what does the historical climate record in texas say about ......knowledge and prediction ability...

What Does the Historical ClimateRecord in Texas Say About

Future Climate Change?

John W. Nielsen-GammonTexas State ClimatologistTexas A&M University

[email protected]

Knowledge and Prediction Ability for Changes in Weather and Climate: Subjective Estimate

100,

000 ye

ars ag

o

10,0

00 yea

rs ago

1,00

0 ye

ars ag

o

100 ye

ars ag

o

10 yea

rs ago

1 ye

ar ago

1 mon

th ago

3 da

ys ago

6 ho

urs ag

o

6 ho

urs fro

m now

3 da

ys fr

om now

1 mon

th fr

om now

1 ye

ar fr

om now

10 yea

rs fr

om now

100 ye

ars fro

m now

1,00

0 ye

ars fro

m now

10,0

00 yea

rs fr

om now

100,

000 ye

ars fro

m now

Cert

ain

ty o

f K

no

wle

dg

e

What happened globally What happened in Texas What will happen globally What will happen in Texas

IPCC Multi-Model Ensemble

IPCC Multi-Model Ensemble,Scenario A1B

Black dots: areas where various computer models agree

A1B Precipitation 2080-99compared to 1980-99

21 Model Results, compiled by IPCC

El Niño Temperature Composite Nov-Mar Anomalies

NOAA-CIRES/

CDC

La Niña Temperature Composite Nov-Mar Anomalies

NOAA-CIRES/

CDC

El Niño Precipitation Composite Nov-Mar Anomalies

NOAA-CIRES/

CDC

La Niña Precipitation Composite Nov-Mar Anomalies

NOAA-CIRES/

CDC

Future vs. Past

• Temperature outlook in Texas fromgreenhouse gases: warmer

• Precipitation outlook in Texas fromgreenhouse gases: probably drier

• Are these expectations consistent withwhat’s been happening over the pastcentury?

The Climate Record

• United States Historical ClimatologyNetwork, Versions 1 and 2– 44-49 stations with long-term, relatively stable

climate records– Corrections for obs time (temperature) and

objectively-identified inhomogeneities– TAMU statistical interpolation to extend to

denser COOP network– Conventional climate division data has issues

PANHANDLEAND PLAINS

FAR WESTTEXAS

WESTCENTRALTEXAS

SOUTHCENTRALTEXAS

SOUTHTEXAS

SOUTHEASTTEXAS

NORTHCENTRALTEXAS

EASTTEXAS

Average Temperature of HCN Stations Within Texas Areas

55

57

59

61

63

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67

69

71

73

751895

1898

1901

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Year

An

nu

al M

ean

Tem

pera

ture

(F)

Panhandle and Plains Far West Texas West Central Texas South Central TexasNorth Central Texas East Texas South Texas Southeast Texas

Linear Temperature Trend, Texas HCN Stations

0

2

4

6

8

10

12

-4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5 4

Trend (Degrees F per Century)

Nu

mb

er

of

Sta

tio

ns

Smoothed Temperatures of HCN Stations Within Texas Areas

55

57

59

61

63

65

67

69

71

73

75

1900

1903

1906

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Year

An

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(F)


Smoothed Temperatures of HCN Stations Within Texas Areas

55

57

59

61

63

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67

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71

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75

1900

1903

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An

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(F)


Deeper cooling thanrest of globe 1955-1975

Faster warming than restof globe 1980-present

Attribution Studies

• Based on atmospheric models driven byobserved sea surface temperatures

• Temperature variations during last half of20th Century largely due to sea surfacetemperature changes (overall, patterns)

• Natural vs. anthropogenic fraction unknown

Annual Texas Precipitation

0

0.5

1

1.5

2

2.51895

1898

1901

1904

1907

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Fra

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Mean



0

0.5

1

1.5

2

2.51895

1898

1901

1904

1907

1910

1913

1916

1919

1922

1925

1928

1931

1934

1937

1940

1943

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1997

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2003

2006

Year

Fra

ctio

n o

f C

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tury

Mean

Panhandle and Plains Far West Texas West Central TexasSouth Central Texas North Central Texas East TexasSouth Texas Southeast Texas Linear (Panhandle and Plains)Linear (Far West Texas) Linear (West Central Texas) Linear (South Central Texas)Linear (North Central Texas) Linear (East Texas) Linear (South Texas)Linear (Southeast Texas)


0.8

0.85

0.9

0.95

1

1.05

1.1

1.15

1.21895

1898

1901

1904

1907

1910

1913

1916

1919

1922

1925

1928

1931

1934

1937

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1943

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1949

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1955

1958

1961

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1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

Year

Fra

ctio

n o

f C

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tury

Mean

Panhandle and Plains Far West Texas West Central TexasSouth Central Texas North Central Texas East TexasSouth Texas Southeast Texas Linear (Panhandle and Plains)Linear (Far West Texas) Linear (West Central Texas) Linear (South Central Texas)Linear (North Central Texas) Linear (East Texas) Linear (South Texas)Linear (Southeast Texas)

Precipitation trends at century-long USHCN stations

Blue: Increasing PrecipitationRed: Decreasing Precipitation

9-yr Smoothed Texas Precipitation

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.41899

1902

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Fra

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tury

Mean


Possible Causes of Precip Increase

• Response to global warming not reproducedby global models?

• Response to increased atmosphericparticulates?

• Response to land use changes: irrigation,surface water, urbanization?

• Response to natural sea surface temperaturevariations?

What does that mean for futureprecipitation?

• Response to global warming not reproducedby global models? Continued Increase

• Response to increased atmosphericparticulates? Slow Decrease

• Response to land use changes: irrigation,surface water, urbanization? Slow Decrease

• Response to natural sea surface temperaturevariations? Rapid Decrease

1901-1925 1926-1950

1951-1975 1976-2000

Fraction of months in drought, based on 12-month total precipitation

Final Remarks

• Temperature likely to go up– Rate of increase faster than global mean since 1980– Important driver of future water demand

• Future precipitation change unknown– We’ve gotten used to a wet climate regime– Climate models: leaning toward less rainfall– Historical trends: more rainfall (11%-12% per century)– What’s causing the historical trend? Is it temporary,

permanent, or growing?• [email protected]

what does the historical climate record in texas say about ......knowledge and prediction ability...

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