David G. Johnson

Smithsonian stratospheric far‐infrared spectrometer and data reduction system

The Smithsonian far-infrared spectrometer is a remote sensing Fourier transform spectrometer that measures the mid- and far-infrared thermal emission spectrum of the stratosphere from balloon and aircraft platforms. The spectrometer has had nine successful balloon flights from 1987 to 1994, flying at float altitudes of 36–39 km and collecting 131 hours of midlatitude stratospheric limb spectra. The spectrometer also flew on a NASA DC-8 aircraft, as part of the second Airborne Arctic Stratospheric Expedition (AASE-II), collecting 140 hours of overhead spectra at latitudes ranging from the equator to the north pole. We present here a brief description of the instrument, a discussion of data reduction procedures, an estimation of both random and systematic errors, an outline of the procedure for retrieving mixing ratio profiles, and an explanation of the method of deriving temperature and pressure from the far- and mid-infrared spectra.

Monoclonal gammopathy and neuropathy: Myelin‐associated glycoprotein reactivity and clinical characteristics

Immunoblot analysis was performed on the serum from 29 patients with polyneuropathy and monoclonal gammopathy. Nine patients had IgM spikes, and six of the nine had reactivity against myelin-associated glycoprotein (MAG) associated with a slowly progressive, predominantly sensory neuropathy. In contrast, 23 patients who lacked anti-MAG reactivity had more severe sensory motor neuropathy. Thus, IgM monoclonal gammopathy with reactivity against MAG may define a distinct clinical entity.

Observations of OH, HO2, H2O, and O3 in the upper stratosphere: Implications for HOx photochemistry

Balloon-borne observations of concentrations of OH, HO2, H2O, and O3 in the middle and upper stratosphere are used to test our understanding of HOx photochemistry. Assuming our photochemical model is complete, the measured [OH] and [HO2] above 38 km (where HOx partitioning is no longer dependent on [NO]) are modeled best by calculations that use a 25% reduction in the ratio of the reaction rate constants for O+HO2 and O+OH as well as either a 25% reduction of the rate constant of OH+HO2 (the primary HOx sink) or a 25% increase in HOx production. All of these changes are consistent with the uncertainties in the recommended rate constants. The kinetic parameters required to explain our observations of [OH] and [HO2] do not lead to a resolution of the long-standing “ozone deficit problem” above 45 km.

Isotopic composition of stratospheric ozone

Using recently measured rates for isotopic variants of the ozone formation reaction O + O 2 + M, we derive expressions for the enrichment of symmetric and asymmetric 50 O 3 3 and 49 O 3 in stratospheric ozone and calculate total enrichments of 123‰ and 107‰ for 50 O 3 and 49 O 3 respectively We compare the calculations with measurements made with the Smithsonian Astrophysical Observatory far-infrared spectrometer during seven balloon flights which took place between 1989 and 1997. We find that the calculations are in reasonable agreement with the average observed enrichments of 102 ±43‰ and 73±60‰ for 50 O 3 and 49 O 3 , respectively, where the errors indicate the estimated accuracy; we also find that our measurements are in agreement with other recent stratospheric and tropospheric measurements. Using our measurements of the enrichment of the asymmetric and symmetric forms of 50 O 3 and 49 O 3 , we estimate branching ratios of 0.43±0.03 and 0.46 ± 0.06 for production of the symmetric isotopomer by the reaction of 16 O with 34 O 2 and 33 O 2 , respectively.

Stratospheric Hydroperoxyl Measurements

The hydroperoxyl radical (HO2) plays a key role in stratospheric chemistry through the HOx catalytic cycle of ozone destruction. Earlier measurements of stratospheric HO2 have given mixed results; some measured mixing ratios greatly exceed theoretical predictions. Measurements of HO2 have now been made with a balloon-borne farinfrared spectrometer. The measured daytime profile is in excellent agreement with theory up to 40 kilometers; above this level the measurements exceed theory by 30 percent, perhaps because of underprediction of ozone at these altitudes. The nighttime HO2 profile is strongly depressed with respect to the daytime profile, in general agreement with theory.

Altered blood T-cell subsets in patients with multiple sclerosis☆

We have found an alteration in T-cell subsets in patients with active multiple sclerosis, specifically an increase in the T4:T8 ratio. These findings have been reproducibly obtained over the past four years, occurring in the majority of acute patients tested early in the course of an attack and in between 25 and 40% of chronic progressive patients, depending on their stage of illness. These changes correlate with pleocytosis in spinal fluid and with other abnormalities of immune function, such as spontaneous immunoglobulin production. They have been helpful in assessing disease activity in patients being treated on a variety of protocols and as part of research studies of immunoregulatory abnormality in multiple sclerosis, but have not been helpful as a diagnostic test for multiple sclerosis. The decrease of these cells in the peripheral blood of patients with active disease may be secondary to migration of these cells to the central nervous system, where they are sequestered.

Detection of HBr and upper limit for HOBr: Bromine partitioning in the stratosphere

We determine mixing ratio profiles for HBr and upper limits for HOBr in the stratosphere with precisions up to 1.7 and 4.8 parts per trillion, respectively, using the combined data from 7 flights of our far-infrared spectrometer. The measurements suggest that in the range 22–34 km the average mixing ratio of HBr is 2.0±0.8, and that the average mixing ratio of HOBr is less than 2.8 ppt. Our measurements of HBr are in reasonable agreement with a photochemical model which includes 0 or 2% production of HBr through the reaction of BrO with HO2, but in strong disagreement with a model including 5 or 10% HBr production.

Antineural antibodies in the serum of patients with amyotrophic lateral sclerosis

Sera from 12 patients with amyotrophic lateral sclerosis (ALS) and 18 controls were screened for antineural antibodies using immunoblotting. No consistent differences were detected between ALS patients and controls, although antibodies to 52,000- and 70,000-dalton proteins in mouse spinal cord were somewhat more common in ALS sera. Antibodies to a protein of approximately 150,000 to 200,000 daltons were also evident. The 70,000- and 52,000-dalton proteins were detected in brain, cerebellum, and liver as well as spinal cord. Immunohistochemistry suggested antibody activity was directed at least in part to neurofilaments. While the antibodies to the 52,000- and 70,000-dalton proteins were more common in ALS than control sera (p < 0.02 and < 0.05, respectively), it is not clear from this initial study that this difference is of clinical or etiologic significance.

The smithsonian astrophysical observatory database SAO92

Abstract The Smithsonian Astrophysical Observatory (SAO) maintains a molecular line database (the SAO line database) for analysis of atmospheric spectra in the far i.r. and longer-wave mid i.r., from 10-800 cm -1 . This database combines the best currently available line parameters, including the HITRAN 1.2 molecular database, the JPL submillimeter, millimeter, and microwave spectral line catalog 3 (JPLSMM), and other available measurements and calculations. The current version of the database contains 154.895 lines from H 2 O, CO 2 , O 3 , N 2 O, CO, CH 4 , O 2 (including the 1 Δ state), NO, SO 2 , NO 2 , NH 3 , HNO 3 , OH, HF, HCl, HBr, HI, ClO, OCS, H 2 CO, HOCl, HCN, H 2 O 2 , O( 3 P ), and HO 2 . The database is available in both HITRAN-type 80 character (SAO92) and 100 character (SAO92A) formats. 1. L.S. Rothman, R.R. Gamache, A. Goldman, L.R. Brown, R.A. Toth, H.M. Pickett, R.L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C.P. Rinsland, and M.A.H. Smith, Appl. Opt. 26 , 4058 (1987). 2. L.S. Rothman, R.R. Gamache, R.H. Tipping, C.P. Rinsland, M.A.H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S.T. Massie, L.R. Brown, and R.A. Toth, JQSRT . 48 , 469 (1992). 3. R.L. Poynter and H.M. Pickett, Submillimeter millimeter and microwave spectral line catalog, Publ. 80-23, revision 2, Jet Propulsion Laboratory, Pasadena, CA (1984).

Measurement of chlorine nitrate in the stratosphere using the ν4 and ν5 bands

We present laboratory measurements of the absorption cross sections of the ν5 band (540–580 cm−1) of chlorine nitrate made under stratospheric conditions of temperature and pressure. We use the measured cross sections and observed mid-infrared stratospheric emission spectra to retrieve mid-latitude vertical mixing ratio profiles for both day and night in the altitude range 20–34 km, and compare the results with a sunset profile obtained simultaneously from solar absorption measurements of the ν4 Q branch at 780 cm−1. The profiles obtained using these two methods are shown to be in excellent agreement, validating retrievals using the ν4 band. We also find good agreement in this altitude range between the observed day/night ratio and the results of a 1-D photochemical model