TY  - JOUR
AU  - Chen, R.
AU  - Liu, J.
AU  - Kang, E.
AU  - Yang, Y.
AU  - Han, C.
AU  - Liu, Z.
AU  - Song, Y.
AU  - Qing, W.
AU  - Zhu, P.
PY  - 2015
DA  - 2015//
TI  - Precipitation measurement intercomparison in the Qilian Mountains, north-eastern Tibetan Plateau
JO  - The Cryosphere
VL  - 9
IS  - 5
AB  - An experimental field study of wind-induced bias inprecipitation measurements was conducted from September 2010 to April 2015at a grassland site (99°52.9´ E, 38°16.1´ N; 2980 m) in the Hulu watershed in the Qilian Mountains, onthe north-eastern Tibetan Plateau, in China. The experiment included (1) anunshielded Chinese standard precipitation gauge (CSPG<sub>UN</sub>; orificediameter = 20 cm, height = 70 cm), (2) a single Alter shield around a CSPG(CSPG<sub>SA</sub>), (3) a CSPG in a pit (CSPG<sub>PIT</sub>) and (4) a Double-FenceInternational Reference (DFIR) with a Tretyakov-shielded CSPG(CSPG<sub>DFIR</sub>). The catch ratio (CR) used the CSPG<sub>DFIR</sub> as a reference(CR = CSPG<sub> X </sub>/CSPG<sub>DFIR</sub>, %; X denotes UN, SA or PIT). The resultsshow that the CSPG<sub>SA</sub>, CSPG<sub>PIT</sub> and CSPG<sub>DIFR</sub> caught 0.9,4.5 and 3.4 % more rainfall; 7.7, 15.6 and 14.2 % more mixedprecipitation (snow with rain, rain with snow); 11.1, 16.0 and20.6 % more snowfall and 2.0, 6.0 and 5.3 % more precipitation(of all types), respectively, than the CSPG<sub>UN</sub> from September 2012 toApril 2015. The CSPG<sub>PIT</sub> and CSPG<sub>DFIR</sub> caught 3.6 and 2.5 %more rainfall; 7.3 and 6.0 % more mixed precipitation; 4.4 and8.5 % more snowfall; and 3.9 and 3.2 % more total precipitation,respectively, than the CSPG<sub>SA</sub>. However, the CSPG<sub>DFIR</sub> caught1.0 % less rainfall; 1.2 % less mixed precipitation; 3.9 % moresnowfall and 0.6 % less total precipitation than the CSPG<sub>PIT</sub>. Frommost to least precipitation measured, the instruments ranked as follows: forrain and mixed precipitation, CSPG<sub>PIT</sub> > CSPG<sub>DFIR</sub> > CSPG<sub>SA</sub> > CSPG<sub>UN</sub>; for snowfall,CSPG<sub>DFIR</sub> > CSPG<sub>PIT</sub> > CSPG<sub>SA</sub> > CSPG<sub>UN</sub>.The CR vs. 10 m wind speed for the period ofprecipitation indicated that with increasing wind speed from 0 to 8.0 m s<sup>−1</sup>,the CR<sub>UN/DFIR</sub> and CR<sub>SA/DFIR</sub> for rainfall decreased slightly. Formixed precipitation, the wind speed showed no significant effect onCR<sub>UN/DFIR</sub> and CR<sub>SA/DFIR</sub> below 3.5 m s<sup>−1</sup>. For snowfall, theCR<sub>UN/DFIR</sub> and CR<sub>SA/DFIR</sub> vs. wind speed showed that CR decreasedwith increasing wind speed. The precipitation measured by the shieldedgauges increased linearly relative to that of the unshielded gauges.However, the increase in the ratio of the linear correlation should dependon specific environmental conditions. A comparison of the wind-induced biasindicates that the CSPG<sub>PIT</sub> could be used as a reference gauge for rain,mixed and snow precipitation events at the experimental site. As both thePIT and DFIR effectively prevented wind from influencing the catch of theprecipitation gauge, the CR<sub>PIT/DFIR</sub> had no relationship with windspeed. Cubic polynomials and exponential functions were used to quantify therelationship between catch ratio and wind speed. For snow, for both eventand daily scales, the CR<sub>UN/DFIR</sub> and CR<sub>SA/DFIR</sub> were significantlyrelated to wind speed; while for rain and mixed precipitation, only theevent scale showed a significant relationship.
ID  - Chen2015
ER  -