1Geography 1001:Climate & VegetationInstructor: Andrés HolzAgenda for Lecture 11: T Oct 2nd• Logistics– 1stExam in 9 days!– Take advantage of my office hours– Students with documented excuses, please email me this week• Review Lecture 10• Lecture 11Review Lecture 9Water Resources:• The Hydrologic Cycle• Our Water Supply– Water in the WestHydrologic Cycle ModelFigure 9.1Water Withdrawal by SectorFigure 9.21Global Water ScarcityFigure 9.222Total water use (2000)Figure 9.11Total water use (2000)Drought throughout this last summer• http://www.drought.unl.edu/dm/12_week.gifChapter 10: Global Climate Systems• Climate components & relationships• Köppen Climate Classification– Criteria– Benefits & Drawbacks• Köppen-Geiger Climate System– Earth’s Climate ClassificationClimate• Climate is weather over time & space (i.e. > 30 days)• Climatology is the study of climate• Climatic regions are areas with similar weather statistics3Climate Components (5)• Insolation• Temperature• Pressure• Air Masses• PrecipitationClimate Components: Insolation,Latitude, and daily & seasonal variationsClimate Components: Temperature,latitudealtitudeLand/water heatingdifferencesCloud coverClimate Components: Pressure,Variation in pressure winds patterns (spatial & temporal) differences in Temps Climate Components: Air Masses,Spatial/ temporal patternsClimate Components: Precipitation4Precipitation in North AmericaFigure 9.6Seasonal Pressure and Precipitation PatternsClimate RelationshipsFigure 10.3Generalized Climate RegionsFigure 10.4Köppen Climate Classification• Empirical (data) system• Began with heat zones in 1884• Published first wall map in 1928Köppen Classification: hierarchical criteria1. Average monthly temperatures2. Average monthly precipitation3. Total annual precipitationDo you think that boundaries of this classification are “perfect”?There are not perfect. Think of the scale…the whole planet!….Thus, the trend is more important than the exact location of theboundaries.5Köppen Classification: benefits & drawbacks• Benefits of this classification– It correlates reasonably with actual world– Standard worldwide and readily available data • Drawbacks (doesn’t include)– Winds, temps extremes, precipitation intensity, amount of sunshine, cloud cover, or net radiation– The causes of precipitation or temperature patternsKöppen-Geiger Climate SystemFigure 10.5Classification Categories (based purely on temperature criteria)• (A) Tropical – equatorial and tropical latitudes• (C) Mesothermal – mid-latitudes, mild winters• (D) Microthermal – mid- and high-latitudes, cold wintersClassification Categories (based purely on temperature criteria)• (E) Polar – high latitudes and polar regions• (H) Highland – compares to lowlands at the same latitude, highlands have lower temperatures• (B) Desert – permanent moisture deficits*Köppen-Geiger Climate SystemFigure 10.56Sub-climates• Within each climates, the subtypes are based on precipitation gradientsTropical Climates (A)• Consistent day length and insolation input produce consistently warm temperatures• Inter Tropical Convergence Zone (ITZC) brings rain as it shifts seasonally with the high sun• Warm ocean temperatures and unstable maritime air massesTropical Climates• Equatorial and tropical latitudes– Tropical Rain Forest Climates – rainy all year– Tropical Monsoon Climates – 6 to 12 months rainy– Tropical Savanna Climates – less than 6 months rainyPrecipitationGradientTropical Climates (A)~36% of the earth’s surface—the most extensive climate category. Tropical Rain Forest Figure 10.7Tropical MonsoonFigure 10.87Tropical SavannaFigure 10.9Mesothermal Climates C• Shifting air masses of maritime and continental origin• Migrating cyclonic and anti-cyclonic systems bring changeable weather conditions and air mass conflicts• Summers transition from hot to warm as you move away from tropicsMesothermal Climates• Midlatitudes, mild winters– Humid Subtropical – hot-summer climates – Marine West Coast – warm to cool summers – Mediterranean – dry-summer climatesPrecipitationGradient(seasonality)Mesothermal Climates (C)• 2ndlargest % of earth’s surface (land-ocean) ~27%. • Area alone is considered only fourth. • Together, A & C climate dominate more than half of earth oceans and about one third of the land area. • ~ 55% of people around the world lives in C’s climates Meso-thermal middle-heat, or middle tempsMesothermal Climates (C)Figure 10.11Mesothermal – Humid Subtropical8Mesothermal – Marine West coastFigure 10.16Mesothermal – MediterraneanMicrothermal Climates D• Mid and high latitudes, cold winters– Humid Continental – hot to warm summers – Subarctic – cool summersAverage Annual TemperatureGradient•Increasing seasonality (daylenght and Sun altitude)• Humid microthermallong winters & some summer warmth. • ~ 21% of earth’s land surface is influenced by these climates = about 7% of earth’s total surface. • These climate experience great temperature ranges, related to continentality and air mass conflicts. • Given the lack of land mass in the S-hemisphere, this climate can only be found in the N-Hemisphere. Microthermal Climates (D)Microthermal Climates (D)Subarctic –Cool SummerFigure 10.199Polar and Highland Climates • Extremes of day length between winter and summer determine the amount of insolation received• Low Sun altitude even during the long summer days is the principal climatic factor• Light-colored surfaces of ice and snow reflect substantial energy away from the ground surface, thus reducing net radiationPolar and Highland Climates • High latitudes and polar regions– Tundra – high latitude and high altitude– Ice Cap and Ice Sheet – permanently frozen– Polar Marine – oceanic association• ~19% of earth’s total surface • This climate have no true summeraverage monthly temps never rises over above 50FPolar Climates (E)Arid and Semiarid Climates B• Dry air in subtropical high-pressure systems dominates• Sometimes form in the rain shadow of mountains• Continental interiors, particularly central Asia, are far from moisture bearing air massesDry, Arid, and Semiarid Climates • Permanent moisture deficits– Arid desert - less that about 35 cm (14 in.) precipitation per year– Semiarid steppe -