München 2019 – scientific programme

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UP: Fachverband Umweltphysik

UP 6: Remote sensing and data analysis methods

UP 6.4: Talk

Wednesday, March 20, 2019, 15:15–15:30, HS 22

Uncertainties in the retrieval of shortwave broadband albedo from satellite, airborne and ground-based radiative measurements — •Christine Pohl, Larysa Istomina, Vladimir Rozanov, Gunnar Spreen, and Georg Heygster — Institut für Umweltphysik, Universität Bremen

Arctic surface shortwave broadband albedo, hereafter called as albedo, is a key quantity determining the Arctic surface radiation energy budget and is closely related to the Arctic climate. Consequently, climate models require an albedo accuracy of 0.02 - 0.05 to simulate the Arctic climate correctly.

Albedo is derived from reflectance measurements by various satellite (e.g. MODIS, AVHRR/3), airborne (e.g. SMART-Albedometer), or field instruments (eg. FIGIFIGO, ASD-spectroradiometer). However, these instruments have various fields of views (FOVs) and different spectral and spatial resolution, which introduces uncertainties in the derived albedo product.

We quantify these uncertainties for typical Arctic surface types under variable solar zenith angles (55°- 80°) using the radiative transfer model SCIATRAN. Spectrally and angularly sparse resolved satellite observations introduces the highest uncertainties in the albedo retrieval, which tend to increase with the solar zenith angle. Uncertainties due to different FOVs can be neglected.