Originally Posted by
PKPF68-77
Icing & the Rostov upper air ascent.
I find the upper air sounding for Rostov for 00Z 19 March 2016 shows the following:
1: Air temperature 0C at 2000-3000ft falling to -10C by 12000ft and -27C at 17000ft.
2: Saturated air, without a break, between about 2000-3000 ft and 17000ft.
3: Air mass stable wrt to saturated air between about 3000 ft and 17000 ft - hence no Cb, but suggestive of thick multilayer cloud, common in frontal zones.
Area of doubt.
As was the case over 50 years ago when I first plotted tephigrams, it seems that even today, the humidity sensors used by different nations behave differently.
Rarely in the UK did we see ascents showing saturated air, without a break, up to great altitudes.
This Rostov ascent shows temperatures and dew points very close together, even above the tropopause! I cannot 100% say that the dew point readings are wrong, but they do appear most anomalous. Sometimes it appears that once the humidity sensor gets a soaking in the lower levels, it may not dry out properly to give accurate readings higher up.
Maybe more up to date meteorologists may like to comment.
Absolutely, it's not a realistic sounding for dew point/humidity. Obviously the humidity sensor remained frozen/iced over during the entire ascent. There was quite some water in the air, but again: Nothing that wouldn't be seen a dozen of times in Scotland, Iceland or else during a winter.