# Presentation: 022763

## Recent Results from Radiosondes and Other Observing Systems

- Dian Seidel
- NOAA Air Resources Lab.
- Silver Spring, MD
- Workshop on Vertical Temperature Changes, Asheville, NC, 27-29 October 2003

## Topics

- Characterizing atmospheric temperature changes
- New NOAA radiosonde datasets
- Intercomparison of satellite and radiosonde datasets
- Removing the stratospheric signal from MSU2 data
- High elevation, surface, and free-air temperatures
- 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

## Data sources: GHCN and UEA

## Data sources: HadRT2.1s and LKS

## 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 30-90Ngreen 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 Sterin
All-Russian Research Institute of Hydrometeorological Information | Global raobs CARDS |
| RSS | Carl Mears, Frank Wentz, Matthias Schabel
Remote Sensing Systems | MSU |
| UAH ver. D | John Christy, Roy Spencer
Univ. of Alabama in Huntsville | MSU |
| UAH ver. 5 | “ | MSU |

## Slide 16

**Notes:**
Notes: (a) LKS ends in 1997, (b) 2 Angell datasets very similar, and smoother than the others because they are interpolated from seasonal, not monthly. Anomalies, (c) RIHMI has less variability than the rest, (d) land or ocean weighting applied to LKS data makes little difference, (e) all the series capture similar features of variability.

## Slide 17

**Notes:**
Note: (a) higher variability of stratosphere than troposphere (previous slide),  (b) all datasets show coherent variation, especially volcanic signals, (c) less cooling in LKS than the others (due to adjustments), (d) less cooling in Angell 54 than Angell 63 due to elimination of anomalous stations, (e) QBO is more obvious in Angell datasets, perhap due to seasonal smoothing.

## Signals of large-scale climate variations

## Slide 19

**Notes:**
Notes: (a) higher autocorrelation in Angell due to use of seasonal anomalies, (b) lower autocorrelation in LKS compared with HadRT in troposphere may be due to adjustments, removing some autocorrelation, (c)  MSU has higher autocorrelation than raobs.

## Slide 21

## 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

- 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 Contour

- Midlatitude MSU 2LT

- Departure

## END