<figure><img src="image_53.png" /></figure>

<figure><img src="image_54.png" /></figure>

<figure><img src="image_55.png" /><figcaption>**Figure 9.** Correlation (R) between the six subcolumn DFS values and the six ozone subcolumns (bottom to top row: 0-6 km, 6-12 km, 12-18 km, 18-24 km, 24-32 km, 32-82 km) for N retrievals by TROPOMI (first column in landscape view). Subsequent columns show the layer-DFS as a function of latitude, time, solar zenith angle (SZA), viewing-zenith angle (VZA), cloud fraction, and surface albedo. 84, 50, and 16 % quantiles are added in red (per station, per season, or for ten bins), together with the overall layer mean (black line). Yearly drifts are added to the temporal dependence plots.</figcaption></figure>
<figure><img src="image_56.png" /></figure>

<figure><img src="image_57.png" /><figcaption>**Figure 10.** Correlation (R) between N lowest five ozone subcolumns as observed by TROPOMI and the coincident vertically integrated ozonesonde measurements (first column in landscape view), and their overall sum (top row). Subsequent columns show the differences between satellite and ozonesonde subcolumns as a function of latitude, time, solar zenith angle (SZA), viewing-zenith angle (VZA), cloud fraction, and surface albedo. 84, 50, and 16 % quantiles are added in red (per station, per season, or for ten bins), together with the overall mean difference (black line), and the product requirements for each subcolumn (grey areas). Yearly drifts are added to the temporal dependence plots.</figcaption></figure>
<figure><img src="image_58.png" /></figure>

<figure><img src="image_59.png" /><figcaption>**Figure 11.** Comparison between S5P RPRO/OFFL ozone number density profile data and all co-located ground-based reference measurements. Every subplot shows six graphs, respectively, from left to right: the difference and the percent relative difference between S5P and ozonesonde (top), tropospheric lidar (middle), or stratospheric lidar (bottom), the chi-square profile, the vertical sensitivity, the altitude registration offset, and the averaging kernel FWHM associated with the satellite retrieval. The colour scale indicates the TROPOMI solar zenith angle. Black dashed lines show mean values (thick lines) and standard deviations (thin lines, around the mean), while white dashed lines indicate the mean difference between the a-priori profile and the reference measurement. Dotted black lines indicate the total ex-ante (inductive) uncertainty of TROPOMI and the reference measurements combined (around the mean difference). The black full lines show the same, after adding the retrieval's smoothing error.</figcaption></figure>
<figure><img src="image_60.png" /><figcaption>**Table A1.** List of northern hemisphere ozonesonde stations providing correlative data for the TROPOMI validation in this work. Subsequent columns show the station name, location, archive / PI institute abbreviation, validation period (Full for the entire five year TROPOMI time range: May 2018 to April 2023), and number of co-locations in the comparative validation. Horizontal black lines separate the latitude zones defined in Figure 3.</figcaption></figure>

<table><thead><tr><th>Name</th><th>Location [°N,°E]</th><th>Archive / PI inst.</th><th>Period [YY/MM]</th><th>Co-locs.</th></tr></thead><tbody><tr><td>Alert</td><td>[82.45, -62.51]</td><td>WOUDC / MSC</td><td>18/05 - 22/06</td><td>91</td></tr><tr><td>Eureka</td><td>[79.99, -85.93]</td><td>WOUDC / MSC</td><td>18/05 - 23/03</td><td>151</td></tr><tr><td>Ny-Alesund</td><td>[78.93, 11.93]</td><td>NDACC / AWI</td><td>18/05 - 23/03</td><td>123</td></tr><tr><td>Resolute</td><td>[74.72, -94.98]</td><td>NDACC / MSC</td><td>18/05 - 20/04</td><td>56</td></tr><tr><td>Scoresbysund</td><td>[70.48, -21.95]</td><td>NDACC / DMI</td><td>Full</td><td>174</td></tr><tr><td>Sodankyla</td><td>[67.37, 26.63]</td><td>NDACC / FMI</td><td>Full</td><td>107</td></tr><tr><td>Jokioinen</td><td>[60.81, 23.50]</td><td>NDACC / FMI</td><td>20/01 - 22/04</td><td>9</td></tr><tr><td>Lerwick</td><td>[60.13, -1.18]</td><td>NDACC / UKMO</td><td>18/05 - 22/09</td><td>201</td></tr><tr><td>Churchill</td><td>[58.74, -94.07]</td><td>NDACC / MSC</td><td>19/01 - 22/02</td><td>103</td></tr><tr><td>Goose Bay</td><td>[53.31, -60.36]</td><td>NDACC / MSC</td><td>18/05 - 22/06</td><td>126</td></tr><tr><td>Legionowo</td><td>[52.40, 20.97]</td><td>NDACC / IMGW</td><td>Full</td><td>238</td></tr><tr><td>Lindenberg</td><td>[52.21, 14.12]</td><td>NDACC / DWD</td><td>Full</td><td>245</td></tr><tr><td>De Bilt</td><td>[52.10, 5.18]</td><td>NDACC / KNMI</td><td>18/05 - 23/03</td><td>195</td></tr><tr><td>Valentia</td><td>[51.94, -10.25]</td><td>NDACC / ME</td><td>Full</td><td>128</td></tr><tr><td>Uccle</td><td>[50.80, 4.35]</td><td>NDACC / RMI</td><td>Full</td><td>659</td></tr><tr><td>Port Hardy</td><td>[50.68, -127.38]</td><td>WOUDC / MSC</td><td>18/06 - 23/03</td><td>117</td></tr><tr><td>Praha</td><td>[50.00, 14.44]</td><td>NDACC / CHMI</td><td>19/01 - 23/04</td><td>234</td></tr><tr><td>Hohenpeissenberg</td><td>[47.81, 11.01]</td><td>WOUDC / DWD</td><td>Full</td><td>626</td></tr><tr><td>Payerne</td><td>[46.82, 6.95]</td><td>WOUDC / MeteoSwiss</td><td>Full</td><td>548</td></tr><tr><td>Obs. Haute Provence</td><td>[43.94, 5.71]</td><td>NDACC / LATMOS</td><td>18/05 - 22/11</td><td>189</td></tr><tr><td>Yarmouth</td><td>[43.87, -66.11]</td><td>WOUDC / MSC</td><td>18/05 - 22/06</td><td>186</td></tr><tr><td>Madrid</td><td>[40.45, -3.72]</td><td>WOUDC / INM</td><td>Full</td><td>236</td></tr><tr><td>Boulder</td><td>[40.03, -105.25]</td><td>NOAA / GML</td><td>23/03</td><td>1</td></tr><tr><td>Tsukuba</td><td>[36.05, 140.13]</td><td>WOUDC / JMA</td><td>Full</td><td>210</td></tr><tr><td>Huntsville</td><td>[34.72, -86.64]</td><td>NOAA / UAH</td><td>18/05 - 20/03</td><td>22</td></tr><tr><td>Izana</td><td>[28.31, -16.50]</td><td>NDACC / AEMET</td><td>18/05 - 22/12</td><td>182</td></tr><tr><td>Taipei</td><td>[25.04, 121.51]</td><td>WOUDC / CWBT</td><td>18/11 - 22/03</td><td>17</td></tr><tr><td>Hong Kong Obs.</td><td>[22.31, 114.17]</td><td>WOUDC / HKO</td><td>18/05 - 22/06</td><td>183</td></tr><tr><td>Hanoi</td><td>[21.03, 105.85]</td><td>SHADOZ / GSFC</td><td>18/05 - 21/11</td><td>84</td></tr><tr><td>Hilo</td><td>[19.72, -155.07]</td><td>NOAA / GML</td><td>Full</td><td>237</td></tr><tr><td>Costa Rica (3 locs.)</td><td>[9.94, -84.04]</td><td>SHADOZ / NCAR</td><td>18/05 - 23/03</td><td>112</td></tr><tr><td>Paramaribo</td><td>[5.81, -55.22]</td><td>NDACC / KNMI</td><td>Full</td><td>161</td></tr><tr><td>Sepang Airport</td><td>[2.73, 101.70]</td><td>SHADOZ / MMD</td><td>18/05 - 22/12</td><td>79</td></tr></tbody></table>
<figure><img src="image_61.png" /><figcaption>**Table A2.** List of southern hemisphere ozonesonde stations providing correlative data for the TROPOMI validation in this work. Subsequent columns show the station name, location, archive / PI institute abbreviation, validation period (Full for the entire five year TROPOMI time range: May 2018 to April 2023), and number of co-locations in the comparative validation. Horizontal black lines separate the latitude zones defined in Figure 3.</figcaption></figure>

<table><thead><tr><th>Name</th><th>Location [°N,°E]</th><th>Archive / PI inst.</th><th>Period [YY/MM]</th><th>Co-locs.</th></tr></thead><tbody><tr><td>San Cristobal</td><td>[-0.92, -89.60]</td><td>SHADOZ / USFQ</td><td>21/12 - 22/12</td><td>23</td></tr><tr><td>Nairobi</td><td>[-1.27, 36.80]</td><td>SHADOZ / MeteoSwiss</td><td>18/06 - 20/03</td><td>43</td></tr><tr><td>Ascension Island</td><td>[-1.98, -14.42]</td><td>SHADOZ / GSFC</td><td>18/05 - 22/09</td><td>144</td></tr><tr><td>Natal</td><td>[-5.83, -35.20]</td><td>SHADOZ / INPE</td><td>18/05 - 22/12</td><td>83</td></tr><tr><td>Watukosek</td><td>[-7.50, 112.60]</td><td>SHADOZ / BRIN</td><td>21/03 - 22/12</td><td>23</td></tr><tr><td>Pago Pago</td><td>[-14.23, -170.56]</td><td>NOAA / GML</td><td>Full</td><td>155</td></tr><tr><td>Suva</td><td>[-18.13, 178.40]</td><td>NOAA / GML</td><td>Full</td><td>54</td></tr><tr><td>St. Denis</td><td>[-20.90, 55.48]</td><td>SHADOZ / LACY</td><td>18/05 - 20/12</td><td>87</td></tr><tr><td>Irene</td><td>[-25.92, 28.22]</td><td>SHADOZ / SAWS</td><td>18/05 - 22/08</td><td>33</td></tr><tr><td>Broadmeadows</td><td>[-37.69, 144.95]</td><td>WOUDC / ABM</td><td>18/05 - 23/02</td><td>226</td></tr><tr><td>Lauder</td><td>[-45.04, 169.68]</td><td>NDACC / NIWA</td><td>18/05 - 22/06</td><td>208</td></tr><tr><td>Macquarie</td><td>[-54.50, 158.95]</td><td>WOUDC / ABM</td><td>18/05 - 23/02</td><td>231</td></tr><tr><td>Ushuaia</td><td>[-54.85, -68.31]</td><td>WOUDC / SMNA</td><td>18/08 - 19/11</td><td>18</td></tr><tr><td>Marambio</td><td>[-64.23, -56.62]</td><td>WOUDC / FMI</td><td>18/08 - 19/11</td><td>43</td></tr><tr><td>Dumont d'Urville</td><td>[-66.67, 140.02]</td><td>NDACC / LATMOS</td><td>18/08 - 19/12</td><td>13</td></tr><tr><td>Davis</td><td>[-68.58, 77.97]</td><td>WOUDC / ABM</td><td>18/08 - 23/02</td><td>166</td></tr><tr><td>Syowa</td><td>[-69.01, 39.58]</td><td>WOUDC / JMA</td><td>18/08 - 23/04</td><td>176</td></tr><tr><td>Neumayer</td><td>[-70.68, -8.26]</td><td>NDACC / AWI</td><td>18/08 - 23/03</td><td>209</td></tr><tr><td>Belgrano</td><td>[-77.77, -38.18]</td><td>NDACC / INTA</td><td>18/10 - 23/02</td><td>52</td></tr><tr><td>Amundsen Scott</td><td>[-89.98, -24.80]</td><td>NOAA / GML</td><td>18/10 - 21/11</td><td>72</td></tr></tbody></table>
<figure><img src="image_62.png" /><figcaption>**Table A3.** List of DIAL stations providing correlative data for the TROPOMI validation in this work. Subsequent columns show the station name, location, archive / PI institute abbreviation, validation period (Full for the entire five year TROPOMI time range), and number of co-locations in the comparative validation. The horizontal black line separates tropospheric (top) and stratospheric (bottom) lidar instruments.</figcaption></figure>

<table><thead><tr><th>Name</th><th>Location [°N,°E]</th><th>Archive / PI inst.</th><th>Period [YY/MM]</th><th>Co-locs.</th></tr></thead><tbody><tr><td>Greenbelt</td><td>[38.99, -76.84]</td><td>TOLNet / GSFC</td><td>20/05 - 21/07</td><td>118</td></tr><tr><td>Langley</td><td>[37.10, -76.39]</td><td>TOLNet / LaRC</td><td>18/05 - 19/11</td><td>15</td></tr><tr><td>Huntsville</td><td>[34.72, -86.64]</td><td>TOLNet / UAH</td><td>18/05 - 20/08</td><td>103</td></tr><tr><td>Table Mountain (t.)</td><td>[34.40, -117.70]</td><td>TOLNet / JPL</td><td>18/05 - 20/07</td><td>456</td></tr><tr><td>Eureka</td><td>[79.99, -85.93]</td><td>NDACC / U. Toronto</td><td>20/03</td><td>2</td></tr><tr><td>Hohenpeissenberg</td><td>[47.81, 11.01]</td><td>NDACC / DWD</td><td>Full</td><td>532</td></tr><tr><td>Obs. Haute Provence</td><td>[43.94, 5.71]</td><td>NDACC / LATMOS</td><td>Full</td><td>595</td></tr><tr><td>Table Mountain (s.)</td><td>[34.40, -117.70]</td><td>NDACC / JPL</td><td>Full</td><td>722</td></tr><tr><td>Mauna Loa</td><td>[19.53, -155.58]</td><td>NDACC / JPL</td><td>18/05 - 22/11</td><td>592</td></tr><tr><td>Lauder</td><td>[-45.04, 169.68]</td><td>NDACC / NIWA</td><td>18/05 - 21/07</td><td>108</td></tr></tbody></table>
<figure><img src="image_63.png" /></figure>

<figure><img src="image_64.png" /></figure>

<figure><img src="image_65.png" /><figcaption>**Figure A1.** The percentage of good quality pixels after applying separately each of the recommended filters on the QA value, cost function and strongly deviating from the a-priori condition (2). Each line represents the average percentage of the same orbit number over all the days of the specific month analysed.</figcaption></figure>
<figure><img src="image_66.png" /></figure>

<figure><img src="image_67.png" /></figure>

<figure><img src="image_68.png" /><figcaption>**Figure A2.** Comparison between S5P RPRO/OFFL ozone number density profile data and all co-located ozonesonde reference measurements, for five latitude bands sorted north to south. Every left subplot shows six graphs, respectively, from left to right: the difference and the percent relative difference between S5P and ozonesonde, the chi-square profile, the vertical sensitivity, the altitude registration offset, and the averaging kernel FWHM associated with the satellite retrieval. The colour scale indicates the TROPOMI solar zenith angle. Black dashed lines show mean values (thick lines) and standard deviations (thin lines, around the mean), while white dashed lines indicate the mean difference between the a-priori profile and the reference measurement. Dotted black lines indicate the total ex-ante (inductive) uncertainty of TROPOMI and the reference measurements combined (around the mean difference). The black full lines show the same, after adding the retrieval's smoothing error. Plots on the right show altitude-dependent yearly drifts for the same ozonesonde comparisons, with two-sigma horizontal error bars resulting from a bootstrapping with 1000 samples.</figcaption></figure>