O4 WP5 - Closure Study


A set of 100 autonomous pyranometer stations was developed at TROPOS, Leipzig to obtain the real-time measurements of downward shortwave global irradiance (in W m-2), ambient air temperature (in K) and relative humidity (in normalized units) at 10 Hz temporal resolution. These stations were setup during HOPE campaigns spatially around (a) Juelich (~ 99 stations spread in 10 x 12 km2) during April-July 2013, and (b) Melpitz (~ 50 stations spread in 3 x 3 km2) during September-October, 2013. Each of these measurements is quality controlled with appropriate screening procedure. Large spatial and temporal variability in cloud induced surface radiation fields is observed. Currently, multi-scale analysis of these high-density surface radiation fields is under progress mainly to understand the optimal spatial and temporal resolutions for studying the cloud radiative effects. Additionally, spatio-temporal analysis between the cloud induced radiation fields obtained from the pyranometer network and METEOSAT SEVIRI satellite images of top of atmosphere high resolution broadband channel (0.4 - 1.1 μm) reflectance for the same domain (shown in the figure) is in progress.

Figure: Comparison of spatial probability distribution functions (PDFs) of SEVIRI HRV channel reflectance and SW global irradiance from pyranometer network on April 25, 2013 at 12:48:25 UTC.