few long- concerning the occurrence of actual atmospheric trends. term weather records exist for these locations. Most atmospheric recordings over oceans are collected from ▸ Summary ships, and these recordings are biased by inconsisten- cies© Jones in the height & Bartlett of the ship-mounted Learning, weatherLLC station, is chapter© Jones introduces & Bartlett the Learning,eld of climatology. LLC It theNOT type FOR of station SALE used, OR the DISTRIBUTION time of observation, and describesNOT the FORscope ofSALE climatology, OR DISTRIBUTION the inherent di er- the composition of ship materials. Furthermore, ences between meteorology and climatology, and the ocean surface temperatures are derived in a variety of associated notions of weather and climate. Meteorology ways, from inserting a thermometer into a bucket of studies changes in weather, the state of atmospheric © Jones & Bartlettcollected Learning, ocean water LLCto recording the temperature© of Jones properties & Bartlett for aLearning, given location LLC over a relatively short NOT FOR SALEwater OR passing DISTRIBUTION through the bilge of the ship (with NOTthe FORperiod SALE of time, OR whileDISTRIBUTION climatology examines weather heat generated by the ship included in the recording). properties over time for a location. Climatology is a Vast tracts of ocean were largely ignored until the recent holistic science in that it involves understanding the

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© Jonesinteraction & Bartlett of theLearning, atmosphere LLC with other aspects of © Joneshydrosphere, & Bartlett cryosphere, Learning, and biosphere. LLC All are impor- the Earth–ocean–atmosphere system using many dif- tant to the establishment of global, hemispheric, and NOT FOR SALE OR DISTRIBUTION NOT FORferent SALE spatial OR and DISTRIBUTION temporal scales. Each scale partially regional climates. de nes the many interlocking sub elds of climatology, Climatic data and calculations also are described, including boundary-layer, physical, hydro-, dynamic, with particular emphasis on climatic normals, extremes, synoptic, regional, paleo-, bio-, and applied climatology. and frequencies. Some causes of spurious climatic data, Interactions occur between© Jones the atmosphere, & Bartlett lithosphere, Learning, such LLC as the urban heat island, ©are Jones also introduced. & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Key Terms Agricultural© Jones climatology & Bartlett Learning,Frequencies LLC © JonesPaleoclimatology & Bartlett Learning, LLC AppliedNOT climatology FOR SALE OR DISTRIBUTIONFriction NOT PhysicalFOR SALE climatology OR DISTRIBUTION Atmosphere Global hydrologic cycle Planetary scale Bioclimatology Human bioclimatology Pressure Biosphere Hydroclimatology Proxy evidence Boundary-layer climatology Hydrosphere Regional climatology © JonesClimate & Bartlett Learning, LLC Lithosphere © Jones & BartlettSynoptic Learning, climatology LLC NOT FORClimatology SALE OR DISTRIBUTION Local scale NOT FOR SALE ORSynoptic DISTRIBUTION scale Cloud seeding Mesoscale Time of observation bias Cryosphere Meteorology Urban heat island Daily mean temperature Microscale Varve Dynamic climatology © Jones & BartlettMomentum Learning, LLC Weather © Jones & Bartlett Learning, LLC Evaporation NOT FOR SALENational OR WeatherDISTRIBUTION Service Wind NOT FOR SALE OR DISTRIBUTION Extremes Normals

Review Questions © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC 1. WhyNOT is FOR the science SALE of OR climatology DISTRIBUTION inherently 5. DescribeNOT the variousFOR SALE spatial andOR temporal DISTRIBUTION scales holistic? of climatology. 2. Brie y describe Earth’s “spheres.” Give examples 6. Discuss the di erent subdisciplines within cli- of how each of the spheres is connected. matology. How are they di erent from/similar 3. Compare and contrast the notions of weather to one another? © Jones & Bartlettand climate. Learning, LLC © Jones7. How & Bartlettare mean temperaturesLearning, LLCcalculated? Discuss NOT FOR4. SALECompare OR andDISTRIBUTION contrast the sciences of meteorol- NOT FORthe problemsSALE OR inherent DISTRIBUTION in the calculation methods. ogy and climatology. 8. What is the urban heat island and why is it relevant to temperature assessment?

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Questions for ThoughtNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 1. ink of several examples of how advancements 3. To what extent are “extreme events” a matter of in science and technology may have helped cli- perspective? matology to evolve as a science since 1950. 4. In what sense might the occurrence of noncata- 2. In© today’sJones age& Bartlett of specialization, Learning, is climatol-LLC strophic© events Jones cause & catastrophicBartlett Learning, events to occur? LLC ogy’sNOT interdisciplinary FOR SALE OR nature DISTRIBUTION an advantage or a NOT FOR SALE OR DISTRIBUTION disadvantage?

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