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| Titel |
Humidity sensor failure: a problem that should not be neglected |
| VerfasserIn |
Y. Liu, N. Tang |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 11 ; Nr. 7, no. 11 (2014-11-25), S.3909-3916 |
| Datensatznummer |
250115960
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| Publikation (Nr.) |
 copernicus.org/amt-7-3909-2014.pdf |
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| Zusammenfassung |
| The problem of abnormally dry bias induced by radiosonde humidity sensor
failure in the low and mid-troposphere is studied based on the global
operational radiosonde relative humidity observations from December 2008 to
November 2009. The concurrent humidity retrievals from the FORMOSAT-3/COSMIC
radio occultation mission are also used to assess the quality of the
radiosonde humidity observations. It is found that extremely dry relative humidity are common in the low and mid-troposphere, with an annual
globally averaged occurrence of 4.2%. These low-humidity observations
usually exist between 20 and 40° latitude in both the Northern Hemisphere and
Southern Hemisphere, and from heights of 700 to 450 hPa. Winter and spring
are the favored seasons for their occurrence, with a maximum fraction of
9.53 % in the Northern Hemisphere and 16.82% in the Southern
Hemisphere. The phenomenon does not result from natural atmospheric
variability, but rather humidity sensor failure. If the performance of
humidity sensors is not good, low-humidity observations occur easily,
particularly when the radiosonde ascends through stratiform clouds with high
moisture content. The humidity sensor cannot adapt to the huge change of the
atmospheric environment inside and outside stratiform clouds, resulting in
sensor failure and no response to atmospheric change. These extremely dry
relative humidity observations are erroneous. However, they have been
archived as formal data and applied in many research studies. This may
seriously undermine the reliability of numerical weather prediction and the
analysis of weather and climate if quality control is not applied before
using these data. |
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