Vaisala LD-40 Ceilometer Cloud Height Measurement up to High ...

Vaisala LD-40 CeilometerCloud Height Measurementup to High Cirrus• 13,000 m (43,000 ft)measurement range• Cirrus cloud detection athigh altitude• Sophisticated algorithmsfor cloud detection• No need for field adjustments• Modular design: subassemblies areeasily replaced in the field withoutoptical realignmentThe Vaisala LD-40 "Tropopauser" is a compact,long-range ceilometer for cloud detection andatmospheric profiling. Operating up to to analtitude of 43,000 feet (13 km), the verticalresolution of the instrument is 25 feet (7.5 m).The measurement principle is based on LIDAR(Light Detection and Ranging). Short pulses oflight are emitted by a laser diode, focused to aparallel beam, and then transmitted vertically intothe atmosphere. Part of the light is scattered backto the ceilometer from the aerosols in theatmosphere.HIGH PERFORMANCE UNDER ALL KINDS OFPRECIPITATIONUsing the backscatter signal, the LD-40 calculatescloud height, the maximum detection range,vertical visibility, and provides precipitationstatus. The standard report includes height valuesfor up to 3 cloud layers. The long measurementrange allows cirrus clouds to be detected at highaltitude. Sophisticated algorithms are employedto ensure reliable cloud detection under all kindsof precipitation. When a cloud base cannot bedistinguished during weather conditionsassociated with very low visibility, verticalvisibility is still reported. The LD-40's ability toreport raw data also makes it a valuable tool foratmospheric research.MINIMAL MAINTENANCE WHATEVER THECLIMATEThe LD-40 operates unattended under all climaticconditions. Internal monitoring ensures reliableoperation: messages are automatically transmittedcontaining information on internal diagnostics.The LD-40 can be operated as a stand-aloneinstrument or as part of a large meteorologicalsystem. Its design is modular: subassemblies suchas the laser transmitter are easily replaced in thefield without optical realignment.

TECHNICAL INFORMATIONPERFORMANCEMeasurement range25 ft to 43,000 ft (8 m to 13,000 m)Resolution 25 ft (8 m)Accuracy (solid target) ± 25 ft (8 m)Measurement cycle15 secondsLaser Stacked diode, InGaAs (MOCVD)Wavelength855 nmEye safetyClass 3A (EN60825-1)OutputHeight of cloud base, up to 3 layersMaximum range of detectionVertical visibilityBackscatter profileInstrument status informationELECTRICALPower supply 230 / 115 VAC +10% -15%Power consumption700 W max. including heatingI/O connectionsData line: RS232/RS422/RS485/modemMaintenance line: RS232MECHANICALDimensionsWeight1260 (h) x 444 (w) x 404 (d)40 kgENVIRONMENTALOperating temperature -40 to 55 °COperating humidityup to 100 % RHWind55 m/sElectrical safety EN 60 950ACCESSORIESCloud Height Simulator for operational testing infield conditionsSolar shutter for protecting against direct solarradiationService tool setPower, data line and accessories are to bespecified when orderingVaisala OyjP.O.Box 26FIN-00421, HelsinkiFINLANDPhone: (+358 9) 894 91Telefax: (+358 9) 894 92227Ref. B210254en-A