The Nature of Weather and Climate

Transcription

1 The Nature of Weather and Climate El Camino Real Texas Master Naturalist Chapter April 14, 2009 Steven Quiring Department of Geography Texas A&M University

2 Climate Controls Outline Precipitation and clouds Temperature Climate Variability in Texas- El Niño Climate Change Weather & Climate Information

3 Climate and Ecosystems Rainfall, temperature, sunshine, humidity Means and extremes Climate controls distribution of natural vegetation Plants in Texas must be: Drought tolerant (esp. in West) Heat tolerant Cold tolerant in North

4 Generalized Climate Regions Figure 10.4

5 Major Terrestrial Biomes Figure 20.3 Biome = A large terrestrial ecosystem characterized by specific plant & animal communities; named based on the dominant vegetation

6 What is needed for precipitation to occur?

7 How does the air get cooled? A) Convergent Lifting B) Convectional Lifting C) Orographic Lifting D) Frontal Lifting (Cold/Warm)

8 A) Cyclonic Lifting e.g., ITCZ Horizontal convergence of air results in upward vertical motion, and

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10 B) Convectional Lifting lower density

11 b. Convective Precipitation Convection = upward motion of heated air (convection cells) Caused by uneven surface heating or mechanical turbulence Convective precipitation is short, intense events Can be scattered, or organized (squall line, tropical cyclone)

12 Convection over Florida Figure 8.8

13 b. Convective Precipitation If the air is moist, the release of latent heat will ensure that the parcel of air remains warmer than the surrounding air If conditions remain favorable, the rising thermal will grow into a thunderstorm

14 C) Orographic Lifting Figure 8.9

15 c. Orographic Lifting Warm moist air is forced over a mountain barrier it cools adiabatically [adiabatic process = air temperature changes due to changes in atmospheric pressure] at the LCL, condensation (and often precipitation) occurs

16 C) Orographic Lifting Figure 8.10

17 Orographic Lifting

18 D) Frontal Lifting Cold Fronts Cold air forces warm air aloft Warm Fronts Warm air moves up and over cold air

19 Cold Front Figure 8.11

20 D. Frontal Lifiting Frontal Uplift - air can be forced upward is through the movement of air masses Air masses = a large body of air, with a set of relatively uniform temperature and moisture properties

21 Cold Front and Squall Line Figure 8.12

22 Warm Front Figure 8.13

23 To get precipitation, you need: 1) Moisture in the atmosphere 2) Cloud condensation nuclei 3) Atmospheric lifting mechanism cause water vapor to cool & condense 4 basic mechanisms

24 What Controls Precipitation? Cool the air until it is saturated Water vapor condenses onto tiny particles as a liquid or solid Precipitation forms when: enough moisture condenses to start droplets falling and colliding, or the air cools enough to start forming ice

25 Cloud & Rain Formation Growth of cloud droplets: 1) condensation; 2) collisioncoalescence; 3) ice crystal growth (Bergeron process) Figure 7.20

26 Cloud Types and Identification ft 6000 to ft < 6000 ft Named based on: a) Height b) Shape Figure 7.23

27 Profile of Atmosphere Layers based on: Composition Temperature Function Figure 3.2

28 Cirrus = thin and wispy Composed of ice crystals; average thickness = ~1 mi Figure 7.23

29 Stratus = flat clouds in layers Figure 7.23

30 Cumulus = puffy clouds in heaps Figure 7.23

31 Nimbostratus = rain Figure 7.23

32 Cumulonimbus = thunderstorm Figure 7.23

33 Cirrostratus Figure 7.23

34 Altocumulus Figure 7.23

35 Altostratus Figure 7.23

36 Advection Fog Figure 7.25

37 Annual Precipitation

38 January Precipitation

39 February Precipitation

40 March Precipitation

41 April Precipitation

42 May Precipitation

43 June Precipitation

44 July Precipitation

45 August Precipitation

46 September Precipitation

47 October Precipitation

48 November Precipitation

49 December Precipitation

50 What controls temperature?

51 Energy Pathways Figure 4.1

52 Solar Energy: Electromagnetic Spectrum Solar constant = 1372 W m -2 Fig. 2.8

53 Solar Energy: Electromagnetic Spectrum 8% 47% 45% McKnight and Hess, 2004

54 Principal Temperature Controls 1) Latitude Amount of solar radiation 2) Altitude High altitude has greater daily range, lower annual average 3) Cloud Cover High albedo = moderate temperatures (cooler days, warmer nights) 4) Land/water (continental vs. maritime)

55 Altitude Lower density reduced ability to absorb and radiate infrared radiation Higher altitudes solar radiation more intense Result = lower avg. temperatures, greater nightime cooling, larger daily temperature range

56 Cloud Cover Clouds lower daily maximum temperatures and raise nighttime minimum temperatures. Why? Night delay release of LW radiation Day reflect insolation

57 Clouds and Temperature Figure 4.7

58 Cirrus (50% albedo) Stratus (90% albedo)

59 Land and Water Contrasts 5) Low albedo 5) High albedo

60 January Average Daily Maximum

61 January Average Daily Minimum

62 July Average Daily Maximum

63 July Average Daily Minimum

64 What are the main causes of climate variability?

65 TAMU OSC EXCEPTIONAL EXTREME 1 MONTH 3 MONTHS SEVERE Ending April 13, 2009 Ending April 13, 2009 MODERATE ABNORMALLY DRY NO DROUGHT 6 MONTHS 18 MONTHS Ending April 13, 2009 Ending April 13, 2009

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67 Climate Variability: El Niño (ENSO)

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69 Normal SSTs in the Central Pacific

70 ENSO In the late 1890s, fishermen along the coast of Peru begin to realize that every 2 to 10 years, with an average frequency of 7 years, there is a failure of the anchovy catch Anchovies feed on phytoplankton which, in turn, feed on nutrients from cold, upwelling waters

71 Later references sometimes refer to this event as a Warm Phase, although El Niño is still used ENSO The loss of the anchovy catch was termed an El Niño event literally, the male child although, in this case, it refers to the Christ Child since the loss occurs in the Southern Hemisphere Summer (around Christmas)

72 El Niño Conditions

73 From International Research Institute for Climate Prediction

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75 El Niño SSTs in the Central Pacific

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77 Sea Surface Temperature Anomalies: El Nino Years

78 La Niña Conditions

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81 La Niña SSTs in the Central Pacific

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83 Sea Surface Temperature Anomalies: La Nina Years

84 U.S. & Global Weather Anomalies

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88 El Nino Cool-Season Precipitation

89 El Nino Cool-Season Temperature

90 La Nina Cool-Season Precipitation

91 La Nina Cool-Season Temperature

92 Current Conditions

93 Niño Region SST Departures ( o C) Recent Evolution The latest weekly SST departures are: Niño 4 Niño 3.4 Niño 3 Niño ºC -0.1ºC 0.1ºC 0.1ºC

94 U.S. Temperature and Precipitation Departures During the Last 90 Days 90-day (ending 12 Apr 2009) % of average precipitation 90-day (ending 11 Apr 2009) temperature departures (degree C)

95 U. S. Seasonal Outlooks April June 2009 Temperature Precipitation These seasonal outlooks combine long-term trends, soil moisture, and some aspects of La Niña.

96 What evidence is there of climate change?

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98 State of the Climate (through 2007) 2007 = 5 th warmest year in the 120+ year instrumental record [2005/1998 = tied for warmest, 2002 = 2 nd warmest, 2003 = 3 rd warmest, 2004 = 4 th warmest] Global temperatures were +0.5 C above the mean 10 warmest years observed in the instrumental record (begins in 1880) have all occurred since 1995

99 2007 Temperature Anomalies

100 Temperature Trends Temperature rise of about 0.17 C/decade (since 1979) Rate of warming is about 3X greater since 1979 consider T of 1.5 C in last 10,000 years and T of

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102 Climate Trends Diurnal temperature range has decreased (min T are warming twice as fast as max T) Precipitation trend = +5 10% for N since 1900 Sea level rise = +2.8 mm/yr since 1993 Snow cover extent has generally decreased Earlier spring melt, later fall frost = longer growing season

103 Climate Change 2007: The Physical Basis IPCC Summary for Policy Makers

104 Earlier spring melt, later fall frost = longer growing season

105 Sea Level Rise

106 Shrinking glaciers Since 1996, rate of loss from Greenland ice sheet has increased by 67% If all of the Greenland ice sheet melted, global sea-level would rise 23 ft (7 m) Annually, it contributes about 0.5 mm (0.02 in.) to global sea-level rise

107 What is causing the climate to change?

108 Causes of Climate Change 1) Natural mechanisms: -variations in solar output -orbital variations -movement of continents -atmosphere/ocean variability -volcanic activity 2) Human mechanisms: -land use/land cover change (e.g., deforestation) -changing atmospheric chemistry (greenhouse gases)

109 Carbon Dioxide Radiative forcing of greenhouse gases is due primarily (~64%) to CO 2 Concentrations have increased from 330 to 383 ppm in the last 30 years Rate of increase since Industrial Revolution unprecedented in the last 10,000 years

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113 How is the climate going to change?

114 General Circulation Models (GCMs) GCMs are the best tool for projecting the response of Earth systems to human (& natural) influences

115 GCM Projections The projected rise in air temperature is 1.8 C to 4.0 C by the year 2100 (best estimate ~3.0 C) Precipitation will likely increase (decrease) in some regions 10 to 20% Decrease in snow cover and sea-ice depth and extent More frequent and intense heat waves, droughts, and heavy precipitation Tropical cyclones may be more intense (IPCC, FAR SPM)

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117 - all models produce maximum warming in high northern latitudes -warming is largest in late autumn and early winter, due to sea ice forming later

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119 Climate Change and Drought in Texas: Past vs. Future John Nielsen-Gammon Texas State Climatologist Texas A&M University The Impact of Global Warming in Texas:

120 PANHANDLE AND PLAINS FAR WEST TEXAS WEST CENTRAL TEXAS SOUTH CENTRAL TEXAS NORTH CENTRAL TEXAS EAST TEXAS SOUTHEAST TEXAS SOUTH TEXAS

121 Dec-Feb Temperatures Year Panhandle and Plains Far West Texas West Central Texas South Central Texas North Central Texas East Texas South Texas Southeast Texas

122 Mar-Apr, Oct-Nov Temperature Year Panhandle and Plains Far West Texas West Central Texas South Central Texas North Central Texas East Texas South Texas Southeast Texas

123 May-Sept Temperature Year Panhandle and Plains Far West Texas West Central Texas South Central Texas North Central Texas East Texas South Texas Southeast Texas

124 Temperature Change (F) Temperature Projections for Texas 6 5 Texas A1B Projections Climate model projections: + 4 F by 2050

125 Precipitation trends at centurylong USHCN stations Blue: Increasing Precipitation Red:

126 during ! Fraction of months below 20th percentile of PDF, 12-month precip We were spoiled

127 December-March Smoothed Precipitation Year Panhandle and Plains Far West Texas West Central Texas South Central Texas North Central Texas East Texas South Texas Southeast Texas

128 April-July Smoothed Precipitation Year Panhandle and Plains Far West Texas West Central Texas South Central Texas North Central Texas East Texas South Texas Southeast Texas

129 August-November Smoothed Precipitation Year Panhandle and Plains Far West Texas West Central Texas South Central Texas North Central Texas East Texas South Texas Southeast Texas

130 Percentage Precipitation Change Precipitation Projections for Texas 20 Texas A1B Projections Climate model projections: probably drier by 2050

131 Sea Level Rise IPCC estimates that global sea level will rise 0.18 to 0.59 m (7 to 23 in.) by 2100 However, this estimate does not consider the large changes in ice sheet mass flux that have been observed since 2003 Actual sea level changes may by larger than those predicted by the IPCC

132 Sea Level Rise Beach erosion Loss of agricultural land Loss of thousands of kilometers of land Displacement of millions of coastal residents

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134 1 m Sea-Level Rise

135 Climate Change Summary Yes, global surface temperatures are rising due to human activities Future = certainly warmer, maybe less rain, definitely more evaporation That scenario could easily happen (and has) even without global warming Year-to-year changes strongly driven by nature

136 Headline: Hundreds Attend Global Warming Protest

137 Weather and Climate Resources Office of the State Climatologist, Texas Online Weather Forecasting learning modules meted.ucar.edu Online training for weather forecasters Monitoring Earth s climate on medium range to interannual time scales

138 Weather and Climate Resources Warnings, short-range forecasts, radar tml Ozone and air quality (current and historic) weather.msfc.nasa.gov Real-time satellite image browser TX Water Information Network (drought, etc.)

139 Help Improve Local Monitoring Community Collaborative Rain, Hail, and Snow Network (CoCoRaHS) Volunteer high-density rain gauge monitoring network More volunteers needed in Texas!

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144 Local Monitoring Tools Office of the State Climatologist, Texas Weekly/monthly climate reports Climate monitoring tools under development

145 The End Contact Info: Steven Quiring, Texas A&M University (979)