BAS ozone bulletin 07/95 issued 1995 Oct 6. Preliminary ozone values from the British Antarctic Survey Faraday station (65 south, 64 west on the coast of the Antarctic Peninsula) show mean ozone values dropping from values of around 290 Dobson Units (DU) at the beginning of August to around 180 DU at the end of September (45% depletion). The first week of October has seen a rise to over 300 DU with the circumpolar high ozone belt moving across the station. Planetary wave activity as the edge of the ozone hole passes over the station is giving day to day variation of around 60 DU. Values are generally similar to those reached in 1993 and 1994. Data from our long term record for the station indicate normal values of around 360 DU for early October (with a range of 280 DU to 470 DU). Faraday preliminary mean daily total ozone (DU) 1995 August 1 - October 5 306 272 276 265 289 333 307 277 241 229 235 218 213 217 277 278 280 268 219 224 232 237 226 214 201 210 205 232 218 208 223 207 203 204 243 201 196 184 186 189 153 194 272 247 220 269 228 167 206 159 142 140 216 198 175 242 204 159 155 214 262 281 371 325 318 310 Faraday preliminary monthly mean total ozone (DU) Aug Sep 246 201 The mean for September is the second lowest September mean recorded at the station, the lowest being 195 DU in 1994. Preliminary ozone measurements from the British Antarctic Survey Halley station (76 south, 26 west on the Brunt ice shelf) show that mean total ozone values have dropped from around 250 DU at the beginning of August to 130 DU in late September (55% depletion). The decline has now halted and ozone values are a little above those at the same time last year. Day to day variation is around 15 DU. Data from our long term record for the station indicate normal values of around 300 DU for the end of September (with a range of 260 DU to 340 DU). Temperatures (100 hPa) near the peak of the ozone layer are now 6x below normal, at around -82xC, and stratospheric clouds are expected to be present. Halley preliminary mean daily total ozone, (DU) (0 indicates no data) 1995 August 1 - October 5 0 0 0 0 0 0 0 221 228 231 248 244 0 0 0 0 0 0 0 0 0 0 0 0 0 0 202 215 187 215 229 199 204 225 217 224 205 213 189 183 206 210 167 188 187 180 160 141 155 160 142 133 137 141 116 121 133 126 135 117 120 123 131 143 137 112 Halley preliminary monthly mean total ozone (DU) Aug Sep 222 168 TOVS satellite images from the US NCEP/NWS/NOAA Climate Prediction Center show that ozone depletion has intensified over the past month, with the ozone "hole" now covering most of the Antarctic continent and centred close to the south pole. Ozone values at Halley are a little above those of last year, because the centre of the hole is further away from Halley than last year. Over the past week the hole has become more triangular in shape, giving much larger day to day variation at Faraday. These triangular lobes are rotating around the Antarctic continent with a period of about a month. This rotation of the "hole" gives rise to the variation in ozone amount seen at Faraday, which is located close to the edge of the hole. If you use or pass on this data please make acknowledgement to J D Shanklin, British Antarctic Survey. Regards, Jon Shanklin