Greens_Win, for your edification
'Class 1
•
Flat, horizontal land, surrounded by an open space, slope less than 1/3 (19°);
•
Ground covered with natural and low vegetation (< 10 cm) representative of the region;
•
Measurement point situated:
o at more than 100 m from heat sources or reflective surfaces (buildings, concrete surfaces, car parks, etc.)
o at more than 100 m from an expanse of water (unless significant of the region)
o away from all projected shade when the Sun is higher than 5°.'
http://www.wmo.int/pages/prog/www/CIMO/CIMO15-WMO1064/1064_en.pdfSiting of measuring equipment, Do you think the photo shows 100m separation?