GRW/SKYRAD/M1 - Daily brief instrument shading
Due to the persistent cloudy conditions at this site this shading of the NIP and PSP is rarely evident in the data. But from approximately 1745 to 1810 GMT from 8/26 to 10/23 and from 3/01 to 4/18 during the AMF deployment years 2009 and 2010, the NIP and PSP are shaded by the 10m met tower to the SE of the Skystand. Data review indicates that the NIP (short_direct_normal) and PSP (down_short_hemisp) are shaded by a single tower pole and possibly other tower mounted objects. The data are not correctable but the azimuth and zenith windows to avoid are: short_direct_normal (NIP instrument) Zenith angle > 62 deg 254 deg < Azimuth angle < 262 deg primary obstruction at 255 deg Az down_short_diffuse(PSP instrument) Zenith angle > 59 deg 246 deg < Azimuth angle < 257 deg primary obstruction at 251.5 deg Az Date ranges this problem will exist for are: 20090301-20090418 (pre-official deployment, data exist) 20090826-20091023 20100301-20100418 20100826-20101023 The QCrad VAP should flag bad data points via its QC logic. Users should either exclude the data within the windows above or review data for outliers in these zenith, azimuth angles.