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| Titel |
Precipitation measurement intercomparison in the Qilian Mountains, north-eastern Tibetan Plateau |
| VerfasserIn |
R. Chen, J. Liu, E. Kang, Y. Yang, C. Han, Z. Liu, Y. Song, W. Qing, P. Zhu |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 9, no. 5 ; Nr. 9, no. 5 (2015-10-28), S.1995-2008 |
| Datensatznummer |
250116862
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| Publikation (Nr.) |
 copernicus.org/tc-9-1995-2015.pdf |
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| Zusammenfassung |
| An experimental field study of wind-induced bias in
precipitation measurements was conducted from September 2010 to April 2015
at a grassland site (99°52.9´ E, 38°16.1´ N; 2980 m) in the Hulu watershed in the Qilian Mountains, on
the north-eastern Tibetan Plateau, in China. The experiment included (1) an
unshielded Chinese standard precipitation gauge (CSPGUN; orifice
diameter = 20 cm, height = 70 cm), (2) a single Alter shield around a CSPG
(CSPGSA), (3) a CSPG in a pit (CSPGPIT) and (4) a Double-Fence
International Reference (DFIR) with a Tretyakov-shielded CSPG
(CSPGDFIR). The catch ratio (CR) used the CSPGDFIR as a reference
(CR = CSPGX/CSPGDFIR, %; X denotes UN, SA or PIT). The results
show that the CSPGSA, CSPGPIT and CSPGDIFR caught 0.9,
4.5 and 3.4 % more rainfall; 7.7, 15.6 and 14.2 % more mixed
precipitation (snow with rain, rain with snow); 11.1, 16.0 and
20.6 % more snowfall and 2.0, 6.0 and 5.3 % more precipitation
(of all types), respectively, than the CSPGUN from September 2012 to
April 2015. The CSPGPIT and CSPGDFIR caught 3.6 and 2.5 %
more rainfall; 7.3 and 6.0 % more mixed precipitation; 4.4 and
8.5 % more snowfall; and 3.9 and 3.2 % more total precipitation,
respectively, than the CSPGSA. However, the CSPGDFIR caught
1.0 % less rainfall; 1.2 % less mixed precipitation; 3.9 % more
snowfall and 0.6 % less total precipitation than the CSPGPIT. From
most to least precipitation measured, the instruments ranked as follows: for
rain and mixed precipitation, CSPGPIT > CSPGDFIR > CSPGSA > CSPGUN; for snowfall,
CSPGDFIR > CSPGPIT > CSPGSA > CSPGUN.
The CR vs. 10 m wind speed for the period of
precipitation indicated that with increasing wind speed from 0 to 8.0 m s−1,
the CRUN/DFIR and CRSA/DFIR for rainfall decreased slightly. For
mixed precipitation, the wind speed showed no significant effect on
CRUN/DFIR and CRSA/DFIR below 3.5 m s−1. For snowfall, the
CRUN/DFIR and CRSA/DFIR vs. wind speed showed that CR decreased
with increasing wind speed. The precipitation measured by the shielded
gauges increased linearly relative to that of the unshielded gauges.
However, the increase in the ratio of the linear correlation should depend
on specific environmental conditions. A comparison of the wind-induced bias
indicates that the CSPGPIT could be used as a reference gauge for rain,
mixed and snow precipitation events at the experimental site. As both the
PIT and DFIR effectively prevented wind from influencing the catch of the
precipitation gauge, the CRPIT/DFIR had no relationship with wind
speed. Cubic polynomials and exponential functions were used to quantify the
relationship between catch ratio and wind speed. For snow, for both event
and daily scales, the CRUN/DFIR and CRSA/DFIR were significantly
related to wind speed; while for rain and mixed precipitation, only the
event scale showed a significant relationship. |
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