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GPM Ground Validation Autonomous Parsivel Unit (APU) at the NSSTC Table of Contents
The Autonomous Parsivel Unit (APU) is an optical disdrometer based on single particle extinction that measures particle size and fall velocity. This APU consists of the Parsivel, which was developed by OTT Messtechnik in Germany, and its support systems, which were designed and built by the University of Alabama in Huntsville. This parsivel dataset gathers data at the National Space Science and Technology Center (NSSTC) , Huntsville, AL when they are not deployed to other sites for the Global Precipitation Measurement (GPM) mission Ground Validation (GV) campaign. The Global Precipitation Measurement (GPM) mission Ground Validation (GV) campaign will use a variety of methods for validation of GPM satellite constellation measurements prior to launch of the GPM Core Satellite, which is currently scheduled for July 2013. The validation effort will entail numerous GPM-specific and joint-agency/international external field campaigns, using state of the art cloud and precipitation observational infrastructure (polarimetric radars, profilers, rain gauges, disdrometers). Surface rainfall will be measured by very dense rain gauge and disdrometer networks at various field campaign sites. These field campaigns will account for the majority of the effort and resources expended by Global Precipitation Measurement (GPM) mission Ground Validation (GV). The primary instrument is the parsivel disdrometer, produced by OTT Messtechnik, Germany. The OTT parsivel disdrometer is a modern, laser-based optical system for measuring all types of precipitation completely and reliably. The transmitter unit of the sensor generates a flat, horizontal beam of light, which the receiver converts into an electrical signal. The signal changes whenever a hydrometeor falls through the beam anywhere within the measurement area. The degree of dimming is a measure of the size of the hydrometeor, and together with the duration of the signal, the fall velocity can be derived. Extinction measurement technique directly measures size and velocity of each single hydrometeor, then derives size spectrum, amount of rainfall, equivalent radar reflectivity, visibility, kinetic energy, and precipitation type. Data are in daily tared files of the form:
which contain hourly data files of the form:
where,
The Parsivel data is recorded every 10 seconds and time stamped by the APU software. The data format is ASCII and organized as follows:
where
20100610000003;APU03,0,026,000,000,000,000,000,000,000,000,000,000,000,000,0 New format as of Feb 25, 2011:
where
A PDF version of the format can be downloaded from here. The data producers are:
To order these data or for further information, please contact:
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