This paper presents an updated trend analysis of water vapour in the lower midlatitude stratosphere from the Boulder balloon-borne NOAA frostpoint hygrometer measurements and from the Halogen Occulation Experiment (HALOE). Two corrections for instrumental bias are applied to homogenise the frostpoint data series. and a quality assessment of all soundings after 1991 is presented. Linea... https://www.parisnaturalfoodes.shop/product-category/colloidal-silicea/