Meteorological Measurement Systems

by Fred V. Brock, Scott J. Richardson

Overview

This book treats instrumentation used in meteorological surface systems, both on the synoptic scale and the mesoscale, and the instrumentation used in upper air soundings. The text includes material on first- and second-order differential equations as applied to instrument dynamic performance, and required solutions are developed. Sensor physics are emphasized in order to explain how sensors work and to explore the strengths and weaknesses of each design type. The book is organized according to sensor type and function (temperature, humidity, and wind sensors, for example), though several unifying themes are developed for each sensor. Functional diagrams are used to portray sensors as a set of logical functions, and static sensitivity is derived from a sensor's transfer equation, focusing attention on sensor physics and on ways in which particular designs might be improved. Sensor performance specifications are explored, helping to compare various instruments and to tell users what to expect as a reasonable level of performance. Finally, the text examines the critical area of environmental exposure of instruments. In a well-designed, properly installed, and well-maintained meteorological measurement system, exposure problems are usually the largest source of error, making this chapter one of the most useful sections of the book.

Product Details

ISBN-13:	9780190285456
Publisher:	Oxford University Press
Publication date:	02/08/2001
Sold by:	Barnes & Noble
Format:	eBook
File size:	13 MB
Note:	This product may take a few minutes to download.

About the Author

both at University of Oklahoma

Table of Contents

1	Overview	1
1.1	Instrument Design and Selection	1
1.1.1	Performance Characteristics	2
1.1.2	Functional Model	2
1.1.3	Sources of Error	4
1.2	Standards	6
1.2.1	Calibration	6
1.2.2	Performance	6
1.2.3	Exposure	6
1.2.4	Procedural	7
1.3	System Integration	8
1.3.1	Instrument Platforms	8
1.3.2	Communication Systems	8
1.3.3	Power Source	10
1.4	Human Aspects of Measurement	11
1.4.1	Human Perception versus Sensor Measurements	11
1.4.2	Reasons for Automation	11
1.4.3	Design, Implementation, and Maintenance of Measurement Systems	12
1.4.4	Interpretation of Sensor Specifications	12
1.4.5	Interpretation of Results	13
1.4.6	Human Judgment	14
1.5	Quality Assurance	15
1.5.1	Laboratory Calibrations	16
1.5.2	Field Intercomparisons	17
1.5.3	Data Monitoring	17
1.5.4	Documentation	18
1.5.5	Independent Review	18
1.5.6	Publication of Data Quality Assessment	19
1.6	Scope of this Text	19
	Questions	19
	Bibliography	20
	General Instrumentation References	21
2	Barometry	22
2.1	Atmospheric Pressure	22
2.2	Direct Measurement of Pressure	23
2.2.1	Mercury Barometers	24
2.2.2	Aneroid Barometers	29
2.3	Indirect Measurement of Pressure	33
2.3.1	Boiling Point of a Liquid	34
2.4	Comparison of Barometer Types	37
2.4.1	Mercury Barometers	38
2.4.2	Aneroid Barometers	38
2.4.3	Hypsometer	38
2.5	Exposure Error	39
2.6	Laboratory Experiment	40
2.7	Calibration of Barometers	42
	Questions	43
	Bibliography	45
3	Static Performance Characteristics	47
3.1	Some Definitions	47
3.2	Static Calibration	49
3.2.1	Definition of Terms Related to the Transfer Plot	50
3.2.2	Calibration Procedure	52
3.3	Example of a Static Calibration	56
3.4	Multiple Sources of Error	57
3.5	Significant Figures	58
	Questions and Problems	60
	Bibliography	61
4	Thermometry	62
4.1	Thermal Expansion	63
4.1.1	Bimetallic Strip	63
4.1.2	Liquid-in-Glass Thermometer	65
4.2	Thermoelectric Sensors	67
4.3	Electrical Resistance Sensors	70
4.3.1	Resistance Temperature Detectors	70
4.3.2	Thermistors	74
4.4	Comparison of Temperature Sensors	76
4.5	Exposure of Temperature Sensors	77
	Questions	82
	Bibliography	84
	Notes	85
5	Hygrometry	86
5.1	Water Vapor Pressure	86
5.2	Definitions	89
5.3	Methods for Measuring Humidity	93
5.3.1	Removal of Water Vapor from Moist Air	93
5.3.2	Addition of Water Vapor to Air	93
5.3.3	Equilibrium Sorption of Water Vapor	96
5.3.4	Measurement of Physical Properties of Moist Air	100
5.3.5	Attainment of Vapor-Liquid or Vapor-Solid Equilibrium	104
5.3.6	Chemical Reactions	107
5.4	Choice of Humidity Sensor	107
5.5	Calibration of Humidity Sensors	108
5.6	Exposure of Humidity Sensors	110
	Questions	111
	Laboratory Exercises	114
	Bibliography	114
	Notes	116
6	Dynamic Performance Characteristics, Part 1	117
6.1	First-Order Systems	118
6.1.1	Step-Function Input	119
6.1.2	Ramp Input	122
6.1.3	Sinusoidal Input	123
6.2	Experimental Determination of Dynamic Performance Parameters	125
6.3	Application to Temperature Sensors	126
	Questions	127
	Bibliography	128
7	Anemometry	129
7.1	Methods of Measurement	129
7.1.1	Wind Force	130
7.1.2	Heat Dissipation	140
7.1.3	Speed of Sound	141
7.2	Calibration	144
7.3	Exposure	144
7.4	Wind Data Processing	144
	Questions	145
	Bibliography	147
8	Dynamic Performance Characteristics, Part 2	151
8.1	Generalized Dynamic Performance Models	151
8.2	Energy Storage Reservoirs	152
8.3	Second-Order Systems	154
8.3.1	Step Function Input	154
8.3.2	Ramp Input	157
8.3.3	Sinusoidal Input	158
8.4	Application to Sensors	159
8.5	Experimental Determination of Dynamic Performance Parameters	162
	Questions	164
	Bibliography	165
9	Precipitation Rate	166
9.1	Definitions	166
9.2	Methods of Measurement	167
9.2.1	Point Precipitation Measurement	167
9.2.2	Radar Rain Measurement	182
	Questions	185
	Bibliography	187
10	Solar and Earth Radiation	189
10.1	Definitions	189
10.2	Methods of Measurement	192
10.2.1	Pyrheliometers	193
10.2.2	Pyranometers	194
10.2.3	Pyrgeometers	197
10.2.4	Pyrradiometers	197
10.3	Measurement Errors	198
10.4	Exposure	199
	Questions	200
	Bibliography	201
11	Visibility and Cloud Height	202
11.1	Definitions	202
11.2	Measurement of Visibility	204
11.2.1	Transmissometer	205
11.2.2	Forward Scatter Meters	206
11.3	Measurement of Cloud Height	207
11.3.1	Rotating Beam Ceilometer	207
11.3.2	Laser Ceilometer	208
	Questions	210
	Bibliography	211
12	Upper Air Measurements	213
12.1	Methods for Making Upper Air Measurements	213
12.1.1	Remote Sensing	214
12.1.2	In-Situ Platforms	214
12.2	Balloons	215
12.3	Wind Measurement	219
12.3.1	Theodolites	220
12.3.2	Radar	223
12.3.3	Navigation Aids	223
12.4	Radiosondes	225
12.5	Exposure Error	228
	Questions	228
	Bibliography	229
13	Sampling and Analog-to-Digital Conversion	231
13.1	Signal Path	232
13.2	Drift	233
13.3	Sampling	233
13.4	Analog-to-Digital Conversion	235
13.5	Information Content of a Signal	239
	Questions	241
	Bibliography	243
A	Units and Constants	245
	International System of Units (SI)	245
	Numerical Values	246
	Bibliography	247
B	Thermistor Circuit Analysis	248
B.1	A Thermistor	248
B.2	A Circuit	250
B.3	An Alternative Calibration Equation	252
C	A Data Logger	253
C.1	The Data Logger	253
C.2	Application in a Measurement System	255
D	Circuits	258
D.1	Fundamentals	258
D.2	Simple Circuits	261
	Questions	263
E	Geophysical Coordinate System	266
E.1	Geophysical versus Mathematical Coordinate System	266
E.2	Mathematical Coordinates	266
E.3	Geophysical Coordinates	267
F	Instrumentation Glossary	269
	Index	285

Editorial Reviews

The textbook covers material that has been used to teach junior-level undergraduate and graduate courses in the school of meteorology at the U. of Oklahoma. Its objective is to examine the physical principles of meteorological sensors, to develop static and dynamic performance concepts, and to explore the concepts of meteorological measurement systems. Annotation c. Book News, Inc., Portland, OR (booknews.com)

Booknews

"This book focuses on three main areas: physical principles of meteorological sensors, development of static and dynamic performance concepts, and analysis of the concepts of meteorological measurement systems. . .The content of this work was used in conjunction with one junior-level and one first-year graduate level college course in instrumentation."—Bulletin of the American Meteorological Society

From the Publisher