1. Handbook on Meteorological Observations
Henk Benschop, Jitze van der Meulen
Royal Netherlands Meteorological Institute

2. Background
The National Meteorological Authority should provide a Manual (or Guide) with Standard procedures on:
definitions of the variables to be observed
functional specifications of each variable
Recommended observation technology (standards)
Siting and exposure of instruments
Station inspection
Data acquisition and data processing (computation)
Data presentation (code formats)
Data validation and archive
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3. Problem
Many guides are available on instrument measurement, data processing and presentation and on weather information services - e.g. CIMO Guide, Manuals on GOS, GDPS, Codes, etc.
But no integral standard manual in which the national standards are stated to provide the data service from OBS to INFO.
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4. Objectives Definitions, units, coding, derived variables
05/12/2018
Objectives
Definitions, units, coding, derived variables
Requirements on range, resolution, measurement uncertainty, frequency of measurements, etc.
Instruments and technical specifications, calibration procedures
Procedures in case of missing data, methods for data validation, procedures on site inspection
Calculation of parameters, formulae to reduce data; encoding
siting and exposure criteria
Inspection criteria
Considerations with respect to the surroundings
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5. Handbook on Observations
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6. Structure in line with CIMO Guide
1. General
2. Temperature
3. Atmospheric pressure
4. Humidity
5. Wind
6. Precipitation
7. Radiation
8. Sunshine duration
9. Visibility
10. Evaporation
11. Soil temperature
12. Upper air pressure, temperature, humidity
13. Upper air wind
14. Present weather, past weather, state of the ground
15. Observation of clouds
16. Ozone measurement
17. Atmospheric composition
18. Seawater temperature
19. Ocean waves
20. Lightning
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7. Contents
1. Description 1.1 name of variable (e.g.. wind, precipitation) definitions units: standard cf. SI (e.g. m/s), or non-standard (e.g kts.) derived variables (e.g. wind speed, -direction) + definition codes and explanations (synop, metar)
2. Operational requirements 2.1 range, e.g m/s resolution, e.g. 0.1 ° C required accuracy, e.g. ± 0.5 hPa required frequency of observations, e.g. every 12 s 2.5 required availability per specific period, e.g. 50 %
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8. Contents (cont.)
3. Instruments and techniques technical specifications of the instruments management, maintenance and calibration procedures
4. Procedures
4.1 procedures in case of missing data procedures for data validation procedures for  control of observation sites (inspection)
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9. Contents (cont.)
5. Calculation of other parameters e.g. formula for reduction to MSL pressure, formula for calculating dew point from U and air-t
6. Siting, requirements with respect to surroundings 6.1 Specific conditions per instrument 6.2 Conditions with respect to the surroundings of the site
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10. Station lay-out
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11. Instrument description
E.g. cup anemometer
steel-cup
A sensor is built into the mechanism the reacts to a signal from the rotating spindle every revolution. Registration of the rotation rate, which is near enough proportional to the prevailing wind speed, is done using a pulse counter. The number of pulses per unit time (e.g. per second) is counted and the speed of rotation is derived from this.
drum with slots
optical sensor with photo cell
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12. Codes (SYNOP, METAR, CLIMAT)
Full explanation of codes, e.g.
code fxfx:
group 910ff: the maximum wind gust in m/s in the 10 minutes preceding the moment of observation {i.e. exactly 5 minutes before every whole hour (UTC)} where this is 5 m/s or more greater than the synchronous value of ff in section 1.
(etc.)
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13. Validation E.g. FX FX must be  FH, otherwise suspect;
FX must be  FF, otherwise suspect;
abs[FXh - (-1/6 (FXh-2+FXh+2) + 2/3 (FXh-1+FXh+1))] must be  8 knots, otherwise FX is suspect;
FX must be  80 knots, otherwise suspect;
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14. Station inspection procedures
Every wind measurement site that has an operational function within the KNMI observation network is inspected on average twice annually by an official from WM/OD/station management. Extra interim inspections can also be carried out on request
The inspection can cover the following checks (example):
d) Comparison of the instantaneous (12") wind speed value measured by the sensor with the instantaneous wind speed value as read off from a reference ...(etc.)
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15. Publication
Strategy: all open to the public (through national meteor. library)
hard copy book, with replaceable loose leaves, yearly updated
electronic versions available on WWW
(Dutch)
(English)
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16. Version management To keep it up-to-date Yearly updates:
procedure for updating text, figures, formulas
list of recipients
chapter ‘ownership’
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17.
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