An improved rocket ozonesonde (ROCOZ‐A): 2. Preparation of stratospheric ozone profiles

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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.

Section: Comparisons With Electrochemical Concentration Cell (Ecc) Ozsupporting

confidence: 87%

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

Barnes¹,

Parsons²,

Grothouse³

1995

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“…The ROCOZ-A rocket ozonesonde is a four-filter sequential-sampling ultraviolet radiometer [Holland et al, 1985;Barnes et al, 1986Barnes et al, , 1989]. The instrument is launched by a Super-Loki booster rocket to an apogee of 70-80 km, where the payload is ejected and parachutes back to the ground.…”

Section: Methodsmentioning

confidence: 99%

Comparison of ozone profiles from ground‐based lidar, electrochemical concentration cell balloon sonde, ROCOZ‐A rocket ozonesonde, and Stratospheric Aerosol and Gas Experiment satellite measurements

McDermid¹,

Godin²,

Barnes³

et al. 1990

A series of coordinated atmospheric ozone profile measurements was made during October and November 1988. The instruments making observations and their locations were as follows. The Jet Propulsion Laboratory (JPL) and Goddard Space Flight Center differential absorption lidar systems were located at the JPL‐Table Mountain Facility 34.4°N, 117.7°W. The electrochemical concentration cell balloon sondes and the rocket ozonesondes were both launched from Point Mugu Naval Air Station at 34.2°N, 119.2°W. Stratospheric Aerosol and Gas Experiment (SAGE II) satellite measurements were at various latitudes and longitudes but only measurements made within 1000 km of both of the above sites were considered for this intercomparison study. It was found that at least for the time of year of the study, SAGE II measurements agreed only when they were made much closer than 1000 km (<500 km) from the other sites, and this is explained in terms of the large latitudinal gradient observed in the ozone concentration profile. Agreement to 5% was seen between the instruments, over the altitude range from 20 to 50 km, when the measurements were made close together in both time and space.

Stratospheric Aerosol and Gas Experiment II and ROCOZ‐A ozone profiles at Natal, Brazil: A basis for comparison with other satellite instruments

Barnes¹,

Mcmaster²,

Chu³

et al. 1991

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We present the results of comparisons of satellite measurements of ozone from the Stratospheric Aerosol and Gas Experiment II (SAGE II) with in situ measurements from ROCOZ-A and electrochemical concentration cell (ECC) ozonesondes at Natal, Brazil (5.9øS, 35.2øW), during the southern hemisphere autumn of 1985. Since data were collected over a region of low ozone variability, comparisons were made of the mean values of 14 SAGE II profiles with the mean values of 7 ROCOZ-A and 7 ECC profiles, rather than of a more limited set of paired comparisons. The basic comparison presented here is ozone number density versus geometric altitude, the fundamental ozone measurement from SAGE II. Over the altitude region from 20 to 52 km SAGE II ozone densities averaged 0.4% lower than ROCOZ-A. The average of the absolute values of the ozone density differences for the two instruments was 2.4% over these altitudes. Owing in large part to the number of profiles in the data sets, the 95% confidence limits for the ozone density differences in these comparisons averaged 3.5% from 20 to 52 km, a significant improvement over previous results. In terms of ozone mixing ratio versus geometric altitude from 20 to 52 km, SAGE II values had a difference of 3.4% from ROCOZ-A (SAGE II higher), an average absolute difference of 3.8%, and an average of 4.7% for the 95% confidence limits. Differences between the ozone density and mixing ratio results are due to the auxiliary temperature and pressure values for the satellite and in situ instruments. The effects of pressure differences on the vertical positioning of the ozone profiles are not important for the altitude-based comparisons of SAGE II and ROCOZ-A. However, they become an important consideration in the comparisons of SAGE II with pressure-based ozone measurements from other satellite instruments. The composite sets of ozone, temperature, and pressure values presented here form an excellent basis for comparisons with other satellite ozone measurements. Experiment II (SAGE II) [Mauldin et al., 1985] was launched in October 1984 on the Earth Radiation Budget satellite (ERBS) and 'continues to make atmospheric measurements in 1990. Ozone measurements from SAGE II have been evaluated [Cunnold et al., 1989], and its ozone profiles have been placed in the archive at the National Space Science Data Center (NSSDC) at NASA's Goddard Space Flight Center, Greenbelt, Maryland. During March and April 1985 these five instruments were operational and providing measurements near Natal, Brazil (5.9øS, 35.2øW) [Barnes et al., 1987]. As part of a support program for satellite ozone instruments, measurements with a rocketborne ozone sensor, the ROCOZ-A ozonesonde, were initiated by NASA in 1983. That program has provided a set of 19 northern mid-latitude ozone profiles during the period from 1983 to 1985 for comparison with satellite ozone measurements [Barnes et al., 1989a]. In addition, the ROCOZ-A program has provided an additional set of seven equatorial ozone profiles at Natal, Brazil, from March 25 to...