The scientist word
Whether you are a meteorological office feeding forecasting models with continuous atmospheric data, or a research institute leading atmospheric research field campaigns, you certainly need to access to a continuous and standardized measurement of atmospheric structures : vertical profile of aerosol structure, evolution of atmospheric boundary layer height, clouds’ height, identification of aerosol plums in industrial areas. Until now, remote-sensing was partly realized by various techniques such as tethered balloons, ceilometers, non eye-safe laboratory LIDARs, passive spatial observations.
None of these allowed to collect simultaneously space resolved, real-time and high-resolution data on aerosol layers. Among these techniques, LIDARs were promising. However, their high level of maintenance discouraged atmospheric scientists and operators from using them as ordinary sensors.
ALS 300 and ALS 450 bring a definitive alternative to this situation by offering an unattended, eye-safe, compact LIDAR with unmatched performance, ideally designed for network atmospheric observations. Co-developed with the Climate and Environmental Science Laboratory (CNRS and CEA, France), ALS is pioneering the era of network LIDAR observations.
PBL tracking
Automatic tracking of the Planetary boundary layer, under different meteorological conditions. ALS series have been validated during an intensive campaign at the French remote sensing site of the Dynamic Meteorology Lab. PBL height is retrieved in a few seconds (final display every 10mn with an accuracy of 15m). This last left picture shows 12 diurnal cycles at Palaiseau, France using an ALS lidar. Purple dots represent data from a standardized LIDAR from the EARLINET network, validated against Meteofrance radiosoundings.
Visibility
ALS 450 provides accurate determination of the extinction profile along the measurement axis of the LIDAR (either vertically or at any angle). The extinction is directly linked to the visibility factor that is commonly used for transport authorities and industries (airports, highways, harbors…). Thus, instead of a local value, visibility information can be provided for any spot, miles away from an airport, collected and sent through conventional data format (met telegram, netcdf etc…)
Fog and Rain
ALS is able to follow the top of the fog layer, and alarm its creation or dissipation based on the intensity and shape of the Lidar echo. We show here an example of rainy event at night, followed by very low and foggy conditions above Palaiseau, France.
Phase of the clouds
ALS 450 enables the discrimination between ice and water droplets within clouds. The two left figures show intensity of extinction against height in a frontal system (Fig. a) and determination of the phase within cloud (Fig. b), deep blue represents water droplets in cloud, or hygroscopic aerosol in the PBL, green and red color indicates ice crystal presence).
.jpg)
Cloud coverage
By using temporal evolution of cloud deck values, or by 3D-scanning the troposphere, ALS offer several possibilities to estimate the cloud.
Multiple cloud & aerosols layering
ALS 450 are able to reach simultaneously all cloud and aerosol layers up to 20km, even the highest thin cirrus layers at 18km in the tropical regions.
Wake Vortex detection
A wake vortex is a dangerous turbulence generated behind an aircraft as it passes through the air. It is extremely hazardous, then it is one of the most limiting factors for the take-off and landing frequency in the airports. WLS70 detects instantaneously a wake turbulence optimizing airport traffic with a consequent increase of passengers safety.
American Meteorological Society annual meeting will be held in Atlanta from the 17th to the 21st of January 2010. The 90th meeting will focus on "Weather, Climate and Subject: New demands on science & services". We will be pleased to welcome you on our [...] Read more »