V. Elias et al., OCCULT PRECIPITATION - SAMPLING, CHEMICAL-ANALYSIS AND PROCESS MODELING IN THE SUMAVA MTS (CZECH-REPUBLIC) AND IN THE TAUNUS MTS (GERMANY), Journal of hydrology, 166(3-4), 1995, pp. 409-420
This paper deals with occult precipitation as a process affecting the
water balance and chemistry. The methods used in assessing the fog-wat
er amount are discussed. A micrometeorological mathematical resistance
model predicted annual gross deposition of cloudwater of 81 mm year(-
1) in the Sumava Mts. (South Bohemia); the net deposition was 47 mm ye
ar(-1). Chemical analyses of occult precipitation (fog- and cloud-wate
r, rime-water) both in the Sumava Mts. (Czech Republic) and in the Tau
nus Mts. (Germany) were made. Cloud- and fog-water samples were collec
ted using active cloud-water collectors installed on the tops of the S
umava and the Taunus Mts. Altogether, 54 samples of cloud- and fog-wat
er and 45 samples of rime-water were collected and analysed. Concentra
tions of the major ions were significantly higher in occult precipitat
ion than in rain-water. Enrichment factors for cloud vs. rain varied f
rom two to 32. In the Sumava Mts. the estimated. wet deposition for NH
4+, NO3- and SO42- via cloud droplet impaction and sedimentation repre
sents 1410 kg km(-2) year(-1), 2650 kg km(-2) year(-1) and 2508 kg km(
-2) year(-1), respectively.