Relations of Water Vapor Transport from Indian Monsoon with That over East Asia and the Summer Rainfall in China

A diagnostic study is made to investigate the relationship between water vapor transport from Indian monsoon and that over East Asia in Northern summer. It is found that water vapor transport from Indian monsoon is inverse to that over East Asia. More (less) Indian monsoon water vapor transport corresponds to less (more) water vapor transport over East Asia and less (more) rainfall in the middle and lower reaches of the Yangtze River valley. The Indian summer monsoon water vapor transport is closely related to the intensity of the western Pacific subtropical high in its southwestern part. The stronger (weaker) the Indian summer monsoon water vapor transport, the weaker (stronger) the western Pacific subtropical high in its southwestern part, which leads to less (more) water vapor transport to East Asia, and thus less (more) rainfall in the middle and lower reaches of the Yangtze River valley. Analysis of the out-going longwave radiation anomalies suggests that the convective heating anomalies over the Indian Ocean may have significant impact not only on the Indian monsoon, but also on the East Asian monsoon.

The Recent Interdecadal and Interannual Variation of Water Vapor Transport over Eastern China

The climatological characteristics and interdecadal variability of the water vapor transport and budget over the Yellow River-Huaihe River valleys （YH1） and the Yangtze River-Huaihe River valleys （YH2） of East China were investigated in this study,using the NCEP/NCAR monthly mean reanalysis datasets from 1979 to 2009.Changes in the water vapor transport pattern occurred during the late 1990s over YH1 （YH2） that corresponded with the recent interdecadal changes in the eastern China summer precipitation pattern.The net moisture influx in the YH1 increased and the net moisture influx in the YH2 decreased during 2000-2009 in comparison to 1979-1999.Detailed features in the moisture flux and transport changes across the four boundaries were explored.The altered water vapor transport over the two domains can be principally attributed to the additive effects of the changes in the confluent southwesterly moisture flow by the Indian summer monsoon and East Asian summer monsoon （related with the eastward recession of the western Pacific subtropical high）.The altered water vapor transport over YH1 was also partly caused by the weakened midlatitude westerlies.

Variations of δ^(18)O in Precipitation along Vapor Transport Paths

Three sampling cross sections along the south path starting from the Tropics through the vapor passage in the Yunnan-Guizhou Plateau to the middle-low reaches of the Yangtze River, the north path from West China, via North China, to Japan under the westerlies, and the plateau path from South Asia over the Himalayas to the northern Tibetan Plateau, are set up, based on the IAEA (International Atomic Energy Agency)/WMO global survey network and sampling sites on the Tibetan Plateau. The variations, and the relationship with precipitation and temperature, of the δ18 O in precipitation along the three cross sections are analyzed and compared. Along the south path, the seasonal differences of mean δ18O in precipitation are small at the stations located in the Tropics, but increase markedly from Bangkok towards the north, with the δ18O in the rainy season smaller than in,the dry season. The δ18O values in precipitation fluctuate on the whole, which shows that there are different vapor sources. Along the north path, the seasonal differences of the mean δ18O in precipitation for the stations in the west of Zhengzhou are all greater than in the east of Zhengzhou. During the cold half of the year, the mean δ18O in precipitation reaches its minimum at Urumqi with the lowest temperature due to the wide, cold high pressure over Mongolia, then increases gradually with longitude, and remains at roughly the same level at the stations eastward from Zhengzhou. During the warm half of the year, the δ18O values in precipitation are lower in the east than in the west, markedly influenced by the summer monsoon over East Asia. Along the plateau path, the mean δ18O values in precipitation in the rainy season are correspondingly high in the southern parts of the Indian subcontinent, and then decrease gradually with latitude. A sharp depletion of the stable isotopic compositions in precipitation takes place due to the very strong rainout of the stable isotopic compositions in vapor in the process of lifting over the southern slope of the Himalayas. The low level of the δ18O in precipitation is from Nyalam to the Tanggula Mountains during the rainy season, but δ18O increases persistently with increasing latitude from the Tanggula Mountains to the northern Tibetan Plateau because of the replenishment of vapor with relatively heavy stable isotopic compositions originating from the inner plateau. During the dry season, the mean δ18O values in precipitation basically decrease along the path from the south to the north. Generally, the mean δ18O in precipitation during the rainy season is lower than in the dry season for the regions controlled by the monsoons over South Asia or the plateau, and opposite for the regions without a monsoon or with a weak monsoon.

Water Vapor Transport and Cross-Equatorial Flow over the Asian-Australia Monsoon Region Simulated by CMIP5 Climate Models

The summer mean water vapor transport （WVT） and cross-equatorial flow （CEF） over the Asian- Australian monsoon region simulated by 22 coupled atmospheric-oceanic general circulation models （AOGCMs） from the World Climate Research Programme＇s Coupled Model Intercomparison Project Phase 5 （CMIP5） were evaluated. Based on climatology of the twentieth-century simulations, most of models have a reason- ably realistic representation of summer monsoon WVT characterized by southeast water vapor conveyor belt over the South Indian Ocean and southwest belt from the Arabian Sea to the East Asian. The correlation coefficients between NCEP reanalysis and simulations of BCC-CSMI-1, BNU-ESM, CanESM2, FGOALS-s2, MIROC4h and MPI-ESM-LR are up to 0.8. The simulated CEF depicted by the meridional wind along the equator includes the Somali jet and eastern CEF in low atmosphere and the reverse circulation in upper atmosphere, which were generally consistent with NCEP reanalysis. Multi-model ensemble means （MME） can reproduce more reasonable climatological features in spatial distribution both of WVT and CEF. Ten models with more reasonable WVT simulations were selected for future projection studies, including BCC- CSMI-1, BNU-ESM, CanESM2, CCSM4, FGOALS-s2, FIO-ESM, GFDL-ESM2G, MRIOCS, MPI-ESM-LR and NorESM-1M. Analysis based on the future projection experiments in RCP （Representative Concentra- tion Pathway） 2.6, RCP4.5, RCP6 and RCP8.5 show that the global warming forced by different RCP scenarios will results in enhanced WVT over the Indian area and the west Pacific and weaken WVT in the low latitudes of tropical Indian Ocean.

Interannual and Interdecadal Variability of Atmospheric Water Vapor Transport in the Haihe River Basin

The seasonal mean atmospheric precipitable water and water vapor transport over the Haihe River Basin （HRB） in North China with a focus on their interannual to interdecadal variability, and then the relationships of the interannual and interdecadal variability of the water cycle over the HRB to the Pacific Decadal Oscillation （PDO） and E1 Nino-Southern Oscillation （ENSO） phenomena were investigated using the observational and National Centers for Environmental Prediction （NCEP） reanalysis data. There was a strong interdecadal variability for the water cycle （such as precipitation and water vapor transport） over the region, with an abrupt change occurring mostly in the mid 1970s. The intensity of the East Asian summer monsoon largely affected the atmospheric water vapor transport. Generally, the net meridional convergence of the water vapor flux over the region was relatively large before 1965, and it declined gradually from then on with a further notable decrease since mid 1970s. Zonal water vapor transport was similar to meridional, but with a much smaller magnitude and no noteworthy turning in the mid 1970s. Results also suggested that the wind field played an important role in the water vapor transport over the HRB before the mid 1960s, and the interdecadal variability of the water cycle （precipitation, water vapor transport, etc.） in the summer was related to the PDO; however, interannual variation of the water vapor transport could also be related to the ENSO phenomena.

Characteristics of the Mean Water Vapor Transport over Monsoon Asia

Based on ECMWF monthly mean data from January 1980 to December 1989,characterishcs of the three-dimensional structure of the mean water vapor transport over Monsoon Asia are described,and the more forportant features of the different regional water vapor transport in the indian Monsoon region and the East AsianMonsoon region are analyzed.It is found that there is a moist tongue extending from the equator POleWard to the Asian Monsoon region.The three-dimensional distributions of the mean water vapor transport fields over the entire globe renect clearly the asymmetry of the Asian Monsoon system,and the existence of a counterrHadley monsoon circulation.The moisture conver-gened(divergence) area in Asia coincides with the connuellt(diffiuent) zone of the monsoon cjrculahon.Furthermore,the moist featllres of the tWo sub-regions of the Asian Monsoon area are different both in their magnitudes and in their seasonal variations.

Interdecadal Variability of Spring Precipitation over South China and Its Associated Atmospheric Water Vapor Transport

The characteristics of spring precipitation and water vapor transport in South China were analyzed by using observational data and the National Centers for Environmental Prediction (NCEP) reanalysis data. The results show that, during the spring, each component of the water cycle (precipitation, wind field, specific humidity, water vapor transport, etc.) in South China exhibits a notable interdecadal variability. An abrupt increase in spring precipitation occurred in the early 1970s. During the dry period from 1958 to 1971, a water vapor flux divergence (positive divQ) existed in South China, which may have led to the deficiency in rainfall. However, during the wet period from 1973 to 1989, there was a remarkable water vapor flux convergence (negative divQ) in South China, which may have resulted in the higher rainfall. The interdecadal variability of water vapor transport is closely related to the interdecadal variability of wind fields, although the interdecadal variability of specific humidity also plays a role to some extent, and the interdecadal variability of the zonal water vapor transport contributes much more to the interdecadal variability of spring precipitation than the meridional water vapor transport.

Water vapor transport over China and its relationship with drought and flood in Yangtze River Basin

The characteristics of water vapor transport(WVT) over China and its relationship with precipitation anomalies in the Yangtze River Basin(YRB) are analyzed by using the upper-air station data in China and ECMWF reanalysis data in summer from 1981 to 2002.The results indicate that the first mode of the vertically integrated WVT is significant whose spatial distribution presents water vapor convergence or divergence in the YRB.When the Western Pacific Subtropical High(WPSH) is strong and shifts southward and westward, the Indian Monsoon Low Pressure(IMLP) is weak, and the northern part of China stands behind the middle and high latitude trough, a large amount of water vapor from the Bay of Bengal(BOB), the South China Sea(SCS) and the western Pacific forms a strong and steady southwest WVT band and meets the strong cold water vapor from northern China in the YRB, thus it is likely to cause flood in the YRB.When WPSH is weak and shifts northward and eastward, IMLP is strong, and there is nearly straight west wind over the middle and high latitude, it is unfavorable for oceanic vapor extending to China and no steady and strong southwest WVT exists in the region south of the YRB.Meanwhile, the cold air from northern China is weak and can hardly be transported to the YRB.This brings on no obvious water vapor convergence, and then less precipitation in the YRB.

Projected changes in summer water vapor transport over East Asia under the 1.5°C and 2.0°C global warming targets

This study investigates changes in summer water vapor transport(WVT) over East Asia under 1.5°C and 2.0°C global warming(GW) for the +4.5 and +8.5 W m-2 Representative Concentration Pathway(RCP) scenarios(RCP4.5 and RCP8.5, respectively). Of the 27 models used, 18 show better skill in simulating the climatological summer WVT over East Asia of the present day. Of those 18, 13 reach 1.5°C and 2.0°C GW for the two RCPs. Based on these 13 models, results show that — relative to the present day-th e summer WVT is enhanced over East Asia under 1.5°C and 2.0°C GW for RCP4.5 and RCP8.5. The inte r-model consistency is higher under 2.0°C GW. Increased water vapor content favors the enhanced WVT over both southern and northern East Asia, while lower-level circulation contributes to the enhanced WVT over southern East Asia. Compared to 1.5°C GW, th e summer WVT under 2.0°C GW is further enhanced over most of East Asia for RCP4.5. For RCP8.5, the summer WVT is also further enhanced over southern East Asia, while this is not the case over northern East Asia. Under the additional 0.5°C GW, the changes in summer WVT, with low in ter-model consistency, are closely related to anomalous lower-level circulation. Precipitation increases over the East China Sea to southern Japan, the Korean Peninsula, and North China, for both RCP4.5 and RCP8.5. However, the changes in precipitation over the South China Sea and Northeast China are different for the two RCPs. This is connected to the difference in the changes of WVT divergence.

Growth of threaded AlN whiskers by a physical vapor transport method

Threaded aluminum nitride （A1N） whiskers are grown by a physical vapor transport method in a radio-frequency induction heating furnace. The resultant whiskers are characterized by X-ray diffraction, Raman scattering, scanning electron microscopy, transmission electron microscopy and photoluminescence. The analysis shows that the whiskers are single-crystalline, wurtzite AIN. The threaded A1N whiskers are 0.5 μm^100 μm in diameter and several millimeters in length in the fiber direction, and have lots of tiny sawteeth on the surface. The morphology of this threaded A1N whisker is beneficial for bonding when the whisker is used in composite. The growth of the whiskers is dominated by the vapor-solid （VS） mechanism, and the particular morphology might result from an oscillating condition produced in the radio-frequency induction heating furnace.

Characteristics of the Correlation between Regional Water Vapor Transport along with the Convective Action and Variation of the Pacific Subtropical High in 1998

This paper explores the impact of the convective action over the low-latitude region, the water vapor transport around the West Pacific subtropical high (WPSH), and its convective action on the seasonal northward jump and southward withdrawal of the WPSH in summer by using the daily data set of NCEP and TBB for 1998. The research shows that in summer, the WPSH moves northward when the convection over the low-latitude tropical region intensifies and the subsidence region of the meridional vertically vertical circulation in meridional direction circulation over the region of 110?150癊 moves northward. Furthermore, as revealed by diagnostic analysis, the subtropical high moves northward after the obvious weakening of the longitudinal water vapor transport over the region around the subtropical high, but withdraws southward a pentad after the reduction of the latitudinal water vapor transport over the tropical West Pacific region. The research results show that the northward jump and southward withdrawal of the WPSH are closely related to the release of the convective latent heat at low latitudes and the water vapor transport at boundaries around WPSH and its convective action. The numerical simulation further validates the above-mentioned correlation between the variation of the action of the subtropical high and the preceding water vapor transport along with the convection characteristics.

Separation of Neighboring REElementsfrom Sm_2O_3Eu_2O_3Gd_2O_3 System by a Stepwise ChlorinationChemical Vapor Transport Reaction

The mutual separation characteristics were investigated for the neighboring Sm, Eu and Gd from their ternary oxide mixture Sm 2O 3 Eu 2O 3 Gd 2O 3 by a stepwise chlorination chemical vapor transport reaction within 6 h using AlCl 3 as complex former. The rare earth chlorides were more readily transported and concentrated in the middle temperature range of 980～1100 K and the transport efficiency was in the order of Sm≈Gd>Eu. The separation factor, expressed as molar ratio for the resulting chlorides, was 1 70 for Eu∶Sm, 1 88 for Eu∶Gd, 1 24 for Sm∶Gd in the higher temperature region, and 2 76 for Sm∶Eu, 2 83 for Gd∶Eu and 1 12 for Gd∶Sm in the lower temperature region, respectively. All results are much higher than those of the conventional wet process.

Inversion of Evaporation and Water Vapor Transport Using HY-2 Multi-Sensor Data

HY-2 satellite is the first marine dynamic environment satellite of China.In this study,global evaporation and water vapor transport of the global sea surface are calculated on the basis of HY-2 multi-sensor data from April 1 to 30,2014.The algorithm of evaporation and water vapor transport is discussed in detail,and results are compared with other reanalysis data.The sea surface temperature of HY-2 is in good agreement with the ARGO buoy data.Two clusters are shown in the scatter plot of HY-2 and OAFlux evaporation due to the uneven global distribution of evaporation.To improve the calculation accuracy,we compared the different parameterization schemes and adopted the method of calibrating HY-2 precipitation data by SSM/I and Global Precipitation Climatology Project(GPCP)data.In calculating the water vapor transport,the adjustment scheme is proposed to match the balance of the water cycle for data in the low latitudes.

Stepwise Chlorination-Chemical Vapor Transport Reactions for Bastnaesite Concentrate

Vapor phase extraction and mutual separation of rare earth (RE) elements from bastnaesite concentrate were investigated using stepwise chlorination chemical vapor transport reactions mediated by vapor complexes LnAl n Cl 3 n +3 (Ln=RE elements). The bastnaesite was heated to 800 K and chlorinated between 800～1300 K with C+Cl 2+SiCl 4 to remove CO 2, SiF 4 and high volatile chlorides. At the temperature of 1300 K for 6 h, the resulted RE chlorides were chemically transported and mutual separated with the vapor complexes while CaCl 2 and BaCl 2 were remained in the residues. Significantly different CVT characteristics were observed for gradually decreased and wave form temperature gradients.

Comparison of ZnO Films Grown on before- and after-vapor Transport Equilibration (VTE) LiAlO_2 Substrates by Pulsed Laser Deposition (PLD)

About φ45 mm LiAlO2 single crystal was grown by Czochralski （Cz） technique. However, the full-width at half-maximum （FWHM） value was high to 116.9 arcsec. After three vapor transport equilibration （VTE） processes, we can obtain high-quality LiAlO2 slice with the FWHM value of 44.2 arcsec. ZnO films were fabricated on as-grown slices and after-VTE ones by pulsed laser deposition （PLD）. It was found that ZnO films on the two slices have similar crystallinity, optical transmittance and optical band gap at room temperature. These results not only show that LAO substrate is suitable for ZnO growth, but also prove that the crystal quality of LAO substrate slightly affects the structural and optical properties of ZnO film.

Preparation of Anhydrous LnCl_3(Ln=Eu, Er, Lu) by Chemical Vapor Transport

Anhydrous lanthanide chlorides LnCl 3(Ln=Eu, Er, Lu) which are not easy to prepare in other ways were prepared by chemical vapor transport(CVT) method. Ln 2O 3 reacted with an excess of Al 2Cl 6 at 300 ℃ to produce LnCl 3. LnCl 3 reacted with Al 2Cl 6 at high temperature to form the gaseous complexes which decomposed at low temperature. LnCl 3 was then separated from other solids by controlling a proper temperature gradient. Residual Al 2Cl 6(g) was removed by the carrier of dry Cl 2 N 2 gases at 200 ℃. The yield rates are >90%, and the purity of products is >99 5%. The high purity of anhydrous lanthanide chlorides can be obtained by CVT method.

γ-LiAlO_2 Single Crystal Grown by Czochralski Technique and Modified by Vapor Transport Equilibration (VTE) Technique

Large-sized （～2 inch, 50.8 mm） γ-LiAlO2 single crystal has been grown by conventional Czochralski （Cz） method, but the crystal has a milky, dendriform center. The samples taken from transparent and milky parts were ground and examined by X-ray diffraction. All diffraction peaks could be indexed in γ-LiAlO2. The crystal quality was characterized by X-ray rocking curve. The full-width at half-maximum （FWHM） values are 116.9 and 132.0 arcsec for transparent and milky parts, respectively. The vapor transport equilibrium （VTE） technique was introduced to modify the crystal quality. After 1000℃/48 h, 1100℃/48 h, 1200℃/48 h VTE processes, the FWHM values dropped to 44.2 and 55.2 arcsec for transparent and milky part, respectively. The optical transmission of transparent part was greatly enhanced from 85% to 90%, and transmission of milky part from 75% to 80% in the range of 190~1900 nm at room temperature. When the VTE temperature was raised to 1300℃, the sample cracked and FWHM values of transparent and milky parts were increased to 55.2 and 80.9 arcsec, respectively. By combining Cz technique with VTE technique, large-sized and high quality γ-LiAlO2 crystal can be obtained.

LONG-DISTANCE-RELAYED WATER VAPOR TRANSPORT EAST OF TIBETAN PLATEAU AND ITS IMPACTS

This paper attempts to reveal a long-distance-relayed water vapor transport(LRWVT) east of Tibetan Plateau and its impacts. The results show that from August to October, east of Tibetan Plateau, there exists a unique LRWVT,and the water vapor from the South China Sea and the western Pacific can affect the Sichuan Basin, Northwest China and other Chinese regions far from the tropical sea through this way. From August to October, the precipitation of the region east of the Plateau is closely linked both in the intra-annual and inter-annual variations, and the LRWVT from the South China Sea and the western Pacific is an important connection mechanism. The large-scale circulation background of the LRWVT impacting the precipitation of the region east of the Plateau is as follows: At high levels,the South Asian High is generally stronger than normal and significantly enhances with its northward advance and eastward extension over the region east of the Plateau. At mid-level, a broad low pressure trough is over Lake Balkhash and its surroundings, and the Western Pacific Subtropical High(WPSH) is northward and westward located, and the western part of Sichuan Basin and the eastern part of Northwest China are located in the west and northwest edge of WPSH.

Mutual separation characteristics for binary oxides Y_2O_3-Ln_2O_3(Ln = Sc,La,Nd,Sm) using stepwise selective chlorination-chemical vapor transport reaction mediated by vapor complexes KLnCl_4

Mutual separation characteristics for binary oxide mixtures Y2O3-Sc2O3, Y2O3-La2O3, Y2O3-Nd2O3 and Y2O3-Sm2O3 using a stepwise selective chlorination-chemical vapor transport（SC-CVT） reaction mediated by vapor complexes KLnCl4 were investigated. The total transported yields of the chlorides produced from the oxide mixtures are in the order of NdCl3>SmCl3>LaCl3>YCl3>ScCl3, the main deposition temperature of the chlorides is in the order of ScCl3<YCl3<SmCl3<NdCl3<LaCl3, and the largest separation factor values are 1 100 for Y∶Sc, 14.88 for Y∶La, 9.86 for Y∶Nd and 16.45 for Y∶Sm in the temperature range from 1 000 K to )1 120 K,) while 157.7 for La∶Y, 51.6 for Nd∶Y and 12.4 for Sm∶Y in the temperature range from 1 200 K to 1 300 K, respectively. The results were discussed on the difference of KScCl4, KYCl4 and KLnCl4 and the selective chlorination of binary oxides at 800 K. Furthermore, the separation characteristics of vapor rare earth complex KLnCl4 were studied compared with those of LnAlnCl3n+3.

Synergistic Effects of Bay of Bengal Tropical Cyclones and Tibetan Plateau Vortices on Water Vapor Transport over the Tibetan Plateau in Early Summer

The Bay of Bengal(BoB)tropical cyclones(TCs)and the Tibetan Plateau vortices(TPVs)are two crucial weather systems influencing the Tibetan Plateau(TP).Their synergistic effects can lead to widespread heavy precipitation events on the TP.In this study,we employ the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model to track the trajectory of water vapor transport during three large-scale precipitation events on the TP under the combined influence of BoB TCs and TPVs.The results indicate that low-level water vapor from the BoB under the influence of BoB TCs was cyclonically entangled into the cyclonic circulation,lifted and transported northward by southwesterly flow to the southeastern part of the TP,which contributes to the moistening of the entire troposphere there.Additionally,convergence of the cyclonic circulation of the TPVs on the northern TP further transports water vapor collected in the southeastern TP northward,conducive to the maintenance and development of precipitation systems,thus inducing widespread heavy precipitation events over the TP.