Download The Nature of Weather and Climate

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 0.17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
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