Evidence of Climate Change in Orlando, Florida

Josh Gray, Andrew Chin, Philip Womble, Sean Weyrich, Holly Padgett

04/21/2009

Precipitation: Overview and Context

• Average annual precipitation is ~48 inches

• Higher precipitation in summer months

• Dominated by frontal systems in the fall and winter, and convective events in the summer and spring

• ENSO variability• Extreme events: tropical

storms• Data from Orlando Int. AP (ID:

086628) (28.43,-81.33) Period of record: 1952-current

Precipitation: Monthly Variability

• The climate record for Orlando indicates that summer months have elevated precipitation

• Summer means are ~7 inches compared with winter means of ~2.5 inches

Precipitation: Annual Variability

• 5 driest years: 2000, 1990, 1955, 1961, 2006• 5 wettest years: 1994, 2002, 1959, 1997, 1991• Slight increase in annual precipitation over the period of record; not

stat. sig. at 5% confidence level• Qualitatively, annual precipitation appears to be increasingly variable

Precipitation: ENSO

• MEI: multivariate ENSO index: weighted average of the main ENSO components: sea level pressure, surface wind, SST, surface air temp, and cloudiness

• Positive values are associated with El Nino and negative values with La Nina

• The Orlando record indicates a strong correlation with MEI

Climate Change: IPCC

• Warmer temperatures lead to increased water vapor• Increased precipitation in intertropical convergence zones, decrease in

subtropics (likely), and increase in subpolar and polar regions (very likely)

• High amount of geographic and temporal uncertainty• Less than 66% of models agree about the sign of the precipitation

change in Florida• Complex interaction with ET leads to high uncertainty as it relates to net

hydrological fluxes for a region

Climate Change: ENSO and Tropical Storms

• Timmerman 1997: Increased frequency of ENSO like events with warming SST

• Observational evidence for increase in tropical cyclones in the N. Atlantic since 1970

• Emanuel 2007: Tropical storms are likely to increase in intensity

• Increased intensity is strongly correlated with increasing SST

Precipitation: Conclusions

• The seasonal pattern of precipitation in Florida is characterized by wet summers

• Strong ENSO influence on temporal precipitation patterns• Climate change is likely to increase ENSO like events and the

intensity of tropical cyclones• Climate change models have a high degree of uncertainty when it

comes to the geographic variability in future precipitation• There are implications for tourism and agriculture, the states two most

important economic sectors, as well as hazard mitigation and response

Cooling Degree Days

• CDD= Avg. Temp. – 65°F• CDD must be greater than or equal to 0• Linear Regression line shows increase of about 4 CDD/year

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 20101600

1800

2000

2200

2400

2600

2800

f(x) = 4.17744897959184 x − 5979.20163265306R² = 0.191586214370946

Accumulation of CDD from June 1 to Sept. 1

Year

CDD

Heating Degree Days

• HDD= 65°F – Avg. Temp.• HDD must be greater than or equal to 0• Linear regression line shows a decrease of about 3.4 HDD/year

– Actually means avg. temps. for this period are increasing over time

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 20100

100

200

300

400

500

600

700

800

900

1000

f(x) = − 3.3619387755102 x + 7135.88244897959R² = 0.106069266197403

Accumulation of HDD from Dec. 1 to Mar. 1

Year

HDD

Growing Degree Days

• GDD= Avg. Temp. - 65°F• GDD must be greater than or equal to 0• Linear regression line shows increase of about 4.8 GDD/year

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 20104200

4400

4600

4800

5000

5200

5400

f(x) = 4.77438775510204 x − 4458.50775510204R² = 0.181528786851236

Accumulation of GDD from Mar. 1 to Sept. 1

Year

GDD

Implications• The increase in CDD will mean that residents/businesses will use

more air conditioning– Increases energy demand increase in C02 emissions

• Decrease in HDD will equate to less heating during the winter season– Decrease in energy demand

• Due to Orlando being relatively warmer than the base temp of 65°F, it is likely that if these trends continue the energy demand will have a net increase

• Increase in GDD could have variable effects– Effects depend on the type of crops being grown and the season

they are being grown in– If GDD continue to rise crops grown in other parts of the SE

might be replaced with more subtropical crops more indicative of South Florida region

Annual Average Mean Temperatures in Orlando, FL

y = 0.0263x + 20.298

R2 = 0.1685

y = 0.0125x + 47.838

R2 = 0.0141

69

70

71

72

73

74

75

76

1950 1960 1970 1980 1990 2000 2010 2020

Year

Tem

pera

ture

(F)

1953-2008

1993-2008

Linear (1953-2008)

Linear (1993-2008)

Annual Average Mean Temperatures in Sanford, FL

y = 0.0137x + 44.52

R2 = 0.0567

y = 0.0791x - 85.9

R2 = 0.2174

69

69.5

70

70.5

71

71.5

72

72.5

73

73.5

74

1940 1950 1960 1970 1980 1990 2000 2010 2020

Year

Tem

pera

ture

(F)

1949-2008

1993-2008

Linear (1949-2008)

Linear (1993-2008)

• Data from Orlando Int’l Airport 1952-present

• Gap from 1971-73 filled with Orlando Exec. Airport

• Site comparison with Sanford, FL (~20 miles NNE)

• Typical annual mean between 70-75 F

• Overall warming trend evident; also during last 16 years

• Seasonal definitions: winter 12/21-3/21, spring 3/22-6/20, summer 6/21-9/22, fall 9/23-12/20

Mean Temperatures

Summer

Average Mean Summer Temperatures in Orlando, FL

y = 0.0233x + 35.761

R2 = 0.1913

y = 0.026x + 30.097

R2 = 0.0241

79

80

81

82

83

84

85

1940 1950 1960 1970 1980 1990 2000 2010 2020

Year

Tem

pera

ture

(F)

1953-2008

1993-2008

Linear (1953-2008)

Linear (1993-2008)

Average Mean Summer Temperatures in Sanford, FL

y = 0.0216x + 38.781

R2 = 0.2484

y = 0.1031x - 123.97

R2 = 0.473

79.5

80

80.5

81

81.5

82

82.5

83

83.5

84

1940 1950 1960 1970 1980 1990 2000 2010 2020

Year

Tem

pera

ture

(F)

1948-2008

1993-2008

Linear (1948-2008)

Linear (1993-2008)

Entire record

Last 16 years

Orlando +.0233 °F/yr.

+.026 °F/yr.

Sanford +.0216 °F/yr.

+.1031 °F/yr.

5 hottest years- 1987, 2005, 1990, 1998, 2007

5 hottest years- 2005, 2007, 2004, 2000, 2006

WinterAverage Mean Winter Temperatures in Orlando, FL

y = 0.0291x + 4.528

R2 = 0.042

y = 0.0749x - 86.987

R2 = 0.0517

56

58

60

62

64

66

68

1940 1950 1960 1970 1980 1990 2000 2010 2020

Year

Tem

pera

ture

(F)

1953-2008

1993-2008

Linear (1953-2008)

Linear (1993-2008)

Average Mean Winter Temperatures in Sanford, FL

y = -0.0163x + 93.656

R2 = 0.014

y = 0.0762x - 90.791

R2 = 0.0509

54

56

58

60

62

64

66

68

1940 1950 1960 1970 1980 1990 2000 2010 2020

Year

Tem

pera

ture

(F)

1948-2008

1993-2008

Linear (1948-2008)

Linear (1993-2008)

Entire record

Last 16 years

Orlando +.0291 °F/yr.

+.0749 °F/yr.

Sanford -.0163 °F/yr.

+.0762 °F/yr.

5 hottest years- 1971, 1988, 1974, 1981, 1996

5 hottest years- 1973, 1956, 1949, 1971, 1988

City Graph Time span Slope R2

Sanford August last 16 0.1218 0.2852Sanford Summer last 16 0.1031 0.473Sanford Annual last 16 0.0791 0.2174Sanford Spring last 16 0.0703 0.0443Sanford Winter last 16 0.0702 0.0509Orlando August last 16 0.0541 0.0515Orlando Fall all 0.0309 0.103Orlando Winter all 0.0291 0.042Sanford Fall all 0.0278 0.0741Orlando Annual all 0.0263 0.1085Orlando Summer last 16 0.026 0.0241Orlando August all 0.0254 0.1696Orlando January all 0.0253 0.011Orlando Winter last 16 0.0249 0.0517Orlando Summer all 0.0233 0.1913Sanford Summer all 0.0216 0.2484Sanford August all 0.021 0.159Orlando Spring all 0.0175 0.0686Sanford Annual all 0.0137 0.0567Orlando Annual last 16 0.0125 0.0141Sanford Spring all 0.0082 0.0107Sanford Fall last 16 0.0036 0.0002Sanford Winter all -0.0163 0.014Sanford January all -0.0255 0.0119Orlando Fall last 16 -0.0343 0.0125Orlando Spring last 16 -0.0516 0.0684Orlando January last 16 -0.0574 0.0096Sanford January last 16 -0.0875 0.0264

Daily Average Temperatures Greater than or Equal to 85 F in Orlando, Florida

y = 0.2192x - 425.7

R2 = 0.1433

-1

4

9

14

19

24

29

34

39

44

49

1950 1960 1970 1980 1990 2000 2010 2020

Year

Nu

mb

er

of

Occu

ren

ces

>= 85 F

Linear (>= 85 F)

Daily Average Temperatures Greater than or Equal to 85 F in Sanford, Florida

y = 0.2558x - 498.62

R2 = 0.2659

-1

4

9

14

19

24

29

34

39

44

49

1940 1950 1960 1970 1980 1990 2000 2010 2020

Year

Nu

mb

er

of

Occu

ren

ces

>=85 F

Linear (>=85 F)

Entire record

Orlando +.2192 days/yr.

Sanford +.2558 days/yr.

Days >85°F

Days <50 °F

Daily Average Temperatures Less than or Equal to 50 F in Orlando, FL

y = -0.1349x + 277.65

R2 = 0.1373

0

5

10

15

20

25

30

1950 1960 1970 1980 1990 2000 2010 2020

Year

Nu

mb

er

of

Occu

ren

ces

<=50 F

Linear (<=50 F)

Daily Average Temperatures Less than or Equal to 50 F in Sanford, FL

y = -0.0379x + 88.004

R2 = 0.0103

0

5

10

15

20

25

30

35

1940 1950 1960 1970 1980 1990 2000 2010 2020

Year

Nu

mb

er

of

occu

ren

ces

<=50 F

Linear (<=50 F)

Entire record

Orlando -.1349 days/yr.

Sanford -.0379 days/yr.

Observations• General heating trend, more evident in summer months• Less distinct winter trend• Top 5 highest slope values in Sanford in last 16 years• Notable cooling trends- last 16 years in January at

both sites, Orlando Fall and Spring last 16 years

Reasoning• Loss of wetlands, forests due to agricultural and urban expansion

influential (Pielke)– Effects on energy budget in summer and winter

• More recent development around Sanford station • Change in duration, timing of Florida’s hot season (Winsberg,

Simmons)• Global climate change effects

Long Term Land Cover Change

(Pielke)

Large majority of land cover change = Wetlands, Forest, GrasslandsUrban, barren

500 m

Large majority of land cover change = Wetlands, Forest, GrasslandsUrban, barren

500 m

Max Temperature Extremes for Orlando Intl Apt, Fl and Sanford, Fl

Number of Days Annually with a Max Temperature Greater Than or Equal to 95 F at Orlando Intl Apt, Fl and Sanford, Fl

y = 0.0845x - 147.77

R2 = 0.0143

y = 0.2345x - 452.82

R2 = 0.1168

0

10

20

30

40

50

60

70

1950 1960 1970 1980 1990 2000 2010

Time (years)

Num

ber

of O

ccur

ance

s

Orlando Intl Apt

Sanford

Linear (Sanford)

Linear (Orlando Intl Apt)

• The years: 1981 (42), 1987 (50), and 1998 (48) were the only times Orlando had more than (or equal to) 40 days with max temperatures greater than or equal to 95 °F.

• The years: 1981 (40), 1998 (62), and 1999 (42) were the only times Orlando had more than (or equal to) 40 days with max temperatures greater than or equal to 95 °F.

• Both sites show growth in the number of days with extreme max temperatures.• The growth in the number of

days is significantly greater for Orlando than Sanford.

Seasonal Variation in Max Temperatures for Orlando Intl Apt, Fl and Sanford, Fl

Average Spring Max Temperature for Orlando Intl Apt, Fl and Sanford, Fl

y = 0.0407x + 4.7741

R2 = 0.1932

y = -0.0138x + 112.67

R2 = 0.0239

80

81

82

83

84

85

86

87

88

89

1940 1950 1960 1970 1980 1990 2000 2010 2020

Time (years)

Tem

pera

ture

(d

eg

rees F

)

Orlando Intl Apt

Sanford

Linear (Orlando IntlApt)Linear (Sanford)

• The average winter and spring max temperatures for Orlando, Fl are increasing at a similar rate.

• Highest winter avg. 77.8 °F in 1974 and 1981 and lowest 66.4 °F in 1957

• Highest spring avg. 88.3 °F in 1978 and lowest 82 °F in 1958

• The average max temperatures for Sanford, Fl are decreasing for both winter and spring, with a greater decrease in winter.

• Highest winter avg. 79.1 °F in 1973 and lowest 65.4 °F in 1977

• Highest spring avg. 88.2 °F in 1998 and lowest 81.3 °F in 1983

Average Winter Max Temperature for Orlando Intl Apt, Fl and Sanford, Fl

y = 0.0479x - 22.003

R2 = 0.0991

y = -0.0334x + 138.73

R2 = 0.0471

65

67

69

71

73

75

77

79

1940 1950 1960 1970 1980 1990 2000 2010 2020

Time (years)

Te

mp

era

ture

s (

de

gre

es

F)

Orlando Intl Apt

Sanford

Linear (Orlando Intl Apt)

Linear (Sanford)

Seasonal Variation in Max Temperatures for Orlando Intl Apt, Fl and Sanford, Fl

Average Summer Max Temperatures for Orlando Intl Apt, Fl and Sanford, Fl

y = -0.0066x + 104.26

R2 = 0.0184

y = 0.0366x + 18.114

R2 = 0.2347

87

88

89

90

91

92

93

94

1940 1950 1960 1970 1980 1990 2000 2010 2020

Time (years)

Tem

per

atu

re (

deg

rees

F)

Orlando Intl Apt

Sanford

Linear (Sanford)

Linear (Orlando Intl Apt)

Average Fall Max Temperatures for Orlando Intl Apt, Fl and Sanford, Fl

y = 0.0472x - 13.658

R2 = 0.1697

y = 0.0138x + 52.2

R2 = 0.0228

75

76

77

78

79

80

81

82

83

84

85

1940 1950 1960 1970 1980 1990 2000 2010 2020

Time (years)

Tem

per

atu

re (

deg

rees

F)

Orlando Intl Apt

Sanford

Linear (Orlando Intl Apt)

Linear (Sanford)

• The average winter and spring max temperatures for Orlando, Fl are increasing at a relatively similar rate.• Highest summer avg. 93.7 °F in 1987 and lowest 87.9 °F in 1965• Highest fall avg. 84.5 °F in 1986 and lowest 75.7 °F in 1963

• The average max temperatures for Sanford, Fl are decreasing in the summer and increasing in the fall.

• Highest summer avg. 92.7 °F in 1951 and 1987 and lowest 89.2 °F in 1988• Highest fall avg. 83.1 °F in 1971 and lowest 76.3 °F in 1987

Orlando Intl Apt, Fl and Sanford, Fl Average Annual Max Temperatures for Orlando Intl Apt, Fl and Sanford, Fl

y = -0.0164x + 115.4

R2 = 0.0105

y = 0.0286x + 25.622

R2 = 0.0467

81

81.5

82

82.5

83

83.5

84

84.5

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Time (years)

Tem

pera

ture

(d

eg

rees F

)

Orlando Intl Apt

Sanford

Linear (Sanford)

Linear (Orlando Intl Apt)

Average Annual Max Temperature for Orlando Intl Apt, Fl and Sanford, Fl

y = 0.0373x + 8.5143

R2 = 0.2237

y = -0.0027x + 87.474

R2 = 0.0018

78

79

80

81

82

83

84

85

86

1940 1950 1960 1970 1980 1990 2000 2010 2020

Time (years)

Te

mp

era

ture

(d

eg

ree

s F

)

Orlando Intl Apt

Sanford

Linear (Orlando Intl Apt)

Linear (Sanford)

• Seasonal and annual trends indicate that the urban Orlando site has an increasing max temperature.

• Seasonal and annual trends indicate that the rural Sanford site has a decreasing max temperature (except in the fall).

• The 15 year timescale above supports both trends

1940 1950 1960 1970 1980 1990 2000 2010 202056

58

60

62

64

66

68

f(x) = 0.00575943361798408 x + 51.1530209473761R² = 0.00645496548837377

Average Annual Low Temperatures for 1952 - 2008

Year

Tem

per

atu

re (

F)

⁰

• Increase in temperature but very small correlation (R²=0.0065)• Increase in less than ½⁰F over the 56 years

AVERAGE ANNUAL LOW TEMPERATURES FOR ORLANDO

1940 1950 1960 1970 1980 1990 2000 2010 20200

10

20

30

40

50

60

f(x) = 0.0134245005281255 x + 24.6410656898218R² = 0.00808653111987756

Seasonal Average Low Temperatures for Winter, 1952 - 2008

Year

Tem

per

atu

re (

F)

⁰

• Winter = December 21 – March 19 • Again, increase in temperature but very small correlation (R²=0.0081)• Increase in almost 1⁰F over the 56 years

WINTER LOW TEMPS

1950 1960 1970 1980 1990 2000 2010 202059

60

61

62

63

64

65

66

67

68

69

f(x) = − 0.00411939524022924 x + 72.445349906833R² = 0.00258925178780545

Seasonal Average Low Temperatures for Spring, 1953 - 2008

Year

Tem

per

atu

re (

F)

⁰

• Spring = March 20 – June 20• Decrease in temperature but very small correlation again (R²=0.0026)• Decrease in less than ½⁰F over the 55 years

SPRING LOW TEMPS

1940 1950 1960 1970 1980 1990 2000 2010 202069

70

71

72

73

74

75

76

f(x) = 0.0114181446609736 x + 50.6110729143859R² = 0.0580012409532158

Seasonal Average Low Temperatures for Summer, 1952 - 2008

Year

Tem

per

atu

re (

F)

⁰

• Summer = June 21 – September 21• Increase in temperature and correlation is larger (R²=0.058)• Increase in about ½⁰F over the 56 years

SUMMER LOW TEMPS

1940 1950 1960 1970 1980 1990 2000 2010 202050

52

54

56

58

60

62

64

66

68

f(x) = 0.0311123275673308 x − 0.855125173344923R² = 0.0624801337588717

Seasonal Average Low Temperatures for Fall, 1952 - 2008

Year

Tem

per

atu

re (

F)

⁰

• Fall = September 22 – December 20• Increase in temperature and relatively larger correlation (R²=0.0625)• Increase in about than 1 ½⁰F over the 56 years

FALL LOW TEMPS

Conclusions and Implications

• In general, temperatures seem to be increasing in Orlando

• Increases due to change in albedo • Heat island affect

• Greater increase in max temperatures than min temperatures

• Less swampland due to development = less precipitation