20-years of day-night TCWV dataset over water in clear sky conditions have been produced applying the Advanced Infra-Red WAter Vapour Estimator (AIRWAVE) algorithm to the measurements of the Along Track Scanning Radiometer (ATSR) missions. The algorithm exploits the dual view of the ATSR instruments and a sea surface emissivity dataset. AIRWAVE has been developed for observations over water surfaces. However, the capability of the AIRWAVE retrieval algorithm could in principle be extended to land surfaces. The main difficulty in exploiting land measurements is linked to the knowledge of the surface emissivity in ATSR infrared channels. Indeed, while sea emissivity is generally close to one and is almost constant all over the globe, land emissivity has strong variations depending on e.g. surface type and vegetation cover. Furthermore, the angular emissivity variations can also be relevant. We have started to study the possibility of extending the AIRWAVE dataset also to land surfaces. For that we have tested the use of different emissivity datasets to perform land clear sky TCWV retrievals. Among the publicly available datasets we have selected to test the emissivity database IREMIS (http://cimss.ssec.wisc.edu/iremis/), the Combined ASTER MODIS Emissivity for Land (CAMEL, https://lpdaac.usgs.gov/node/1238) and the emissivity retrieved from SEVIRI infrared channels. The performance of the use of these databases on ATSR measurements will be assessed with the aid of the data contained into the ESA DUE GlobVapour project (http://www.globvapour.info/). The TCWV part of the GlobVapour project is composed by data from SSM/I over sea and from MERIS over land. In this work we will show the results of the application of the AIRWAVE algorithm to measurements over land. We will critically compare the results obtained using the three selected emissivity databases, assessing their performance through the comparison of the obtained results with correlative GlobVapour data.
Extension of the AIRWAVE Total Column of Water Vapor retrieval from ATSR measurements over land
B M Dinelli;E Castelli;E Papandrea;
2018
Abstract
20-years of day-night TCWV dataset over water in clear sky conditions have been produced applying the Advanced Infra-Red WAter Vapour Estimator (AIRWAVE) algorithm to the measurements of the Along Track Scanning Radiometer (ATSR) missions. The algorithm exploits the dual view of the ATSR instruments and a sea surface emissivity dataset. AIRWAVE has been developed for observations over water surfaces. However, the capability of the AIRWAVE retrieval algorithm could in principle be extended to land surfaces. The main difficulty in exploiting land measurements is linked to the knowledge of the surface emissivity in ATSR infrared channels. Indeed, while sea emissivity is generally close to one and is almost constant all over the globe, land emissivity has strong variations depending on e.g. surface type and vegetation cover. Furthermore, the angular emissivity variations can also be relevant. We have started to study the possibility of extending the AIRWAVE dataset also to land surfaces. For that we have tested the use of different emissivity datasets to perform land clear sky TCWV retrievals. Among the publicly available datasets we have selected to test the emissivity database IREMIS (http://cimss.ssec.wisc.edu/iremis/), the Combined ASTER MODIS Emissivity for Land (CAMEL, https://lpdaac.usgs.gov/node/1238) and the emissivity retrieved from SEVIRI infrared channels. The performance of the use of these databases on ATSR measurements will be assessed with the aid of the data contained into the ESA DUE GlobVapour project (http://www.globvapour.info/). The TCWV part of the GlobVapour project is composed by data from SSM/I over sea and from MERIS over land. In this work we will show the results of the application of the AIRWAVE algorithm to measurements over land. We will critically compare the results obtained using the three selected emissivity databases, assessing their performance through the comparison of the obtained results with correlative GlobVapour data.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
