Satellite-based Observational Study of the Tibetan Plateau Vortex: Features of Deep Convective Cloud Tops

2018 ◽  
Vol 36 (2) ◽  
pp. 189-205 ◽  
Author(s):  
Yi-Xuan Shou ◽  
Feng Lu ◽  
Hui Liu ◽  
Peng Cui ◽  
Shaowen Shou ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Observational Study ◽  
Convective Cloud ◽  
The Tibetan Plateau ◽  
Tibetan Plateau Vortex ◽  
Cloud Tops ◽  
Deep Convective Cloud

scholarly journals Tibetan Plateau Vortex‐Associated Precipitation and Its Link with the Tibetan Plateau Heating Anomaly

2021 ◽  
Author(s):  
Zhiqiang Lin ◽  
Weidong Guo ◽  
Xiuping Yao ◽  
Jun Du ◽  
Wenkai Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Tibetan Plateau Vortex ◽  
Heating Anomaly

scholarly journals Retrieving Vertical Air Velocity in Convective Cloud over the Tibetan Plateau from TIPEX-III Cloud Radar Doppler Spectra

2017 ◽  
Author(s):  
Jiafeng Zheng ◽  
Liping Liu ◽  
Keyun Zhu ◽  
Jingya Wu ◽  
Binyun Wang
Keyword(s):  
Tibetan Plateau ◽  
Numerical Models ◽  
Convective Cloud ◽  
Small Scale ◽  
The Tibetan Plateau ◽  
Air Velocity ◽  
Cloud Radar ◽  
Radar Measurements ◽  
Result Merging ◽  
Air Motion

In the summertime, convections occur frequently over the Tibetan Plateau (TP) because of the large dynamic and thermal effects of the landmass. Measurements of vertical air velocity in convective cloud are useful for advancing our understanding of the dynamic and microphysical mechanisms of clouds and can be used to improve the parameterization of current numerical models. This paper presents a technique for retrieving high-resolution vertical air velocity from convective cloud over the TP, by using Doppler spectra from a vertically pointing Ka-band cloud radar. The method is based on the development of a “small-particle-traced” idea and the necessary data processing and uses three modes of radar. Spectral broadening corrections, uncertainty estimations, and result merging are used to ensure accurate results. Qualitative analysis of two typical convective cases shows that the retrievals are reliable and agree with the expectant results inferred from other radar measurements. A quantitative retrieval of vertical air motion from a ground-based optical disdrometer is used to preliminarily validate our radar-derived results. The comparison illustrates that while the data trends from the two methods of retrieval are similar, with the updrafts and downdrafts coinciding, cloud radar has a much higher resolution and can reveal the small-scale variation of vertical air motion.

scholarly journals Object-Based Evaluation of MERRA Cloud Physical Properties and Radiative Fluxes during the 1998 El Niño–La Niña Transition

2012 ◽  
Vol 25 (21) ◽  
pp. 7313-7327 ◽  
Author(s):  
Derek J. Posselt ◽  
Andrew R. Jongeward ◽  
Chuan-Yuan Hsu ◽  
Gerald L. Potter
Keyword(s):  
Optical Depth ◽  
Tropical Rainfall Measuring Mission ◽  
Convective Cloud ◽  
Shortwave Radiation ◽  
Total Water ◽  
Water Path ◽  
Convective Systems ◽  
Cloud Properties ◽  
Cloud Tops ◽  
Deep Convective Cloud

The Modern-Era Retrospective Analysis for Research and Application (MERRA) is a reanalysis designed to produce an improved representation of the Earth’s hydrologic cycle. This study examines the representation of deep convective clouds in MERRA, comparing analyzed liquid and ice clouds with deep convective cloud objects observed by instruments on the Tropical Rainfall Measuring Mission satellite. Results show that MERRA contains deep convective cloud in 98.1% of the observed cases. MERRA-derived probability density functions (PDFs) of cloud properties have a similar form as the observed PDFs and exhibit a similar trend with changes in object size. Total water path, optical depth, and outgoing shortwave radiation (OSR) in MERRA are found to match the cloud object observations quite well; however, there appears to be a bias toward higher-than-observed cloud tops in the MERRA. The reanalysis fits the observations most closely for the largest class of convective systems, with performance generally decreasing with a transition to smaller convective systems. Comparisons of simulated total water path, optical depth, and OSR are found to be highly sensitive to the assumed subgrid distribution of condensate and indicate the need for caution when interpreting model-data comparisons that require disaggregation of grid-scale cloud to satellite pixel scales.

Intercomparison of Deep Convection over the Tibetan Plateau–Asian Monsoon Region and Subtropical North America in Boreal Summer Using CloudSat/CALIPSO Data

2011 ◽  
Vol 24 (8) ◽  
pp. 2164-2177 ◽  
Author(s):  
Yali Luo ◽  
Renhe Zhang ◽  
Weimiao Qian ◽  
Zhengzhao Luo ◽  
Xin Hu
Keyword(s):  
North America ◽  
Tibetan Plateau ◽  
Asian Monsoon ◽  
Deep Convection ◽  
Local Environment ◽  
Boreal Summer ◽  
The Tibetan Plateau ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Cloud Tops

Abstract Deep convection in the Tibetan Plateau–southern Asian monsoon region (TP–SAMR) is analyzed using CloudSat and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data for the boreal summer season (June–August) from 2006 to 2009. Three subregions are defined—the TP, the southern slope of the plateau (PSS), and the SAMR—and deep convection properties (such as occurrence frequency, internal vertical structure, system size, and local environment) are compared among these subregions. To cast them in a broader context, four additional regions that bear some similarity to the TP–SAMR are also discussed: East Asia (EA), tropical northwestern Pacific (NWP), and western and eastern North America (WNA and ENA, respectively). The principal findings are as follows: 1) Compared to the other two subregions of the TP–SAMR, deep convection over the TP is shallower, less frequent, and embedded in smaller-size convection systems, but the cloud tops are more densely packed. These characteristics of deep convection over the TP are closely related to the unique local environment, namely, a significantly lower level of neutral buoyancy (LNB) and much drier atmosphere. 2) In a broader context in which all seven regions are brought together, deep convection in the two tropical regions (NWP and SAMR; mostly over ocean) is similar in many regards. A similar conclusion can be drawn among the four subtropical continental regions (TP, EA, WNA, and ENA). However, tropical oceanic and subtropical land regions present some significant contrasts: deep convection in the latter region occurs less frequently, has lower cloud tops but comparable or slightly higher tops of large radar echo (e.g., 0 and 10 dBZ), and is embedded in smaller systems. The cloud tops of the subtropical land regions are generally more densely packed. Hence, the difference between the TP and SAMR is more of a general contrast between subtropical land regions and tropical oceanic regions during the boreal summer. 3) Deep convection over the PSS possesses some uniqueness of its own because of the distinctive terrain (slopes) and moist low-level monsoon flow. 4) Results from a comparison between the daytime (1:30 p.m.) and nighttime (1:30 a.m.) overpasses are largely consistent with researchers’ general understanding of the diurnal variation of tropical and subtropical deep convection.

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