Equatorial ozone profiles from the ground to 52 km during the southern hemisphere autumn

Self Cite

The Stratospheric Ozone Intercomparison Campaign (STOIC) was designed to compare proposed instruments for the Network for the Detection of Stratospheric Change (NDSC) with established measurement techniques. Ground‐based measurements were conducted at Table Mountain, California (34.4°N, 117.7°W), and rocket profiles were made at San Nicolas Island, California (33.3°N, 119.5°W). In an effort to estimate site‐to‐site differences during the intercomparison, daily soundings were made with balloon‐borne electrochemical concentration cell (ECC) ozonesondes at the two sites. Comparisons have been made of the mean values for the soundings at each site. The soundings showed small temperature differences between the two sites with the nighttime Table Mountain measurements up to 2°K cooler than the daytime San Nicolas Island temperatures. Day/night temperature corrections based on the emissivity and absorptivity of the thermistors in the balloon instruments can account for these apparent temperature differences. Ozone partial pressure profiles from the ECCs have been used to estimate atmospheric ozone variability during STOIC. Above 20 km, the lowest altitude for the STOIC comparisons, the average data sets from both sites showed standard deviations that were at or below the estimated 5–6% profile‐to‐profile repeatability for the ozonesondes. This indicates that atmospheric ozone variability was only of the order of a few percent above 20 km during the 2 weeks of the STOIC campaign. Above 20 km the ozone partial pressures over the Table Mountain site averaged 2.0% lower than over San Nicolas Island.

Section: Instrument Descriptionmentioning

confidence: 99%

Electrochemical concentration cell ozone soundings at two sites during the Stratospheric Ozone Intercomparison Campaign

Barnes¹,

Torres²

1995

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“…Overall, the comparisons in Figures 4a and 4b are consistent with previous ROCOZ-A/ECC comparisons [Barnes et al, 1987]. In general, the rocket instrument has averaged about 5% higher than the balloon sondes at altitudes below 25 km.…”

Section: In Addition the Comparisons In Figures 4a And 4b Show A 5-6mentioning

confidence: 99%

“…The set of ROCOZ-A measurements from the two STOIC campaigns is given in Tables 2 through 7. These values are presented as 2-km averages in the same manner as previous ROCOZ-A results [Barnes et al, 1987. Table 2 gives ROCOZ-A results as ozone column amounts, which are the fundamental ozone measurements by the instruments.…”

Section: Introductionmentioning

confidence: 99%

ROCOZ‐A ozone measurements during the Stratospheric Ozone Intercomparison Campaign (STOIC)

Barnes¹,

Parsons²,

Grothouse³

1995

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We present a set of ROCOZ‐A (rocket ozonesonde) ozone measurements during the October/November 1988 (pre‐STOIC) and the July/August 1989 Stratospheric Ozone Intercomparison Campaign (STOIC) in southern California. ROCOZ‐A and its associated electrochemical concentration cell (ECC) ozonesondes participated in the comparisons as established techniques for the validation of lidar and microwave instruments that have been proposed for the Network for the Detection of Stratospheric Change (NDSC). For the proposed network instruments, STOIC has provided a picture of their performance characteristics in 1989 and has given an estimate of their future performance in the NDSC. For ROCOZ‐A, STOIC has added new information on its accuracy and precision. It is this continuing characterization that gives ROCOZ‐A its value in comparisons. The STOIC comparisons show a shift of 5–6% in ROCOZ‐A ozone densities (ROCOZ‐A higher) from October/November 1988 to July/August 1989. This shift has been seen in comparisons with the Stratospheric Aerosol and Gas Experiment II (SAGE II), ECC ozonesondes, and the Jet Propulsion Laboratory (JPL) lidar. The source of this shift has not been determined. Until this new error source is resolved, we recommend that the previously quoted accuracy estimate for ROCOZ‐A ozone measurements be increased from 5–7% to 8–10%. About 2% of the difference between ROCOZ‐A ozone measurements and those from the proposed network instruments in 1989 appears to be due to differences in atmospheric ozone between the two STOIC sites. A correction for these site‐to‐site differences brings the ROCOZ‐A ozone measurements within 10% of all of the other STOIC instruments, and the average agreement (ROCOZ‐A 6% higher) becomes consistent with the historical set of ROCOZ‐A comparisons. The STOIC comparisons have shown structures in stratospheric ozone that cannot be resolved by ROCOZ‐A with its 4‐km vertical resolution. In addition, comparisons with nighttime measurements from the Millitech microwave above 45 km show a divergence from the daytime ROCOZ‐A values that agrees with the general characteristics of the diurnal cycle in upper stratospheric ozone that is predicted by photochemical models. Evidence of this ozone cycle is also seen in ROCOZ‐A comparisons with the SAGE II zonal mean above 45 km but not in comparisons with the nighttime measurements from the JPL lidar. The effects of diurnal ozone change in the upper stratosphere and mesosphere will be an important consideration in future comparisons of NDSC instruments.

“…March/April 1985 [Barnes et al, 1987a]. The Wallops measurement series described here was initiated for correlative support of ozone measurements from four NASA and National Oceanic and Atmospheric Administration (NOAA) satellites.…”

Section: A Series Of 19 Rocoz-a Launches Was Performed At the Nasa Wamentioning

confidence: 99%

“…/'For multiple flights, the launch times and the solar zenith angles represent the mean values for the series. [Barnes et al, , 1987a]. In the previous data sets the radiosonde pressures were taken directly from the aneroid sensor from the ground to the burst altitude of the balloons.…”

Section: Rocoz-a Flight and A Super-loki Datasonde Launch Immediatelymentioning

confidence: 99%

An improved rocket ozonesonde (ROCOZ‐A): 3. Northern mid‐latitude ozone measurements from 1983 to 1985

Barnes¹,

Chamberlain²,

Parsons³

et al. 1989

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We report the results of a set of ozone measurements at the NASA Wallops Flight Facility (37.8°N, 75.5°W) from August 1983 to September 1985. Nineteen profiles were obtained during this period, using ROCOZ‐A and electrochemical concentration cell ozonesondes, standard U.S. meteorological radio‐sondes, and Super‐Loki datasondes. Complete profiles of ozone, pressure, and temperature were obtained from the ground to 52 km, and 18 of the profiles correspond to site overpasses by ozone instruments on NASA and National Oceanic and Atmospheric Administration (NOAA) satellites. The profiles from this data set show reasonable agreement with established ozone climatologies. The annual ozone variability from the data set is roughly two thirds of the variability from the ozone model for the U.S. Standard Atmosphere (1976). The agreement between total ozone measurements from this data set and concurrent Dobson direct‐Sun total ozone measurements is excellent. The precision of ROCOZ‐A ozone values has been measured at the 3% level (1σ), and the accuracy of the ozone values is estimated at 5–7%. Since the ROCOZ‐A radiometers are expendable, the long‐term repeatability of the ozone measurements is based on a calibration facility which uses standards that are traceable to the National Bureau of Standards (NBS). The assembly of ROCOZ‐A ozone, pressure, and temperature measurements presented here allows the use of this data set as a transfer standard between satellite instruments with different fundamental ozone measurements. In addition, this data set can be used for comparisons of modeled and measured ozone amounts in the stratosphere and lower mesosphere. Such comparisons should prove valuable, since model results are typically 30–50% lower than measured ozone concentrations at altitudes above 35 km.