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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 Outline • Climate Controls – Precipitation and clouds – Temperature • Climate Variability in Texas- El Niño • Climate Change • Weather & Climate Information 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 Generalized Climate Regions Figure 10.4 Major Terrestrial Biomes Biome = A large terrestrial ecosystem characterized by specific plant & animal communities; named based on the dominant vegetation Figure 20.3 What is needed for precipitation to occur? How does the air get cooled? A) Convergent Lifting B) Convectional Lifting C) Orographic Lifting D) Frontal Lifting (Cold/Warm) A) Cyclonic Lifting e.g., ITCZ • Horizontal convergence of air results in upward vertical motion, and B) Convectional Lifting lower density 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) Convection over Florida Figure 8.8 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 C) Orographic Lifting Figure 8.9 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 C) Orographic Lifting Figure 8.10 Orographic Lifting D) Frontal Lifting • Cold Fronts – Cold air forces warm air aloft • Warm Fronts – Warm air moves up and over cold air Cold Front Figure 8.11 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 Cold Front and Squall Line Figure 8.12 Warm Front Figure 8.13 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 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 Cloud & Rain Formation Growth of cloud droplets: 1) condensation; 2) collisioncoalescence; 3) ice crystal growth (Bergeron process) Figure 7.20 Cloud Types and Identification 19000 ft 6000 to 19000 ft < 6000 ft Named based on: a) Height b) Shape Figure 7.23 Profile of Atmosphere • Layers based on: – Composition – Temperature – Function Figure 3.2 Cirrus = thin and wispy Composed of ice crystals; average thickness = ~1 mi Figure 7.23 Stratus = flat clouds in layers Figure 7.23 Cumulus = puffy clouds in heaps Figure 7.23 Nimbostratus = rain Figure 7.23 Cumulonimbus = thunderstorm Figure 7.23 Cirrostratus Figure 7.23 Altocumulus Figure 7.23 Altostratus Figure 7.23 Advection Fog Figure 7.25 Annual Precipitation January Precipitation February Precipitation March Precipitation April Precipitation May Precipitation June Precipitation July Precipitation August Precipitation September Precipitation October Precipitation November Precipitation December Precipitation What controls temperature? Energy Pathways Figure 4.1 Solar Energy: Electromagnetic Spectrum Solar constant = 1372 W m-2 Fig. 2.8 Solar Energy: Electromagnetic Spectrum 8% 47% 45% McKnight and Hess, 2004 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) 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 Cloud Cover • Clouds lower daily maximum temperatures and raise nighttime minimum temperatures. Why? – Night – delay release of LW radiation – Day – reflect insolation Clouds and Temperature Figure 4.7 Stratus (90% albedo) Cirrus (50% albedo) Land and Water Contrasts 5) Low albedo 5) High albedo January Average Daily Maximum January Average Daily Minimum July Average Daily Maximum July Average Daily Minimum What are the main causes of climate variability? TAMU OSC EXCEPTIONAL EXTREME 1 MONTH 3 MONTHS SEVERE Ending April 13, 2009 Ending April 13, 2009 MODERATE ABNORMALLY DRY 6 MONTHS Ending April 13, 2009 NO DROUGHT 18 MONTHS Ending April 13, 2009 Climate Variability: El Niño (ENSO) Normal SSTs in the Central Pacific 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 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) Later references sometimes refer to this event as a Warm Phase, although El Niño is still used El Niño Conditions From International Research Institute for Climate Prediction El Niño SSTs in the Central Pacific Sea Surface Temperature Anomalies: El Nino Years La Niña Conditions La Niña SSTs in the Central Pacific Sea Surface Temperature Anomalies: La Nina Years U.S. & Global Weather Anomalies El Nino Cool-Season Precipitation El Nino Cool-Season Temperature La Nina Cool-Season Precipitation La Nina Cool-Season Temperature Current Conditions http://www.cpc.noaa.gov/products/analysis_monitoring/enso_update/sstanim.shtml Niño Region SST Departures (oC) Recent Evolution The latest weekly SST departures are: Niño 4 0.0ºC Niño 3.4 -0.1ºC Niño 3 0.1ºC Niño 1+2 0.1ºC 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) U. S. Seasonal Outlooks April – June 2009 Temperature Precipitation These seasonal outlooks combine long-term trends, soil moisture, and some aspects of La Niña. What evidence is there of climate change? State of the Climate (through 2007) • 2007 = 5th warmest year in the 120+ year instrumental record [2005/1998 = tied for warmest, 2002 = 2nd warmest, 2003 = 3rd warmest, 2004 = 4th warmest] • Global temperatures were +0.5°C above the 1961-1990 mean • 10 warmest years observed in the instrumental record (begins in 1880) have all occurred since 1995 2007 Temperature Anomalies Temperature Trends • Temperature rise of about 0.17C/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 Climate Trends • Diurnal temperature range has decreased (min T are warming twice as fast as max T) • Precipitation trend = +5–10% for 30–85°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 Climate Change 2007: The Physical Basis IPCC Summary for Policy Makers Earlier spring melt, later fall frost = longer growing season Sea Level Rise 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 What is causing the climate to change? 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) Carbon Dioxide • Radiative forcing of greenhouse gases is due primarily (~64%) to CO2 • 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 How is the climate going to change? General Circulation Models (GCMs) • GCMs are the best tool for projecting the response of Earth systems to human (& natural) influences 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) - all models produce maximum warming in high northern latitudes -warming is largest in late autumn and early winter, due to sea ice forming later 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: http://www.texasclimate.org/ PANHANDLE AND PLAINS WEST CENTRAL TEXAS FAR WEST TEXAS NORTH CENTRAL TEXAS SOUTH CENTRAL TEXAS SOUTH TEXAS EAST TEXAS SOUTHEAST TEXAS Dec-Feb Temperatures 3 Average Temperature (F) 2 1 0 -1 -2 -3 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 Year Panhandle and Plains North Central Texas Far West Texas East Texas West Central Texas South Texas South Central Texas Southeast Texas 2000 Mar-Apr, Oct-Nov Temperature 3 Temperature (F) 2 1 0 -1 -2 -3 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 Year Panhandle and Plains North Central Texas Far West Texas East Texas West Central Texas South Texas South Central Texas Southeast Texas 2000 May-Sept Temperature 3 Temperature (F) 2 1 0 -1 -2 -3 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 Year Panhandle and Plains North Central Texas Far West Texas East Texas West Central Texas South Texas South Central Texas Southeast Texas 2000 Temperature Projections for Texas 6 Texas A1B Projections 5 Temperature Change (F) 4 3 2 1 0 -1 2000 2010 2020 2030 2040 2050 2060 Climate model projections: + 4 °F by 2050 Precipitation trends at centurylong USHCN stations Blue: Increasing Precipitation Red: Fraction of months below 20th percentile of PDF, 12-month precip 190119261925 1950 19762000 19511975 We were spoiled during 1976-2000! December-March Smoothed Precipitation 1.8 1.4 1.2 1 0.8 0.6 0.4 0.2 Year Panhandle and Plains North Central Texas Far West Texas East Texas West Central Texas South Texas South Central Texas Southeast Texas 2001 1998 1995 1992 1989 1986 1983 1980 1977 1974 1971 1968 1965 1962 1959 1956 1953 1950 1947 1944 1941 1938 1935 1932 1929 1926 1923 1920 1917 1914 1911 1908 1905 1902 0 1899 Fraction of Long-Term Mean Precip 1.6 April-July Smoothed Precipitation 1.8 1.4 1.2 1 0.8 0.6 0.4 0.2 Year Panhandle and Plains North Central Texas Far West Texas East Texas West Central Texas South Texas South Central Texas Southeast Texas 2001 1998 1995 1992 1989 1986 1983 1980 1977 1974 1971 1968 1965 1962 1959 1956 1953 1950 1947 1944 1941 1938 1935 1932 1929 1926 1923 1920 1917 1914 1911 1908 1905 1902 0 1899 Fraction of Long-Term Mean Precip 1.6 August-November Smoothed Precipitation 1.8 1.4 1.2 1 0.8 0.6 0.4 0.2 Year Panhandle and Plains North Central Texas Far West Texas East Texas West Central Texas South Texas South Central Texas Southeast Texas 2001 1998 1995 1992 1989 1986 1983 1980 1977 1974 1971 1968 1965 1962 1959 1956 1953 1950 1947 1944 1941 1938 1935 1932 1929 1926 1923 1920 1917 1914 1911 1908 1905 1902 0 1899 Fraction of Long-Term Mean Precip 1.6 Precipitation Projections for Texas 20 Percentage Precipitation Change Texas A1B Projections 10 0 -10 -20 2000 2010 2020 2030 2040 2050 2060 Climate model projections: probably drier by 2050 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 Sea Level Rise • Beach erosion • Loss of agricultural land • Loss of thousands of kilometers of land • Displacement of millions of coastal residents http://www.cresis.ku.edu/research/data/sea_level_rise/index.html 1 m Sea-Level Rise 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 Headline: Hundreds Attend Global Warming Protest Weather and Climate Resources http://atmo.tamu.edu/osc – Office of the State Climatologist, Texas • www.met.tamu.edu/class/wflm – Online Weather Forecasting learning modules • meted.ucar.edu – Online training for weather forecasters • www.cdc.noaa.gov – Monitoring Earth’s climate on medium range to interannual time scales Weather and Climate Resources • www.srh.noaa.gov/hgx – Warnings, short-range forecasts, radar • www.tceq.state.tx.us/nav/data/air_met_data.h tml – Ozone and air quality (current and historic) • weather.msfc.nasa.gov – Real-time satellite image browser • www.txwin.net – TX Water Information Network (drought, etc.) Help Improve Local Monitoring • Community Collaborative Rain, Hail, and Snow Network (CoCoRaHS) • http://www.cocorahs.org/ • Volunteer high-density rain gauge monitoring network • More volunteers needed in Texas! Local Monitoring Tools • • • • Office of the State Climatologist, Texas http://atmo.tamu.edu/osc Weekly/monthly climate reports Climate monitoring tools under development The End • Contact Info: – Steven Quiring, Texas A&M University – [email protected] – http://geog.tamu.edu/~squiring/ – (979) 458-1712