The starting point is measurements with a naturally ventilated Assmann psychrometer, described in WMO CIMO Guide No. 8 of 2008 [2] as a standard psychrometer. (Sections 4.2.2 / 4.2.6 / 4.9.7) In Part 1, the saturated vapor pressure in [hPa] over ice and then over water is given in a table for comparison according to two different formulas. The partial vapor pressure PVp [hPa], the relative humidity U = R.Hum [%] and the frost point temperature tFrost [°C] are calculated from the temperatures determined on the dry and wet thermometer, whereby only the values U = R.Hum and tFrost [°C] are listed in the tables. All values were calculated using a C program in Visual Studio 2010 on a 64-bit platform and double precision. The relative humidity and the frost point temperature were used for the output. with one decimal place, the saturated vapor pressure with four decimal places. The decimal separators are shown as , (comma), for better readability, thousand separators are inserted as . (dot).
