My quick look at the soundings last evening identified two RSS flights that exhibited strongly super-adiabatic lapse rates in shallow layers aloft. These soundings were taken at Birmingham, AL, and Sterling, VA.
Note that the RRS operational procedures indicate that layers such as these should be removed via manual editing by the operator, and provide instructions for how this should be done.
Figure 1 (00Z BMX)
The layer of interest here extends from about 630 mb to 610 mb. The sonde apparently had moisture on the thermistor, and perhaps on the hygristor. When the instrument exited a deep, cloudy layer it encountered very dry air aloft and evaporative cooling of the sensors probably produced the super-adiabatic layer.
Figure 2 (00Z IAD)
The layer of interest here is only about 10 mb deep and is located near 740 mb. The reason for this super-adiabatic layer is not obvious, since the entir atmosphere appears to be quite moist. The sounding apparently did not exit cloud into a very dry layer above. It is possible that the instrument was in a saturated updraft and exited the updraft suddenly. It is also possible that the hygristor did not respond adequately to a layer that was considerably drier than the data indicate.
During the next few months I'll be paying particular interest in identifying soundings in which bad data have complicated the diagnosis of CAPE or potentially caused forecasting difficulties.
If readers note soundings that seem to be candidates, as per above, for closer examination, please feel free to alert me to them. Thanks, Bob bob@squidinkbooks.com
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