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

Abstract

The NASA Wallops Flight Facility (WFF; Wallops Is., VA, USA) is the longest continuously operating ozonesonde station in the continental United States (since 1970). The well‐established WFF ozonesonde system comprises a Science Pump Corporation (SPC) electrochemical concentration cell (ECC) ozone sensor with a 1% potassium iodide and phosphate buffer sensing solution type (SST), interfaced with a Lockheed Martin Sippican radiosonde that provides winds, GPS coordinates, pressure, temperature, and relative humidity. A major milestone has been achieved with the reprocessing of the WFF ozone profiles during the digital measurement era (since 1995) to remove known biases and improve overall accuracy. We present an overview of the reprocessing methods and evaluate the homogenized data set relative to the original records, colocated Dobson, and satellite overpasses. Reprocessing yields modest changes in total column ozone by up to 3%, affirming the high data quality of the original ozone records. First estimates of ozone uncertainty are summarized and found to be consistent with estimates from previous studies. WFF has a history of evaluating ozonesonde performance via dual sonde launches that have tested standard operating procedures and combinations of ECC sensors and SST formulae. This rich data set illustrates how various ECC/SST combinations affect the ozone measurement. Results from the dual launches reaffirm the World Meteorological Organization recommended standard operating procedures where the ozone agreement between the SPC/1% Buffer and EN‐SCI/0.5% Half Buffer pair is well within ±5% throughout the profile. Tests of the SST under field conditions reveal the high sensitivity of ozone measurements to the buffer strength.

Tropospheric Ozone Assessment Report: Tropospheric ozone from 1877 to 2016, observed levels, trends and uncertainties

“…The overall accuracy of the global ozonesonde network has improved: at many important sites the historical record has been homogenized, by correcting for known changes in station records (e.g. Tarasick et al, 2016;van Malderen et al, 2016;Witte et al, 2017Witte et al, , 2019. In addition, spatial inhomogeneity has been reduced by adopting strict standard operating procedures (Smit and ASOPOS panel, 2011).…”

A Post‐2013 Dropoff in Total Ozone at a Third of Global Ozonesonde Stations: Electrochemical Concentration Cell Instrument Artifacts?

“…During the period 2013 through 2017, data from more than 25 ozonesonde stations were reprocessed (Sterling et al, 2018; Tarasick et al, 2016; Thompson et al, 2017; Van Malderen et al, 2016; Witte et al, 2017; Witte et al, 2019). In general, the reprocessed data show significant improvements in comparison with independent total column ozone (TCO) measurements.…”

Improving ECC Ozonesonde Data Quality: Assessment of Current Methods and Outstanding Issues

“…While spatial inhomogeneity has been reduced, and the overall accuracy of the global ozonesonde network improved, by adopting strict standard operating procedures (Smit & ASOPOS Panel, 2014), there is more that can be achieved by improving SOPs and homogenizing the historical record. Efforts to date (e.g., Sterling et al., 2018; Tarasick et al., 2016; Thompson et al., 2017; 2019; van Malderen et al., 2016; Witte et al., 2017; 2019) have reduced both stratospheric and tropospheric biases, and improved agreement with coincident total ozone measurements. New merged global data sets (Hassler et al., 2018; McPeters & Labow, 2012; Moeini et al., 2019) that include ozonesonde data additionally justify this effort.…”