Recent Results from Radiosondes and Other Observing Systems

Dian SeidelNOAA Air Resources Lab.

Silver Spring, MD

Workshop on Vertical Temperature Changes, Asheville, NC, 27-29 October 2003

Topics1. Characterizing atmospheric temperature

changes2. New NOAA radiosonde datasets3. Intercomparison of satellite and radiosonde

datasets4. Removing the stratospheric signal from

MSU2 data5. High elevation, surface, and free-air

temperatures6. Integrating proxies for tropospheric

temperature

Characterizing atmospheric temperature changes

• Linear trends are simplistic descriptors of temperature change

• Some temperature changes appear to be abrupt

• “Slopes and steps” models are almost as simple, but better characterize the data

• Quantitative temperature changes are very sensitive to the statistical model chosen

Surface (1900-2002)

1880 1900 1920 1940 1960 1980 2000 2020

T A

nom

aly

(K)

-4

-3

-2

-1

0

1

61.6%

69.9%

49.5%

70.7%

0.66K

0.87K

0.42K

0.87K

0.099 0.000 0.172 K/dec

0.063 K/dec

Data sources: GHCN and UEA

Troposphere - Raobs 850-300 hPa (1958-2001)

1950 1960 1970 1980 1990 2000 2010

T A

nom

aly

(K)

-4

-3

-2

-1

0

1

32.2%

32.4%

36.5%

41.8%

0.52K

0.49K

0.32K

0.35K

-0.094 0.089 K/dec

0.116 K/dec

Data sources: HadRT2.1s and LKS

Stratosphere - MSU 4 (1979-2001)

1975 1980 1985 1990 1995 2000 2005

T A

nom

aly

(K

)

-5

-4

-3

-2

-1

0

1

43.0%

35.9%

83.6%

86.8%

-1.13K

-1.03K

-0.82K

-0.88K-0.348

0.085 -0.006K/dec

-0.470 K/dec

Data sources: UAH ver. 5.0 and RSS

New NOAA radiosonde datasets

• 54-station network (Angell, J. Climate, 2003)

• Adjusted LKS 87-station network (Lanzante, Klein, Seidel, J. Climate, 2003)

• RATPAC – radiosonde atmospheric temperature products for assessing climate (not yet avail.)

Angell’s 63-to-54-station network

Identification of

anomalous stations

Effect of removing 9 stations

Lanzante-Klein-Seidel 87-station network

Sensitivity of trends to LKS adjustments

(solid)

blue 30-90Ngreen 30N-30S

red 30-90S

NOAA RATPAC

• ARL/GFDL/NCDC collaboration, supported by OGP/CCDD

• Uses LKS data as a core• Network expansion would introduce

more uncertainty• Extends beyond 1997 using first

difference method and postCARDS data• Relies on station history metadata to

identify break points

Intercomparison of satellite and radiosonde datasets

Seidel, Angell, Christy, Free, Klein, Lanzante, Mears, Parker, Schabel, Spencer, Sterin, Thorne, and Wentz (submitted to J. Climate)

Dataset Investigators & Institution Source

Angell-63 Jim Angell --- NOAA 63 raob stations

Angell-54 “ 54 raob stations

HadRT David Parker, Margaret Gordon, Peter Thorne --- Met Office

Global raobs CLIMAT

LKS John Lanzante, Steve Klein,Dian Seidel --- NOAA

87 raob stations CARDS

RIHMI Alex SterinAll-Russian Research Institute of Hydrometeorological Information

Global raobs CARDS

RSS Carl Mears, Frank Wentz, Matthias SchabelRemote Sensing Systems

MSU

UAH ver. D John Christy, Roy SpencerUniv. of Alabama in Huntsville

MSU

UAH ver. 5 “ MSU

1960 1970 1980 1990 2000 2010

-10.00.0

10.0

-0.50.00.5

-0.50.00.5

-0.50.00.5

-0.50.00.5

-1.0-0.50.00.51.01.5

-1.0-0.50.00.51.0

25.025.0

MSU 2LT

MSU 2

850-300 hPa

300-100 hPa(tropics)

100-50 hPa

MSU 4

-SOI

QBO

Multi-Dataset-Average Layer-Mean Time Series

Global 850-300 hPa

1960 1970 1980 1990 2000 2010

-0.50-0.250.000.25

-0.250.000.25

-0.250.000.25

-0.250.000.25

-0.250.000.25

-0.250.000.25

AVG

Angell-63

Angell-54

HadRT

RIHMI

LKS

Multi-Dataset Average and Differences from Average

Signals of large-scale climate variations

QB

O

0.00

0.02

0.04

0.06100-50 hPa MSU 4

Ang

ell-6

3

Ang

ell-5

4

Had

RT

RIH

MI

LKS

UA

H

RS

S

Had

RT

LKS

Pin

atu

bo

0.00.51.01.52.0

Ang

ell-6

3

Ang

ell-5

4

Had

RT

RIH

MI

LKS

UA

H

RS

S

Had

RT

LKS

EN

SO

0.000.040.080.120.16

19

76

-77

0.0

0.4

0.8

1.2

100-50 hPa

850-300 hPa

850-300 hPa

MSU 4

MSU 2

GLOBE NH SH TROPICS

-0.3

-0.2

-0.1

0.0

0.1

0.2

Angell-63Angell-54HadRTLKSRIHMI

1958-1997 300-100 hPaTemperature Trends (K/decade)

MSU 2GLOBE NH SH TROPICS

-0.2

-0.1

0.0

0.1

0.2

UAH MSU ver. D UAH MSU ver. 5 RSS MSU HadRT LKS

MSU 4

GLOBE NH SH TROPICS

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

1979-1997 Temperature Trends (K/decade)

GLOBE NH SH TROPICS-0.20

-0.15

-0.10

-0.05

0.00

0.05

FULLLKS (87 stns)Angell-63HadATpostCARDS

Effect of Subsampling on1979-1997 MSU2 Trends

(K/decade)

Removing the stratospheric signal from MSU2 data

• Qiang Fu, Celeste Johanson, Steve Warren, Dian Seidel

• Submitted, do not cite• qfu@atmos.washington.edu

High elevation, surface, and free-air temperatures

• Motivated partly by observations of recent rapid glacial retreat

• Seidel and Free (Climatic Change, 2003)

• Pepin and Losleben (Intl. J. Clim., 2002)

• Climatic Change, 2003. Special Issue edited by H. Diaz

Mountain Ranges Sampled by Paired Radiosonde Sites

Mountain Minus Low SiteTemperature Difference Trend

Degrees per Decade

-1.5 -1.0 -0.5 0.5 1.0 1.50.0

Latit

ude

-40

-20

0

20

40

60SFCMTN1KM2KM

p value

0.0 0.2 0.4 0.6 0.8 1.0

• Ongoing work by Pepin incorporates surface station data and upper air data from radiosondes and reanalysis

• Glacial retreat, especially in tropics, may be more influenced by hydrologic changes than warming.

Integrating proxies for tropospheric temperature

• Total column water vapor (Wentz and Schabel, Nature, 2000)

• Tropopause height and pressure, particularly in the tropics (Randel et al., JGR, 2000; Seidel et al., JGR, 2001; Santer et al., JGR, 2003)

• Polar vortex (Frauenfeld and Davis, JGR, 2003; Angell, JGR, 2001)

• Others?

1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001

1.5

1.0

0.5

0

-1.5

-1.0

-0.5

300 hPa Center ContourMidlatitude MSU 2LT

Dep

artu

re

END