Page 117 - 《高原气象》2022年第6期

高 原 气 象 41 卷
1480

The Mountainous and Plain Areas on the Northeastern Margin of the Qaidam

Basin Contrast Study on Raindrop Spectrum Characteristics

1
PENG Wang ，LI Qiong ，WEI Jiahua 1，2，3 ，QIAO Zhen ，SHEN Weiwen ，
1，2
1，2
1，2
BAI Wenwen ，HE Julong ，QI Changxian 1
1，2
1，2
（1. School of Water Resources and Electric Power，Laboratory of Ecological Protection and High Quality Development
in the Upper Yellow River，Qinghai University，Xining 810016，Qinghai，China；
2. State Key Laboratory of Plateau Ecology and Agriculture，Qinghai University，Xining 810016，Qinghai，China；
3. State Key Laboratory of Hydroscience and Engineering，Tsinghua University，Beijing 100084，China）
Abstract：Based on the rain drop size distribution（DSD）observation data at different altitudes of Zongwulong
mountain on the northeast edge of Qaidam Basin from July to September 2020，the contribution of different parti‐
cle size raindrop microphysical parameters，particle size particle number concentration average spectrum，micro‐
physical characteristic parameters and the relationship between reflectivity factor and rain rate（Z-R）under differ‐
ent rain rate were studied. The results show that the number density of raindrops is mainly contributed by small
raindrops，while medium raindrops and heavy raindrops are the main contributions of reflectivity factor Z，rain
rate R and liquid water content W. The contribution of heavy raindrops to Z，R and W is higher in Mountain Site
with higher altitude. The spectral width of Mountain Site in light rain，moderate rain and heavy rain is wider，
and the particle number concentration at the end of heavy rain drops is higher under different rain rate. The lifting
of terrain can significantly promote the N（D）of larger raindrops. The mass weighted average diameter（D ）in‐
M
creases with the increase of altitude，and the raindrop diameter increases when R is higher. The generalized trun‐
cation parameter（log N ）will first increase and then decrease with the increase of rain rate. Smaller raindrops
10
w
are the main source of rainfall. Rainfall in Qaidam Basin has its unique rain drop size distribution structure char‐
acteristics. The distribution of log N and D of Mountain Site is more discrete，and the log N of Mountain Site
w
10
M
10
w
is lower and D is higher than that of Plain Site. If the unified precipitation estimation formula Z=300R 1. 4 were ad‐
M
opted，the rainfall will be overestimated，and the overestimation of rainfall at Mountain Site will be more seri‐
ous.
Key words：Qaidam Basin；rain drop size distribution；terrain；microphysical characteristic parameters；Z-R re‐
lationship