Deformation thermometer-
A thermometer using transducing elements that deform with temperature.
Deposit gauge-
The general name for instruments used in air pollution studies for determining the amount of material deposited on a given area during a given time.
Dew gauge-
Instrument for measuring the amount of dew deposited per unit area.
Dewpoint hygrometer-
An instrument for determining the dewpoint.
Differential absorption hygrometer-
A type of spectral hygrometer using at least two closely spaced wavelengths.
Differential absorption lidar thermometer-
An active remote sensor that measures temperature using a laser.
Diffusion hygrometer-
A hygrometer based upon the diffusion of water vapor through a porous membrane.
Dines radiometer-
An instrument for measuring radiant energy.
Diode laser-
Solid-state laser in which lasing is achieved by passing an injection current through the active region of
a semiconductor across the p–n junction.
Dipole antenna-
A type of antenna for transmitting or receiving electromagnetic radiation, most often in the radio frequency band.
Disdrometer-
An instrument that measures and records the sizes of raindrops.
Disk hardness gauge-
An instrument for measuring snow hardness in terms of the resistance of snow to the pressure exerted by a disk attached
to a spring-loaded rod.
Doppler lidar-
A laser radar (lidar) that can determine radial velocity (velocity toward or away from the laser) of the air by measuring the frequency shift of the returning light that was scattered from atmospheric aerosols,
compared to the original transmitted frequency.
Doppler radar-
A radar that detects and interprets the Doppler effect in terms of
the radial velocity of a target.
Doppler sodar-
An acoustic radar (sodar) that can determine radial velocity (velocity toward or away from the sodar) of the air by measuring the frequency shift of the returning sound waves that were scattered from regions of turbulent fluctuations of air temperature,
compared to the original transmitted frequency.
Dosimeter-
An instrument for measuring the ultraviolet in solar and sky radiation.
Drag anemometer-
An anemometer that measures the wind
velocity by sensing the drag force on an object, commonly a cylinder or sphere,
placed in the flow.
Drag sphere anemometer-
A device that measures wind speed by the drag force the wind produces
on a solid sphere.
Dropsonde-
A radiosonde with a parachute dropped
from an airplane carrying receiving equipment for the purpose of obtaining an upper-air
sounding during descent.
Drosometer -
An instrument used to measure the amount of dew formed on a given surface.
Dry bulb thermometer-
In a psychrometer, the thermometer that has a dry bulb and therefore directly measures air temperature.
Dual channel radar-
A radar capable of simultaneously receiving signals with polarizations identical and orthogonal to that of the transmitted signal.
Dual polarization radar-
A radar capable of transmitting and receiving two orthogonal polarizations.
Dual wavelength radar-
A radar capable of transmitting signals having two wavelengths and measuring separately the echoes at the two wavelengths.
Duplexer-
A radio device that allows a single antenna to serve as both the transmitter and the receiver.
Dustfall jars-
Devices for the removal of relatively large particles from ambient air
by means of gravitational sedimentation.
Dye laser-
Laser in which the radiation from a fixed-wavelength laser is focused into an organic dye,
which then emits at a longer wavelength.
