Homogenizing and Estimating the Uncertainty in NOAA’s Long Term Vertical Ozone Profile Records Measured with the Electrochemical Concentration Cell Ozonesonde

Abstract

Abstract. NOAA's program of long term monitoring of the vertical distribution of ozone with Electrochemical ConcentrationCell (ECC) ozonesondes has undergone a number of changes over the 50 year record. In order to produce a homogenous data set, these changes must be documented and where necessary, appropriate corrections applied. This is the first comprehensive and consistent reprocessing of NOAA's ozonesonde data records that corrects for these changes using the rawest form of the 15 data (cell current and pump temperature) in native resolution as well as a point by point uncertainty calculation that is unique to each sounding. The reprocessing is carried out uniformly at all eight ozonesonde sites in NOAA's network with differences in sensing solution and ozonesonde types accounted for in the same way at all sites. The corrections used to homogenize the NOAA ozonesonde data records greatly improve the ozonesonde measurements with an average one sigma uncertainty of ±4-6% in the stratosphere and ±5-20% in the troposphere. A comparison of the integrated column ozone from the ozonesonde 20 profile with co-located Dobson spectrophotometers total column ozone measurements shows agreement within ±5% for >70% of the profiles. Very good agreement is also found in the stratosphere between ozonesonde profiles and profiles retrieved from the Solar Backscatter Ultraviolet Instruments (SBUV).

The NASA Wallops Flight Facility Digital Ozonesonde Record: Reprocessing, Uncertainties, and Dual Launches

“…Uncertainties in the background/current term (red) are highest around the tropopause region where ozone measurements are a minimum (gray line) and I B approaches I M , meaning the total uncertainty approaches the measured signal. This is similar to the results in Witte et al () that reported on ozone uncertainties in the reprocessed tropical Southern Hemisphere Additional Ozonesondes data set and Sterling et al () that presented uncertainty estimates for profiles at eight NOAA ozonesonde stations.…”

“…Over time, refinements in operating procedure protocols, changes in the ECC instrument, and adjustments in the sensing solution have created inhomogeneities in the long‐term station data records (van Malderen et al, ; Sterling et al, ; Tarasick et al, ; Witte et al, ). We apply well‐established guidelines from Smit12 for reprocessing and homogenizing the July 1995 to July 2018 WFF ozonesonde records.…”

“…We assume Smit and ASOPOS () simulated a midlatitude “clean air” profile where I M is small relative to I B in the lower troposphere, resulting in the Δ I B /Δ I M term being dominant. Sterling et al () provided an evaluation of the ozone uncertainty budget for an individual launch at the Boulder, CO, USA site. Similar to our analysis, total ozone uncertainties for the Boulder case maximize at 7.5% around the tropopause and are a minimum in the stratosphere where the uncertainty due to the conversion efficiency dominates.…”

“…Significant outcomes from the ASOPOS community are (1) recommended standard operating procedures (SOPs) for ECCs that are outlined in the WMO/GAW (World Meteorological Organization/Global Atmospheric Watch) Report #201 (Smit & ASOPOS, ), (2) guidelines for reprocessing ozonesonde data records to correct for known biases in the measurement system, published in Smit and O3S‐DQA (; hereafter referred to as Smit12), and (3) a method for estimating ozone partial pressure uncertainties in the ozonesonde measurement system, also in Smit12. To date, data records from roughly 30 stations worldwide have been reprocessed and evaluated using the Smit12 guidelines (van Malderen et al, ; Sterling et al, ; Tarasick et al, ; Thompson et al, ; Witte et al, , ).…”

First Reprocessing of Southern Hemisphere ADditional OZonesondes Profile Records: 3. Uncertainty in Ozone Profile and Total Column

“…Van Malderen et al () also applied Smit12 uncertainties to the ECC ozonesonde measurements at Uccle (Belgium). Sterling et al () applied the formula to two SHADOZ stations (Hilo, Hawaii, and Pago Pago, American Samoa), Boulder, CO, and the South Pole, and Tarasick et al () applied their own uncertainty estimates to the Canadian ozonesonde records, taking into account the uncertainty terms in equation . We take advantage of theses studies to compare with our methods and results.…”