The MLS HO₂ Product

Contact: Herbert Pickett

Basic Information HO2 is an important reactive species in atmospheric chemistry.

The HO2 Molecule

The standard product for HO₂ is taken from the 640 GHz (Core+R4A) retrieval. Simulations indicate closure for HO₂ day/night differences to better than 10% above 22 hPa. Without taking day/night (ascending/descending) differences the closure in the simulations is at times larger than the expected daytime HO₂ concentration.

Significant averaging (e.g., weekly zonal means) is required to obtain useful HO₂ data from MLS observations. Averages of nighttime observations (from the descending part of the orbit), when HO₂ abundances are expected to be essentially zero show significant non-zero values, indicative of biases. These need to be removed before any scientific study by taking day/night (or ascending/descending) differences. We believe that these differences will be reliable at levels at and above the 22 hPa pressure surfaces. At pressures greater than 22 hPa the bias is larger than we can confidently expect simple day/night differences to remove.

HO₂ is being validated using the balloon-borne FIRS-2 instrument. Preliminary results for September 23, 2004, for the region of Ft. Sumner, NM show excellent agreement between FIRS-2 and MLS [Pickett et al., 2005].1

(map from 2005d264)

2008

1. Pickett, H.M., B.J. Drouin, T. Canty, R.J. Salawitch, R.A. Fuller, V.S. Perun, N.J. Livesey, J.W. Waters, R.A. Stachnik, S.P. Sander, W.A. Traub, K.W. Jucks, K. Minschwaner, "Validation of Aura Microwave Limb Sounder OH and HO₂ measurements", vol 113, pgs. D16S30, 2008. Reprint

2007

1. Kovalenko, L.J., K.W. Jucks, R.J. Salawitch, G.C. Toon, J-F. Blavier, D.G. Johnson, A. Kleinbohl, N.J. Livesey, J.J. Margitan, H.M. Pickett, M.L. Santee, B. Sen, R.A. Stachnik, J.W. Waters, "Observed and Modeled HOCl Profiles in the Midlatitude Stratosphere: Implication for Ozone Loss", vol 34, pgs. L19801, 2007. Reprint
2. Mueller, E.R., R. Henschke, W.E. Robotham, L.A. Newman, L.M. Laughman, R.A. Hart, J. Kennedy, H.M. Pickett, "Terahertz local oscillator for the Microwave Limb Sounder on the Aura Satellite", vol 46, num no. 22, pgs. 4907-4915, 2007. Reprint
3. Verronen, P.T., C.J. Rodger, M.A. Clilverd, H.M. Pickett, E. Turunen, "Latitudinal extent of the January 2005 solar proton event in the Northern Hemisphere from satellite observations of hydroxyl", vol 25, pgs. 2203-2215, 2007. Reprint

2006

1. Cofield, R.E., P.C. Stek, "Design and field-of-view calibration of 114-660 GHz optics of the Earth Observing System Microwave Limb Sounder", vol 44, num no. 5, pgs. 1166-1181, 2006. Reprint
2. Canty, T., H.M. Pickett, R.J. Salawitch, K.W. Jucks, W.A. Traub, J.W. Waters, "Stratospheric and Mesospheric HO_x: Results from Aura MLS and FIRS-2", vol 33, pgs. L12802, 2006. Reprint
3. Pickett, H.M., B.J. Drouin, T. Canty, L.J. Kovalenko, R.J. Salawitch, N.J. Livesey, W.G. Read, J.W. Waters, K.W. Jucks, W.A. Traub, "Validation of Aura MLS HO_x measurements with remote-sensing balloon instruments", vol 33, pgs. L01808, 2006. Reprint
4. Pickett, H.M., W.G. Read, K.K. Lee, Y.L. Yung, "Observation of Night OH in the Mesosphere", vol 33, pgs. L19808, 2006. Reprint

1997

1. Osterman, G.B., R.J. Salawitch, B. Sen, G.C. Toon, R.A. Stachnik, H.M. Pickett, J.J. Margitan, J-F. Blavier, D.B. Peterson, "Balloon-borne measurements of stratospheric radicals and their precursors: Implications for the production and loss of ozone", vol 24, pgs. 1107-1110, 1997. Reprint

1992

1. Stachnik, R.A., J.C. Hardy, J.A. Tarsala, J.W. Waters, N.R. Erickson, "Submillimeterwave heterodyne measurements of stratospheric ClO, HCl, O₃, and HO₂: First results", vol 19, pgs. 1931-1934, 1992. Reprint

Site Manager: Nathaniel Livesey
Webmaster: Brian Knosp