"What's new" Archive: 2006

8 December 2006: Rollout of "beta version" of updated MLS website
11 September 2006: New EOS MLS Principal Investigator Named

Dr. Nathaniel Livesey has replaced Dr. Joe Waters as the EOS MLS Principal Investigator. Dr. Livesey will now be responsible for ensuring that MLS overall scientific objectives are met. Dr. Waters will be staying on with the EOS MLS project through June 2007.
18 May 2006: Bands 10 and 29 Turned Back ON

MLS bands 10 and 29 were turned off to due to signal degredations to determine whether or not their operational lifetime can be extended by duty-cycling. Both bands were recently turned back ON and after careful study, it has been determined that both bands will meet their operational, 5-year goal.

4 May 2006: Change in responsibilities for some MLS data products

Mark Filipiak's leaving the UK MLS team and Hugh Pumphrey's responsibilities as lecturer at the University of Edinburgh have necessitated some changes in responsibilities for the MLS data products, which are reflected in the following updated list of responsibilities:

MLS data product(s)	responsible individual
temperature, geopotential height	Michael Schwartz
stratospheric O₃, HCl, HOCl	Lucien Froidevaux
BrO, upper tropospheric O₃, upper tropospheric / lower stratospheric CO	Nathaniel Livesey
upper tropospheric H₂O, volcanic SO₂	Bill Read
cloud ice	Dong Wu
stratospheric H₂O, N₂O	Alyn Lambert
OH and HO₂	Herb Pickett
ClO, HNO₃, CH₃CN	Michelle Santee
HCN, upper stratospheric and above CO	Hugh Pumphrey

17 April 2006: MLS 640 GHz bands 10 (ClO) and 29 (HOCl) turned off

Following degradation in their output power levels, MLS bands 10 and 29 (both part of the same signal path) were turned off to determine whether their operational lifetime can be extended by duty-cycling. The current plan is to turn these bands back on in mid-late May to observe the onset of Antarctic chlorine activation.

ClO continues to be measured by band 5 of the MLS 190 GHz radiometer with ~2x larger noise than the 640 GHz band 10 measurements; the band 5 ClO data are available as the "ClO-190" swath in the L2GP-DGG file. See the supplement to the version 1.5 MLS Level 2 data quality document for details on this product. HOCl is not measured by other MLS bands.
16 February 2006: Start MLS v01.52 data processing; impact on data products
Contact: Lucien Froidevaux
- MLS data users should use Version 1.52 data, with files starting Feb. 16, 2006, because band 13 (part of the 640 GHz radiometer) experienced a degradation in output power level, and was turned off to extend its operational lifetime through duty-cycling. Band 13 had provided the main measurement for HCl, but v1.52 makes use of channels from overlapping band 14, with little overall impact or loss of science. Version 1.52 represents a minor change overall and only affects some of the MLS products coming from the 640 GHz radiometer retrievals. Also, a bug fix (unrelated to band 13) in v1.52 has helped the OH retrievals, which now have significantly fewer bad profiles, by properly accounting for bad radiances that occur (daily) in the THz radiometer data.
  3C
- Band 13 was turned on for about half the day on Feb. 23, and will now be duty-cycled (nominally one day per month) to extend its operational lifetime, while providing a spot check on the band 14 HCl measurements.
- Version 1.52 ignores band 13 and proceeds as if it were off. In addition to v1.52 processing, MLS data will be processed on those special (band 13 on) days with v1.51 software, for internal MLS usage (those days can be made available to interested users upon request).
- Impact of switch to v1.52 for MLS products (versus v1.51):
  - HCl: This product is slightly affected by the switch to v1.52. For pressures less than or equal to 68 hPa, mean values are affected by less than 5% (values are up to a few % larger for P < 3 hPa, and up to 5% smaller for 7 hPa < P < 22 hPa); precision is degraded by 20-30%. Values for P > 68 hPa increase by about 10% in v1.52. Height-resolution gets somewhat poorer in the upper stratosphere and lower mesosphere (6.5 to 8.5 km instead of 5.5 to 6.5 km). Precise time series analyses across the Feb. 16 boundary will require reprocessing of MLS data with a common software version.
  - HOCl: We do not recommend the use of HOCl from v1.52 data, except possibly near 2 to 3 hPa, where the impact of switching to the new data version is minimal. The loss of band 13 and indirect effects arising from slight changes in the 640 GHz ozone retrieval lead to poorer HOCl retrievals, with some negative values near 10 hPa (day and night values affected in a similar way). Precision is not significantly affected.
  - ClO: ClO is only marginally affected, mainly in the lower stratosphere (by a few hundredths of a ppbv), as long as day-night differences are performed, as recommended for this region (see the V1.5 Level 2 data quality and description document; available from MLS website mls.jpl.nasa.gov).
  - OH: A bug fix (unrelated to band 13) in v1.52 has helped the OH retrievals, which now have significantly fewer bad profiles, by now properly accounting for bad radiances that occur (daily) in the THz radiometer data.
  - HO2: The impact on this product is negligible, as long as day-night differences are performed, as recommended (see the V1.5 Level 2 data quality and description document; available from MLS website mls.jpl.nasa.gov).
  - BrO: BrO is slightly affected but is not considered suitable for scientific use in either v1.51 or v1.52 data.
  - N2O: There is no impact for this product.
27 March 2006: MLS upper tropospheric weekly maps now available on website
Contact: Jonathan Jiang

Global maps of weekly-average MLS measurements of upper tropospheric cloud ice, relative humidity with respect to ice, water vapor, CO, O₃ and temperature are now available from the MLS web site data page. Included for comparison are maps for the same period of GEOS-CHEM model (driven by GMAO GEOS-4 meteorological data) near-real-time output for CO and O₃, and GMAO GEOS-4 first look output for water vapor. Maps are currently available for MLS v01.51 and v01.52 data at 100, 147, and 215 hPa pressure surfaces.

These plots are available at: http://mls.jpl.nasa.gov/data/dataimage.html