A Numerical Investigation on Microphysical Properties of Clouds and Precipitation over the Tibetan Plateau in Summer 2014

Precipitation microphysics over the Tibetan Plateau (TP) remain insufficiently understood, due to the lack of observations and studies. This paper presents a comprehensive investigation of the raindrop size distribution (DSD) for rainfall that happened on the eastern slope of TP in summer. DSD differences between different rain types and under different rain rates are investigated. Confidential empirical relationships between the gamma shape and slope parameters, and between reflectivity and rain rate are proposed. DSD properties in this area are also compared with those in other areas. The results indicate that the stratiform and convective rains contribute to different rain duration and amount, with diverse rainfall macro- and microphysical properties. The rain spectra of two rain types can become broader with higher concentrations as the rain rate increases. DSDs in this area are different to those in other areas. The stratiform DSD is narrower than that in the non-plateau area. The two rain types of this area both have higher number concentrations for 0.437–1.625 mm raindrops than those of the mid-TP. The relationships of shape–slope parameters and reflectivity–rain rate in this area are also different from those in other areas. The rain spectra in this area can produce a larger slope parameter under the same shape parameter than in the mid-TP. The convective rain can produce a smaller rain rate under the same reflectivity. The accuracy proposed reflectivity–rain rate relationship in application to quantitative rainfall estimation is also discussed. The results show that the relationship has an excellent performance when the rain rate exceeds 1 mm h−1.

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Aircraft measurement campaign on summer cloud microphysical properties over the Tibetan Plateau

Scientific Reports ◽

10.1038/s41598-019-41514-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Yi Chang ◽

Xueliang Guo ◽

Jie Tang ◽

Guangxian Lu

Keyword(s):

Tibetan Plateau ◽

The Tibetan Plateau ◽

Aircraft Measurement ◽

Measurement Campaign ◽

Microphysical Properties

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Evaluation and utilization of CloudSat and CALIPSO data to analyze the impact of dust aerosol on the microphysical properties of cirrus over the Tibetan Plateau

Advances in Space Research ◽

10.1016/j.asr.2018.07.004 ◽

2019 ◽

Vol 63 (1) ◽

pp. 2-15 ◽

Cited By ~ 1

Author(s):

Baiwan Pan ◽

Zhendong Yao ◽

Minzhong Wang ◽

Honglin Pan ◽

Lingbing Bu ◽

...

Keyword(s):

Tibetan Plateau ◽

Dust Aerosol ◽

The Tibetan Plateau ◽

Microphysical Properties ◽

The Impact

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Toward Understanding the Properties of High Ice Clouds at the Naqu Site on the Tibetan Plateau Using Ground-Based Active Remote Sensing Measurements Obtained during a Short Period in July 2014

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-16-0038.1 ◽

2016 ◽

Vol 55 (11) ◽

pp. 2493-2507 ◽

Cited By ~ 13

Author(s):

Chuanfeng Zhao ◽

Liping Liu ◽

Qianqian Wang ◽

Yanmei Qiu ◽

Wei Wang ◽

...

Keyword(s):

Tibetan Plateau ◽

The Tibetan Plateau ◽

Regression Equations ◽

Ice Clouds ◽

Cloud Radar ◽

Microphysical Properties ◽

Short Period ◽

Ice Water Content ◽

Cloud Ice ◽

Ice Water

AbstractThis study describes the microphysical properties of high ice clouds (with bases above 5 km) using ground-based millimeter cloud radar cirrus-mode observations over the Naqu site of the Tibetan Plateau (TP) during a short period from 6 to 31 July 2014. Empirical regression equations are applied for the cloud retrievals in which the parameters are given on the basis of a review of existing literature. The results show a unimodal distribution for the cloud ice effective radius re and ice water content with maximum frequencies around 36 μm and 0.001 g m−3, respectively. Analysis shows that clouds with high ice re are more likely to occur at times from late afternoon until nighttime. The clouds with large (small) re mainly occur at low (high) heights and are likely orographic cumulus or stratocumulus (thin cirrus). Further analysis indicates that ice re decreases with increasing height and shows strong positive relationships between ice re (μm) and depth h (m), with a regression equation of re = 35.45 + 0.0023h + (1.7 × 10−7)h2. A good relationship between ice re and temperature T (°C) is found, re = 44.65 + 0.1438T, which could serve as a baseline for retrieval of characteristic ice re properties over the TP.

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Vertical Structures and Physical Properties of the Cold-Season Stratus Clouds Downstream of the Tibetan Plateau: Differences between Daytime and Nighttime

Journal of Climate ◽

10.1175/jcli-d-14-00063.1 ◽

2014 ◽

Vol 27 (18) ◽

pp. 6857-6876 ◽

Cited By ~ 14

Author(s):

Yi Zhang ◽

Haoming Chen ◽

Rucong Yu

Keyword(s):

Tibetan Plateau ◽

Large Scale ◽

Single Layer ◽

Cold Season ◽

Cloud Fraction ◽

The Tibetan Plateau ◽

Stratus Clouds ◽

Microphysical Properties ◽

Integrated Optical ◽

Macrophysical Properties

Abstract This study compares the daytime–nighttime (DN) differences in the occurrence frequencies and macrophysical, microphysical, and radiative vertical structures of the single-layer stratus clouds downstream of the Tibetan Plateau (TP) during the boreal cold season (November–April) using four CloudSat products. The stratus cloudy profiles are selected and the midtopped stratus profiles are further classified into nimbostratus (NI) and altostratus (AS) according to the cloud-top height and column-integrated optical depth. It is found that the entire stratus and NI profiles tend to occur more frequently in the daytime, while the AS cloud occurs more frequently in the nighttime. Consistent with the DN differences in the occurrence frequencies, the AS tends to be much thicker with larger cloud fraction in the nighttime, while the NI becomes slightly thicker with larger cloud fraction in the daytime. An analysis of the ambient dynamic and thermodynamic fields associated with stratus formation suggests that it is the DN difference in the large-scale low-level lifting that leads to the corresponding differences of the occurrences and macrophysical properties. In contrast, the optical depths of the NI and AS clouds become larger and smaller from daytime to nighttime, respectively, which is attributed to the microphysical properties. The occurrence frequencies in small droplet particle sizes increase (NI) and decrease (AS) from daytime to nighttime, leading to the corresponding variations of the cloud radiative property.

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A Comparative Study on the Vertical Structures and Microphysical Properties of Stratiform Precipitation over South China and the Tibetan Plateau

Remote Sensing ◽

10.3390/rs13152897 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2897

Author(s):

Jingshu He ◽

Jiafeng Zheng ◽

Zhengmao Zeng ◽

Yuzhang Che ◽

Min Zheng ◽

...

Keyword(s):

Tibetan Plateau ◽

South China ◽

Sample Selection ◽

Doppler Velocity ◽

The Tibetan Plateau ◽

Atmospheric Conditions ◽

Melting Layer ◽

Microphysical Properties ◽

Raindrop Size Distribution ◽

Stratiform Precipitation

Under different water vapor and dynamic conditions, and the influence of topographies and atmospheric environments, stratiform precipitation over South China and the Tibetan Plateau can produce different features. In this study, stratiform precipitation vertical characteristics, bright-band (BB) microstructures, and the vertical variations of the raindrop size distribution (DSD) over a low-altitude site (Longmen site, 86 m) in South China and a high-altitude site (Nagqu site, 4507 m) on the Tibetan Plateau were comprehensively investigated and compared using measurements from a Ka-band millimeter-wave cloud radar (CR), a K-band microrain radar (MRR), and a Parsivel disdrometer (disdrometer). A reliable BB identification scheme was proposed on the basis of CR variables and used for stratiform precipitation sample selection and further statistics and analysis. Results indicate that melting layers over the Longmen are much higher and slightly thicker than those over the Nagqu due to significant differences in atmospheric conditions. For stratiform precipitation, vertical air motions and radar variables over the two sites show different variation trends from cloud top to the ground. Vertical air motions are very weak in the stratiform precipitation over the Longmen, whereas updrafts are more active over the Nagqu. Above the melting layer, radar equivalent reflectivity factor Ze (mean Doppler velocity VM) gradually increases (decreases) as height decreases over the two sites, but the aggregation rate for ice particles over the Longmen can be faster. In the melting layer, Ze (VM) at the BB bottom/center over the Longmen is larger (smaller) than those over the Nagqu for the reason that melted raindrops in the melting layers over the Longmen are larger than those over the Nagqu. Below the melting layer, profiles of radar variables and DSDs show completely different behaviors over the two sites, which reflects that the collision, coalescence, evaporation, and breakup processes of raindrops are different between the two sites. Over the Longmen, collision and coalescence dominate the precipitation properties; in particular, from 2.0–2.8 km, the breakup process competes with collision–coalescence processes but later is overpowered. In contrast, due to the lower BB heights over the Nagqu, collision and coalescence dominate raindrop properties. Comparisons of raindrop spectra suggest that the concentration of small (medium-to-large) raindrops over the Nagqu is much higher (slightly lower) than that over the Longmen. Therefore, the mass-weighted mean diameter Dm (the generalized intercept parameter Nw) over the Nagqu is smaller (larger) than that over the Longmen.

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