# Presentation: 944849

## Status of TES and sonde O3 profile comparisons

- Helen Worden
- TES Team
- Jet Propulsion Laboratory
- California Institute of Technology

## TES Measurement Status

- Global Surveys (with limb scans) taken 9/04-4/05
- 73 16-orbit Global Surveys acquired with limb data.
- Nadir targets ~5°apart along orbit track (2 nadir scans averaged).
- Global Surveys without limb scans started 5/05
- 3x more nadir targets, ~1.6° separation, not averaged.
- Limb mode still available for special observations, but removed from the Global Survey mode to preserve instrument lifetime.
- No data for June 2005 due to instrument in safe mode.
- Current pause in data collection due to sudden rise in ICS (interferometer control system) motor current.
- Step/Stare, Stare and Transect modes used for special observations
- AVE 10/04-11/04 & PAVE 1/05-2/05
- S. Atlantic 9/04-10/04, 1/05-2/05
- N. America 7/31/05-8/06/05
- Lake Tahoe (stare mode for geolocation, radiance val.) 8/05-9/05
- S. America (biomass burning transects) 8/05-9/05

**Notes:**
Safe mode due to persistent ICS velocity errors. Had to change fault protection limits to allow ICS stop without going to safe mode.
Currently we are revisiting contingency procedures for motor current events, ICS stall.
Also working to expedite optical bench warm-up - should allow ~2x improvement in CO product due to better optical alignment.
Expect to resume operations by 10/04.

Notes:
Encoder bearings in ICS had wrong criteria for lubricant amount - cause of life-test unit failure was chemical breakdown of lubricant

## Slide 3

## Slide 4

## Slide 5

## TES Data Availability

- Current TES data at the Langley ASDC is v1.0, Beta
- Nadir scenes only.
- L2 retrievals from special observation data to start delivery 10/05.
- Caveats listed for L1B calibration and L2 land retrieval issues.
- Data taken during AVE 04 available at AVDC.
- Data taken during PAVE 05 to be delivered to AVDC 9/05.
- Next release (v2.0) in spring 2006
- L1B calibration improved substantially & validated
- Will include limb retrievals (with HNO3)
- HDO product added for nadir views

**Notes:**
- SIPS is resolving throughput problems
- Hope to have reprocessing *completed* for v2.0 by spring 2006.

## L2 Products Available at DAAC: Blue = Global Survey data available, Dark Grey = data to be delivered, 

**Light Grey = Focal Plane De-ice**

**Notes:**

111 G.S. since activation, 28 at DAAC as of 9/19 (run 2147 taken 9/20/04 is also there)
almost all L1B data is avail. - started delivery 1/05; L2 started delivery 7/05
Forward processing always starts with current GS

## PROCEDURE FOR COMPARISONS

- Apply averaging kernel, *A**TES*, and *a priori* constraint:

- _PROCEDURE FOR COMPARISONS_

## PROCEDURE (cont.)

- Measurement Error + Cross-State Errors

- _PROCEDURE (cont.)_

- O3 Sonde from Ascension Island
- 7.95°S, 14.37°W
- Launched 10/11/2004, 13:50 UTC
- Closest TES nadir measurement
- (Step/Stare run 2199):
- 7.756°S, 12.934°W
- (160 km away)
- DOFS: 3.7
- Vertical res: 6 to 9 km
- (avg = 7.2 km)
- in troposphere < 200 mb

## Sonde/Nadir Measurement

- Coincidence Criteria
- applied for fall 2004 (9/20 - 11/17) TES data
- both global survey & step/stare runs)
-  Initial: 600 km, 48 hours (800 km for AVE), Chi2 < 1.8
- => 55 coincidences
-  More selective: |Sonde-TES T_diff| < 5K,  lat. < 55°
- => 44 coincidences

## Slide 11

## Sonde (w/TES AK) - TES comparisons:

- Ozone and Temperature profiles

## Comparison of 3 sonde profiles (with TES AK) and 3 TES retrieved profiles - tropics

-       sonde		     TES retrieval	         initial guess

## Comparison of 3 sonde profiles (with TES AK) and 3 TES retrieved profiles - sub-tropics/mid-latitude

-       sonde		     TES retrieval	         initial guess

## TES vs. sonde O3 averages for mid-lat & tropics

- Upper Trop
- (UT)
- 500mb>p>pTP

- Lower Trop
- (LT)
- p > 500mb

- 28 coincidences

- 16 coincidences

**Notes:**
Mid lat > 25deg

##  We have also looked at UT & LT differences vs:

- 	distance to sonde site (km)
- 	time (hrs)
- 	retrieval 2
- 	retrieved cloud top pressure
- 	avg. sonde vmr
-  Hard to see any definite trends...
-  Next: improved L1B calibration

## Note improvement is mainly in the upper trop. as expected since lower radiances had the largest correction. 

- Note improvement is mainly in the upper trop. as expected since lower radiances had the largest correction.

**Notes:**
We have been working since we started taking data to assess and improve our radiometric calibration. Our primary metric for improvement has been our comparisons with AIRS spectra over selected homogeneous targets, taken 15 minutes ahead of us. We have improved our brightness temperature differences with AIRS from over 1K to less than .5 K. This has significant consequences for T and O3 retrievals.

## L1B calfit prototype

-  comparison

- This doesn’t have as good a time coincidence as the previous comparison, but still shows improvement in the upper trop.

- Sonde comparison
- with current L1B

## This comparison was good before, but we still see improvements in lower strat.

## T profiles (sonde vs. TES)

- R7 L1B comparison

- L1B calfit prototype
-  comparison

## T_atm at 215 mb

- Current L1B
- Prototype L1B

**Notes:**
New calibration is significant, especially in upper trop. We have been spending a large effort to get this right. Our metric has been AIRS radiances over selected homogenous scenes, with the criteria of 0.5 K for BT differences.

## O3 at      215 mb

- current L1B
- Prototype L1B

## Conclusions:

-  Comparisons to O3 sondes for current TES (v1, beta quality) data available at DAAC show:
-  TES is able to detect expected variability in the lower troposphere.
-  Bias in the upper troposphere
-  	- latitude dependent
- 	- peaked at 200 - 150 hPa
-  Comparisons for data with improved L1B calibration (only 3 avail.) show less bias in UT.

## Backup Slides

## TES Retrieval Error

- (Total Error Covariance)

- (Smoothing Error)

- (Cross-Term Error
- includes T, H2O for joint retrieval with O3)

- (Measurement Error)

- (Systematic Errors)

- Where **A** is the averaging kernel, **M** is a linear mapping matrix on pressure levels, **G **is the gain matrix and **K** is Jacobian matrix.

## Slide 26

## Sonde (w/TES AK) - TES comparisons:

- O3 relative and error weighted differences

## Differences vs. latitude & sonde O3 vmr averages

- Upper
- Trop
- (UT)

- Lower
- Trop
- (LT)

## Error weighted differences vs. distance & retrieval 2

- Upper
- Trop
- (UT)

- Lower
- Trop
- (LT)

## TES Nadir Step & Stare Observations near Ascension Island

## TES Nadir Step & Stare Observations for 10/31/2004 (AVE)