# Presentation: 502364

## John Lanzante GFDL/NOAA

**     ****surface since the advent of modern measurement methods?**

**John Lanzante GFDL/NOAA**

**Upper-air/Radiosonde Perspective – esp. 2 studies:**
- 	**o LKS (Lanzante/Klein/Seidel, 2003, JCLIM)**
- 		*** Homogenizes T for a global set of 87 stations**
**	****	***** Both unadjusted & adjusted data available**
- 	**o Seidel et al. (2003, JCLIM, in review)**
- 		*** Intercomparison of 5 radiosonde & 3 satellite (MSU) datasets**

-  **Focus:**
- 	**o Stratosphere, Troposphere & (Troposphere-Surface) Difference**
**	****o Trends *****and***** *****range of estimates/uncertainties***
***	*****o Time periods: Radiosonde era ~1958 & Satellite era ~1979**

## => Limitation: Apples vs. Oranges Comparisons

_**5 Radiosonde Datasets**_** ****	****(****Angell-63 & 54, HadRT, LKS_adj, [RIHMI[****)**
**Stratosphere (100-50 hPa) ****	****~  -.45 (~  -.55 to  -.37 ****[-.22]****) ****K/decade**
**Troposphere (850-300 hPa)****	****~ +.10 (~ +.08 to +.12 ****[+.04]****) ****K/decade**

_**1979-1997 – Global Trends**_** ****	****(Seidel et al; in review, JCLIM)**
**	****  ****Radiosonde****	****   Satellite**

**	****HadRT****	****LKS_adj**	**UAH****	****RSS**

**Stratosphere (MSU4)****	****-.93****	****-.76****	****-.53****	**** -.45**
**Troposphere (MSU2)****	****-.15****	****-.05****	****-.05****	****+.04**

**=>**** ****Limitation: Apples vs. Oranges Comparisons**
**      ****Inconsistent spatial & temporal sampling, data handling, etc.**

_**Radiosonde:**_
**Angell-63= ****63 Stations (Angell)****	****Angell-54=**** ****54 Stations (Angell)**
**HadRT=**** ****Gridded (Parker et al.)****	**** ****LKS=**** ****87 Stations (Lanzante et al.)**
**RIHMI=**** ****Gridded (Sterin)**
_**Satellite-Microwave Sounding Unit (MSU):**_
**UAH=**** ****Gridded (Christy & Spencer)****	****RSS=**** ****Gridded (Wentz et al.)**

**_________________________________________________________**

## 1979-1997 – Global Trends 	(LKS = Lanzante/Klein/Seidel)

_**Identical sampling**_**	****   Radiosonde****	****   Satellite**

_**[spatial/temporal]**_**	****LKS_un****	****LKS_adj**		**UAH**
**Stratosphere (MSU4)****	****-.86****	****-.65****	****	****-.57**
**Troposphere (MSU2)****	****-.11****	****-.06****	****	****-.03**

_**Radiosonde:**_
**LKS_un =**** ****87 Stations (Lanzante et al.) – **_**No**_** homogeneity adjustments**
**LKS_adj=**** ****87 Stations (Lanzante et al.) – Homogeneity adjusted**
_**Satellite-Microwave Sounding Unit (MSU):**_
**UAH=**** ****87 Stations ****(Christy & Spencer)**

**________________________________________________________**

** ****=>****Homogeneity adjustment reduces disparity considerably**

**Colder****  ********  ****LKS_un****  <  ****LKS_adj****  <  ****UAH****  <  ****RSS****  ********  ****Warmer**

**=>**** ****But (from previous slide) RSS still warmer than UAH:**

**=>**** More radiosonde adjustment needed ?**

## Source:

**Source:**
**LKS**
**Zone:**
**30N-30S**
**Stations:**
**20**** & ****16**
**Lapse:**
**Smooth monthly**
**Trends:**
**1979-1997**
**Levels:**
**Surface-700**

**Tropical Lower-Tropospheric Lapse (surface-700 hPa)**

**=>**** 1976/77 Jump down**
**=>**** ENSO (reduced amplitude after 1976/77)**
**=>**** ****Satellite-era trends: Sensitive to radiosonde data homogenization**

## 1979-97 Trend of Tropical Lapse (surface-700 hPa) [K/decade]

_**1979-97 Trend of Tropical Lapse (surface-700 hPa) [K/decade]**_
**	****	****	****	**** ****(1)****	**** (2)****	**** (3)****	****(Source: LKS)**
**LKS Unadjusted****	****	****.17****	****.17****	****.10**
**LKS Adjusted****	****	****.10****	****.00****	****.00**
**Brown et al. (2000)   ~.20**
**Gaffen et al. (2000)   ~.08**

**(1) =**** Difference in separate trends surface & 700**
**(2) =** **Trend of monthly (surface-700) time series at each station**
**(3) =** **Same as (2) except reduced network (1959-1997)**

**=> ****Caution in interpreting lapse trends:**
**	****complexities & sensitivities**

## Challenges – Issues Which Need To Be Resolved

******Reconcile trend differences between datasets:**
- 	**o Sonde vs. sonde, satellite vs. satellite, sonde vs. satellite**
**	****o Sampling: spatial & temporal differences?**
**	****o ****Better understanding of inhomogeneities & adjustment methods**
**	****o Other data handling issues? {quality control, etc.}**

**Lapse rate variations:**
- 	**o Tropics:**
- 		*** How much of trend since 1979 is real?**
**	****	***** What’s going on with 1976/77?**
- 	**o What about extratropics?**

## * THE END *

*** THE END ***

## Source:

**Source:**
**LKS=**
**Lanzante/Klein/Seidel**
**Region:**
**Global= (87 Stations)**
**Temperature:**
**Smooth monthly**
**Arrows:**
**Major volcanoes**
**Levels:**
**400 hPa & 70 hPa**

**Stratosphere:   Cooling trend ~1980, Volcanoes, QBO**
**Troposphere:   Quasi-linear warming trend ~ 1960s, ENSO & other**

## Source:

**Source:**
**LKS=**
**Lanzante/Klein/Seidel**
**Zones/Stations:**
**NH= 30-90N    /   37**
**TP= 30N-30S   /   24**
**SH= 30-90S     /      8**
**Temperature:**
**Smooth monthly**
**Vertical Bar:**
**1976/77**
**Level:**
**400 hPa**

**NH:         Warming since ~1980**
**SH:          Warming ~1960s to ~1980 [very few stations]**
**Tropics:  Jump up ~1976/77**

## 1958-1997 – Global Trends	(Seidel et al; in review, JCLIM) [K/decade]

_**5 Radiosonde Datasets**_** ****	****Ang63    Ang54    HadRT  LKS_adj    RIHMI**
**Stratosphere (100-50 hPa) ****	**** -.55      -.48      -.44      -.37      -.22**
**Troposphere (850-300 hPa)****	****+.08     +.11     +.09     +.12     +.04**

_**1979-2001 – Global Trends**_** ****	****(Seidel et al; in review, JCLIM)**
**	****  ****Radiosonde****	****   Satellite**

**	****HadRT****	****LKS_adj**	**UAH****	****RSS**

**Stratosphere (MSU4)****	****-.88****	****     -- ****	**** -.52****	**** -.43**
**Troposphere (MSU2)****	****-.08****	****     -- ****	****+.01****	****+.10**

_**Radiosonde:**_
**Angell-63= ****63 Stations (Angell)****	****Angell-54=**** ****54 Stations (Angell)**
**HadRT=**** ****Gridded (Parker et al.)****	**** ****LKS=**** ****87 Stations (Lanzante et al.)**
**RIHMI=**** ****Gridded (Sterin)**
_**Satellite-Microwave Sounding Unit (MSU):**_
**UAH=**** ****Gridded (Christy & Spencer)****	****RSS=**** ****Gridded (Wentz et al.)**

**Supplementary material: Seidel et al. 2003**

## Lapse (surface-700 hPa) Trends 1979-1997

***** Unadjusted= red  ***** Adjusted= blue  ***** Arrow up/down= 0.2 K/decade
***** Blue only: no adjustment ***** Red only: delete (too little data for trend)

## Surface Temperature Trends 1979-1997

**Surface Temperature Trends 1979-1997**

***** Unadjusted= red  ***** Adjusted= blue  ***** Arrow up/down= 0.2 K/decade
***** Blue only: no adjustment ***** Red only: delete (too little data for trend)

## Lower Tropospheric Lapse Rate 1979-97

_**Controversy (Debate & NRC Committee)**_
- 	o +CO2 GCMs  more warming aloft than surface (tropics)
- 	o Satellite era    more warming at surface
**Q: Are lapse rate trends sensitive to adjustment & other details?**

_**Trend of Surface-700 hPa T (1979-97) [K/decade]**_
- 			(1)	(2)	(3)
- 	NH	Un	.25	.17	.15	Low sensitivity
- 	NH	Adj	.18	.16	.16
- 	SH	Un	-.11	-.04	-.23	Small number of stations
- 	SH	Adj	.15	.14	.05	Surface T sensitive to adjustment
- 	Tropics	Un	.17	.17	.10	Surface T sensitive to adjustment
- 	Tropics	Adj	.10	.00	.00	Brown et al. ~.20; Gaffen et al. ~.08
- 	Globe	Un	.13	.16	.11	Some sensitivity
- 	Globe	Adj	.10	.14	.07

*** ****Caution in interpreting lapse trends** [spatial & temporal complexities]
- (1) = Difference in separate trends surface & 700
- (2) = Trend of monthly time series: surface-700
- (3) = Same as (2) except reduced network (1959-97)

## Lower Tropospheric Lapse Rate 1959-97

_**Trend of Surface-700 hPa T (1979-97) [K/decade]**_
- 			(1)	(2)	(3)
- 	NH	Un	.06	.06	.06
- 	NH	Adj	.03	.00	.00
- 	SH	Un	-.41	.01	-.02
- 	SH	Adj	-.23	.04	.-06
- 	Tropics	Un	.00	-.06	-.08
- 	Tropics	Adj	-.08	-.05	-.07
- 	Globe	Un	.01	.02	.00		Globe	Adj	-.05	.00	-.04

- = Difference in separate trends surface & 700
- (2) = Trend of monthly time series: surface-700
- (3) = Same as (2) except reduced network (1959-97)

## Lower Tropospheric Lapse Rate Time Series

**Lower Tropospheric Lapse Rate Time Series**

- Ticks:
-    0.2 K

- o Median sfc-700 over all stations in a zone (smoothed)  [1959-97 stations]
- o Red = Unadjusted       o **C****o****l****o****r****e****d**** ****=**** A****d****j****u****s****t****e****d**
**o**** SH: ****Very sensitive to adjustment; limited spatial sampling**
**o ****NH:**** 1979-97 trend is fortuitous; multi-year time scales dominate**
**o ****Tropics:**** ****Lags SOI ~ 6 mon. (weaker after ‘76); 1976-77 dominates**
-                   **1979-97 trend is a subtle feature!**

## 87 Station Network

**87 Station Network**

**Latitude Zones (for analyses):**
- 	**NH** 	(30-90N) 	~ 35 stations
- 	**Tropics** (30N-30S) 	~ 25-30 stations
- 	**SH** 	(30-90S) 	~ 8-15 stations

## Slide 17

## Slide 18