230
Laser
Emission lines:
Absorption lines:
Pulse energy:
Pulse-pair repetition rate
Wavelength selection
Receiver optics
Detector
Amplifier bandwidth
Digitizer
Sensitivity
Depth resolution
Pulse pairs per profile
Minimum/Maximum distance
Cross sensitivity:
signal
reference
signal
reference
signal
reference
DF, pulsed
DF P2 (3), 3.636 24 /-lm
DF P2 (5), 3.698 23 /-lm
H 37 CI P(6), 3.636 19 /-lm
H 35 CI P(8), 3.699 59 /-lm
10 mJ
30 mJ
1 Hz
Grating
0.50-m afocal Cassegrain
lnSb, liquid-nitrogen cooled
500 kHz to 2 MHz, adjustable
10 bit, 10 MHz
300 ppb
>5m
15 to 150
C. Weitkamp
100/500 to 300/1500 m, adjustable
± 6 ppb @ 300 ppm CO2
+ 5 ppb @ 2 ppm CH4
+ 4 ppb @ 2.4% (100% r.h. at 20°C)
± 2 ppb @ 78%
Table 10.2: Technical data of shipborne HCllidar.
the results indicate that HCI from at-sea incineration of organochlorine waste does in no way
threaten marine or terrestrial ecosystems. From a scientific point of view there is no reason for
phasing out the technique as was done several years later upon pressure by a number of groups
that claim to fight for the protection of the environment.
10.3.2 ARGOS: 0 3 , S02, aerosols
The gases that contribute most to urban air pollution are sulfur dioxide, nitrogen oxides, and
ozone; other gases, even if important from a photochemical, toxicologic or olfactory point of
view, occur in much smaller concentrations. A system that is well suited for the measurement
of S02, N02, 0 3 and a number of other gases is ARGOS, the acronym standing for" Advanced
Remote Gaseous Oxides Sensor". ARGOS, although also a DAS lidar, differs from the HCllidar
in a number of important features. For one thing, ARGOS contains two lasers that are fired with
50 /-lS of delay to produce a signal and a reference pulse well within the critical 1-ms interval.
Next, wavelengths of ARGOS are freely tunable so optimum on and off-resonance wavelengths
can be chosen for the measurement of each gas. While delivering pulse energies of the same
order of magnitude, the repetition rate is 10 times higher, allowing shorter measurement times.
Finally ARGOS is equipped with an acoustic wind profiler that provides the data necessary for
the transformation of measured concentration distributions into emission and flux or transport
values. For full mobility on land ARGOS is built into an 8.6-m standard truck. Figure 10.10
shows a block diagram of the system. Technical data are given in Table 10.3. Table 10.4 gives
the performance data of ARGOS. Although measured for S02, they differ quite little for 0 3
and N02; it must be noted, however, that not all of these data are obtained simultaneously
Laser
Emission lines:
Absorption lines:
Pulse energy:
Pulse-pair repetition rate
Wavelength selection
Receiver optics
Detector
Amplifier bandwidth
Digitizer
Sensitivity
Depth resolution
Pulse pairs per profile
Minimum/Maximum distance
Cross sensitivity:
signal
reference
signal
reference
signal
reference
DF, pulsed
DF P2 (3), 3.636 24 /-lm
DF P2 (5), 3.698 23 /-lm
H 37 CI P(6), 3.636 19 /-lm
H 35 CI P(8), 3.699 59 /-lm
10 mJ
30 mJ
1 Hz
Grating
0.50-m afocal Cassegrain
lnSb, liquid-nitrogen cooled
500 kHz to 2 MHz, adjustable
10 bit, 10 MHz
300 ppb
>5m
15 to 150
C. Weitkamp
100/500 to 300/1500 m, adjustable
± 6 ppb @ 300 ppm CO2
+ 5 ppb @ 2 ppm CH4
+ 4 ppb @ 2.4% (100% r.h. at 20°C)
± 2 ppb @ 78%
Table 10.2: Technical data of shipborne HCllidar.
the results indicate that HCI from at-sea incineration of organochlorine waste does in no way
threaten marine or terrestrial ecosystems. From a scientific point of view there is no reason for
phasing out the technique as was done several years later upon pressure by a number of groups
that claim to fight for the protection of the environment.
10.3.2 ARGOS: 0 3 , S02, aerosols
The gases that contribute most to urban air pollution are sulfur dioxide, nitrogen oxides, and
ozone; other gases, even if important from a photochemical, toxicologic or olfactory point of
view, occur in much smaller concentrations. A system that is well suited for the measurement
of S02, N02, 0 3 and a number of other gases is ARGOS, the acronym standing for" Advanced
Remote Gaseous Oxides Sensor". ARGOS, although also a DAS lidar, differs from the HCllidar
in a number of important features. For one thing, ARGOS contains two lasers that are fired with
50 /-lS of delay to produce a signal and a reference pulse well within the critical 1-ms interval.
Next, wavelengths of ARGOS are freely tunable so optimum on and off-resonance wavelengths
can be chosen for the measurement of each gas. While delivering pulse energies of the same
order of magnitude, the repetition rate is 10 times higher, allowing shorter measurement times.
Finally ARGOS is equipped with an acoustic wind profiler that provides the data necessary for
the transformation of measured concentration distributions into emission and flux or transport
values. For full mobility on land ARGOS is built into an 8.6-m standard truck. Figure 10.10
shows a block diagram of the system. Technical data are given in Table 10.3. Table 10.4 gives
the performance data of ARGOS. Although measured for S02, they differ quite little for 0 3
and N02; it must be noted, however, that not all of these data are obtained simultaneously