scholarly journals The Impact of the NAO on the Delayed Break-Up Date of Lake Ice over the Southern Tibetan Plateau

2018 ◽  
Vol 31 (22) ◽  
pp. 9073-9086 ◽  
Author(s):  
Yong Liu ◽  
Huopo Chen ◽  
Huijun Wang ◽  
Yubao Qiu
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
North Atlantic ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Freezing Process ◽  
Lake Ice ◽  
Break Up ◽  
The Impact ◽  
Ice Phenology

The changing characteristics of lake ice phenology over the Tibetan Plateau (TP) are investigated using historical satellite retrieved datasets during 2002–15 in this study. The results indicate that the freezing process mainly starts in December, and the ice melting process generally occurs in April for most lakes. However, the changes in lake ice phenology have varied depending on the location in recent years, with delayed break-up dates and prolonged ice durations in the southern TP, but no consistent changes have occurred in the lakes in the northern TP. Further analysis presents a close connection between the variation in the lake ice break-up date/ice duration over the southern TP and the winter North Atlantic Oscillation (NAO). The positive NAO generally excites an anomalous wave activity that propagates southward from the North Atlantic to North Africa and, in turn, strengthens the African–Asian jet stream at its entrance. Because of the blocking effect of the TP, the enhanced westerly jet can be divided into two branches and the south branch flow can deepen the India–Myanmar trough, which further strengthens the anomalous cyclonic circulation and water vapor transport. Therefore, the increased water vapor transport from the northern Indian Ocean to the southern region of the TP can increase the snowfall over this region. The increased snow cover over the lake acts as an insulating layer and lowers the lake surface temperature in the following spring by means of snow–ice feedback activity, resulting in a delayed ice break-up date and the increased ice duration of the lakes over the southern TP in recent years.

Role of Tibetan Plateau in Northern Drought induced by Changes in Subtropical Westerly Jet

2021 ◽  
pp. 1-40
Author(s):  
Qingzhe Zhu ◽  
Yuzhi Liu ◽  
Tianbin Shao ◽  
Run Luo ◽  
Ziyuan Tan
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
North China ◽  
Lower Troposphere ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Westerly Jet ◽  
The Impact ◽  
Subtropical Westerly Jet

AbstractThe Tibetan Plateau (TP), the “Water Tower of Asia”, plays an important role in the water cycle. However, few studies have linked the TP’s water vapor supply with the climate over North China. In this study, we found that changes in the subtropical westerly jet (SWJ) dynamically induce drought in North China, and the TP plays an important role in this relationship. During July-August for the period of 1981-2019, the SWJ center between 75°E and 105°E obviously shifted northward at a rate of 0.04° per year. Correspondingly, the zonal winds in the southern subtropics were incredibly weakened, causing the outflow of water vapor from the TP to decrease dramatically. Combined with numerical simulations, we discovered that a reduction in water vapor transport from the TP can obviously decrease the precipitation over North China. Sensitivity experiments demonstrated that if the water vapor outflow from the eastern border of the TP decreases by 52.74%, the precipitation in North China will decrease by 12.69% due to a decrease in the local cloud fraction caused by a diminished water vapor content in the atmosphere. Therefore, although less water vapor transport occurs in the upper troposphere than in the lower troposphere, the impact of transport from the TP in the former on the downstream precipitation cannot be ignored.

Modulation of coupled modes of Tibetan Plateau heating and Indian Summer Monsoon on summer rainfall over Central Asia

2021 ◽  
pp. 1-54
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
Central Asia ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Diabatic Heating ◽  
Summer Rainfall ◽  
Hadley Cell ◽  
Vapor Transport ◽  
Water Vapor Transport

Abstract It has been suggested that summer rainfall over Central Asia (CA) is significantly correlated with the summer thermal distribution of the Tibetan Plateau (TP) and the Indian summer monsoon (ISM). However, relatively few studies have investigated their synergistic effects of different distribution. This study documents the significant correlations between precipitation in CA and the diabatic heating of TP and the ISM based on the results of statistical analysis and numerical simulation. Precipitation in CA is is dominated by two water vapor transport branches from the south which are related to the two primary modes of anomalous diabatic heating distribution related to the TP and ISM precipitation, that is, the “+-” dipole mode in the southeastern TP and the Indian subcontinent (IS), and the “+-+” tripole mode in the southeastern TP, the IS, and southern India. Both modes exhibit obvious mid-latitude Silk Road pattern (SRP) wave trains with cyclone anomalies over CA, but with different transient and stationary eddies over south Asia. The different locations of anomalous anticyclones over India govern two water vapor transport branches to CA, which are from the Arabian Sea and the Bay of Bengal. The water vapor flux climbs while being transported northward and can be transported to CA with the cooperation of cyclonic circulation. The convergent water vapor and ascending motion caused by cyclonic anomalies favor the precipitation in CA. Further analysis corroborates the negative South Indian Ocean Dipole (NSIOD) in February could affect the tripole mode distribution of TP heating and ISM via the atmospheric circulation, water vapor transport and an anomalous Hadley cell circulation. The results indicate a reliable prediction reference for precipitation in CA.

scholarly journals The Impact of Diffusive Water Vapor Transport on Snow Profiles in Deep and Shallow Snow Covers and on Sea Ice

2020 ◽  
Vol 8 ◽  
Author(s):  
Mahdi Jafari ◽  
Isabelle Gouttevin ◽  
Margaux Couttet ◽  
Nander Wever ◽  
Adrien Michel ◽  
...  
Keyword(s):  
Water Vapor ◽  
Sea Ice ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The Impact

scholarly journals Precipitation and Water Vapor Transport in the Southern Hemisphere with Emphasis on the South American Region

2009 ◽  
Vol 48 (9) ◽  
pp. 1902-1912 ◽  
Author(s):  
Josefina Moraes Arraut ◽  
Prakki Satyamurty
Keyword(s):  
Water Vapor ◽  
South America ◽  
North Atlantic ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The South ◽  
Meridional Transport ◽  
Moisture Flow ◽  
The North ◽  
The North Atlantic

Abstract December–March climatologies of precipitation and vertically integrated water vapor transport were analyzed and compared to find the main paths by which moisture is fed to high-rainfall regions in the Southern Hemisphere in this season. The southern tropics (20°S–0°) exhibit high rainfall and receive ample moisture from the northern trades, except in the eastern Pacific and the Atlantic Oceans. This interhemispheric flow is particularly important for Amazonian rainfall, establishing the North Atlantic as the main source of moisture for the forest during its main rainy season. In the subtropics the rainfall distribution is very heterogeneous. The meridional average of precipitation between 35° and 25°S is well modulated by the meridional water vapor transport through the 25°S latitude circle, being greater where this transport is from the north and smaller where it is from the south. In South America, to the east of the Andes, the moisture that fuels precipitation between 20° and 30°S comes from both the tropical South and North Atlantic Oceans whereas between 30° and 40°S it comes mostly from the North Atlantic after passing over the Amazonian rain forest. The meridional transport (across 25°S) curve exhibits a double peak over South America and the adjacent Atlantic, which is closely reproduced in the mean rainfall curve. This corresponds to two local maxima in the two-dimensional field of meridional transport: the moisture corridor from Amazonia into the continental subtropics and the moisture flow coming from the southern tropical Atlantic into the subtropical portion of the South Atlantic convergence zone. These two narrow pathways of intense moisture flow could be suitably called “aerial rivers.” Their longitudinal positions are well defined. The yearly deviations from climatology for moisture flow and rainfall correlate well (0.75) for the continental peak but not for the oceanic peak (0.23). The structure of two maxima is produced by the effect of transients in the time scale of days.

scholarly journals The Impact of the Sierra Nevada on Low-Level Winds and Water Vapor Transport

2007 ◽  
Vol 8 (4) ◽  
pp. 790-804 ◽  
Author(s):  
Jinwon Kim ◽  
Hyun-Suk Kang
Keyword(s):  
Water Vapor ◽  
Sierra Nevada ◽  
Climate Model ◽  
Northern Region ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Western Slope ◽  
Mountain Range ◽  
Low Level ◽  
The Impact

Abstract To understand the influence of the Sierra Nevada on the water cycle in California the authors have analyzed low-level winds and water vapor fluxes upstream of the mountain range in regional climate model simulations. In a low Froude number (Fr) regime, the upstream low-level wind disturbances are characterized by the rapid weakening of the crosswinds and the appearance of a stagnation point over the southwestern foothills. The weakening of the low-level inflow is accompanied by the development of along-ridge winds that take the form of a barrier jet over the western slope of the mountain range. Such upstream wind disturbances are either weak or nonexistent in a high-Fr case. A critical Fr (Frc) of 0.35 inferred in this study is within the range of those suggested in previous observational and numerical studies. The depth of the blocked layer estimated from the along-ridge wind profile upstream of the northern Sierra Nevada corresponds to Frc between 0.3 and 0.45 as well. Associated with these low-level wind disturbances are significant low-level southerly moisture fluxes over the western slope and foothills of the Sierra Nevada in the low-Fr case, which result in significant exports of moisture from the southern Sierra Nevada to the northern region. This along-ridge low-level water vapor transport by blocking-induced barrier jets in a low-Fr condition may result in a strong north–south precipitation gradient over the Sierra Nevada.

scholarly journals Quantitative Analysis of Water Vapor Transport during Mei-Yu Front Rainstorm Period over the Tibetan Plateau and Yangtze-Huai River Basin

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Hao Yang ◽  
Guan-yu Xu ◽  
Xiaofang Wang ◽  
Chunguang Cui ◽  
Jingyu Wang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Indian Ocean ◽  
Tibetan Plateau ◽  
Heavy Rainfall ◽  
Initial Position ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Huai River ◽  
The Indian Ocean

There are continuous precipitation systems moving eastward from the Tibetan Plateau to the middle and lower reaches of the Yangtze-Huai River during the Mei-yu period. We selected 20 typical Mei-yu front precipitation cases from 2010 to 2015 based on observational and reanalysis data and studied the characteristics of their environmental fields. We quantitatively analyzed the transport and sources of water vapor in the rainstorms using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT_4.9) model. All 20 Mei-yu front precipitation cases occurred in a wide region from the Tibetan Plateau to the Yangtze-Huai River. The South Asian high and upper level jet stream both had strong intensities during the Mei-yu front rainstorm periods. Heavy rainfall mainly occurred in the divergence zone to the right of the high-level jet and in the convergence zone of the low-level jet, where strong vertical upward flows provided the dynamic conditions required for heavy rainfall. The water vapor mainly originated from the Indian Ocean, Bay of Bengal, and South China Sea. 52% of the air masses over the western Tibetan Plateau originated from Central Asia, which were rich in water vapor. The water vapor contribution at the initial position was only 41.5% due to the dry, cold air mass over Eurasia, but increased to 47.6% at the final position. Over the eastern Tibetan Plateau to the Sichuan Basin region, 40% of the air parcels came from the Indian Ocean, which was the main channel for water vapor transport. For the middle and lower reaches of the Yangtze River, 37% of the air parcels originated from the warm and humid Indian Ocean. The water vapor contribution at the initial position was 38.6%, but increased to 40.2% after long-distance transportation.

scholarly journals A vertical transport window of water vapor in the troposphere over the Tibetan Plateau with implication for global change

2021 ◽  
Author(s):  
Xiangde Xu ◽  
Chan Sun ◽  
Deliang Chen ◽  
Tianliang Zhao ◽  
Jianjun Xu ◽  
...  
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
Global Change ◽  
Dynamic Effect ◽  
High Water ◽  
Vertical Transport ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The Arctic ◽  
The Tibetan Plateau

Abstract. By using the multi-source data of meteorology over recent decades, this study discovered a summertime “hollow wet pool” in the troposphere with a center of high water vapor over Asian water tower (AWT) on the Tibetan Plateau (TP), where is featured by a vertical transport “window” in the troposphere. The water vapor transport in the upper troposphere extends from the vertical transport window over the TP with the significant connections among the Arctic, Antarctic and TP regions, highlighting an effect of TP’s vertical transport window of tropospheric vapor in the “hollow wet pool” on global change. The vertical transport window was built by the AWT’s thermal forcing in associated with the dynamic effect of the TP’s “hollow heat island”. Our study improve the understanding on the vapor transport over the TP with an important implication to global change.

scholarly journals Analysis of the 2008 heavy snowfall over South China using GPS PWV measurements from the Tibetan Plateau

2010 ◽  
Vol 28 (6) ◽  
pp. 1369-1376 ◽  
Author(s):  
Y. Xie ◽  
F. Wei ◽  
G. Chen ◽  
T. Zhang ◽  
L. Hu
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
South China ◽  
Numerical Models ◽  
Heavy Precipitation ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Good Opportunity ◽  
The One

Abstract. Four successive storms with freezing rain and snow blanketed South China from 10 January–2 February 2008, when the precipitation increased more than 200%–300% above the average for the corresponding period. The unusual atmospheric circulation associated with these disasters was caused by many complex physical processes, one of which was the active southern branch of currents over low latitude ocean areas which provided plenty of water vapor for South China. The ground-based GPS Precipitable Water Vapor (PWV) measurements on the Tibetan Plateau, supported by the China and Japan Intergovernmental Cooperation Program (JICA), has compensated for the lack of conventional observations of atmospheric water vapor in this area and provided a good opportunity to analyze the character of the water vapor transport in the four heavy precipitation processes. It was found that the GPS stations located on the southeastern Tibetan Plateau were on the route of the water vapor transport during 25 January–29 January and 31 January–2 February when two heavy precipitation events occurred over South China. The increasing trend from the one to two days pre-observation by the GPS stations was then associated with the heavy precipitation. Precipitation during 10 January–16 January and 18 January–22 January was significantly related to the abnormal variation of the one day pre-observation by the GPS stations located on the northeastern Tibetan Plateau. This research indicates that ground-based GPS measurements are applicable to data assimilation in operational numerical models.

scholarly journals The impact of thermal conductivity and diffusion rates on water vapor transport through gas diffusion layers

2009 ◽  
Vol 190 (2) ◽  
pp. 485-492 ◽  
Author(s):  
Sergei F. Burlatsky ◽  
Vadim V. Atrazhev ◽  
Mallika Gummalla ◽  
Dave A. Condit ◽  
Fuqiang Liu
Keyword(s):  
Thermal Conductivity ◽  
Water Vapor ◽  
Gas Diffusion ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Gas Diffusion Layers ◽  
Diffusion Layers ◽  
Diffusion Rates ◽  
The Impact ◽  
And Diffusion
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