Intercomparisons of Water Vapor Intercomparisons of Water Vapor Measurements during IHOP_2002 Measurements during IHOP_2002 – Radiosonde and Dropsonde – Radiosonde and Dropsonde Junhong (June) Wang Junhong (June) Wang NCAR Atmospheric Technology NCAR Atmospheric Technology Division Division Acknowledgement: Kate Beierle, Scot Loeher, ARM EDC
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Intercomparisons of Water Vapor Measurements during IHOP_2002 – Radiosonde and Dropsonde Junhong (June) Wang NCAR Atmospheric Technology Division Acknowledgement:
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Intercomparisons of Water Vapor Intercomparisons of Water Vapor Measurements during IHOP_2002 Measurements during IHOP_2002
– Radiosonde and Dropsonde– Radiosonde and Dropsonde
Comparisons at 18:04 UTC on June 9Comparisons at 18:04 UTC on June 9
QTRH
Performance in Clouds (Dycoms-II)Performance in Clouds (Dycoms-II)
Marine Stratus Cumulus clouds
Time lag error
Time-lag ErrorTime-lag Error
ConclusionsConclusions
1. The Sippican (VIZ) carbon hygristor used in 14% of global radiosonde stations fails to respond to humidity changes in the UT, sometimes even in the middle troposphere. This lack of response has produced significant and artificial humidity changes in the UT when the transition occurred and resulted in incapability of carbon hygristor to measure vertical and seasonal variations of humidity in UT.
2. Vaisala RS80-H Humicap used in ~51% of global radiosonde stations agrees very well with the SW in the middle and lower troposphere, but has dry biases in the UT.
3. Comparisons of seven years of data from two neighboring stations (Norman and ARM-B6) show unexplained significant and consistent drier RS90 than RS80-H (~5%) in UT and warmer temperature (~0.5C) in the middle and upper troposphere at ARM-B6 than at Norman when Vaisala sondes were launched at both sites.
4. The dry bias in dropsonde humidity data found by previous studies are preliminarily evaluated by comparing with co-located radiosonde data during IHOP. The comparison shows good agreements except inside moist layers.
Comparisons between VIZ and RS80-HComparisons between VIZ and RS80-H
No response
Descending region
Ascending region
Descendingregion
Matching dropsonde with C-130 Matching dropsonde with C-130 ascending/descending profileascending/descending profile
Height and Temperature at No-Response LevelHeight and Temperature at No-Response Level
Comparisons between RS80-H and RS80-H/RS90Comparisons between RS80-H and RS80-H/RS90
RS90 (B6) v.s. RS80H (Norman)
during IHOP (N=52)
RS80H (B6) v.s. RS80H (Norman)
1999/2000 (N=158)
Significant and consistent drier RS90 than RS80-H in UT
Significant and consistent warmer temperature in the middle and upper troposphere at ARM-B6 than at Norman when Vaisala sondes were launched at both sites.
Comparisons of Comparisons of dropsonde and dropsonde and