2. Thermometer Variable: temperature Units: Degrees Celsius ( o C) Accuracy: marked to 0.5 o C Cost: £10 Site: in the shade (e.g. a Stevenson Screen) Mercury (or sometimes coloured alcohol) in the bulb expands and contracts up the calibrated tube with changes in the ambient air temperature

4. Max & Min Thermometer Details as for thermometer, except an index marker is pushed up or down by the tube of mercury to indicate the maximum or minimum

6. Whirling hygrometer Variables: temperature and wet bulb temperature Units: Kelvin or Degrees Celsius Accuracy: marked to 0.5 o C (range -5 to +50 o C) Cost: £45 Site: in the shade Whirl it round your head so the thermometer bulbs are well ventilated and there is sufficient evaporation from the wet bulb to achieve lowest possible temperature.

8. Assman psychrometer Similar to the whirling hygrometer, but uses a wind up fan to ventilated the dry and wet bulb thermometers.

10. Humidity slide rule Variable: converts between water vapour content measures Units: n/a Accuracy: ~1 % Cost: cheap! Site: n/a A ready-reckoner for conversion between, e.g. wet bulb temperature and relative humidity

12. Barograph (recording Barometer) Variable: atmospheric pressure Units: millibars (mb) or Pascals (Pa) Accuracy: ~0.1 mb Cost: ? Site: Anywhere An aneroid barometer contains a partial vacuum in the sealed metal aneroid cell, hence changes in pressure are amplified by movements of the arm attached to the cell.

14. Net radiometer Variables: upwelling and downwelling radiation Units: W m -2 Accuracy: ? Cost: ? Site: Exposed site without shading Dark surfaces absorb longwave or shortwave radiation, causing a change in voltage which can be measured electronically and converted to radiation.

16. Dome solarimeter Variable: solar radiation Units: W m -2 Accuracy: ? Cost: ? Site: exposed As for net radiometers

18. Tipping bucket raingauge Variable: rain rate and amount Units: mm Accuracy: 0.2 mm Cost: £300-£700 Site: exposed horizontal location Rain falls into cone and tips a small bucket once full, with that time recorded, thus a rain rate can be observed. Cone amplifies signal.

20. Air meter Variable: the “run of air” & hence wind speed Units: m & m s -1 Accuracy: dependent on the observation time Cost: no longer available. Site: away from buildings, etc Impeller spun round by the wind, turning dials to measure the wind run.

22. Handheld anenometer Variable: wind speed (instantaneous) Units: m s -1 or equivalent Accuracy: poor. Cost: cheap Site: handheld Wind blows the cups around to give an instantaneous reading.

24. Sodar (Acoustic Radar) Variable: Backscatter Units: amplitude Accuracy: ? Site: away from buildings, people, & noise! Cost: ~£1000-10,000 Acoustic pulses are scattered back to the receiver, from small-scale density changes (e.g. turbulence), with the volume and time-lag measured to give amplitude and range.

25. Sodar (Acoustic Radar) Variable: Backscatter Units: amplitude Accuracy: ? Site: away from buildings, people, & noise! Cost: ~£1000-10,000 Acoustic pulses are scattered back to the receiver, from small-scale density changes (e.g. turbulence), with the volume and time-lag measured to give amplitude and range.

27. Doppler sodar Variable: Backscatter & derived wind profiles Units: n/a and m/s Accuracy: ~1 m/s Site: remote! Cost: £10,000 Acoustic beams fired in several directions, so scatters relative movement can be determined, and hence wind speed & direction in 3D.

28. Doppler sodar Variable: Backscatter & derived wind profiles Units: n/a and m/s Accuracy: ~1 m/s Site: remote! Cost: £10,000 Acoustic beams fired in several directions, so scatters relative movement can be determined, and hence wind speed & direction in 3D.

30. Radiosonde (Upper air sounding) Variables: an atmospheric sounding (i.e. vertical profile) of, typically, pressure, temperature, relative humidity & wind Units: various Accuracy: various Cost: £100 per sonde Site: away from buildings, good spatial representation, often airports Balloon is filled with Helium gas and released rising up few metres per second, the radiosonde measures and transmits data to a ground station

31. Radiosonde (Upper air sounding) Variables: an atmospheric sounding (i.e. vertical profile) of, typically, pressure, temperature, relative humidity & wind Units: various Accuracy: various Cost: £100 per sonde Site: away from buildings, good spatial representation, often airports Balloon is filled with Helium gas and released rising up few metres per second, the radiosonde measures and transmits data to a ground station

33. Radar Variables: Backscatter, usually from hydrometeors, such as rain drops, hail, snow, etc. Units: backscatter amplitude Accuracy: ? Site: away from buildings, good spatial distribution Cost: £10,000-£1millions Radio waves emitted and reflected back, with return amplitude and time-lag giving backscatter intensity and range. These can be related to precipitation intensity. Doppler radars also available.

34. Radar Variables: Backscatter, usually from hydrometeors, such as rain drops, hail, snow, etc. Units: backscatter amplitude Accuracy: ? Site: away from buildings, good spatial distribution Cost: £10,000-£1millions Radio waves emitted and reflected back, with return amplitude and time-lag giving backscatter intensity and range. These can be related to precipitation intensity. Doppler radars also available.

35. Radar Variables: Backscatter, usually from hydrometeors, such as rain drops, hail, snow, etc. Units: backscatter amplitude Accuracy: ? Site: away from buildings, good spatial distribution Cost: £10,000-£1millions Radio waves emitted and reflected back, with return amplitude and time-lag giving backscatter intensity and range. These can be related to precipitation intensity. Doppler radars also available.

37. Satellites! Variable: Radiation & derived brightness temperature Units: W & derived K Resolution: down to < 1 km Site: space! Either geostationary or polar orbits Cost: millions & millions Passive satellites measure up- welling radiation at various wavelengths (visible, infra red & microwave) Active satellites work more like radars.

38. Satellites! Variable: Radiation & derived brightness temperature Units: W & derived K Resolution: down to < 1 km Site: space! Either geostationary or polar orbits Cost: millions & millions Passive satellites measure up- welling radiation at various wavelengths (visible, infra red & microwave) Active satellites work more like radars.

39. Satellites! Variable: Radiation & derived brightness temperature Units: W & derived K Resolution: down to < 1 km Site: space! Either geostationary or polar orbits Cost: millions & millions Passive satellites measure up- welling radiation at various wavelengths (visible, infra red & microwave) Active satellites work more like radars.

40. Observing scenarios: You have been tasked with determining the structure & governing physics of the wind field over Greenland – discuss in groups how to achieve this challenge.