# Presentation: 273373

## MLS Overview: Instrument Performance and Data Products

**Joe Waters**
**Aura Science Team Meeting**
**The Hague, Netherlands**
**8 November 2005**

## MLS major milestones since launch 

**Began production processing with ****updated Version 1.51 algorithms ......................................****	****28 Jan 05**
**Began making V1.51 Level 2 data ****publicly available ................................................................****	****15 Feb 05**
**Released MLS Data Quality Document for V1.51****(‘required reading’ for data users)****  ....................................****	****1 Aug 05**
**Completed V1.51 reprocessing of all ‘old’ data,    ****(continue processing all new incoming data) .................****	****25 Oct 05 **
**Goal for beginning production processing with ****Version 2 algorithms ..............................................................****	****Aug 06**

**MLS major milestones since launch **

## MLS Instrument Performance

**Instrume****nt ****performance has been excellent overall **
**In full-up science mode since 13 August 2004**
**No major problems have been encountered**
**Calibration accuracy is ~1% for the GHz bands and ****~2% for the THz bands, documented in IEEE papers: **
**Jarnot, et al.:  GHz radiometric and spectral cal & performance**
**Cofield and Stek:  GHz field-of-view cal & performance**
**Pickett:  THz cal & performance**
**Following chart shows examples of performance**

## Instrument Performance Examplesand Level 2 Retrieval Residuals

**Vertical bars (not visible in most cases) give the predicted noise for the averages shown here**
**Equivalent integration time is ~10 minutes for signal and residual, ~1 hour for baseline**

## MLS Daily Ops Calendar: 13 Aug 04 – 31 Oct 05 

**Colors show fraction of **_**total**_** time each 24 hours that has good data from **_**all**_** MLS spectral bands**
**94% since start of science ops on 13 Aug 04 **
**98% since instrument ops stabilized on 11 Dec 04**
**All data processed through Level 2 for all products**

##       MLS Geophysical Data Products 

**Lines are for V1.51 data, where thin lines indicate averages are always needed**
**Standard vertical grid for V1.51 is 6 per decade P for P > 0.1 hPa,  ****3 per decade for P < 0.1 hPa, and cloud ice has 12 per decade P**
**Dots indicate goals for future versions of data**

**MLS data quality document should be read & understood before using data**
**Register at http://mls.jpl.nasa.gov to receive updates of information on data**

**      ****MLS Geophysical Data Products **

## MLS V1.51 Data  

**All MLS V1.51 data products are publicly available for the entire Aura mission to date**
**from **_**http://disc.gsfc.nasa.gov/data/dataset/MLS**_** (GSFC DAAC)**
**First phase of data validation has been completed**
**Overview for T, O****3****, H****2****O, HCl, N****2****O, HNO****3****, and CO are in Froidevaux, et al., ‘MLS Early Validation’ paper, IEEE Aura issue, in press. **
**preprint available from **_**http://mls.jpl.nasa.gov**_** (MLS web site)**
**Additional validation results are in presentations given at the September 2005 Aura Data Validation meeting  **
**available at **_**http://avdc.gsfc.nasa.gov**_** (Aura Validation Data Center)  **
**Following charts give some representative examples of data**

## MLS O3 data  

**Many comparisons of strato- spheric O****3**** have been made**
**MLS generally agrees to ****5-10% with other validated accurate data sets**
**Some examples are at right **
**Slope of MLS differences with height is under investigation**
**Fewer comparisons of tropo-spheric O****3**** have been possible**
**Plot at right shows MLS O****3**** at 100, 147, and 215 hPa scattered against co-located AVE aircraft measurements made with NOAA photometer**
**These, and other comparisons, suggest that MLS V1.51 UT O****3**** has a scaling error of ~ +25% and a bias of ~ +50 ppbv**

## MLS OH data  

**Enhanced ****mesospheric OH on ****18 Jan 05**

**MLS OH data  **

**MLS, ****balloon, model comparisons**

**Monthly zonal mean ****OH at ****equator**

**MLS OH (and HO****2****) and correlative balloon measurements agree to within error bars  **
**MLS observations show no evidence for****the “HO****x**** dilemma” seen by MAHRSI **
**See Pickett et al. GRL paper, and****Salawitch et al. poster this meeting**
**Solar-proton enhanced OH (and HO****2****) in ****mesosphere seen in 4 events to date**
**Associated O****3**** loss also detected**
**See Pickett paper at this meeting**
**Now investigating annual cycle****variation seen in OH**
**Not yet sure whether ****observed variation****at lowest altitudes ****(46 hPa) is real or  ****is an artifact**

## Suite of Daily MLS Stratospheric Data Shown here in equivalent lat / potential temperature coords(plot by Gloria Manney, available at http://mls.jpl.nasa.gov for each day of data) 

**example****here ****is for ****Sep 21 2005**
**vertical axis is potential temperature, from 390 K ****to 1800 K****(~15-50 km)**
**horizontal axis is equivalent latitude, ****from ****80S to 80N**
**white overlays ****are scaled potential vorticity**

## Examples of N2O and HNO3 data at θ = 490K Selected days:  26 Sep 2004 through 1 Apr 2005

**N****2****O**
**ppbv**

**Examples of N****2****O and HNO****3**** data at ****θ**** = ****490K ****Selected days:  26 Sep 2004 through 1 Apr 2005**
**white contours are GMAO potential vorticity for vortex edge****(plots by Michelle Santee and Nathaniel Livesey)**** **

**300**

**25**

**HNO****3**
**ppbv**

**10**

**0**

## MLS Cloud Ice Water Content (IWC) Data

**(a) Aura MLS:  Jan 2005**

**(b) ECMWF analyses:  Jan 2005**

**(c) UCLA-Liou GCM:  5-year Jan mean**

**(d) GFDL-RAS ****GCM****:  18-year Jan mean**

**(e) NCAR CAM3 GCM: 10-year Jan mean**

**(f) GFDL-Donner GCM: 20-yr Jan mean**

**MLS Cloud Ice Water Content (IWC) Data**

**from ****J-F Li ****et al., GRL, ****vol. 32, L14826, 2005**

**MLS IWC appears qualitatively correct, based on comparisons with **
**(a) AIRS ‘window’ radiances   (b) MODIS cloud optical depth, eff. radius ****(c) AMSU-B IWP,        (d) ECMWF analyses           (e) operational OLR **
**Monthly-mean MLS IWC is thought quantitatively correct to a factor of 2, limited mainly by assumptions on ice particle size distribution**
**Images below compare January means of IWC at 150 hPa from ****(a) MLS, (b) ECMWF analyses and (c-f) GCM climatologies**

## MLS Upper Trop Data:  18-24 Sep 05 Weekly Map + GEOS-CHEM model for same time (from Qinbin Li)

**white contour is GMAO tropopause PV; black is MLS cloud ice indicative of deep convection**
**                                                                                           ****(plots by Jonathan Jiang****)**** **

**maps here are for 215 hPa**

## MLS Upper Trop Data:  18-24 Sep 05 Weekly Map + GEOS-CHEM model for same time (from Qinbin Li)

**white contour is GMAO tropopause PV; black is MLS cloud ice indicative of deep convection**
**                                                                                           ****(plots by Jonathan Jiang****)**** **

**maps here are for 215 hPa**

## MLS Data Product Summary

|  |  | Priorities for Version 2 data |
| --- | --- | --- |
| data product | Status of Version 1.51 data  | green indicates highest overall priorities |
|  |  | blue indicates intermediate overall priorities |
|  |  | violet indicates low overall priority |
| BrO | not useful | produce useful product |
| CH3CN | not produced as standard product  | use better forward model, produce as standard product |
| ClO | validated for use per documentation | fix negative bias (~0.3 ppbv) at lowest altitudes |
| CO | problems in some regions | improve quality of upper trop data, fix vert. osc. in stratosphere |
| GPH | validated for use per documentation | fix high bias in 100 hPa reference level |
| H2O | validated for use per documentation | increase upper trop vertical grid to 12 levels per decade P |
| HCl | validated for use per documentation | fix small negative biases in winter vortex; extend vertical range |
| HCN | problems in some regions | use better a priori and forward model to improve product |
| HNO3 | validated for use per documentation | if ~30% high-bias relative to IR is traced to MLS, fix it |
| HO2 | validated for use per documentation | choose better parameter for smoothing versus precision |
| HOCl | problems in some regions | extend vertical range  |
| ice | unvalidated, but thought useful  | improve expected accuracy and vertical range; produce IWP |
| N2O | validated for use per documentation | improve convergence of retrievals in lowermost stratosphere |
| O3 | validated for use per documentation | improve quality of data in upper troposphere |
| OH | validated for use per documentation | improve vertical resolution in mesosphere; improve lower strat product if further investigations on v1.5 indicate this needed |
| RHi | problems in some regions | improve, by using better vertical resolution of V2 H2O and T  |
| T | validated for use per documentation | increase upper trop vertical grid to 12 levels per decade P |
| SO2 |  not in V1.51, but produced ‘off-line’ | produce as standard product  |

**MLS Data Product Summary**

## MLS Summary

**Instrument is performing excellently overall **
**1-2% radiometric calibration accuracy**
**High ‘duty cycle’ in producing good science data**
**98% overall since instrument operations stabilized on 11 Dec 2004**
**All Level 2 geophysical data for all of mission are publicly available**
**Essential that users be familiar with MLS Data Quality Document**
**First phase of data validation has been completed**
**Overview for 7 products in Froidevaux et al., IEEE Aura issue paper **
**Additional results in Sep 2005 Aura Validation Meeting presentations **
**Scientific results are starting to be produced**
**Reprints/preprints of 9 GRL papers available at http://mls.jpl.nasa.gov**

## Backup Charts

## MLS BrO data  

**Averaging (e.g., monthly zonal means) ****is required to obtain useful S/N**
**MLS measures two BrO spectral ****lines, at 650.2 and 624.8 GHz**
**Examples of measured and fitted****650 GHz BrO line are shown at right**
**Version 1.51 BrO is **_**not**_** useful **
**Oscillations in v1.5 retrievals**
**Version 2 will produce a ****useful product**
**An ‘offline’ retrieval is now ****producing useful data**
**Mission-average results are ****shown at right, compared with ****v1.5 and SLIMCAT model **

**MLS BrO data  **

**        ****MLS v1.51            SLIMCAT         MLS ‘offline’**

**(figures by Nathaniel Livesey)**

## MLS Upper Trop Data:  18-24 Sep 05 Weekly Map + GEOS-CHEM model for same time (from Qinbin Li)

**white contour is GMAO tropopause PV; black is MLS cloud ice indicative of deep convection**
**                                                                                           ****(plots by Jonathan Jiang****)**** **

**maps here are for 147 hPa**