Article

Quality assessment of Izaña's upper-air water vapour measurement techniques: FTIR, Cimel, MFRSR, GPS, and Vaisala RS92

Atmospheric Measurement Techniques Discussions 01/2009; DOI: 10.5194/amtd-2-1625-2009
Source: DOAJ

ABSTRACT At the Izaña Atmospheric Research Centre water vapour amounts are measured routinely by different techniques since many years. We intercompare the total precipitable water vapour amounts measured between 2005 and 2009 by a Fourier Transform Infrared (FTIR) spectrometer, a Multifilter rotating shadow-band radiometer (MFRSR), a Cimel sunphotometer, a Global Positioning System (GPS) receiver, and daily radiosondes (Vaisala RS92). In addition we intercompare the water vapor profiles measured by the FTIR and the radiosondes. The long-term intercomparison assures that our study well represents the large water vapour variabilities that occur in the troposphere and allows a reliable empirical quality assessment for the different water vapour dataset. We examine how the data quality of the different techniques depends on atmospheric conditions and estimate the dry bias of the techniques which are restricted to clear sky observations.

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