1. In situ sounding of radiative flux profiles through the Arctic lower troposphere
- Author
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Becker, Ralf, Maturilli, Marion, Philipona, Rolf, Behrens, Klaus, Deutscher Wetterdienst, Meteorologisches Observatorium Lindenberg, Tauche, Germany, Helmholtz-Centre for Polar and Marine Research, Alfred Wegener Institute, Potsdam, Germany, and Federal Office of Meteorology and Climatology MeteoSuisse, Chemin de l’Aerologie, Payerne, Switzerland
- Subjects
Albedo ,010504 meteorology & atmospheric sciences ,Radiative cooling ,0208 environmental biotechnology ,02 engineering and technology ,Atmospheric sciences ,01 natural sciences ,Troposphere ,Radiative flux ,Arctic ,Altitude ,Clouds ,Radiative transfer ,0105 earth and related environmental sciences ,General Environmental Science ,Atmosphere ,Longwave ,020801 environmental engineering ,ddc:551.5 ,Overcast ,13. Climate action ,General Earth and Planetary Sciences ,Environmental science ,Heating rates ,In-situ profiling - Abstract
In situ profiles and fixed-altitude time series of all four components of net radiation were obtained at Ny-Ålesund, Svalbard (78.9° N, 11.9° E), in the period May 04–21, 2015. Measurements were performed using adapted high-quality instrumentation classified as “secondary standard” carried by a tethered balloon system. Balloon-lifted measurements of albedo under clear-sky conditions demonstrate the local dependence on altitude and on the surface inhomogeneity of this parameter over coastal terrain of Ny-Ålesund. Depending on the surface composition within the sensor’s footprint near the coastline, the albedo over predominantly snow-covered surfaces was found to decrease to 0.548 and 0.452 at 494 m and 881 m altitude compared with 0.731 and 0.788 measured with near-surface references, respectively. Albedo profiles show an all-sky maximum at 150 m above surface level due to local surface inhomogeneity, and an averaged vertical change rate of − 0.040/100 up to 750 m aboveground level (clear sky) and − 0.034/100 m (overcast). Profiling of arctic low-level clouds reveals distinct vertical gradients in all radiative fluxes but longwave upward at the cloud top. Observed radiative cooling at the top of a partly dissolving stratus cloud with heating rates of − 40.4 to − 62.1 Kd−1 in subsequent observations is exemplified., Bundesrepublik Deutschland, Deutscher Wetterdienst, vertreten durch den Vorstand, Deutsche Meteorologische Bibliothek (4242)
- Published
- 2020