| Autor: |
Castelli, Elisa, Papandrea, Enzo, Di Roma, Alessio, Dinelli, Bianca Maria, Casadio, Stefano, Bojkov, Bojan |
| Předmět: |
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| Zdroj: |
Atmospheric Measurement Techniques Discussions; 2018, p1-25, 25p |
| Abstrakt: |
The Total Column Water Vapour (TCWV) is a key atmospheric variable and its evaluation is generally performed, at global scale, through the use of satellite data. Recently a new algorithm, called AIRWAVE (Advanced Infra-Red Water Vapour Estimator), has been developed for the retrieval of the TCWV from the Along-Track Scanning Radiometer (ATSR) instrument series. The AIRWAVE algorithm performs the TCWV retrieval exploiting the dual view of the ATSR instruments using the infra-red channels at 10.8 and 12 μm and combining nadir and forward observation geometries. The algorithm was used to produce a TCWV database from the whole ATSR mission. When compared to independent TCWV products, AIRWAVE Version 1 (V1) database shows very good agreement with almost no bias all over the ATSR missions, with the exception of the polar and the costal region where AIRWAVE underestimate the TCWV amount. In this paper we describe an updated version of the algorithm, specifically developed to overcome these problems. The AIRWAVE Version 2 (V2) accounts for the atmospheric variability at different latitudes and the associated seasonality. In addition, the dependency of the retrieval parameters on satellite across-track viewing angles is now explicitly handled. With the new algorithm we produced a second version of the AIRWAVE dataset. As for V1, the quality of V2 dataset is assessed through the comparison with the Special Sensor Microwave/Imager (SSM/I) and with the Analyzed Radiosounding Archive (ARSA) TCWV data. Results show significant improvements in both biases and RMSE, especially in polar and costal regions. A qualitative and quantitative estimate of the main error sources affecting the V2 TCWV dataset is also given. The new dataset has also been used to estimate the water vapour climatology from the 1991-2012 time series. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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