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It has been observed for many African languages that focussed subjects
have to appear outside of their syntactic base position, as opposed to
focussed objects, which can remain in-situ. This is known as subjectobject
asymmetry of focus marking, which Fiedler et al. (2010) claim
to hold also for Akan. Genzel (2013), on the other hand, argues that
Akan does not exhibit a subject-object focus asymmetry. A questionnaire
study and a production experiment were carried out to investigate
whether focussed subjects may indeed be realized in-situ in Akan. The
results suggest that (i) focussed subjects do not have to be obligatorily
realized ex-situ, and that (ii) the syntactic preference for the realization
of a focussed subject highly depends on exhaustivity.
Retrieval of water constituents from hyperspectral in-situ measurements under variable cloud cover
(2018)
Remote sensing and field spectroscopy of natural waters is typically performed under clear skies, low wind speeds and low solar zenith angles. Such measurements can also be made, in principle, under clouds and mixed skies using airborne or in-situ measurements; however, variable illumination conditions pose a challenge to data analysis. In the present case study, we evaluated the inversion of hyperspectral in-situ measurements for water constituent retrieval acquired under variable cloud cover. First, we studied the retrieval of Chlorophyll-a (Chl-a) concentration and colored dissolved organic matter (CDOM) absorption from in-water irradiance measurements. Then, we evaluated the errors in the retrievals of the concentration of total suspended matter (TSM), Chl-a and the absorption coefficient of CDOM from above-water reflectance measurements due to highly variable reflections at the water surface. In order to approximate cloud reflections, we extended a recent three-component surface reflectance model for cloudless atmospheres by a constant offset and compared different surface reflectance correction procedures. Our findings suggest that in-water irradiance measurements may be used for the analysis of absorbing compounds even under highly variable weather conditions. The extended surface reflectance model proved to contribute to the analysis of above-water reflectance measurements with respect to Chl-a and TSM. Results indicate the potential of this approach for all-weather monitoring.