scholarly journals The Phenomenon of Diurnal Variations for Summer Deep Convective Precipitation over the Qinghai-Tibet Plateau and Its Southern Regions as Viewed by TRMM PR

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 745
Author(s):  
Jing Luo ◽  
Jianqiu Zheng ◽  
Lei Zhong ◽  
Chun Zhao ◽  
Yunfei Fu
Keyword(s):  
Surface Wind ◽  
Diurnal Variations ◽  
Precipitation Intensity ◽  
Convective Precipitation ◽  
Tibet Plateau ◽  
Peak Time ◽  
Diurnal Changes ◽  
The Mean ◽  
Height Fields ◽  
Qinghai Tibet Plateau

This study analyzed the diurnal variations of summer deep convective precipitation (DCP) over the Qinghai-Tibet Plateau (QTP) and its southern region. The results show that DCP is the main type of precipitation over the QTP. The precipitation intensity of DCP is less than 3 mm/h over the QTP, which is much lower than the precipitation intensity in non-plateau regions. DCP over non-plateau regions is related to the convergence of surface wind, but that over the QTP are not. The mean maximum echo of DCP is less than 26 dBZ over the QTP, less than in non-plateau regions. The mean altitude of maximum echo decreases from about 7.5 km in the western plateau to 6 km in the eastern plateau, while it reaches only 4.5–5 km in the non-plateau region. The DCP frequency peak occurs in the afternoon in the major area of the QTP including valley region. The peak time of DCP frequency is different from its intensity, and the former is 1 to 2 h earlier. Study also indicates strong diurnal variations in frequency, intensity, and the maximum echo over the QTP, which is consistent with diurnal changes of geopotential height fields of 500 hPa and 200 hPa.

Comparison of Diurnal Variations in Precipitation Systems Observed by TRMM PR, TMI, and VIRS

2008 ◽  
Vol 21 (16) ◽  
pp. 4011-4028 ◽  
Author(s):  
Munehisa K. Yamamoto ◽  
Fumie A. Furuzawa ◽  
Atsushi Higuchi ◽  
Kenji Nakamura
Keyword(s):  
Diurnal Variation ◽  
Deep Convection ◽  
Heavy Rain ◽  
Diurnal Variations ◽  
Convective Precipitation ◽  
Time Shift ◽  
Mature Stage ◽  
Peak Time ◽  
The Tibetan Plateau ◽  
Near Surface

Abstract Tropical Rainfall Measuring Mission (TRMM) data during June–August 1998–2003 are used to investigate diurnal variations of rain and cloud systems over the tropics and midlatitudes. The peak time of the coldest minimum brightness temperature derived from the Visible and Infrared Scanner (VIRS) and the maximum rain rate derived from the Precipitation Radar (PR) and the TRMM Microwave Imager (TMI) are compared. Time distributions are generally consistent with previous studies. However, it is found that systematic shifts in peak time relative to each sensor appeared over land, notably over western North America, the Tibetan Plateau, and oceanic regions such as the Gulf of Mexico. The peak time shift among PR, TMI, and VIRS is a few hours. The relationships among the amplitude of diurnal variation, convective frequency, storm height, and rain amount are further investigated and compared to the systematic peak time shifts. The regions where the systematic shift appears correspond to large amplitude of diurnal variation, high convective frequency, and high storm height. Over land and over ocean near the coast, the relationships are rather clear, but not over open ocean. The sensors likely detect different stages in the evolution of convective precipitation, which would explain the time shift. The PR directly detects near-surface rain. The TMI observes deep convection and solid hydrometeors, sensing heavy rain during the mature stage. VIRS detects deep convective clouds in mature and decaying stages. The shift in peak time particularly between PR (TMI) and VIRS varies by region.

scholarly journals Observed Microphysical Characteristics of Stratiform and Convective Precipitation over an Inland Arid Region of the Qinghai–Tibet Plateau

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2300
Author(s):  
Hongwei Xie ◽  
Peichong Pan ◽  
Haiyun Shi ◽  
Ji Chen ◽  
Jinzhao Wang
Keyword(s):  
Arid Region ◽  
Rainfall Intensity ◽  
Radar Reflectivity ◽  
Convective Precipitation ◽  
Tibet Plateau ◽  
Raindrop Size Distribution ◽  
Stratiform Precipitation ◽  
Raindrop Size ◽  
Qinghai Tibet Plateau ◽  
Reflectivity Factor

This study analyzed the microphysical characteristics of stratiform and convective precipitation over an inland arid region of Qinghai–Tibet Plateau in summer for the first time. The observed precipitation data were from the OTT Parsivel2 laser raindrop spectrometer and the raindrop size distribution can be described by a gamma distribution and a general exponential distribution. The results indicate that: (1) compared to the exponential distribution, the gamma distribution is the better function with which to describe the raindrop size distribution in this region; (2) the raindrop sizes are mainly below 1 mm, and the raindrop sizes which contribute most to the rainfall intensity are below 2 mm for stratiform precipitation and convective precipitation; (3) the mean values of microphysical parameters, e.g., rainfall intensity, radar reflectivity factor, and liquid water content, are higher for convective precipitation than stratiform precipitation; and (4) the standard Z–R relationship underestimates the radar reflectivity factor in this region. Overall, the obtained results will enhance our understanding and facilitate future studies regarding the microphysical characteristics of precipitation in such regions. For example, the obtained Z–R relationship can be a reference for estimating the radar reflectivity factor in this region with higher accuracy.

Diurnal Variations in Rainfall and Precipitation Asymmetry of Tropical Cyclones in the Northwest Pacific Region

2021 ◽  
pp. 1-52
Author(s):  
Xinyan Zhang ◽  
Weixin Xu
Keyword(s):  
Diurnal Cycle ◽  
Radial Distance ◽  
Vertical Wind Shear ◽  
Early Morning ◽  
Diurnal Variations ◽  
Precipitation Intensity ◽  
Northwest Pacific ◽  
Diurnal Changes ◽  
Precipitation Frequency ◽  
Diurnal Variability

AbstractThis study investigates diurnal variations of tropical cyclone precipitation in the northwest Pacific (NWP) region, including the South China Sea (SCS) and adjacent landmasses. Diurnal cycles of TC rainfall show significant land-sea contrasts. The primary peak of (unconditional) mean TC rain rate occurs in the early morning (06 LT) and the afternoon (15 LT) over the ocean and land, respectively. Both the total and heavy TC precipitation extend further inland in the afternoon, while nocturnal heavy TC rain is more confined to the coast. A significant semidiurnal cycle of TC precipitation is observed over the ocean, i.e., a secondary peak near 18 LT. The diurnal cycle of TC rainfall also depends on precipitation frequency, intensity, and radial distance from the TC center. Over the ocean, though TC precipitation intensity shows a pronounced diurnal cycle, its precipitation frequency exhibits virtually no diurnal variation. Over land, TC precipitation frequency markedly peaks in the afternoon (15 LT), while its precipitation intensity interestingly maximizes in the early morning (03-06 LT). Diurnal variations of TC asymmetric rainfall structure are consistent with diurnal changes of vertical wind shear. Over the SCS, maximum precipitation located in the downshear-left quadrant and is the most extensive in the morning. However, this heavy rain area shrinks and shifts downshear-ward in the afternoon, consistent with changes of the magnitude (reduced) and direction (clockwise) of shear. In contrast, TCs over the open ocean of NWP (OWP) have little diurnal variability of precipitation asymmetry, due mainly to a diurnally invariant shear environment.

scholarly journals Seasonal Differences in Precipitation Sensitivity to Soil Moisture in Bangladesh and Surrounding Regions

2017 ◽  
Vol 30 (3) ◽  
pp. 921-938 ◽  
Author(s):  
Shiori Sugimoto ◽  
Hiroshi G. Takahashi
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Precipitation Intensity ◽  
Convective Precipitation ◽  
Diurnal Changes ◽  
Precipitation Frequency ◽  
Seasonal Differences ◽  
Southern Plains ◽  
Simulated Precipitation ◽  
Seasonal And Diurnal Variations

Abstract Precipitation sensitivity to soil moisture and its seasonal and diurnal changes are investigated in Bangladesh and surrounding regions using a regional climate model with a 5-km grid spacing. In the control experiment, soil moisture is calculated by a land surface scheme, and simulated accuracy of seasonal and diurnal variations in precipitation intensity and frequency is capable of assessing the soil moisture impact on precipitation. In sensitivity experiments with wetter land surfaces, daytime precipitation intensity decreases over the southern plains for both the premonsoon and mature monsoon seasons because of the weakening of surface heating and vertical mixing in the planetary boundary layer (PBL). Weakened vertical turbulent flux of moisture reduces condensation heating and upward motion in the mid- and upper troposphere, which suppresses development of convective precipitation. The simulated precipitation intensity response to soil moisture suggests that land surface wetness contributes to the seasonal contrast in observed precipitation intensity (i.e., stronger in the premonsoon than the mature monsoon seasons). Meanwhile, the precipitation frequency response to soil moisture varies with season and by region. Over the southern plains in the wet land surface experiments, daytime precipitation frequency decreases (increases) during the premonsoon (mature monsoon) season compared with the dry land surface experiments, as influenced by seasonal differences in relative humidity and the condensation process in the lower troposphere. Around the northern mountainous area, higher soil moisture increases precipitation frequency regardless of season because of additional water vapor supply from the ground and frequent orographic precipitation forced by the mountainous topography.

Legacy effect of warming on the heterotrophic respiration of alpine grassland on the Qinghai-Tibet Plateau

2021 ◽  
Vol 166 ◽  
pp. 104093
Author(s):  
Fei Peng ◽  
Wenjuan Zhang ◽  
Chimin Lai ◽  
Chengyang Li ◽  
Quangang You ◽  
...  
Keyword(s):  
Heterotrophic Respiration ◽  
Alpine Grassland ◽  
Tibet Plateau ◽  
Legacy Effect ◽  
Qinghai Tibet Plateau

scholarly journals Demographic history and genomic response to environmental changes in a rapid radiation of wild rats

2021 ◽  
Author(s):  
Deyan Ge ◽  
Anderson Feijó ◽  
Zhixin Wen ◽  
Alexei V Abramov ◽  
Liang Lu ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Demographic History ◽  
Terrestrial Ecosystems ◽  
Tibet Plateau ◽  
Global Changes ◽  
Rapid Radiation ◽  
Protein Functions ◽  
Wild Rats ◽  
Qinghai Tibet Plateau ◽  
Genomic Response

Abstract For organisms to survive and prosper in a harsh environment, particularly under rapid climate change, poses tremendous challenges. Recent studies have highlighted the continued loss of megafauna in terrestrial ecosystems and the subsequent surge of small mammals, such as rodents, bats, lagomorphs, and insectivores. However, the ecological partitioning of these animals will likely lead to large variation in their responses to environmental change. In the present study, we investigated the evolutionary history and genetic adaptations of white-bellied rats (Niviventer Marshall, 1976), which are widespread in the natural terrestrial ecosystems in Asia but also known as important zoonotic pathogen vectors and transmitters. The southeastern Qinghai-Tibet Plateau (QHTP) was inferred as the origin center of this genus, with parallel diversification in temperate and tropical niches. Demographic history analyses from mitochondrial and nuclear sequences of Niviventer demonstrated population size increases and range expansion for species in Southeast Asia, and habitat generalists elsewhere. Unexpectedly, population increases were seen in N. eha, which inhabits the highest elevation among Niviventer species. Genome scans of nuclear exons revealed that among the congeneric species, N. eha has the largest number of positively selected genes. Protein functions of these genes are mainly related to olfaction, taste and tumor suppression. Extensive genetic modification presents a major strategy in response to global changes in these alpine species.

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