scholarly journals Simulation of summer precipitation diurnal cycles over the Tibetan Plateau at the gray-zone grid spacing for cumulus parameterization

2020 ◽  
Vol 54 (7-8) ◽  
pp. 3525-3539 ◽  
Author(s):  
Tinghai Ou ◽  
Deliang Chen ◽  
Xingchao Chen ◽  
Changgui Lin ◽  
Kun Yang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Summer Precipitation ◽  
Cumulus Parameterization ◽  
The Tibetan Plateau ◽  
Gray Zone ◽  
Grid Spacing ◽  
Diurnal Cycles

scholarly journals Diurnal variation of summer precipitation over the Tibetan Plateau: a cloud-resolving simulation

2012 ◽  
Vol 30 (11) ◽  
pp. 1575-1586 ◽  
Author(s):  
◽  
◽  
◽  
Keyword(s):  
Tibetan Plateau ◽  
Diurnal Variation ◽  
Summer Precipitation ◽  
Weather Research And Forecasting ◽  
The Tibetan Plateau ◽  
Good Correspondence ◽  
Diurnal Cycles ◽  
Regional Circulation ◽  
Trmm Precipitation ◽  
Diurnal Rainfall

Abstract. In this study, the Weather Research and Forecasting model was used to simulate the diurnal variation in summer precipitation over the Tibetan Plateau (TP) at a cloud-resolving scale. Compared with the TRMM, precipitation data shows that the model can well simulate the diurnal rainfall cycle with an overall late-afternoon maximum precipitation in the central TP and a nighttime maximum in the southern edge. The simulated diurnal variations in regional circulation and thermodynamics are in good correspondence with the precipitation diurnal cycles in the central and southern edge of TP, respectively. A possible mechanism responsible for the nocturnal precipitation maximum in the southern edge has been proposed, indicating the importance of the TP in regulating the regional circulation and precipitation.

Convection permitting simulation of summer precipitation over the Tibetan Plateau

2021 ◽  
Author(s):  
Zhaoyang Liu ◽  
Yanhong Gao
Keyword(s):  
Water Resources ◽  
Tibetan Plateau ◽  
Water Cycle ◽  
Global Climate ◽  
Summer Precipitation ◽  
The Tibetan Plateau ◽  
Hydrological Process ◽  
Diurnal Cycles ◽  
Precipitation Measurement ◽  
Global Precipitation

<p>The Tibetan Plateau (TP), known as the "Third Pole" and "Water Tower of Asia", plays an essential role in the regional water cycle and global climate change through its unique topography and abundant water resources. Precipitation is an important part of the hydrological process, but realistically simulating precipitation over the TP is still a major challenge for most models, which hinders our understanding of the strength of the land-atmosphere interaction and its influences on regional, or even global climate and water cycle. In order to better depict precipitation spatial and temporal distributions over the TP, a 4-km convection permitting modelling (CPM) and a 28-km dynamical downscale modelling (DDM) using the weather Research and Forecasting model (WRF) were conducted for a summer (from June to August 2014). WRF simulations are evaluated against CMA in-situ observations, the Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of water resources (APHRODITE), the Global Precipitation Measurement (GPM), as well as two reanalysis datasets ERA-Interim and ERA5. We focus on the added values of the CPM in summer precipitation simulations, in terms of the spatial seasonal mean precipitation amounts, spatial distributions, and diurnal cycles. We found the six datasets (CPM, DDM, APHRODITE, GPM, ERA-Interim and ERA5) showed great differences in summer precipitation over the TP. The great advantages of CPM and DDM over reanalyses are observed. Slight improvements are found in CPM over DDM as well. Mechanisms for these differences will be explored.</p>

scholarly journals Atmospheric Thermal and Dynamic Vertical Structures of Summer Hourly Precipitation in Jiulong of the Tibetan Plateau

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 505
Author(s):  
Yonglan Tang ◽  
Guirong Xu ◽  
Rong Wan ◽  
Xiaofang Wang ◽  
Junchao Wang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Tibetan Plateau ◽  
Precipitation Amount ◽  
Summer Precipitation ◽  
The Tibetan Plateau ◽  
Hourly Precipitation ◽  
Air Convection ◽  
Precipitation Variation ◽  
Long Term Observation

It is an important to study atmospheric thermal and dynamic vertical structures over the Tibetan Plateau (TP) and their impact on precipitation by using long-term observation at representative stations. This study exhibits the observational facts of summer precipitation variation on subdiurnal scale and its atmospheric thermal and dynamic vertical structures over the TP with hourly precipitation and intensive soundings in Jiulong during 2013–2020. It is found that precipitation amount and frequency are low in the daytime and high in the nighttime, and hourly precipitation greater than 1 mm mostly occurs at nighttime. Weak precipitation during the daytime may be caused by air advection, and strong precipitation at nighttime may be closely related with air convection. Both humidity and wind speed profiles show obvious fluctuation when precipitation occurs, and the greater the precipitation intensity, the larger the fluctuation. Moreover, the fluctuation of wind speed is small in the morning, large at noon and largest at night, presenting a similar diurnal cycle to that of convective activity over the TP, which is conductive to nighttime precipitation. Additionally, the inverse layer is accompanied by the inverse humidity layer, and wind speed presents multi-peaks distribution in its vertical structure. Both of these are closely related with the underlying surface and topography of Jiulong. More studies on physical mechanism and numerical simulation are necessary for better understanding the atmospheric phenomenon over the TP.

scholarly journals IMPACT OF TIBETAN PLATEAU SNOW COVER ON ABRUPT INTERDECADAL PRECIPITATION CHANGE OVER THE INDOCHINA PENINSULA IN THE MID-1990S

2019 ◽  
Vol XLII-3/W9 ◽  
pp. 57-62
Author(s):  
Y. Ha ◽  
Y. M. Zhu ◽  
Y. J. Hu ◽  
Z. Zhong
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
Summer Precipitation ◽  
Tropical Indian Ocean ◽  
Western Pacific Subtropical High ◽  
Precipitation Change ◽  
Interdecadal Change ◽  
Northwestern Pacific ◽  
The Tibetan Plateau ◽  
Indochina Peninsula

Abstract. Abrupt interdecadal changes in summer precipitation (May – September) over the Indochina Peninsula in the past 40 years have been investigated based on the NCEP-NCAR reanalysis product over 1979–2013 and multiple precipitation datasets. The mechanism for the abrupt change is explored. Results indicate that an abrupt interdecadal change in summer precipitation over the Indochina Peninsula occurred in the middle 1990s, and the annual mean summer precipitation during 1994–2002 increased by about 10% compared to that during 1982–1993. The most significant precipitation change occurred in the central and northern peninsula. Further analysis reveals that the interdecadal decrease in snow cover over the Tibetan Plateau in the winter and spring contributed to the summer precipitation increase over the Indochina Peninsula. The decrease in snow cover over the Tibetan Plateau actually increased the thermal contrast between the Tibetan Plateau and the tropical Indian Ocean-northwestern Pacific, leading to intensified summer monsoon over the northwestern Pacific and the South China Sea. As a result, westerly anomalies occurred from the Bay of Bengal to the northwestern Pacific, while anomalous cyclonic circulation prevailed in the upper levels above East Asia. Correspondingly, the western Pacific subtropical high weakened and shifted eastward. Under the joint effects of the above circulation patterns, the atmosphere became wetter in the Indochina Peninsula and summer precipitation increased. Results of the present study provide a theoretical basis for the prediction of long-term summer precipitation change in the Indochina Peninsula.

Spatially coherent clusters of summer precipitation extremes in the Tibetan Plateau: Where is the moisture from?

2020 ◽  
Vol 237 ◽  
pp. 104841 ◽  
Author(s):  
Yingzhao Ma ◽  
Mengqian Lu ◽  
Cameron Bracken ◽  
Haonan Chen
Keyword(s):  
Tibetan Plateau ◽  
Summer Precipitation ◽  
Precipitation Extremes ◽  
The Tibetan Plateau

Diurnal Variations of Warm-Season Precipitation East of the Tibetan Plateau over China

2011 ◽  
Vol 139 (9) ◽  
pp. 2790-2810 ◽  
Author(s):  
Xinghua Bao ◽  
Fuqing Zhang ◽  
Jianhua Sun
Keyword(s):  
Tibetan Plateau ◽  
Warm Season ◽  
Propagation Speed ◽  
Western Pacific Subtropical High ◽  
Diurnal Variations ◽  
The Tibetan Plateau ◽  
Diurnal Cycles ◽  
Thermally Driven ◽  
The Difference ◽  
Precipitation Cycle

This study explores the diurnal variations of the warm-season precipitation to the east of the Tibetan Plateau over China using the high-resolution NOAA/Climate Prediction Center morphing technique (CMORPH) precipitation data and the Global Forecast System (GFS) gridded analyses during mid-May to mid-August of 2003–09. Complementary to the past studies using satellite or surface observations, it is found that there are strong diurnal variations in the summertime precipitation over the focus domain to the east of the Tibetan Plateau. These diurnal precipitation cycles are strongly associated with several thermally driven regional mountain–plains solenoids due to the differential heating between the Tibetan Plateau, the highlands, the plains, and the ocean. The diurnal cycles differ substantially from region to region and during the three different month-long periods: the pre-mei-yu period (15 May–15 June), the mei-yu period (15 June–15 July), and the post-mei-yu period (15 July–15 August). In particular, there is a substantial difference in the propagation speed and eastward extent of the peak phase of the dominant diurnal precipitation cycle that is originated from the Tibetan Plateau. This diurnal peak has a faster (slower) eastward propagation speed, the more (less) coherent propagation duration, and thus covers the longest (shortest) distance to the east during the pre-mei-yu (post-mei-yu) period than that during the mei-yu period. The differences in the mean midlatitude westerly flow and in the positioning and strength of the western Pacific subtropical high during different periods are the key factors in explaining the difference in the propagation speed and the eastward extent of this dominant diurnal precipitation cycle.

scholarly journals Performance of a New Convective Parameterization Scheme on Model Convergence in Simulations of a Tropical Cyclone at Grey-Zone Resolutions

2014 ◽  
Vol 71 (6) ◽  
pp. 2078-2088 ◽  
Author(s):  
Yuan Sun ◽  
Lan Yi ◽  
Zhong Zhong ◽  
Yao Ha
Keyword(s):  
Tropical Cyclone ◽  
Radial Pressure ◽  
Cumulus Parameterization ◽  
Parameterization Scheme ◽  
Convective Heating ◽  
Finite Limit ◽  
Grey Zone ◽  
Gray Zone ◽  
Grid Spacing ◽  
Intensity Changes

Abstract The latest version of the Weather Research and Forecasting model (WRFV3.5) is used to evaluate the performance of the Grell and Freitas (GF13) cumulus parameterization scheme on the model convergence in simulations of a tropical cyclone (TC) at gray-zone resolutions. The simulated TC intensity converges to a finite limit as the grid spacing varies from 7.5 to 1 km. The reasons for the model convergence are investigated from perspectives of subgrid-scale processes and thermodynamic and dynamic structures. It is found that the impacts of above factors are notably different with varying model resolutions. The convective heating and drying increase as the grid spacing decreases, which inhibits the explicit microphysical parameterization preventing the simulated TC from overly intensifying. As the grid spacing decreases from 7.5 to 5 km, the TC intensity increases because of a stronger secondary circulation, a larger magnitude and proportion of strong eyewall updraft, and a greater amount of latent heating in the eyewall. As the grid spacing decreases from 5 to 3 km, the radius of maximum wind (RMW) decreases and the radial pressure gradient increases leading to an increase in TC intensity. The simulated TC intensity changes slightly as the grid spacing decreases from 3 to 1 km since the RMW and the storm structure both change little. The slight changes in the simulated TC intensity at such high resolutions indicate a great model convergence. Therefore, the GF13 presents an appropriate option that increases the model convergence in the TC intensity simulation at gray-zone resolution.

scholarly journals Estimating Summer Precipitation Over the Tibetan Plateau With Geostatistics and Remote Sensing

2013 ◽  
Vol 33 (4) ◽  
pp. 424-436 ◽  
Author(s):  
Shi-Guang Xu ◽  
Zheng Niu ◽  
Da Kuang ◽  
Yan Shen ◽  
Wen-Jiang Huang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Tibetan Plateau ◽  
Summer Precipitation ◽  
The Tibetan Plateau
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