気温の観測 / Strangeways (2010) Measuring Global Temperatures

  • Ian STRANGEWAYS, 2010: Measuring Global Temperatures: Their Analysis and Interpretation. Cambridge UK: Cambridge University Press, 233 pp. ISBN 978-0-521-89848-5.

水文・地上気象の現場観測の方法の教科書Measuring the Natural Environment[読書ノート]の著者Strangewaysによる新しい本。この間にはPrecipitationという本(2007年)も出している(わたしはまだ読んでいないが)。

第6章で海洋内部の温度の観測(とくにアルゴフロート)、第10章で上空の大気の温度の観測(ラジオゾンデそのほか)、第1章で温度変化の主要な原因である放射(太陽放射と大気からの熱赤外放射)の観測を扱ってはいるが、主要な話題は、地上気温と海面水温である。

そして、前半の話題は地上気温と海面水温の観測技術である。

第2章では、温度観測センサーつまり温度計について、ガリレオの同時代人から歴史をたどったうえで、今使われている主要な機器の原理を述べる。

第3章では、気温をはかる温度計にあたる放射をさえぎる百葉箱(Stevenson screen, この英語のさす範囲は「百葉箱」よりも狭いようだが)その他の覆いを紹介する。

第4章では、観測機器の較正や保守に関する注意点にふれ、さらに、陸上の観測場所の立地条件について、観測露場(met. enclosure)の設計、都市化の影響などについて論じている。

第5章では、海上の気温および海面水温について、その定義から始め(海面水温の意味は文脈によって違うので要注意なのだ)、船やブイによる観測のしかたを紹介する。

ここまではMeasuring the Natural Environmentとよく似ており、議論の重なるところもあるようだ。百葉箱、観測露場、海面水温測定用「バケツ」のいろいろな型を示す写真は前の本よりも詳しくて興味深い。

後半の大部分は、この観測値から世界を代表する数値を得る手順とその結果の話だ。とくにイギリスの研究者の仕事が紹介されている。陸上の気温の総合を担当してきたのは、2009年の電子メール暴露で時の人になってしまったEast Anglia大学CRU(気候研究所)のPhil Jonesなのだ。海上のデータを扱っているのはイギリス気象庁ハドレーセンターのDavid Parker, Chris Follandたちだ。

第8章には、Jonesの仕事を例として、解析の手順が説明されている。まず、各観測地点の気温について、時系列としてデータの質の大きな異変がないことを確認し、一定期間の平均値(平年値)を求め、その先では平年値からの偏差について作業する。次に、観測地点での値から規則的な緯度経度の格子点での値を統計的に推定する。それを集計して全球・半球などの代表値を求める。海上も手順はだいたい同じだが、船の位置は一定でないので、平年値と偏差は緯度経度の升目ごとに求めることになる。

第9章では、この総合された観測値の時系列に見られる特徴とその議論が紹介される。エルニーニョ・南方振動、火山噴火の影響の話もあるが、話題はだんだん20世紀を通じた温暖化傾向にしぼられていく。著者はもちろん温室効果気体増加が重要だと考えているが、太陽活動の、成層圏あるいは雲を通じての影響の大きさは不確定だとする。

また、20世紀後半以来の気温の日較差(最高と最低の差)の減少傾向もとりあげる(アメリカNational Climatic Data CenterのRussell Voseたちによる解析)。半球・季節別に見ると、南半球の冬にはこの減少傾向はないそうだ。

最後の第11章は観測方法にもどり、世界を代表する値の変化傾向を知るという目的をも意識して、観測網をどう改良していったらよいかの展望を述べている。

[2019-04-20補足] 折りかえしのあとにくわしい目次をつける。(小さい見出しまでひろったので長くなってしまった。)

== 目次 ==
[Contents p.vii]
Preface p.xi
Acknowledgements p.xiii
List of acronyms p.xv[-xviii]
1. The balance of energy p.1
+ Solar radiation p.1
– – Passage of radiation throught the atmosphere
– – Sensible heat flux
– – Soil heat flux
– – Latent heat flux
– – Convection and clouds
– – The tropopause
+ Infrared radiation and the greenhouse effect p.7
+ Measuring the radiation p.10
– – Sunshine duration
– – Solar radiation [これは直達日射をさしている]
– – Total incoming solar radiation
– – Net radiation
– – Radiation processes over the oceans
+ Changes in solar activity and climate change p.14
– – Milankovitch cycles
– – Sunspots
– – Changes in the solar constant
– – – Changes due to Earth’s elliptical orbit [Solar constantに含めるのは不適切だと思うが、地球に届く総量の変化]
– – – Changes in the Sun itself
– – Changes in the Sun’s ultraviolet output
– – The Sun’s magnetic field and cosmic rays
+ References p.17
2. Thermometry p.18
+ Air thermometers p.18
– – Philo of Byzantium and Hero of Alexandria
– – Della Porta and Santorio in Italy
– – Fludd in England and Drebbel in Holland
+ Liquid-in-glass thermometers p.20
– – Jean Rey
– – Ferdinand II, Grand Duke of Tuscany
– – Boulliau in France and Boyle in England
+ Fixed points and scales p.23
– – Christian Huygens
– – Bartolo, Eschinardi and Renaldini in Italy
– – Dalencé in Holland and de la Hire in France
– – Newton, Patrick and Hauksbee in England
– – Rømer in Denmark
– – Fahrenheit in Poland and Holland
– – Réaumur in France
– – Delisle
+ ‘Centigrade’ scales p.27
– – Delisle, Micheli, Horrebow and Réaumur
– – Celcius, Ekström, Strömer, Linnaeus and Christin
+ The absolute, or thermodynamic, temperature scale p.29
– – Guillaume Amontons
– – William Thompson [Kelvin]
+ The International Practical Temperature Scale p.30
+ Modern thermometers p.31
– – Liquid-in-glass
– – – ‘Present temperature’
– – – Maximum and minimum thermometers
– – Zero drift
– – Bimetallic thermographs
+ Electrical thermometers p.36
– – Platinum resistance thermometers
– – Thermistors
– – Thermocouples
– – Thermal capacitors
+ Satellite measurements of surface temperature p.39
– (-> Appendix D; Chapter 10 for sounders)
+ References p.39
3. Screens, stands and shelters p.40
+ The needs for thermometer protection p.40
+ The evolved screens p.40
– – Open shelters
– – – George Martin
– – – James Glaisher
– – – Henry Lawson and the Reverend Stow
– – – H. Marié-Davy and Charles Sainte-Claire Deville
– – Fully enclosed screens
– – – The Plymouth Dockyard screen
– – – The Kew stand
– – – The Stevenson screen
– – – The cotton region shelter
– – – Screens on ships
– – – Heinrich Wild
– – – Signal Service thermometer shelter
– – Aspirated screens
– – Miniature screens for automatic weather stations (AWSs)
– – Height of screens
– – Continuity of records
– – Comparison of screen performance
+ References p.52
4. Measuring land surface air temperature p.54
+ The origin of data p.54
+ The instruments p.55
– – Thermometers
– – Screens
– – – Screens at tropical and polar sites
– – Instrument calibration
– – Instrument maintenance
+ Met enclosures p.60
– – Exposure of screens
– – Representativeness of sites
– – – The urban heat island and land-use changes
– – Met enclosure maintenance
– – – Short-term, local maintenance
– – – Long-term stability
+ References p.68
5. Measuring sea surface and marine air temperatures p.70
+ A brief history of measurements at sea p.70
+ Air versus sea temperatures p.71
+ Definition of ‘sea surface temperature’ p.72
– – The skin temperature
– – The sub-skin sea surface temperature
– – The surface temperature at depth
– – The foundation temperature
+ Ships as instrument platforms p.73
– – Ocean weather ships (OWS)
– – The voluntary observing fleet (VOF)
– – Decline in the number of voluntary observing ships
+ Measuring air temperature on ships p.75
+ Measuring sea surface temperature (SST) on ships p.76
– – Buckets
– – Engine-room intakes
– – Hull temperatures
– – Differences between buckets, ERI and hull measurements
– – A submersible electrical thermometer
+ Buoys as instrument platforms p.89
– – Moored buoys
– – – Air temperature measurements on moored buoys
– – – Sea surface temperature measured by moored buoys
– – – Telemetering the measurements to base
– – – Buoy location systems
– – Drifting buoys
– – – Joseph Louis Lagrange and Leonhard Euler
– – – Lagrangian Buoys
– – – Construction of the buoys
– – – Accuracy of the SST data from drifting buoys
+ References p.89
6. Measuring sea temperature profiles p.92
+ The bathythermograph p.92
+ Argo: a drifting profiler float p.93
– – Origins of Argo
– – The Argo hardware
– – Argo and Jason
– – The uses of Argo, Jason and XBT measurements
+ References p.100
7. Global instrument networks p.102
+ First station compilations p.102
+ World Weather Records (WWR) p.103
+ The Climatic Research Unit (CRU) network p.103
+ The Global Historical Climatology Network (GHCN) p.104
+ The Global Climate Observing System (GCOS) p.104
– – Land surface air temperature stations
– – GCOS ocean networks
+ The adequacy of the GCOS network p.109
– – Global coverage
– – Data quality
– – Local microclimates
– – Site representatives
+ Using Google Earth to access GCOS site conditions p.111
– – Google Earth
– – Evaluating instrument sites from Google Earth imagery
+ Disseminating the data p.112
+ References p.113
8. From point measurements to global averages p.115
+ Data from the land p.115
– – Working in averages
– – – Calculating the average
– – – Time of taking the measurements
– – Working in ‘anomalies’
– – Homogeneity
– – Working in grids
– – – Different methods of gridding
– – – The climate anomaly method
– – – Are anomalies weightless?
– – – ‘Spatial degrees of freedom’
– – – Effect of missing grids
– – Datasets from the land
+ Data from the oceans p.129
– – Weighting SST anomalies
– – Producing gridded values of SST
– – Datasets from the sea
+ Combining sea and land datasets p.131
– – Equivalence between land air and sea surface data
– – – Choice between SST and MAT
– – The blending process
– – Producing global datasets
+ References p.134
9. Changes in air and sea temperatures p.137
+ The datasets p.137
– – Trendlines
+ Causes of temperature change p.139
– – Measurements versus model projections
– – Teleconnections
– – – The Southern Oscillation
– – – The Pacific Decadal Oscillation
– – – Other Oscillations
– – – Influence of the oscillations
– – Volcanic activity
– – Solar activity
– – Clouds
– – Changes in atmospheric circulation
– – Increases level of carbon dioxide
– – Changes introduced by changing site conditions and changing instruments
+ Hemispheric and global temperature changes since 1850 p.150
– – Land air temperatures
– – – Northern Hemisphere land air temperatures
– – – Southern Hemisphere land air temperatures
– – – Global land air temperatures
– – Sea surface temperatures
– – – Northern Hemisphere sea surface temperatures
– – – Southern Hemisphere sea surface temperatures
– – – Global sea surface temperatures
– – Land-air and sea-surface temperature combined
– – – Northern Hemisphere land-air and sea-surface temperatures
– – – Southern Hemisphere land-air and sea-surface temperatures
– – – Global land-air and sea-surface temperatures
– – Recent temperature changes
– – – Land air temperatures
– – – Sea surface temperatures
– – – Land and sea temperatures combined
+ Central England Temperature since 1659 p.171
– – The dataset
– – – Temperatures from 1659 to 2008
– – – Temperatures from 1850 to 2008
– – – Temperatures from 1975 to 2008
+ Changes in maximum and minimum temperatures p.176
– – Early investigations (the 1990s)
– – Later investigations (2001-2006)
– – Recent investigations (2007 onwards)
– – – Northern Hemisphere
– – – Southern Hemisphere
– – Causes of the changes in DTR
+ References p.185
10. Temperature profiles through the atmosphere p.187
+ Early measurements p.187
+ Radiosondes p.188
– – The hardware
– – – Sonde temperature sensors
– – – Accuracy, calibration and errors
– – Review of performance and of corrections
+ Sounders p.195
– – Principles
– – Brightness temperature and algorithms
– – Obtaining temperature profiles from sounder measurements
– – Assessment of sounder performance
+ Temperature profiles from sonde data p.198
– – Causes of tropospheric warming
– – Global temperature trends through the full depth of the troposphere
– – Temperature trends in the mid-troposphere at 67.5 {deg} N in winter
+ References p.204
11. Future climate measurements p.206
+ The Global Climate Observing System p.206
+ A new instrument network p.207
– – Number of stations required
– – Purposes of the new network
+ Design of the new stations p.208
– – General concept
– – Temperature
– – – The sensors
– – – The screens
– – – Sea surface temperature
– – Precipitation
– – Other variables
– – Power supplies
– – – Power supplies for aspirated screens
+ Data telemetry p.211
– – On land
– – Over the oceans
+ Site locations p.211
+ Cost and management p.212
+ Concluding remarks p.212
+ References p.212
Appendix A. The gas laws p.213
– Boyle’s law
– Charles’s law
– The Pressure law
– The ideal gas equation
Appendix B. Relative humidity and dew point p.214
– Evaporation
– Saturation
– Other units
Appendix C. The electromagnetic spectrum p.216
– The most-used wavebands
Appendix D. Satellite measurements of surface temperature p.219
– Satellite orbits
– Measuring the radiation
– – Radiometers
– – – Visible wavelengths
– – – Infrared wavelengths
– – Scanning radiometers
– – – Scanning radiometers in polar orbits
– – – Scanning radiometers in geostationary orbits
– – Multispectral scanners
– – Sounders
– – Calibration of radiometers
– – – Visible channels
– – – Infrared channels
– Brightness temperature
– Algorithms
– Temperature at the surface
– – Skin temperature
– – Land surface air temperatures
– – Sea surface temperatures
– The strengths and weaknesses of remote sensing
– – Spatial and temporal restraints
– – Clouds and night
– – Scaling
– – Accuracy and ground-truth
Appendix E. Metadata p.226
– Metadata are data about data
– Reference
Appendix F. The Southern Oscillation Index p.227
– References
Index p.228[-233]

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