Guide to meteorological instruments and methods of observation 7th Edition

Guide to Meteorological Instruments and Methods of Observation......Page 1
PREFACE......Page 5
Contents, p. 1......Page 7
Contents, p. 2......Page 8
PART I. MEASUREMENT OF METEOROLOGICAL VARIABLES......Page 9
PART I. Contents, p. 1......Page 11
PART I. Contents, p. 2......Page 12
PART I. Contents, p. 3......Page 13
PART I. Contents, p. 4......Page 14
1.1 Meteorological observations......Page 15
1.3 General requirements of a meteorological station......Page 16
1.4 General requirements of instruments......Page 20
1.5 Measurement standards and definitions......Page 21
1.6 Uncertainty of measurements......Page 23
Annex 1.A Regional centres......Page 31
Annex 1.B Operational measurement uncertainty requirements and instrument performance......Page 33
Annex 1.C Station exposure description......Page 39
References and further reading......Page 41
2.1 General......Page 43
2.2 Liquid-in-glass thermometers......Page 46
2.3 Mechanical thermographs......Page 52
2.4 Electrical thermometers......Page 53
2.5 Radiation shields......Page 58
Annex Defining the fixed points of the international temperature scale of 1990......Page 60
References and further reading......Page 62
3.1 General......Page 65
3.2 Mercury barometers......Page 67
3.3 Electronic barometers......Page 72
3.4 Aneroid barometers......Page 75
3.5 Barographs......Page 76
3.7 Barometric change......Page 77
3.9 Barometer exposure......Page 78
3.10 Comparison, calibration and maintenance......Page 79
3.11 Adjustment of barometer readings to other levels......Page 84
3.12 Pressure tendency and pressure tendency characteristic......Page 85
Annex 3.A Correction of barometer readings to standard conditions......Page 86
Annex 3.B Regional standard barometers......Page 89
References and further reading......Page 90
4.1 General......Page 91
4.2 The psychrometer......Page 96
4.3 The hair hygrometer......Page 102
4.4 The chilled-mirror dewpoint hygrometer......Page 104
4.5 The lithium chloride heated condensation hygrometer (dew cell)......Page 107
4.6 Electrical resistive and capacitive hygrometers......Page 110
4.8 Safety......Page 111
4.9 Standard instruments and calibration......Page 113
Annex 4.A Definitions and specifications of water vapour in the atmosphere......Page 116
Annex 4.B Formulae for the computation of measures of humidity(see also section 4.1.2)......Page 119
References and further reading......Page 120
5.1 General......Page 121
5.2 Estimation of wind......Page 123
5.4 Cup and propeller sensors......Page 124
5.6 Other wind sensors......Page 125
5.8 Data-processing methods......Page 126
5.9 Exposure of wind instruments......Page 128
5.10 Calibration and maintenance......Page 131
Annex The effective roughness length......Page 132
References and further reading......Page 133
6.1 General......Page 135
6.3 Non-recording precipitation gauges......Page 137
6.4 Precipitation gauge errors and corrections......Page 140
6.5 Recording precipitation gauges......Page 142
6.6 Measurement of dew, ice accumulation and fog precipitation......Page 145
6.7 Measurement of snowfall and snow cover......Page 148
Annex 6.A Precipitation intercomparison sites......Page 152
Annex 6.B Suggested correction procedures for precipitation measurements......Page 153
References and further reading......Page 154
7.1 General......Page 157
7.2 Measurement of direct solar radiation......Page 161
7.3 Measurement of global and diffuse sky radiation......Page 167
7.4 Measurement of total and long-wave radiation......Page 175
7.5 Measurement of special radiation quantities......Page 180
7.6 Measurement of UV radiation......Page 181
Annex 7.A Nomenclature of radiometric and photometric quantities......Page 187
Annex 7.B Meteorological radiation quantities, symbols and definitions......Page 189
Annex 7.C Specifications for world, regional and national radiation centres......Page 191
Annex 7.D Useful formulae......Page 193
Annex 7.E Diffuse sky radiation — correction for a shading ring......Page 195
References and further reading......Page 196
8.1 General......Page 199
8.2 Instruments and sensors......Page 201
8.5 Calibration......Page 205
8.6 Maintenance......Page 207
Annex Algorithm to estimate sunshine duration from direct global irradiance measurements......Page 208
References and further reading......Page 209
9.1 General......Page 211
9.2 Visual estimation of meteorological optical range......Page 215
9.3 Instrumental measurement of the meteorological optical range......Page 218
References and further reading......Page 224
10.1 General......Page 227
10.2 Atmometers......Page 228
10.3 Evaporation pans and tanks......Page 229
10.4 Evapotranspirometers (lysimeters)......Page 232
10.5 Estimation of evaporation from natural surfaces......Page 233
References and further reading......Page 236
11.1 General......Page 237
11.2 Gravimetric direct measurement of soil water content......Page 239
11.3 Soil water content: indirect methods......Page 240
11.4 Soil water potential instrumentation......Page 242
11.5 Remote sensing of soil moisture......Page 244
11.6 Site selection and sample size......Page 245
References and further reading......Page 246
12.1 General......Page 249
12.2 Radiosonde electronics......Page 254
12.3 Temperature sensors......Page 255
12.4 Pressure sensors......Page 257
12.5 Relative humidity sensors......Page 260
12.6 Ground station equipment......Page 263
12.7 Radiosonde operations......Page 264
12.8 Radiosondes errors......Page 266
12.9 Comparison, calibration and maintenance......Page 276
12.10 Computations and reporting......Page 279
Annex 12.A Accuracy requirements (standard error) for upper-air measurements for synoptic meteorology, interpreted for conventional upper-air and wind measurements......Page 282
Annex 12.B Performance limits for upper wind and radiosonde temperature, relative humidity and geopotential height......Page 283
Annex 12.C Guidelines for organizing radiosonde intercomparisons and for the establishment of test sites7......Page 288
References and further reading......Page 292
13.1 General......Page 295
13.2 Upper-wind sensors and instruments......Page 298
13.3 Measurement methods......Page 304
13.4 Exposure of ground equipment......Page 306
13.5 Sources of error......Page 307
13.6 Comparison, calibration and maintenance......Page 312
13.7 Corrections......Page 313
References and further reading......Page 315
14.1 General......Page 317
14.2 Observation of present and past weather......Page 318
14.4 Special phenomena......Page 321
Annex Criteria for light, moderate and heavy precipitation intensity1......Page 323
References and further reading......Page 324
15.1 General......Page 327
15.2 Estimation and observation of cloud amount, height and type......Page 329
15.4 Measurement of cloud height using a searchlight......Page 331
15.6 Rotating‑beam ceilometer......Page 333
15.7 Laser ceilometer......Page 334
References and further reading......Page 337
16.1 General......Page 339
16.2 Surface ozone measurements......Page 341
16.3 Total ozone measurements......Page 342
16.4 Measurements of the vertical profile of ozone......Page 349
16.5 Corrections to ozone measurements......Page 354
16.6 Aircraft and satellite observations......Page 355
Annex 16.A Units for total and local ozone......Page 356
Annex 16.B Measurement theory......Page 358
References and further reading......Page 360
17.2 Measurement of specific variables......Page 365
17.3 Quality assurance......Page 374
References and further reading......Page 376
PART II. OBSERVING SYSTEMS......Page 379
PART II. Contents, p. 1......Page 381
PART II. Contents, p. 2......Page 382
PART II. Contents, p. 3......Page 383
1.1 General......Page 385
1.2 Automatic weather station hardware......Page 387
1.3 Automatic weather station software......Page 394
1.5 Central network data processing......Page 401
1.6 Maintenance......Page 402
1.7 Calibration......Page 403
1.8 Training......Page 404
References and further reading......Page 406
2.1 General......Page 407
2.2 Surface wind......Page 409
2.3 Visibility......Page 410
2.4 Runway visual range......Page 411
2.5 Present weather......Page 415
2.6 Cloud......Page 416
2.8 Dewpoint......Page 417
2.9 Atmospheric pressure......Page 418
2.11 Automated meteorological observing systems......Page 420
2.13 Ice sensor......Page 421
2.15 Other relevant observations......Page 422
References and further reading......Page 423
3.2 Pressure and Mach number......Page 425
3.3 Air temperature......Page 428
3.4 Wind speed and direction......Page 429
3.5 Turbulence......Page 430
3.6 Relative humidity......Page 432
3.9 Future AMDAR systems......Page 433
References and further reading......Page 435
4.2 Observations from ships......Page 437
4.3 Moored buoys......Page 453
4.5 Towers and platforms......Page 454
4.6 Drifting buoys......Page 455
Annex Descriptions of precipitation for use by ship-borne observers......Page 456
References and further reading......Page 458
5.2 Ground-based remote-sensing techniques......Page 461
5.3 In situ measurements......Page 466
References and further reading......Page 470
6.2 Wind measurement......Page 473
6.3 Temperature measurement by immersion thermometry......Page 475
6.4 Temperature measurement by inflatable falling sphere......Page 477
6.6 Networks and comparisons......Page 478
References and further reading......Page 480
7.1 General......Page 481
7.2 The direction finding lightning location system......Page 483
7.3 Examples of time-of-arrival location systems......Page 485
7.4 Comparisons of direction-finder and time-of-arrival networks......Page 487
7.6 Presentation and distribution of lightning data......Page 488
References and further reading......Page 489
8.1 General......Page 491
8.2 Operational satellite systems......Page 493
8.3 Meteorological observations......Page 498
8.4 Related facilities......Page 520
Annex 8.A Advanced very high resolution radiometer channels......Page 524
Annex 8.B HIRS channels and their applications......Page 525
References and further reading......Page 526
9.1 General......Page 527
9.2 Radar technology......Page 530
9.3 Propagation and scattering of radar signals......Page 537
9.4 Velocity measurements......Page 539
9.5 Sources of error......Page 541
9.6 Optimizing radar characteristics......Page 542
9.7 Radar installation......Page 544
9.8 Calibration and maintenance......Page 545
9.9 Precipitation measurements......Page 546
9.10 Severe weather detection and nowcasting applications......Page 550
9.11 High frequency radars for ocean surface measurements......Page 552
References and further reading......Page 553
10.1 Balloons......Page 557
10.2 Balloon behaviour......Page 558
10.3 Handling balloons......Page 559
10.5 Gases for inflation......Page 561
10.6 Use of hydrogen and safety precautions......Page 563
References and further reading......Page 566
11.1 General......Page 567
11.2 Choosing a location and site for an urban station......Page 573
11.3 Instrument exposure......Page 574
11.4 Metadata......Page 586
11.6 Summary of key points for urban stations......Page 588
References and further reading......Page 590
12.1 General......Page 593
12.3 Observed variables......Page 594
12.4 Choosing the road weather station equipment......Page 597
12.6 Central control and data-acquisition computer......Page 598
12.9 Measurement quality control......Page 599
12.10 Road weather station maintenance......Page 600
12.11 Training......Page 601
References and further reading......Page 602
PART III. QUALITY ASSURANCE AND MANAGEMENTOF OBSERVING SYSTEMS......Page 603
PART III. Contents, p. 1......Page 605
PART III. Contents, p. 2......Page 606
1.1 General......Page 607
1.2 The ISO 9000 family, ISO /IEC 17025, ISO /IEC 20000 and the WMO Quality Management Framework......Page 608
1.3 Introduction of quality management......Page 612
1.4 Accreditation of laboratories......Page 614
1.6 Factors affecting data quality......Page 615
1.7 Quality assurance (quality control)......Page 618
1.9 Data homogeneity and metadata......Page 620
1.10 Network management......Page 622
References and further reading......Page 624
2.1 General......Page 625
2.2 Time series, power spectra and filters......Page 627
2.3 Determination of system characteristics......Page 635
2.4 Sampling......Page 636
References and further reading......Page 640
3.1 General......Page 641
3.2 Sampling......Page 642
3.5 Averaging......Page 643
3.7 Corrections......Page 644
3.9 Compiling metadata......Page 645
References and further reading......Page 646
4.1 General......Page 647
4.2 Testing......Page 648
4.3 Calibration......Page 650
4.4 Intercomparisons......Page 652
Annex 4.A Procedures of WMO global and regional intercomparisons of instruments......Page 654
Annex 4.B Guidelines for organizing WMO intercomparisons of instruments......Page 655
Annex 4.C Reports of international comparisons conducted under the auspices of CIMO......Page 660
References and further reading......Page 662
5.2 Appropriate training for operational requirements......Page 663
5.3 Some general principles for training......Page 664
5.4 The training process......Page 668
5.5 Resources for training......Page 673
Annex Regional training centres......Page 677
References and further reading......Page 678
APPENDIX LIST OF CONTRIBUTORS TO THE GUIDE......Page 679