scholarly journals Tropospheric Water Vapor Transport as Determined from Airborne Lidar Measurements

2010 ◽  
Vol 27 (12) ◽  
pp. 2017-2030 ◽  
Author(s):  
Andreas Schäfler ◽  
Andreas Dörnbrack ◽  
Christoph Kiemle ◽  
Stephan Rahm ◽  
Martin Wirth
Keyword(s):  
Water Vapor ◽  
Wind Speed ◽  
Moisture Transport ◽  
Lower Troposphere ◽  
Airborne Lidar ◽  
Vapor Transport ◽  
Specific Humidity ◽  
Water Vapor Transport ◽  
Horizontal Wind ◽  
Warm Sector

Abstract The first collocated measurements during THORPEX (The Observing System Research and Predictability Experiment) regional campaign in Europe in 2007 were performed by a novel four-wavelength differential absorption lidar and a scanning 2-μm Doppler wind lidar on board the research aircraft Falcon of the Deutsches Zentrum für Luft- und Raumfahrt (DLR). One mission that was characterized by exceptionally high data coverage (47% for the specific humidity q and 63% for the horizontal wind speed υh) was selected to calculate the advective transport of atmospheric moisture qυh along a 1600-km section in the warm sector of an extratropical cyclone. The observations are compared with special 1-hourly model data calculated by the ECMWF integrated forecast system. Along the cross section, the model underestimates the wind speed on average by −2.8% (−0.6 m s−1) and overestimates the moisture at dry layers and in the boundary layer, which results in a wet bias of 17.1% (0.2 g kg−1). Nevertheless, the ECMWF model reproduces quantitatively the horizontally averaged moisture transport in the warm sector. There, the superposition of high low-level humidity and the increasing wind velocities with height resulted in a deep tropospheric layer of enhanced water vapor transport qυh. The observed moisture transport is variable and possesses a maximum of qυh = 130 g kg−1 m s−1 in the lower troposphere. The pathways of the moisture transport from southwest via several branches of different geographical origin are identified by Lagrangian trajectories and by high values of the vertically averaged tropospheric moisture transport.

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.

Patterns of Water Vapor Transport in the Eastern United States

2020 ◽  
Vol 21 (9) ◽  
pp. 2123-2138
Author(s):  
Natalie Teale ◽  
David A. Robinson
Keyword(s):  
United States ◽  
Water Vapor ◽  
Moisture Transport ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Self Organizing Map ◽  
Eastern United States ◽  
Precipitation Regime ◽  
Vapor Flux ◽  
Transport Patterns

AbstractThis study presents a climatology of water vapor fluxes for the eastern United States and adjacent Atlantic with particular focus on the Northeast. Pathways of moisture transport comprising this climatology were discerned using a self-organizing map methodology ingesting daily integrated vapor transport data from ECMWF ERA-Interim Reanalysis from 1979 to 2017 at a 2.5° × 2.5° spatial resolution. Sixteen spatially distinct moisture transport patterns capture the variety of water vapor transport in the region. The climatology of water vapor transport is precisely and comprehensively defined via synthesis of spatial and temporal characteristics of the fluxes. Each flux has a distinct seasonality and frequency. The fluxes containing the highest amounts of moisture transport occur less frequently than those with less moisture transport. Because the patterns showing less moisture transport are prevalent, they are major contributors to the manner in which water vapor is moved through the eastern United States. The spatial confinement of fluxes is inversely related to persistence, with strong, narrow bands of enhanced moisture transport most often moving through the region on daily time scales. Many moisture fluxes meet a threshold-based definition of atmospheric rivers, with the diversity in trajectories and moisture sources indicating that a variety of mechanisms develop these enhanced moisture transport conditions. Temporal variability in the monthly frequencies of several of the fluxes in this study aligns with changes in the regional precipitation regime, demonstrating that this water vapor flux climatology provides a precise moisture-delivery framework from which changes in precipitation can be investigated.

scholarly journals Subseasonal Variations of Wintertime North Pacific Evaporation, Cold Air Surges, and Water Vapor Transport

2017 ◽  
Vol 30 (23) ◽  
pp. 9475-9491 ◽  
Author(s):  
Xuejuan Ren ◽  
Xiu-Qun Yang ◽  
Haibo Hu
Keyword(s):  
Water Vapor ◽  
North Pacific ◽  
Wave Train ◽  
Vapor Transport ◽  
Specific Humidity ◽  
Water Vapor Transport ◽  
Vapor Source ◽  
Air Mass ◽  
Cold Air ◽  
The North

This study addresses subseasonal variations of oceanic evaporation E over the North Pacific during winter and the connection with the cold air surges (CASs) and atmospheric water vapor transport using the OAFlux and ERA-Interim daily data. By performing an empirical orthogonal function (EOF) analysis, two dominant modes of subseasonal evaporation anomaly E′ are identified: a zonal wave train–like pattern (EOF1) and an east negative–west positive dipolar pattern (EOF2) in the midlatitude basin. Further analyses yield the following conclusions. 1) The Siberian high (SH)-related CAS has a crucial role in generation of the EOF1 mode of E′. When the dry and cold air mass passes the region of the warm Kuroshio and its extension [Kuroshio–Oyashio Extension (KOE)], the increased air–sea temperature and moisture differences and intensified wind speed lead to the above-normal oceanic E, and vice versa. 2) The Aleutian low (AL)-related CAS contributes to the EOF2 mode of E′. The intensified AL transports a dramatically colder and drier air mass toward the KOE region and a slightly warmer and wetter one toward the west coast of North America, leading to the east negative–west positive structure of E′ in the midlatitude basin. 3) A quasi-linear relationship exists between E′ and divergent water vapor transport anomalies over the KOE region. Positive (negative) E′ is generally accompanied by anomalous vapor source (sink). 4) The divergent water vapor transport anomalies associated with the two EOFs are preliminarily decided by their individual lower-level wind field anomalies and second by the meridional inhomogeneity of subseasonal specific humidity anomalies. Hydroclimate effects on precipitation over the pan–North Pacific region are also discussed.

scholarly journals Evaluation of Nonhydrostatic Simulations of Northeast Pacific Atmospheric Rivers and Comparison to in Situ Observations

2015 ◽  
Vol 143 (9) ◽  
pp. 3556-3569 ◽  
Author(s):  
Daniel L. Swain ◽  
Bereket Lebassi-Habtezion ◽  
Noah S. Diffenbaugh
Keyword(s):  
Water Vapor ◽  
High Resolution ◽  
Extreme Values ◽  
Lower Troposphere ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Neutral Stability ◽  
Horizontal Structure ◽  
Atmospheric Rivers ◽  
Extreme Precipitation Events

Abstract Atmospheric rivers are long, narrow bands of concentrated atmospheric water vapor transport that provide an important atmospheric linkage between the subtropics and the midlatitudes, facilitating over 90% of meridional water vapor flux and often resulting in extreme precipitation events in regions of enhanced coastal orography. In this investigation, the authors conduct continuous (3 month), large-domain (3600 km × 3200 km), high-resolution (4 km), nonhydrostatic simulations using the Weather Research and Forecasting (WRF) Model and compare the observations to previously reported dropsonde observations from the California Land-Falling Jets Experiment (CALJET) and the Pacific Land-Falling Jets Experiment (PACJET) in order to address an existing gap in knowledge regarding the ability of atmospheric models to simulate the finescale vertical and horizontal structure of atmospheric rivers. The WRF simulations reproduce key structural and thermodynamic characteristics of atmospheric rivers—including well-defined corridors of strong water vapor transport, moist-neutral stability in the lower troposphere, and strong low-level jet/water vapor transport maxima near ~1 km MSL. While WRF does generally capture the extreme values of instantaneous vertically integrated water transport—a defining feature of real-world atmospheric rivers—constituent variables exhibit biases relative to observations, including −11.2% for integrated vapor transport, +5.9% for integrated water vapor, and −17.7% for 1 km MSL wind speed. Findings suggest that high-resolution nonhydrostatic atmospheric simulations are an appropriate tool for investigating atmospheric rivers in contexts where finescale spatial structure and realistic water vapor transport maxima are important.

scholarly journals How Do Atmospheric Rivers Form?

2015 ◽  
Vol 96 (8) ◽  
pp. 1243-1255 ◽  
Author(s):  
H. F. Dacre ◽  
P. A. Clark ◽  
O. Martinez-Alvarado ◽  
M. A. Stringer ◽  
D. A. Lavers
Keyword(s):  
Water Vapor ◽  
Cold Front ◽  
High Water ◽  
Water Vapor Content ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Long Distance ◽  
Atmospheric Rivers ◽  
Atmospheric River ◽  
Warm Sector

Abstract The term “atmospheric river” is used to describe corridors of strong water vapor transport in the troposphere. Filaments of enhanced water vapor, commonly observed in satellite imagery extending from the subtropics to the extratropics, are routinely used as a proxy for identifying these regions of strong water vapor transport. The precipitation associated with these filaments of enhanced water vapor can lead to high-impact flooding events. However, there remains some debate as to how these filaments form. In this paper, the authors analyze the transport of water vapor within a climatology of wintertime North Atlantic extratropical cyclones. Results show that atmospheric rivers are formed by the cold front that sweeps up water vapor in the warm sector as it catches up with the warm front. This causes a narrow band of high water vapor content to form ahead of the cold front at the base of the warm conveyor belt airflow. Thus, water vapor in the cyclone’s warm sector, not long-distance transport of water vapor from the subtropics, is responsible for the generation of filaments of high water vapor content. A continuous cycle of evaporation and moisture convergence within the cyclone replenishes water vapor lost via precipitation. Thus, rather than representing a direct and continuous feed of moist air from the subtropics into the center of a cyclone (as suggested by the term “atmospheric river”), these filaments are, in fact, the result of water vapor exported from the cyclone, and thus they represent the footprints left behind as cyclones travel poleward from the subtropics.

The contribution of föhn winds to northeast Greenland summer melt and their relationship with atmospheric rivers

2021 ◽  
Author(s):  
Kyle Mattingly ◽  
Jenny Turton ◽  
Jonathan Wille ◽  
Xavier Fettweis ◽  
Brice Noël
Keyword(s):  
Water Vapor ◽  
Moisture Transport ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Detection Algorithm ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Atmospheric Rivers ◽  
Regional Climate Model Output ◽  
Surface Melt

<p>Atmospheric Rivers (ARs), narrow filaments of concentrated water vapor transport, have direct impacts on the surface mass balance (SMB) of the western Greenland Ice Sheet through increased summer melting in the ablation area and increased snowfall in higher altitudes. Here, we show that an additional effect of ARs on SMB comes from the development of föhn winds, whereby the air is adiabatically warmed as it descends. As ARs pass over the ice sheet and deposit precipitation in northwest Greenland, the air subsequently flows down the leeward slope and the warm, dry conditions contribute to increased melting in the northeast, and more specifically on the Nioghalvfjerdsfjorden (or 79N) Glacier.</p><p> </p><p>We identify föhn conditions using an automated detection algorithm applied to MAR and RACMO2 regional climate model output. These data are paired with an AR detection algorithm and self-organizing map (SOM) classification applied to MERRA-2 and ERA5 reanalyses, in order to investigate connections between regional circulation patterns, ARs, föhn winds, and ice sheet SMB. We find that föhn conditions and associated surface melt are increased for periods of 1–3 days after anomalous southerly and southwesterly water vapor transport by ARs through Baffin Bay and the Nares Strait. Approximately 70% of the ARs which make landfall in the northwest sector of Greenland lead to the development of föhn winds on the northeast coast. The frequency of AR-induced föhn conditions in the northeast has increased in the last 40 years, in line with an increase in the strongest ARs in the northwest. We also find that anomalous northerly moisture transport from the Lincoln Sea generates enhanced melt in the lowest (0–500m) elevations of northeast Greenland, while below-average surface melt occurs during all other identified moisture transport regimes.</p>

scholarly journals Melatonin and Pathological Cell Interactions: Mitochondrial Glucose Processing in Cancer Cells

2021 ◽  
Vol 22 (22) ◽  
pp. 12494
Author(s):  
Russel J. Reiter ◽  
Ramaswamy Sharma ◽  
Sergio Rosales-Corral ◽  
Walter Manucha ◽  
Luiz Gustavo de Almeida Chuffa ◽  
...  
Keyword(s):  
Water Vapor ◽  
Water Cycle ◽  
Lower Troposphere ◽  
Tropical Pacific ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Atmospheric Water ◽  
Maritime Continent ◽  
Easterly Wind

The Tibetan Plateau (TP), atmosphere, and Indo-Pacific warm pool (IPWP) together constitute a regional land–atmosphere–ocean water vapor transport system. This study uses remote sensing data, reanalysis data, and observational data to explore the spatiotemporal variations of the summer atmospheric water cycle over the TP and its possible response to the air–sea interaction in the IPWP during the period 1958–2019. The results reveal that the atmospheric water cycle process over the TP presented an interannual and interdecadal strengthening trend. The climatic precipitation recycle ratio (PRR) over the TP was 18%, and the stronger the evapotranspiration, the higher the PRR. On the interdecadal scale, the change in evapotranspiration has a significant negative correlation with the Pacific Decadal Oscillation (PDO) index. The variability of the water vapor transport (WVT) over the TP was controlled by the dynamic and thermal conditions inside the plateau and the external air–sea interaction processes of the IPWP. When the summer monsoon over the TP was strong, there was an anomalous cyclonic WVT, which increased the water vapor budget (WVB) over the TP. The central and eastern tropical Pacific, the maritime continent and the western Indian Ocean together constituted the triple Sea Surface Temperature (SST) anomaly, which enhanced the convective activity over the IPWP and induced a significant easterly wind anomaly in the middle and lower troposphere, and then generated pronounced easterly WVT anomalies from the tropical Pacific to the maritime continent and the Bay of Bengal. Affected by the air–sea changes in the IPWP, the combined effects of the upstream strengthening and the downstream weakening in the water vapor transport process, directly and indirectly, increased the water vapor transport and budget of TP.

scholarly journals Airborne lidar observations of water vapor transport

2012 ◽  
Author(s):  
Christoph Kiemle ◽  
Andreas Schafler ◽  
Martin Wirth ◽  
Andreas Fix ◽  
Stephan Rahm
Keyword(s):  
Water Vapor ◽  
Airborne Lidar ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Lidar Observations

scholarly journals Water Vapor Transport Paths and Accumulation during Widespread Snowfall Events in Northeastern China

2013 ◽  
Vol 26 (13) ◽  
pp. 4550-4566 ◽  
Author(s):  
Bo Sun ◽  
Huijun Wang
Keyword(s):  
Water Vapor ◽  
Eastern China ◽  
Northeastern China ◽  
Vapor Transport ◽  
Specific Humidity ◽  
Water Vapor Transport ◽  
The Sea Of Japan ◽  
Atmospheric Flow ◽  
Precipitation Gauge ◽  
Humidity Field

Abstract This study aims to identify the distinct characteristics of water vapor transport (WVT) and its role in supplying moisture for widespread snowfall (WS) events in northeastern China (NEC). Fifty WS events in NEC were selected based on cumulative precipitation gauge data taken at 12-h intervals from 1980 to 2009 and a qualified set of criteria. The evolution of WVT during WS events in NEC was analyzed using 6-h ECMWF Interim Re-Analysis (ERA-Interim) data and discussed in regard to WVT paths and water vapor budgets over NEC. The results of this analysis indicate that southerly WVT, which carries moisture over eastern China, its adjacent seas, and the Sea of Japan, has played a key role in supplying water vapor for WS, which is quite different from the climatology of winter WVT. Moreover, the results indicate that there tends to be an 18-h lag between the WVT budget and precipitation, resulting in a great amount of water vapor accumulating over NEC before WS. The amount of preaccumulated water vapor could account for about 47% of the total precipitation, whereas synchronous WVT could only supply a limited amount of moisture that could hardly sustain WS. In addition, the original atmospheric moisture over NEC has likely made a considerable contribution to WS. The lag between the WVT budget and precipitation appears to be an outcome of the cooperation between the atmospheric flow field and the specific humidity field.

scholarly journals North Atlantic Integrated Water Vapor Transport—From 850 to 2100 CE: Impacts on Western European Rainfall

2020 ◽  
Vol 33 (1) ◽  
pp. 263-279 ◽  
Author(s):  
Pedro M. Sousa ◽  
Alexandre M. Ramos ◽  
Christoph C. Raible ◽  
M. Messmer ◽  
Ricardo Tomé ◽  
...  
Keyword(s):  
Water Vapor ◽  
Moisture Transport ◽  
Western Europe ◽  
Vapor Transport ◽  
First Century ◽  
Water Vapor Transport ◽  
British Isles ◽  
Precipitation Decrease ◽  
Twenty First Century

AbstractMoisture transport over the northeastern Atlantic Ocean is an important process governing precipitation distribution and variability over western Europe. To assess its long-term variability, the vertically integrated horizontal water vapor transport (IVT) from a long-term climate simulation spanning the period 850–2100 CE was used. Results show a steady increase in moisture transport toward western Europe since the late-nineteenth century that is projected to expand during the twenty-first century under the RCP8.5 scenario. The projected IVT for 2070–99 significantly exceeds the range given by interannual–interdecadal variability of the last millennium. Changes in IVT are in line with significant increases in tropospheric moisture content, driven by the concurrent rise in surface temperatures associated with the anthropogenic climate trend. On regional scales, recent and projected precipitation changes over the British Isles follow the global positive IVT trend, whereas a robust precipitation decrease over Iberia is identified in the twenty-first century, particularly during autumn. This indicates a possible extension of stable and dry summer conditions and a decoupling between moisture availability and dynamical forcing. The investigation of circulation features reveals a mean poleward shift of moisture corridors and associated atmospheric rivers. In particular, in Iberia, a significant increase in the frequency of dry weather types is observed, accompanied by a decrease in the frequency of wet types. An opposite response is observed over the British Isles. These changes imply a stronger meridional north–south dipole in terms of pressure and precipitation distributions, enhancing the transport toward central Europe rather than to Iberia.

Sign in / Sign up

Export Citation Format

Share Document