4. Ozone and Water Vapor

S. Oltmans (Editor), M. Clark, R. Evans, E. Hackathorn, J. Harris, B. Johnson, G. Koenig,

M. O’Neill, D. Quincy, and H. Vömel

4.1. Continuing Programs

4.1.1. Total Ozone Observations

Total ozone observations continued throughout 1996 and 1997 at 15 of the 16 stations that comprise the U.S. Dobson spectrophotometer network (Table 4.1). Of the 16 stations, 5 were operated by CMDL personnel, 5 by the National Weather Service (NWS), 2 are domestic cooperative stations, and 4 are foreign cooperative stations. All stations are either fully or semiautomated. A Brewer ozone spectrophotometer was operated at Boulder during this period.

TABLE 4.1. U.S. Dobson Ozone Spectrophotometer Station Network for 1996-1997

Station

Period of Record

Instrument No.

Agency

Bismarck, North Dakota

Jan. 1, 1963-present

33

NOAA

Caribou, Maine

Jan. 1, 1963-present

34

NOAA

Wallops Is., Virginia

July 1, 1967-present

38

NOAA; NASA

SMO

Dec. 19, 1975-present

42

NOAA

Tallahassee, Florida

May 2, 1964-Nov. 30, 1989;

Nov. 1, 1992-present

58

NOAA; Florida State University

Boulder, Colorado

Sept. 1, 1966-present

61

NOAA

Fairbanks, Alaska

March 6, 1984-present

63

NOAA; University of Alaska

Lauder, New Zealand

Jan. 29, 1987-present

72

NOAA; NIWA

MLO

Jan. 2, 1964-present

76

NOAA

Nashville, Tennessee

Jan. 2, 1963-present

79

NOAA

Perth, Australia

July 30, 1984-present

81

NOAA; Australian Bureau Meteorology

SPO

Nov. 17, 1961-present

82

NOAA

Haute Provence, France

Sept. 2, 1983-present

85

NOAA; CNRS

Huancayo, Peru

Feb. 14, 1964-Dec. 31, 1992

87

NOAA; IGP

BRW

June 6, 1986-present

91

NOAA

Fresno, California

June 22, 1983-March 13, 1995

94

NOAA

Hanford, California

March 15, 1995-present

94

NOAA

The Peruvian station was still out of operation at the end of 1997, although reports indicate a new baseline monitoring station is almost completed. A date for beginning Dobson observations has not yet been established. The Tallahassee station moved from the regional airport to the Florida State University (FSU) campus when the building housing the National Weather Service Office (NSWO) was demolished. The NWSO is temporarily located in the Tallahassee airport terminal until the permanent station is completed on the FSU campus.

Provisional daily total ozone amounts, applicable to local apparent noon for the stations listed in Table 4.1, were archived at the World Ozone and Ultraviolet Radiation Data Centre (WOUDC), 4905 Dufferin Street, Ontario M3H 5T4, Canada, in Ozone Data for the World. Table 4.2 lists the monthly mean of the total ozone amounts measured at the various stations. (Monthly means are made for stations where observations were made on at least 10 days each month.)

TABLE 4.2. Provisional 1996 Monthly Mean Total Ozone Amounts (DU)

Station

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

1996

Bismarck, North Dakota

343

367

364

367

346

317

314

292

293

275

301

324

Caribou, Maine

353

373

377

371

391

341

333

312

291

289

289

321

Wallops Is., Virginia

320

340

339

348

338

315

304

301

286

269

282

283

SMO

240

241

237

247

244

241

245

250

256

266

257

253

Tallahassee, Florida

285

303

312

313

317

-

-

-

-

-

267

256

Boulder, Colorado

328

324

337

329

305

294

286

279

281

269

265

294

UAF-GI, Alaska

-

[377]

384

379

356

339

311

291

309

[318]

-

-

Lauder, New Zealand

259

265

262

273

289

306

329

368

356

360

344

306

MLO

245

250

268

276

280

276

267

261

256

252

239

237

Nashville, Tennessee

309

326

333

333

300

307

306

296

285

272

272

284

Perth, Australia

272

260

-

-

-

-

-

302

310

313

303

280

SPO

266

246

[238]

[222]

[234]

[230]

[193]

-

142

176

283

Haute Provence, France

338

363

337

355

349

336

334

307

317

286

290

303

Huancayo, Peru

Station closed

BRW

-

-

394

420

362

338

315

296

293

[314]

-

-

Hanford, California

307

320

322

321

316

314

301

291

287

280

266

275

1997

Bismarck, North Dakota

349

353

355

371

329

325

309

293

274

283

297

333

Caribou, Maine

376

363

382

381

359

347

332

318

291

289

303

334

Wallops Is., Virginia

294

304

317

339

330

323

319

304

294

291

292

308

SMO

[244]

-

-

241

241

235

231

238

244

252

261

250

Tallahassee, Florida

[266]

300

[297]

305

299

297

289

285

291

-

Boulder, Colorado

310

323

310

348

315

302

298

284

273

280

293

310

UAF-GI, Alaska

-

[403]

386

397

[378]

327

319

280

282

[328]

-

-

Lauder, New Zealand

279

-

265

271

276

297

306

324

324

326

317

299

MLO

224

250

-

-

265

273

265

259

256

253

254

246

Nashville, Tennessee

292

295

291

322

319

[323]

301

288

280

282

297

303

Perth, Australia

258

251

270

261

257

261

275

288

307

298

292

278

SPO

277

275

-

[260]

[265]

[268]

[265]

[247]

-

136

203

274

Haute Provence, France

330

318

322

328

333

354

339

312

293

280

291

312

Huancayo, Peru

Station closed

BRW

-

[401]

390

388

374

335

315

287

288

-

-

-

Handford, California

291

304

294

328

307

317

308

[295]

[272]

284

279

304

Monthly mean ozone values in square brackets are derived from observations made on fewer than 10 days per month.

An analysis of this data was made to ascertain the trend in total ozone and the results published by Komhyr et al. [1997]. The resultant trends are summarized in Table 4.3.

TABLE 4.3. Annual and Seasonal Trends (in % per Decade) Derived From Re-Evaluated Dobson Spectrophotometer Total Ozone Data Obtained During 1979-1996 at 16 NOAA and Cooperative Station, Allowing for Solar and QBO Equatorial Wind Effects

Annual

Dec.-Feb.

March-May

June-Aug.

Sept.-Nov.

Station

Latitude

Longitude

Trend

Std. Error

Trend

Std. Error

Trend

Std. Error

Trend

Std. Error

Trend

Std. Error

Caribou, Maine*

46.9°N

68.0°W

-3.75

0.64

-4.46

1.54

-4.67

1.02

-3.21

0.71

-2.28

1.02

Bismarck, North Dakota*

46.8°N

100.8°W

-2.86

0.59

-2.50

1.33

-4.81

0.93

-2.00

0.86

-1.70

0.88

Boulder, Colorado*

40.0°N

105.3°W

-3.34

0.57

-2.77

1.20

-5.94

1.11

-2.51

0.65

-1.51

0.83

Wallops Is., Virginia*

37.9°N

75.5°W

-3.52

0.66

-4.01

1.30

-4.46

1.19

-3.05

0.80

-2.29

1.04

Fresno, California*

36.8°N

86.6°W

-3.15

0.66

-3.46

1.16

-4.65

1.25

-2.46

0.86

-1.72

1.13

Tallahassee, Tennessee*

119.7°W

-3.74

1.17

-2.81

1.72

-4.27

2.53

-3.70

1.48

-4.14

1.15

Nashville, Tennessee*

36.3°N

84.3°W

-3.41

0.69

-2.10

1.21

-4.36

1.30

-3.36

1.10

-3.67

1.21

MLO*

19.5°N

155.6°W

-0.37

0.70

-0.91

1.06

-0.39

1.28

-0.17

0.86

-0.02

0.68

SMO*

14.3°S

170.6°W

-1.30

0.61

-1.37

0.85

-1.75

0.76

-1.24

0.99

-0.86

0.81

Huancayo, Peru‡

12.1ºS

75.3°W

-1.85

0.43

-0.63

0.63

-1.29

0.68

-3.74

0.81

-1.64

0.73

Perth, Australia†

31.9ºS

116.0°E

-0.79

0.66

-2.79

0.84

-0.80

1.35

0.96

1.52

-0.53

0.98

Lauder, New Zealand§

45.0ºS

169.7°W

0.93

1.03

-3.34

1.12

-0.58

1.79

5.02

2.34

2.51

2.13

Poker Flat, Alaska†¥

65.1ºN

147.5°W

-5.61

2.13

-

-

-8.70

3.20

-4.03

1.92

-1.27

4.65

BRW*¥

71.3ºN

156.6°W

-3.25

1.14

-

-

-4.40

1.61

-3.01

1.19

-1.14

2.36

Haute Provence, France†

43.9ºN

5.7°E

-4.31

1.08

-5.26

2.33

-7.96

1.90

-2.22

1.26

-0.25

1.43

SPO*¶

90ºS

24.8°W

-12.18

2.20

-7.09

1.23

-5.90

1.81

-10.20

1.93

-19.58

4.34

Average over first five stations (1979-1996)

-3.32

-12.18

2.20

-7.09

1.23

-2.64

-1.90

Average over first five stations (1979-1995)

Average over first five stations (1979-1994)

Estimated trend uncertainties are standard errors (s.e.) where 2 (s.e.) ~95% confidence interval.

*Period of record: 1979-1996

†Period of record: 1984-1996

‡Period of record: 1979-1992

§Period of record: 1987-1996

¥For Poker Flat and BRW the annual trend estimates are based on March through October data only, while “September-November” trend estimates are based on September-October data only.

¶For SPO the annual trend is based on daylight (October 15 through February) data only. The “March-November.” trend is for October 15-31 and November data only.

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