# Presentation: 336178

## EOS Microwave Limb Sounder

- _Nathaniel J. Livesey_, Joe W. Waters, Lucien Froidevaux, William G. Read, Michelle L. Santee, Dong L. Wu,Jonathan H. Jiang, Gloria L. Manney, Hui Su,Alyn Lambert, Michael J. Schwartz, Laurie J. Kovalenko,Yibo B. Jiang, Robert F. Jarnot, Richard E. Cofield,Paul C. Stek
**Jet Propulsion Laboratory,****California Institute of Technology**
- Hugh C. Pumphrey, Robert S. Harwood
**University of Edinburgh**

## MLS Science and measurement goals

- Track the recovery of the ozone layer
- Understand aspects of how atmospheric composition affects climate
- Quantify aspects of pollution in the *upper* troposphere

- MLS report, Aura Science Team, September 2006

## Significant MLS events

| 15 July 2004 | Aura launch |
| --- | --- |
| 24 July 2004 | MLS ‘first light’ |
| 13 August 2004 | Start routine MLS operations (L2 data produced 95% of the time since) |
| 15 February 2005 | First public release of v1.5 data |
| 15 February 2006 | Start duty cycling of HCl band 13 to conserve lifetime(HCl measurements now taken from band 14)  |
| June/July 2006 | End of funding for Mark Filipiak and Carlos Jimenez at University of Edinburgh, their responsibilities transferred to JPL team |
| 22 August 2006 | Start generating v2.1 data for selected days |
| 11 September 2006 | Joe Waters steps down as Principal Investigator.Nathaniel Livesey is new MLS P.I. |
| November 2006 | Version 2.2 starts production |
| 1 March 2007 | MLS validation papers submitted to Aura special issue |

- More details on instrument issues and changes in product responsibilities given in later slides

- MLS report, Aura Science Team, September 2006

## Starting in February 2006, signs of aging seen in primary 640 GHz HCl band (B13)
Thought due to radiation hardness issues identified in a particular batch of transistors shortly before launch
HCl data now taken from from adjacent band (B14)
B14 covers most of HCl line and also an isotopic HCl line
B13 to be operated on occasional days to ensure consistency

- Thought due to radiation hardness issues identified in a particular batch of transistors shortly before launch
- HCl data now taken from from adjacent band (B14)
- B14 covers most of HCl line and also an isotopic HCl line
- B13 to be operated on occasional days to ensure consistency

**MLS HCl and ClO band lifetime issues**

- Occasional small decreases in signal level seen in 640 GHz ClO band
- At the current rate of decay, it will last nominal mission lifetime
- ClO also measured at 190 GHz

- MLS report, Aura Science Team, September 2006

## MLS cloud ice data and model studies

- MLS provides new global maps of cloud ice water
- Initial comparisons with the ECMWF model (right) showed disagreements
- ECMWF is using MLS data to justify new cloud microphysics parameterizations
- This is leading to significant model improvements, particularly for tropical deep convection

- “...The MLS cloud ice product, and research led by the JPL team (J.-L. Li et al. 2005; GRL) has, for the first time, given us concrete additional information confirming the under-prediction of upper-tropospheric cloud ice and information on its vertical distribution...”
- Philippe BougeaultHead of ECMWF research department(unsolicited letter to Phil DeCola)

- MLS report, Aura Science Team, September 2006

## MLS studies ‘super greenhouse effect’

**MLS studies ‘super greenhouse effect’**

- New MLS observations quantify the sharp increase in upper tropospheric cloud ice and water vapor with increasing sea surface temperature (SST) greater than 300K
- This implies that “convective water vapor feedback” is responsible for ~65% of the previously-known tropical “super greenhouse effect”

- Greenhouse parameter (*g*) is fraction of radiation emitted by Earth’s surface that is *not* radiated to space

*Su et al., GRL 2006 (see also talk 10:30am Friday)*

- “Super greenhouse effect” is change in gradient of *g* for SST > 300K (green line is MLS estimated convective contribution)

- MLS report, Aura Science Team, September 2006

## Shortcut to stratosphere over Tibetan Plateau

**Shortcut to stratosphere over Tibetan Plateau**

- MLS shows a large area of enhanced CO and water vapor at 100 hPa in the south Asia region during August
- Back trajectory studies indicate that the Tibetan Plateau is the preferred route for this air to enter the stratosphere
- While there is more convection (and pollution) over the Indian subcontinent, the convection over the Tibetan Plateau is stronger and can reach higher (partly due to the warmer tropopause)
*Fu et al., PNAS 2006 (see also talk 9:30am Thursday) *

- (a) Concentration of high (>80 ppbv) 100 hPa CO samples from MLS
- (b,c) Distribution of same air 5, 20 days earlier (from back trajectory calculations)

- MLS report, Aura Science Team, September 2006

## MLS sees new ‘tape recorder’ signals

- The water vapor ‘tape recorder’ signal is well established
- Imprint of the seasonal tropopause temperature cycle is carried upwards in the humidity of slowly ascending stratospheric air

-      CO anomaly

- MLS has also seen ‘tape recorder’ like signals in CO, HCN and O3
- Reflecting cycles in tropospheric pollution
- CO tape recorder described in *Schoeberl et al., [GRL 2006]*
- More details in posters by Mark Schoeberl and Hugh Pumphrey at this meeting

- MLS report, Aura Science Team, September 2006

## MLS studies the ‘HOx dilemma’

- MLS (red) is in good agreement with balloon (green, blue) HOx observations
- MLS data also show excellent agreement with models
*[Pickett et al., GRL 2006]*
*[Canty et al., GRL 2006]*
- See also Tim Canty’s poster (Wed/Thu) and Herb Pickett’s talk in the radicals session (Tuesday pm)

**MLS observations do not indicate a ‘HO****x**** dilemma’**

- MLS report, Aura Science Team, September 2006

## Some other recent MLS publications

**Some other recent MLS publications**

- Quantification of 2004/2005 Arctic Ozone loss	*[Manney et al., GRL 2006]*
- Studies of polar vortex dehydration	*[Jimenez et al., GRL 2006] *
- Simultaneous observations of a polar vortex filament by MLS and Mauna Loa Lidar	*[Leblanc et al., GRL 2006]*
- Seasonal cycles in CO and O3 in the tropical tropopause region	*[Folkins et al., GRL 2006]*
- MLS upper stratospheric BrO observations used to estimate 18.6±5.5pptv of Bry	*[Livesey et al., GRL 2006]*

- MLS

- MLS report, Aura Science Team, September 2006

## MLS version 2.x data processing

- Version 1.5 started production in January 2005
- We expect version 2.2 to be the ‘definitive’ MLS data set for 2–3 years
- Reprocessing all the data since launch will take ~1.5 years
- Version 2.2 processing is planned to start in November 2006
- A few significant days of ‘preliminary’ version 2.1 data have been generated for this meeting
- Significant improvements in v2.1 over v1.5 include:
- Better vertical resolution for UTLS temperature and water vapor
- Less ‘noisy’ CO in the upper troposphere (see later slide)
- Elimination of high bias in stratospheric HNO3
- Far fewer ‘bad retrievals’ for OH
- Improved performance for mesospheric Temperature, H2O, O3, CO

- MLS report, Aura Science Team, September 2006

## Example of MLS v2.1 upper trop. CO

- Comparison of v1.51 (left) and v2.10 (right) 215 hPa CO
- Orange points are those identified as potentially affected by clouds

- Clouds have less impact on CO data than in v1.51
- We also see less ‘fuzz’ in the new data
- This has led to a significant decrease in suspected high bias

- Note change of color scales

- 28 January 2005

- MLS report, Aura Science Team, September 2006

## Planned validation papers from MLS team

| Temperature and GPH | Michael Schwartz et al. |
| --- | --- |
| H2O and relative humidity | William Read et al. (upper troposphere)Alyn Lambert et al. (stratosphere / mesosphere, possibly same paper as N2O) |
| Cloud ice | Dong Wu et al. |
| O3 | Nathaniel Livesey et al. (upper troposphere, same paper as UT CO)Lucien Froidevaux et al. (stratosphere / mesosphere)Yibo Jiang et al. (comparisons with sondes and ground based) |
| HNO3 | Michelle Santee et al. |
| ClO | Michelle Santee et al. |
| HCl | Lucien Froidevaux et al. |
| HOCl | Lucien Froidevaux et al. (short paper, if any) |
| BrO | Laurie Kovalenko et al. |
| N2O | Alyn Lambert et al. (possibly same paper as stratospheric H2O) |
| OH, HO2 | Herbert Pickett et al. |
| CO | Nathaniel Livesey et al. (upper troposphere, same paper as UT O3)Hugh Pumphrey et al. (stratosphere / mesosphere) |
| HCN | Pumphrey et al. |
| SO2 | Read et al. (short paper, if any) |
| Non-coincident validation | Gloria Manney et al. |
| SLIMCAT model | Robert Harwood et al. |

- MLS report, Aura Science Team, September 2006

## MLS Science team responsibility updates

| David Cuddy | MLS project manager |
| --- | --- |
| Lucien Froidevaux | Deputy Principal Investigator, validation; stratospheric and mesospheric O3, HCl, HOCl |
| Robert Harwood | (Edinburgh) United Kingdom Principal Investigator |
| Robert Jarnot | Instrument science, calibration and Level 1 algorithms |
| Jonathan Jiang | Cloud validation - morphology and model comparisons |
| Yibo Jiang | Stratospheric and mesospheric O3, Level 3 algorithms |
| Laurie Kovalenko | Chemical modeling; BrO |
| Alyn Lambert | Retrieval science; stratospheric and mesospheric H2O, N2O |
| Nathaniel Livesey | Principal Investigator; upper tropospheric O3 and CO, BrO |
| Gloria Manney | Dynamical consistency of MLS data and derived meteorological products |
| Herbert Pickett | OH and HO2 |
| Hugh Pumphrey | (Edinburgh) HCN, stratospheric and mesospheric CO |
| William Read | Measurement science and forward model; upper tropospheric H2O, SO2 |
| Michelle Santee | Polar processes; ClO, HNO3, CH3CN |
| Michael Schwartz | Temperature, geopotential height, and tangent pressure |
| Hui Su | Upper tropospheric analysis |
| Joe Waters | Principal Investigator ‘emeritus’ |
| Dong Wu | Cloud ice water content |

- MLS report, Aura Science Team, September 2006